JP6980453B2 - Waste heat utilization system - Google Patents

Description

The present invention relates to an exhaust heat utilization system that recovers the exhaust heat of a generator such as a fuel cell, raises the temperature of the water in the hot water storage tank, and uses the hot water stored in the hot water storage tank for heating or hot water supply.

FIG. 38 simply shows an example of the waste heat utilization system as described above, and utilizes the heat of the hot water in the hot water storage tank for floor heating. Cold water is supplied to the hot water storage tank from the bottom. To recover the exhaust heat of the fuel cell, the water in the hot water storage tank is taken out from the lower part of the hot water storage tank, heated by the exhaust heat generated by the power generation of the fuel cell, and circulated to the exhaust heat recovery circuit returned to the upper part of the hot water storage tank. Will be. Therefore, a temperature stratification is formed in which low temperature water (for example, 10 ° C.) is present in the lower part of the hot water storage tank and hot water (for example, 60 ° C.) is present in the upper part of the hot water storage tank.

In floor heating, hot water in the hot water storage tank is circulated through the primary side circulation circuit that returns from the upper part of the hot water storage tank to the lower part of the hot water storage tank via the primary side of the water-water heat exchanger, and the secondary side of the water-water exchanger. The heat medium fluid (water, etc.) is circulated in the secondary side circulation circuit via the side and the floor heating mat. The heat of the hot water extracted from the upper part of the hot water storage tank is transferred to the heat medium fluid circulating in the secondary circulation circuit, and this heat is dissipated in the floor heating mat.

Here, in the waste heat recovery, assuming that the water at 10 ° C. extracted from the lower part of the hot water storage tank is heated to 60 ° C. and returns to the upper part of the hot water storage tank, the ideal state is the waste heat recovery as shown in FIG. 38. The hot water at 60 ° C. taken out from the upper part of the hot water storage tank with the same circulation amount as the side is heat exchanged by the water-water heat exchanger, and the temperature drops to 10 ° C. and returns to the hot water storage tank. In this ideal state, the amount of heat substantially equal to the amount of heat recovered from the waste heat is consumed by the floor heating, and the temperature stratification in the hot water storage tank is maintained for a long time.

On the other hand, as shown in FIG. 39, as the room warms up, the amount of heat dissipated by the floor heating mat decreases, so even if the hot water at 60 ° C taken out from the upper part of the hot water storage tank is heat exchanged by the water-water heat exchanger. It only drops to about 30 ° C to 40 ° C and returns to the bottom of the hot water storage tank. Therefore, the waste heat recovery side has to cool the equipment with hot water of 40 ° C. taken out from the lower part of the hot water storage tank, and in some cases, it is necessary to stop the power generation of the fuel cell. The floor heating mat is an example, and any type of heating radiator that uses hot water can be used.

In Patent Document 1 below, when the temperature of the returned water after heat exchange by the water-water heat exchanger becomes high, the returned water is returned to an intermediate portion different from the lower part of the hot water storage tank. Then, a waste heat utilization system that maintains the state where cold water exists at the bottom of the hot water storage tank is disclosed.

Patent No. 4820213

In order to prevent the situation as shown in FIG. 39, it is conceivable to increase the size of the water-water heat exchanger or to separately install a radiator downstream of the water-water heat exchanger to dissipate heat. There are problems such as installation. Further, if the temperature stratification is allowed to collapse as shown in FIG. 39, it is necessary to sacrifice the utilization efficiency in hot water supply, the power generation efficiency in the fuel cell, and the power generation maintenance as described above. On the other hand, as disclosed in Patent Document 1, when a plurality of return ports are provided in the hot water storage tank and these are switched, it is inevitable that the cost will increase due to the complicated structure.

The present invention is intended to solve the above-mentioned problems, and when hot water in a hot water storage tank is used as a heat source for floor heating or the like without causing an increase in size of a water-water heat exchanger or complication of a device. It is an object of the present invention to provide a waste heat utilization system capable of dealing with a case where the return temperature of the hot water to the hot water storage tank is high.

The gist of the present invention for achieving such an object lies in the inventions of the following paragraphs.

[1] A hot water storage tank to which water is supplied from the lower part and water taken out from the lower part of the hot water storage tank are recovered from the waste heat of a predetermined generator to raise the temperature, and then returned to the upper part of the hot water storage tank. Department and
The heat exchanger of the auxiliary heat source machine, the radiator, the secondary side of the water-water heat exchanger, and the heat dissipation circuit in which the heat medium fluid circulates via the first circulation pump.
A heat storage utilization circulation circuit that returns from the upper part of the hot water storage tank to the lower part of the hot water storage tank via the primary side of the water-water heat exchanger and the second circulation pump.
When the heat dissipation operation is performed by the radiator, the heat medium fluid is circulated in the heat dissipation circuit and the circulating heat medium fluid is heated by the auxiliary heat source machine, and the heat medium fluid is used in the heat radiation circuit. Is circulated and the hot water in the hot water storage tank is circulated to the heat storage utilization circulation circuit so as to return from the upper part of the hot water storage tank to the lower part of the hot water storage tank via the primary side of the water-water heat exchanger. A control unit that selects and executes one of the operations,
Equipped with
In the heat dissipation operation, the control unit selects the heat storage utilization operation if the predetermined conditions are not satisfied even when hot water having a temperature that can be used for the heat storage utilization operation exists in the upper part of the hot water storage tank. The waste heat utilization system is characterized in that the generator is stopped and the hot water is scheduled to be supplied from the hot water storage tank by the next scheduled operation time of the generator.

In the above invention, even if hot water having a temperature that can be used for heat storage utilization operation exists in the upper part of the hot water storage tank, if the predetermined conditions are not satisfied (for example, the return temperature from the primary side of the water-water heat exchanger). If it is expected that the temperature will increase), do not select (select and execute) the heat storage utilization operation.

In the above invention, if the generator is stopped and there is a plan to supply hot water from the hot water storage tank by the time when the generator is scheduled to operate next, a heat storage utilization operation is performed to return from the water-water heat exchanger. Even if the temperature rises, hot water is discharged from the hot water storage tank and cold water is replenished to the bottom of the hot water storage tank before the next generator starts operating. Therefore, if the above conditions are satisfied, the heat storage utilization operation can be selected, and if not, the heat storage utilization operation is not selected.
[2] The control unit is the first circulation pump so that the temperature of water returning to the hot water storage tank via the primary side of the water-water heat exchanger does not exceed a predetermined temperature in the heat storage utilization operation. And the circulation amount of either one or both of the second circulation pumps are adjusted.
The waste heat utilization system according to [1].
[3] With a hot water storage tank where water is supplied from the bottom
A waste heat recovery unit that recovers the waste heat of a predetermined generator, raises the temperature of the water taken out from the lower part of the hot water storage tank, and then returns the water to the upper part of the hot water storage tank.
The heat exchanger of the auxiliary heat source machine, the radiator, the secondary side of the water-water heat exchanger, and the heat dissipation circuit in which the heat medium fluid circulates via the first circulation pump.
A heat storage utilization circulation circuit that returns from the upper part of the hot water storage tank to the lower part of the hot water storage tank via the primary side of the water-water heat exchanger and the second circulation pump.
When the heat dissipation operation is performed by the radiator, the heat medium fluid is circulated in the heat dissipation circuit and the circulating heat medium fluid is heated by the auxiliary heat source machine, and the heat medium fluid is used in the heat radiation circuit. Is circulated and the hot water in the hot water storage tank is circulated to the heat storage utilization circulation circuit so as to return from the upper part of the hot water storage tank to the lower part of the hot water storage tank via the primary side of the water-water heat exchanger. A control unit that selects and executes one of the operations,
Equipped with
In the heat dissipation operation, the control unit selects the heat storage utilization operation if the predetermined conditions are not satisfied even when hot water having a temperature that can be used for the heat storage utilization operation exists in the upper part of the hot water storage tank. In addition, in the heat storage utilization operation, the first circulation pump and the second circulation so that the temperature of the water returning to the hot water storage tank via the primary side of the water-water heat exchanger does not exceed a predetermined temperature. Adjust the circulation volume of both pumps
A waste heat utilization system characterized by this.
In the above invention, when the return temperature from the water-water heat exchanger becomes high, the water-water heat is controlled by lowering the rotation speed of the second circulation pump or increasing the rotation speed of the first circulation pump. Increase the efficiency of heat exchange in the exchanger and lower the return temperature.

[ 4 ] The waste heat utilization according to any one of [1] to [3], wherein the predetermined condition includes that the temperature of the heat medium fluid in the heat dissipation circuit is equal to or lower than the predetermined temperature. system.

In the above invention, if the temperature of the heat medium fluid in the heat dissipation circuit is equal to or lower than the predetermined temperature, it is considered that the return temperature from the water-water heat exchanger when the heat storage utilization operation is executed is low. Therefore, if the above conditions are satisfied, the heat storage utilization operation can be selected, and if not, the heat storage utilization operation is not selected.

[ 5 ] The required temperature for the heat dissipation operation includes a first required temperature and a second required temperature lower than the first required temperature.
The waste heat utilization system according to any one of [1] to [4 ], wherein the predetermined condition includes that the required temperature for the heat dissipation operation is the second required temperature.

In the above invention, if the required temperature of the heat dissipation operation is the second required temperature, the heat storage utilization operation can be selected, and if the required temperature of the heat dissipation operation is not the second required temperature, the heat storage utilization operation is not selected.

[ 6 ] The return position when returning the water after passing through the primary side of the water-water heat exchanger to the hot water storage tank in the heat storage utilization circulation circuit is set to the lower part of the hot water storage tank or the hot water storage tank. A return position switching part for switching whether to use the middle part of the hot water storage tank above the lower part is provided.
In the heat storage utilization operation, when the temperature of the water returning to the hot water storage tank via the primary side of the water-water heat exchanger is equal to or lower than the first temperature, the control unit sends the water to the lower part of the hot water storage tank. When the temperature of the returned water exceeds the first temperature, the switching unit is controlled so that the water that has passed through the primary side of the water-water heat exchanger is returned to the intermediate portion of the hot water storage tank. The waste heat utilization system according to any one of [1] to [ 5].

In the above invention, when the return temperature from the water-water heat exchanger becomes high during the heat storage utilization operation, the hot water is switched to return to the middle part of the hot water storage tank. As a result, the temperature rise at the bottom of the hot water storage tank is avoided, and the heat storage utilization operation can be continued for a longer period of time.

According to the waste heat utilization system according to the present invention, the hot water is stored when the hot water in the hot water storage tank is used as a heat source for floor heating or the like without causing the water-water heat exchanger to become large or complicated. It is possible to deal with the adverse effect of increasing the return temperature to the tank.

It is a figure which shows the schematic structure of the waste heat utilization system which concerns on embodiment of this invention. It is a figure which shows the flow of the heating operation when the control policy 1 is adopted alone. It is a figure which shows the flow of the heating operation when the control policy 2 is adopted alone. It is a figure which shows the flow of the heating operation when the control policy 1 and the control policy 2 are adopted. It is a figure which shows the flow of the heating operation when the control policy 3 is adopted alone. It is a figure which shows the flow of the heating operation when the control policy 3 and the control policy 1 are combined. It is a figure which shows the flow of the heating operation when the control policy 3 and the control policy 2 are combined. It is a flow chart which shows the continuation of FIG. It is a figure which shows the flow of the heating operation when the control policy 3, the control policy 2, and the control policy 1 are combined. It is a flow chart which shows the continuation of FIG. It is a figure which shows the flow of the heating operation when the control policy 4 and the control policy 1 are combined. It is a figure which shows the flow of the heating operation when the control policy 4 and the control policy 2 are combined. It is a figure which shows the flow of the heating operation when the control policy 4, the control policy 2, and the control policy 1 are combined. It is a figure which shows the flow of the heating operation when the control policy 3 and the control policy 4 are combined. It is a figure which shows the flow of the heating operation when the control policy 4, the control policy 3, and the control policy 1 are combined. It is a figure which shows the flow of the heating operation when the control policy 4, the control policy 3, and the control policy 2 are combined. It is a flow chart which shows the continuation of FIG. It is a figure which shows the flow of the heating operation when the control policy 4, the control policy 3, the control policy 2, and the control policy 1 are combined. It is a flow chart which shows the continuation of FIG. FIG. 20 is a flow chart showing a heating operation when the control policy 5 and the control policy 1 are combined. It is a figure which shows the flow of the heating operation when the control policy 5 and the control policy 2 are combined. It is a figure which shows the flow of the heating operation when the control policy 5, the control policy 2, and the control policy 1 are combined. It is a figure which shows the flow of the heating operation when the control policy 5 and the control policy 3 are combined. It is a figure which shows the flow of the heating operation when the control policy 5, the control policy 3, and the control policy 1 are combined. It is a figure which shows the flow of the heating operation when the control policy 5, the control policy 3, and the control policy 2 are combined. It is a flow chart which shows the continuation of FIG. It is a figure which shows the flow of the heating operation when the control policy 5, the control policy 3, the control policy 2, and the control policy 1 are combined. It is a flow chart which shows the continuation of FIG. 27. It is a figure which shows the flow of the heating operation when the control policy 5, the control policy 4, and the control policy 1 are combined. It is a figure which shows the flow of the heating operation when the control policy 5, the control policy 4, and the control policy 2 are combined. It is a figure which shows the flow of the heating operation when the control policy 5, the control policy 4, the control policy 2, and the control policy 1 are combined. It is a figure which shows the flow of the heating operation when the control policy 5, the control policy 4, and the control policy 3 are combined. It is a figure which shows the flow of the heating operation when the control policy 5, the control policy 4, the control policy 3, and the control policy 1 are combined. It is a figure which shows the flow of the heating operation when the control policy 5, the control policy 4, the control policy 3, and the control policy 2 are combined. It is a flow chart which shows the continuation of FIG. 34. It is a figure which shows the flow of the heating operation when the control policy 5, the control policy 4, the control policy 3, the control policy 2, and the control policy 1 are combined. It is a flow chart which shows the continuation of FIG. 36. It is a figure which shows the ideal operating state in which a temperature stratification is formed in a hot water storage tank. It is a figure which shows the operating state which the return temperature from a hot water mat is high, and the temperature stratification in a hot water storage tank collapsed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a waste heat utilization system 2 according to an embodiment of the present invention. The waste heat utilization system 8 recovers the waste heat of a predetermined generator (here, the fuel cell 2) and raises the temperature of the water taken out from the hot water storage tank 10 and the lower part of the hot water storage tank 10, and then raises the temperature of the hot water storage tank 10. The exhaust heat recovery unit 20 to be returned to the upper part of the above, the hot water heater 30 as an auxiliary heat source machine, the floor heating mat 40 connected to the heating circuit of the hot water heater 30 as a radiator, and the heating circuit of the hot water heater 30. A water-water heat exchanger 50 for raising the temperature of the circulating heat medium fluid (here, water) by the heat of the hot water in the hot water storage tank 10, and a control unit 60 for controlling the operation of the exhaust heat utilization system 8. Be prepared for it.

Here, the waste heat recovery unit 20 recovers the waste heat of the fuel cell 2 during power generation to raise the temperature of the hot water in the hot water storage tank 10.

The hot water storage tank 10 is a closed container having a substantially cylindrical hollow shape, and a water supply port 11 is provided at the lower part of the hot water storage tank 10 and a hot water outlet 12 is provided at the upper part of the hot water storage tank 10. A water supply pipe 71 is connected to the water supply port 11, and cold water is replenished into the hot water storage tank 10 from the water supply port 11.

The hot water storage tank 10 has a capacity of, for example, about 100 liters. The hot water storage tank 10 has temperature sensors 13 (13a to 13e) that detect the water temperature at each of the water levels of 20, 40, 60, and 80 liters from the bottom and at a water level of approximately 100 liters. It is provided.

The waste heat recovery unit 20 includes a heat exchanger 21 for recovering waste heat for recovering the waste heat of the fuel cell 2 and a circulation pump 22 for recovering the waste heat. The inlet side of the waste heat recovery unit 20 and the lower intake port 14 of the hot water storage tank are connected by a heat recovery low temperature pipe 24, and the outlet side of the waste heat recovery unit 20 and the upper return port 15 of the hot water storage tank 10 are connected. It is connected by a heat recovery high temperature pipe 25. A heat recovery low temperature side temperature sensor 26 for detecting the water temperature in the pipe is provided in the middle of the heat recovery low temperature pipe 24. A heat recovery high temperature side temperature sensor 27 for detecting the water temperature in the pipe is provided in the middle of the heat recovery high temperature pipe 25.

The exhaust heat recovery circuit is a path that exits from the lower intake port 14 of the hot water storage tank 10, passes through the heat recovery low temperature pipe 24, the waste heat recovery unit 20, and the heat recovery high temperature pipe 25, and returns from the upper return port 15 to the hot water storage tank 10. ..

The water-water heat exchanger 50 is provided with the primary side heat exchange pipe 51 and the secondary side heat exchange pipe 52 in contact with each other, and heat is exchanged between them. The inlet side of the primary side heat exchange pipe 51 of the water-water heat exchanger 50 and the upper intake port 16 of the hot water storage tank 10 are connected by a high temperature pipe 53 using waste heat, and the outlet side of the primary side heat exchange pipe 51 and the hot water storage tank 10 are connected. The lower return port 17 of the above is connected by a low temperature pipe 54 using waste heat. A three-way valve (tank return three-way valve 55) is connected in the middle of the low-temperature pipe 54 that utilizes waste heat.

Specifically, the outlet side of the primary side heat exchange pipe 51 is connected to the first connection port of the tank return three-way valve 55, and further, the second connection port of the tank return three-way valve 55 and the lower return port 17 are connected. Further, the third connection port of the tank return three-way valve 55 is connected to the intermediate return port 18 provided at the water level in the middle of the hot water storage tank 10 by the tank intermediate return pipe 56. In the communication state of the tank return three-way valve 55, the first connection port and the second connection port communicate with each other, the lower position where the third connection port is closed, and the first connection port and the third connection port communicate with each other. It is possible to switch to the intermediate position where the second connection port is closed.

A second circulation pump (heat storage pump 57) is connected to the exhaust heat utilization low temperature pipe 54 between the first connection port of the tank return three-way valve 55 and the outlet side of the primary side heat exchange pipe 51 of the water-water heat exchanger 50. And a tank return temperature sensor 58 is provided.

The path from the upper intake port 16 of the hot water storage tank 10 to the hot water storage tank 10 from the intermediate return port 18 or the lower return port 17 via the primary side heat exchange pipe 51 of the water-water heat exchanger 50 is used as a heat storage utilization circulation circuit. ..

The hot water supply heater 30 has a hot water supply function that heats and raises the temperature of hot water flowing in from the water supply connection port 31 and sends it out (supplys hot water) to a faucet, a shower, or the like, and a heating function that circulates hot water to the floor heating mat 40 to heat it. It is equipped with.

Regarding the hot water supply function, the hot water supply heater 30 includes a hot water supply heat exchanger 32 and a burner (not shown) for heating the heat exchanger 32. The hot water flowing in from the water supply connection port 31 is discharged via the hot water supply heat exchanger 32. By heating the hot water supply heat exchanger 32 with a burner that burns the combustion gas, the temperature of the hot water passing through the hot water supply heat exchanger 32 is raised. A hot water supply temperature sensor 33 for detecting the hot water supply temperature is provided on the outlet side of the hot water supply heat exchanger 32.

The upper water intake port 16 of the hot water storage tank 10 and the water supply connection port 31 of the hot water supply heater 30 are connected by a backup heat source machine pipe 34, and a water supply branch branched from the water supply pipe 71 is formed in the middle of the backup heat source machine pipe 34. The pipe 36 is joined and connected via the mixer 35. A tank outlet temperature sensor 37 that detects the temperature of hot water passing through the junction is provided in the middle of the backup heat source machine piping 34 upstream from the confluence of the water supply branch pipe 36, and the backup heat source piping 34 downstream from the confluence. A mixing temperature sensor 38 is provided in the middle of the above.

Regarding the heating function, the hot water supply heater 30 includes a heat exchanger 39 for heating, a burner (not shown) for heating the heat exchanger 39, a heat exchanger 39 for heating, a floor heating mat 40, and water-water heat exchange. A heating circuit (heat dissipation circuit) is formed via the secondary side heat exchange pipe 52 of the vessel 50. Specifically, the exit side of the heating heat exchanger 39 and the entrance side of the floor heating mat 40 are connected by a heating going pipe 41, and the exit side of the floor heating mat 40 and the secondary side of the water-water heat exchanger 50 are connected. It is connected to the inlet side of the heat exchange pipe 52 by a waste heat utilization pipe 42. Further, the outlet side of the secondary side heat exchange pipe 52 of the water-water heat exchanger 50 and the inlet side of the heating heat exchanger 39 of the hot water supply heater 30 are connected by a heating return pipe 43. ..

Further, a three-way valve (heating switching valve 44) is inserted in the middle of the waste heat utilization pipe 42. Specifically, the waste heat utilization pipe 42 on the side leading to the outlet side of the floor heating mat 40 is connected to the first connection port of the heating switching valve 44, and the water-water heat exchanger 50 is connected to the second connection port. The waste heat utilization pipe 42 on the side leading to the entry side of the next side heat exchange pipe 52 is connected. One end of the waste heat utilization bypass pipe 45 is connected to the third connection port of the heating switching valve 44, and the other end of the exhaust heat utilization bypass pipe 45 is joined and connected in the middle of the heating return pipe 43. The heating switching valve 44 has a heat storage side in which the first connection port and the second connection port are communicated with each other and the third connection port is closed, and a combustion side in which the first connection port and the third connection port are communicated with each other and the second connection port is closed. You can switch to and.

A first circulation pump (heating pump 46) and a heating return temperature sensor 47 are provided in the heating return pipe 43 between the confluence of the exhaust heat utilization bypass pipe 45 and the inlet side of the heating heat exchanger 39. In the middle of the heating going pipe 41, a heating going temperature sensor 48 for detecting the temperature of hot water sent from the outlet side of the heating heat exchanger 39 to the floor heating mat 40 is provided.

The control unit 60 comprehensively controls various operations of the waste heat utilization system 8. The control unit 60 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like as main units. A signal indicating the detection result output by various temperature sensors and other sensors is input to the control unit 60, and a signal instructing the operation of the heating pump 46, the heat storage utilization pump 57, and the exhaust heat recovery heat exchanger 21 is input. , A signal instructing switching of the tank return three-way valve 55 and the heating switching valve 44, a control signal of the mixer 35, and the like are output. Further, the control unit 60 is connected to a remote controller (remote controller) (not shown) that accepts operations such as turning on / off of various operations and setting the temperature, and displays the operating status and the set temperature.

Next, various operations in the waste heat utilization system 8 will be described.

<Hot water supply operation>
The hot water supply operation is an operation of discharging hot water to a shower or the like. In the hot water supply operation, when there is hot water with a temperature exceeding the hot water supply set temperature at the top of the hot water storage tank 10, the burner for the hot water supply heat exchanger 32 is not burned, and the hot water of the hot water supply set temperature is discharged so that the hot water is discharged. Adjust 35. If there is not enough hot water at the upper part of the hot water storage tank 10 at a temperature capable of the above operation, the burner for the hot water supply heat exchanger 32 is burned, and the hot water storage tank 10 is sent to the water supply connection port 31 through the backup heat source machine piping 34. The inflowing hot water is heated to the set temperature for hot water supply and discharged. At this time, if the hot water outlet temperature exceeds the hot water supply set temperature even if the burner for the hot water supply heat exchanger 32 is burned to the minimum, the mixer 35 is adjusted to mix the water supply. In the hot water supply operation, cold water is supplied to the hot water storage tank 10 from the water supply port 11 at the lower part of the hot water storage tank 10 by the amount of hot water discharged from the upper water intake port 16 of the hot water storage tank 10.

<Waste heat recovery operation>
In the waste heat recovery operation, the waste heat recovery circulation pump 22 is driven. When the exhaust heat recovery circulation pump 22 is driven, the water at the bottom of the hot water storage tank 10 is taken out from the lower intake port 14, and the heat recovery low temperature pipe 24, the exhaust heat recovery unit 20 (exhaust heat recovery circulation pump 22, When circulating the exhaust heat recovery circuit so as to return to the upper part of the hot water storage tank 10 from the upper return port 15 via the heat recovery heat exchanger 21) and the heat recovery high temperature pipe 25, and passing through the waste heat recovery unit 20 on the way. Is heated to. By such an operation, a temperature stratification is formed inside the hot water storage tank 10 with a low temperature at the lower part and a high temperature at the upper part.

<Heating operation>
The heating operation includes a heat storage heating operation (heat storage operation) that heats using the heat of the hot water at the top of the hot water storage tank 10, and heating with the heat obtained by burning the burner for the heating heat exchanger 39. There is a heating combustion operation (operation using an auxiliary heat source machine), and these can be switched according to the situation.

In the heating combustion operation, the heating switching valve 44 is set on the combustion side that bypasses the water-water heat exchanger 50, the heating pump 46 is operated, the burner for the heating heat exchanger 39 is set, and the heating forward temperature sensor 48 is used. Burn so that the detected temperature of is the target value.

In the heating operation using heat storage, the heating switching valve 44 is set on the heat storage side where the hot water of the heating circuit passes through the secondary side heat exchange pipe 52 of the water-water heat exchanger 50, and the burner for the heat exchanger 39 for heating is set. Burning is turned off and the heating pump 46 is activated. Further, the tank return three-way valve 55 is set at a lower position where hot water returns from the lower return port 17 to the hot water storage tank 10 or an intermediate position where hot water returns from the intermediate return port 18 to the hot water storage tank 10 to operate the heat storage pump 57. .. In the heat storage utilization heating operation, hot water taken out from the upper intake port 16 of the hot water storage tank 10 is circulated in the heat storage utilization circulation circuit, and the heat of the hot water is transferred to the hot water circulating on the heating circuit side to the water-water heat exchanger 50. The temperature of the hot water circulating in the heating circuit is raised by transmitting the heat.

In the control of heating operation, when the difference between the heating set temperature and the room temperature (low room temperature is low) is large, there is a request to send high temperature (for example, 60 ° C.) hot water to the floor heating mat 40 (heating temperature 60 ° C. request). When the difference between the set heating temperature and the room temperature is small, a request for sending low temperature (for example, 40 ° C.) hot water to the floor heating mat 40 (heating temperature 40 ° C. request) is generated.

By the way, when the room is warmed and the amount of heat dissipated by the floor heating mat 40 is reduced in the heat storage utilization heating operation, the hot water (for example, hot water at 60 ° C.) taken out from the upper intake port 16 of the hot water storage tank 10 is discharged. Even if heat is exchanged by the water-water heat exchanger 50, the temperature drops only to about 30 ° C to 40 ° C and returns to the lower part of the hot water storage tank 10. Therefore, if the waste heat recovery operation is performed in such a state, the waste heat is recovered by exchanging heat with the hot water of 40 ° C. taken out from the lower part of the hot water storage tank 10 by the waste heat recovery unit 20. Cooling capacity is reduced. If the cooling capacity is significantly reduced, the power generation of the fuel cell 2 must be stopped.

In order to avoid such a situation, in the present invention, the execution of the heat storage utilization heating operation is restricted based on a predetermined condition. Specifically, there are the following five control policies for controlling the heating operation using heat storage.

<Control policy 1>
If the condition that the fuel cell 2 is stopped and the hot water supply schedule from the hot water storage tank 10 is scheduled by the next operation schedule (power generation schedule) time of the fuel cell 2 is not satisfied, the heat storage utilization heating operation is not selected (does not perform). ..

If the fuel cell 2 is stopped and there is a plan to supply hot water from the hot water storage tank 10 by the time when the fuel cell 2 is scheduled to operate next (power generation is scheduled), the water temperature at the bottom of the hot water storage tank 10 rises due to the execution of the heat storage utilization heating operation. Even so, cold water is replenished to the hot water storage tank 10 by the use of hot water supply by the start of the next power generation. Therefore, even if the heating operation using heat storage is executed, it does not affect the next power generation operation of the fuel cell 2.

<Control policy 2>
If the temperature of the hot water in the heating circuit is not below a predetermined threshold, the heating operation using heat storage is not selected (does not perform). That is, if the heating operation is a so-called cold start, the heat storage utilization heating operation is permitted, and if it is already warm, the heat storage utilization heating operation is prohibited.

If the heating operation is in the cold start state, the amount of heat dissipated by the floor heating mat 40 is large, so that when the heat storage utilization heating operation is performed, the return from the primary side heat exchange pipe 51 of the water-water heat exchanger 50 The temperature becomes low, and the water temperature at the bottom of the hot water storage tank 10 does not rise or is small. Therefore, the exhaust heat of the fuel cell 2 can be efficiently recovered by the exhaust heat recovery operation, and the power generation operation of the fuel cell 2 is not hindered.

<Control policy 3>
When the required heating temperature is below the predetermined temperature (for example, 40 ° C or less), the heating operation using heat storage can be selected, and when the required heating temperature exceeds the specified temperature, the heating operation using heat storage is not selected (prohibited). When the room is warm, the required heating temperature becomes low, so if the upper part of the hot water storage tank 10 is 40 ° C. or higher, the heating operation using heat storage is possible even when there is no hot water such as 60 ° C. If the return temperature from the water-water heat exchanger 50 becomes high, the heat storage utilization heating operation may be stopped.

<Control policy 4>
When the return temperature from the primary side heat exchange pipe 51 of the water-water heat exchanger 50 is equal to or lower than the predetermined temperature, the return hot water from the water-water heat exchanger 50 is returned to the hot water storage tank 10 from the lower return port 17. If the temperature exceeds a predetermined temperature, the temperature is returned to the hot water storage tank 10 from the intermediate return port 18.

The control policy 4 is a control for continuing the heating operation using heat storage for a longer period of time. If the return temperature from the primary side heat exchange pipe 51 of the water-water heat exchanger 50 becomes high during the heating operation using heat storage, the tank return three-way valve 55 is used to return this hot water to the middle part of the hot water storage tank 10. Switch. As a result, the temperature rise of the lower part of the hot water storage tank 10 is avoided.

<Control policy 5>
The amount of hot water circulated by the heating pump 46 and the heat storage utilization pump 57 is controlled so that the return temperature from the primary side heat exchange pipe 51 of the water-water heat exchanger 50 does not exceed a predetermined temperature.

The control policy 5 is a control for continuing the heating operation using heat storage for a longer period of time. When the return temperature from the primary side heat exchange pipe 51 becomes high, the heat in the water-water heat exchanger 50 is controlled by reducing the rotation speed of the heat storage utilization pump 57 and increasing the rotation speed of the heating pump 46. Increase the efficiency of replacement and lower the return temperature.

Hereinafter, the details of the operation of the heating operation when the control policies 1 to 5 are adopted alone or when a plurality of control policies are combined will be described with reference to the flow chart. If the control policy 4 is not implemented, the tank return three-way valve 55, the intermediate return port 18, and the tank intermediate return pipe 56 are unnecessary in the configuration of FIG. 1, and the low temperature pipe 54 using waste heat is water-water heat. The outlet side of the primary side heat exchange pipe 51 of the exchanger 50 may be connected to the lower return port 17 of the hot water storage tank 10.

FIG. 2 shows the flow of heating operation when the control policy 1 is adopted alone. When the heating operation is turned on by the remote controller (step S101), the control unit 60 first turns on the heating pump 46 (step S102). Then, it is determined whether or not there is hot water having a temperature of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S103). If there is no hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S103; No), the process proceeds to step S109 and the heating combustion operation is performed.

If there is hot water at 60 ° C. on the upper part of the hot water storage tank 10 (step S103; Yes), it is checked whether or not the fuel cell 2 has stopped power generation (step S104). If the fuel cell 2 is not stopped in power generation (step S104; No), the process proceeds to step S109 and the heating combustion operation is performed. If the fuel cell 2 is out of power generation (step S104; Yes), it is checked whether or not there is a plan to use hot water supply (for example, a reservation setting for hot water filling in the bath) before the next power generation schedule (step S105). If there is no plan to use the hot water supply by the next power generation schedule (step S105; No), the process proceeds to step S109 and the heating combustion operation is performed.

If there is a plan to use hot water supply by the next power generation schedule (step S105; Yes), the heat storage utilization pump 57 is turned on, the heating switching valve 44 is set to the heat storage side, and the heat storage utilization heating operation is started (step S106). The tank return three-way valve 55 is fixed at the lower position. Steps S104 and S105 correspond to the control of the control policy 1.

During the heating operation using heat storage, it is monitored whether or not there is hot water of 60 ° C or higher in the upper part of the hot water storage tank 10 (step S107), and while there is hot water of 60 ° C or higher in the upper part of the hot water storage tank 10 (step). S107; No), the heating operation using heat storage is continued. When the temperature of the hot water in the upper part of the hot water storage tank 10 becomes less than 60 ° C. (step S107; Yes), the heat storage utilization heating operation is stopped (step S108). Specifically, the heat storage utilization pump 57 is stopped, and the process proceeds to step S109. In the control of control policy 1, cold water is scheduled to be replenished to the lower part of the hot water storage tank 10 before the start of power generation. Do not do.

In step S109, the heating switching valve 44 is switched to the combustion side that bypasses the secondary side heat exchange pipe 52 of the water-water heat exchanger 50, and the heating combustion operation is started.

After that, when the heating operation is turned off by the remote control operation (step S110), the heating switching valve 44 is set to the combustion side, the heating pump 46 is stopped, and the heating combustion operation (burning of the burner for the heating heat exchanger 39 is also performed). (Turn off) is stopped (step S111).

FIG. 3 shows the flow of heating operation when the control policy 2 is adopted alone. When the heating operation is turned on by the remote controller (step S201), the control unit 60 turns on the heating pump 46 (step S202). Then, it is determined whether or not the temperature of the hot water in the heating circuit is equal to or lower than a predetermined threshold value (whether or not it is a cold start) (step S203). If the temperature of the hot water in the heating circuit is not equal to or lower than a predetermined threshold value (step S203; No), the process proceeds to step S210 to perform the heating combustion operation. The judgment in step S203 corresponds to the control policy 2.

If the temperature of the hot water in the heating circuit is equal to or lower than a predetermined threshold value (step S203; Yes), it is determined whether or not there is hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S204). If there is no hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S204; No), the process proceeds to step S210 and the heating combustion operation is performed.

If there is hot water of 60 ° C or higher above the hot water storage tank 10 (step S204; Yes), the heat storage utilization pump 57 is turned on, the heating switching valve 44 is set on the heat storage side, and the heat storage utilization heating operation is started (step S204; Yes). Step S205). The tank return three-way valve 55 is fixed at the lower position.

During the heat storage utilization heating operation, whether or not the temperature of the hot water in the heating circuit is below the threshold value (step S206), and whether or not there is hot water of 60 ° C. or higher above the hot water storage tank 10 (step S207). It is monitored whether or not the return temperature from the water-water heat exchanger 50 to the lower part of the hot water storage tank 10 is 40 ° C. or higher (step S208). The temperature in the heating circuit is below the threshold value (step S206; Yes), there is hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S207; Yes), and the return temperature to the lower part of the hot water storage tank 10 is less than 40 ° C. In the case of (step S208; No), the heat storage utilization heating operation is continued.

When the temperature in the heating circuit is not below the threshold value (step S206; No), or when the temperature of the hot water in the upper part of the hot water storage tank 10 becomes less than 60 ° C. (step S207; No), or to the lower part of the hot water storage tank 10. When the return temperature becomes 40 ° C. or higher (step S208; Yes), the heat storage utilization heating operation is stopped and the heat storage utilization pump 57 is stopped (step S209). The determination in step S206 also corresponds to control policy 2.

After that, the heating switching valve 44 is switched to the combustion side that bypasses the secondary side heat exchange pipe 52 of the water-water heat exchanger 50, and the heating combustion operation is started (step S210). When the heating operation is turned off by the remote control operation (step S211), the heating switching valve 44 is set to the combustion side, the heating pump 46 is stopped, and the heating combustion operation is stopped (step S212).

FIG. 4 shows the flow of heating operation when the control policy 1 and the control policy 2 are combined. The same process as in FIG. 3 is assigned the same step number as in FIG. In the process of FIG. 4, step S204-01 and step S204-02 are added after step S204 as processes corresponding to the control policy 1. Others are the same as in FIG. 3, and the description thereof will be omitted.

In step S204-01, it is checked whether or not the fuel cell 2 is stopped in power generation, and if it is not in power generation (step S204-01; No), the process proceeds to step S210 and the heating combustion operation is performed. If the fuel cell 2 is out of power generation (step S204-01; Yes), it is checked whether or not there is a plan to use hot water supply by the next power generation schedule (step S204-02). If there is no plan to use hot water supply by the next power generation schedule (step S204-02; No), the process proceeds to step S210 to perform heating combustion operation. If there is a plan to use hot water supply by the next power generation schedule (step S204-02; Yes), the heat storage utilization heating operation is started (step S205).

FIG. 5 shows the flow of heating operation when the control policy 3 is adopted alone. When the heating operation is turned on by the remote controller (step S301), the control unit 60 turns on the heating pump 46, sets the heating switching valve 44 on the combustion side, and starts the heating combustion operation (step S302).

After that, if the heating temperature requirement is not the heating temperature requirement of 40 ° C. (step S303; No), or the heating temperature requirement is the heating temperature requirement of 40 ° C., but there is no hot water of 40 ° C. or higher in the upper part of the hot water storage tank 10 (step S303; No). Step S304; No), the heating combustion operation is continued.

If there is a requirement for a heating temperature of 40 ° C (step S303; Yes) and there is hot water of 40 ° C or higher above the hot water storage tank 10 (step S304; Yes), the heating combustion operation is stopped (heat exchange for heating). Turn off the burner for the device 39), turn on the heat storage utilization pump 57, switch the heating switching valve 44 to the heat storage side, and start the heat storage utilization heating operation (step S305).

While there is hot water of 40 ° C or higher in the upper part of the hot water storage tank 10 (step S306; Yes) and the return temperature from the water-water heat exchanger 50 to the lower part of the hot water storage tank 10 is less than 40 ° C (step S307; No). Continue heating operation using heat storage.

When there is no hot water of 40 ° C or higher in the upper part of the hot water storage tank 10 (step S306; No) or when the return temperature from the water-water heat exchanger 50 to the lower part of the hot water storage tank 10 becomes 40 ° C or higher (step S307; Yes). ), The heat storage utilization pump 57 is stopped, and the heat storage utilization heating operation is stopped (step S308). Then, the heating switching valve 44 is switched to the combustion side, and the heating combustion operation for burning the burner for the heating heat exchanger 39 is started (step S309).

After that, when the heating operation is turned off by the remote control operation (step S310), the heating switching valve 44 is set to the combustion side, the heating pump 46 is stopped, and the heating combustion operation is stopped (step S311).

FIG. 6 shows the flow of heating operation when the control policy 3 and the control policy 1 are combined. The same process as in FIG. 5 is assigned the same step number as in FIG. 5, and the description thereof will be omitted. In the process of FIG. 6, after step S304, as a process corresponding to the control policy 1, step S304-01 for checking whether the fuel cell 2 is stopped in power generation and a schedule for using hot water supply by the next power generation schedule are scheduled. Step S304-02 for checking whether or not there is is added. Others are the same as in FIG.

7 and 8 are flow charts showing a heating operation when the control policy 3 and the control policy 2 are combined. When the heating operation is turned on by the remote controller (step S331), the control unit 60 turns on the heating pump 46 (step S332). Then, it is determined whether or not the temperature of the hot water in the heating circuit is equal to or lower than a predetermined threshold value (step S333, control policy 2). If the temperature of the hot water in the heating circuit is not equal to or lower than a predetermined threshold value (step S333; No), the process proceeds to step S340 to perform the heating combustion operation.

If the temperature of the hot water in the heating circuit is equal to or lower than a predetermined threshold value (step S333; Yes), it is determined whether or not there is hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S334). If there is no hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S334; No), the process proceeds to step S340 and the heating combustion operation is performed.

When there is hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S334; Yes), the heat storage utilization pump 57 is turned on, the heating switching valve 44 is set to the heat storage side, and the heat storage utilization heating operation is started (step S335). ). The tank return three-way valve 55 is fixed at the lower position.

During the heat storage utilization heating operation, whether or not the temperature in the heating circuit is below the threshold value (step S336, control policy 2) and whether or not there is hot water of 60 ° C. or higher above the hot water storage tank 10 (step S337). ), Whether or not the return temperature from the water-water heat exchanger 50 to the lower part of the hot water storage tank 10 has reached 40 ° C. or higher (step S338) is monitored. The temperature in the heating circuit is below the threshold value (step S336; Yes), there is hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S337; Yes), and the return temperature to the lower part of the hot water storage tank 10 is less than 40 ° C. During (step S338; No), the heating operation using heat storage is continued.

When the temperature in the heating circuit is not below the threshold value (step S336; No), or when the temperature of the hot water in the upper part of the hot water storage tank 10 becomes less than 60 ° C. (step S337; No), or to the lower part of the hot water storage tank 10. When the return temperature becomes 40 ° C. or higher (step S338; Yes), the heat storage utilization heating operation is stopped and the heat storage utilization pump 57 is stopped (step S339). After that, the heating switching valve 44 is switched to the combustion side that bypasses the secondary side heat exchange pipe 52 of the water-water heat exchanger 50, and the heating combustion operation is started (step S340).

During the heating combustion operation, the required heating temperature and the temperature of the hot water in the upper part of the hot water storage tank 10 are monitored. The heating temperature is not required to be 40 ° C (60 ° C required) (step S341; No), or the heating temperature is required to be 40 ° C (step S341; Yes), but there is no hot water above 40 ° C at the top of the hot water storage tank 10 (step S342; If No), the heating combustion operation is continued.

During the heating combustion operation, when the heating temperature is required to be 40 ° C. (step S341; Yes) and there is hot water of 40 ° C. or higher above the hot water storage tank 10 (step S342; Yes), the heating combustion operation is stopped. (Turn off the burner for the heating heat exchanger 39), turn on the heat storage utilization pump 57, switch the heating switching valve 44 to the heat storage side, and start the heat storage utilization heating operation (step S343).

During the heat storage utilization heating operation, the hot water temperature at the upper part of the hot water storage tank 10 and the return temperature to the lower part are monitored. While there is hot water of 40 ° C. or higher in the upper part of the hot water storage tank 10 (step S344; Yes) and the return temperature to the lower part of the hot water storage tank 10 is less than 40 ° C. (step S345; No), the heat storage utilization heating operation is continued.

When there is no hot water of 40 ° C. or higher in the upper part of the hot water storage tank 10 (step S344; No) or when the return temperature to the lower part of the hot water storage tank 10 becomes 40 ° C. or higher (step S345; Yes), the heat storage utilization pump 57 is turned on. It is stopped, and the heat storage utilization heating operation is stopped (step S346). Then, the heating switching valve 44 is switched to the combustion side to start the heating combustion operation (step S347).

After that, when the heating operation is turned off by the remote control operation (step S348), the heating switching valve 44 is set to the combustion side, the heating pump 46 is stopped, and the heating combustion operation is stopped (step S349).

9 and 10 are flow charts showing a heating operation when the control policy 3, the control policy 2, and the control policy 1 are combined. The same parts as those in FIGS. 7 and 8 are assigned the same step numbers. In FIG. 9, after step S334 in FIG. 7, as a process corresponding to the control policy 1, step S334-01 for checking whether or not the fuel cell 2 has stopped power generation, and a plan to use hot water supply by the next power generation schedule. Step S334-02 for checking whether or not there is is added. In FIG. 10, after step S342 in FIG. 8, as a process corresponding to the control policy 1, step S342-01 for checking whether or not the fuel cell 2 has stopped power generation, and a plan to use hot water supply by the next power generation schedule. A step S342-02 for checking whether or not there is is added.

FIG. 11 is a flow chart showing a heating operation when the control policy 4 and the control policy 1 are combined. When the heating operation is turned on by the remote controller (step S401), the control unit 60 turns on the heating pump 46 (step S402) and determines whether or not there is hot water of 60 ° C. or higher above the hot water storage tank 10. Determine (step S403). If there is no hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S403; No), the process proceeds to step S413 and the heating combustion operation is performed.

When there is hot water at 60 ° C. on the upper part of the hot water storage tank 10 (step S403; Yes), it is checked whether or not the fuel cell 2 has stopped power generation (step S404). If the fuel cell 2 is not stopped in power generation (step S404; No), the process proceeds to step S413 and the heating combustion operation is performed. If the fuel cell 2 is out of power generation (step S404; Yes), it is checked whether or not there is a plan to use hot water supply by the next power generation schedule (step S405). If there is no plan to use the hot water supply by the next power generation schedule (step S405; No), the process proceeds to step S413 and the heating combustion operation is performed.

If there is a plan to use hot water supply by the next power generation schedule (step S305; Yes), turn on the heat storage utilization pump 57, set the heating switching valve 44 to the heat storage side, and set the tank return three-way valve 55 to the lower position. Then, the heating operation using heat storage is started (step S406).

During the heat storage utilization heating operation, the upper part of the hot water storage tank 10 and the return temperature from the water-water heat exchanger 50 to the hot water storage tank 10 are monitored. While there is hot water of 60 ° C. or higher at the top of the hot water storage tank 10 (step S407; Yes) and the return temperature is less than 40 ° C. (step S408; No), the tank return three-way valve 55 is maintained in the lower position. Performs heating operation using heat storage. If there is hot water of 60 ° C or higher above the hot water storage tank 10 (step S407; Yes) and the return temperature reaches 40 ° C or higher (step S408; No), the tank return three-way valve 55 is switched to the intermediate position (step). S409, control policy 4).

After that, while there is hot water of 60 ° C. or higher above the hot water storage tank 10 (step S410; Yes) and the return temperature to the hot water storage tank 10 is less than 50 ° C. (step S411; No), the return position is set to the intermediate position. Continue the heating operation using heat storage. Since the temperature stratification in the hot water storage tank 10 is formed, the return temperature of 50 ° C. is allowed when returning to the intermediate position.

When there is no hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 during the heat storage utilization heating operation (step S407; No or step S410; No), the heat storage utilization pump 57 is turned off and the heat storage utilization heating is performed. The operation is stopped (step S412).

In step S413, the heating switching valve 44 is switched to the combustion side to start the heating combustion operation. After that, when the heating operation is turned off by the remote control operation (step S414), the heating switching valve 44 is set to the combustion side, the heating pump 46 is stopped, and the heating combustion operation is stopped (step S415).

FIG. 12 is a flow chart showing a heating operation when the control policy 4 and the control policy 2 are combined. When the heating operation is turned on by the remote controller (step S431), the control unit 60 turns on the heating pump 46 (step S432). Then, it is determined whether or not the temperature of the hot water in the heating circuit is equal to or lower than a predetermined threshold value (step S433). If the temperature of the hot water in the heating circuit is not equal to or lower than a predetermined threshold value (step S433; No), the process proceeds to step S444 to perform the heating combustion operation.

If the temperature of the hot water in the heating circuit is equal to or lower than a predetermined threshold value (step S433; Yes), it is determined whether or not there is hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S434). If there is no hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S434; No), the process proceeds to step S444 to perform heating combustion operation.

If there is hot water at 60 ° C. above the hot water storage tank 10 (step S434; Yes), the heat storage utilization pump 57 is turned on, the heating switching valve 44 is on the heat storage side, and the tank return three-way valve 55 is on the lower position. The heating operation using heat storage is started (step S435).

During the heat storage utilization heating operation, whether or not the temperature in the heating circuit is below the threshold value (step S436), whether or not there is hot water of 60 ° C. or higher above the hot water storage tank 10 (step S437), water-. It is monitored whether or not the return temperature from the water heat exchanger 50 to the hot water storage tank 10 is 40 ° C. or less (step S438). The temperature in the heating circuit is below the threshold (step S436; Yes), the temperature of the hot water at the top of the hot water storage tank 10 is 60 ° C. or higher (step S437; Yes), and the water-water heat exchanger 50 is transferred to the hot water storage tank 10. While the state of the return temperature of less than 40 (step S438; No) continues, the tank return three-way valve 55 is maintained at the lower position to perform the heat storage utilization heating operation.

Although the temperature in the heating circuit is below the threshold value (step S436; Yes) and the temperature of the hot water at the top of the hot water storage tank 10 is 60 ° C. or higher (step S437; Yes), the water-water heat exchanger 50 to the hot water storage tank 10 When the return temperature to is 40 or more (step S438; Yes), the tank return three-way valve 55 is switched to the intermediate position (step S439, control policy 4). After that, the temperature in the heating circuit is below the threshold value (step S436; Yes), there is hot water of 60 ° C. or higher at the upper part of the hot water storage tank 10 (step S410; Yes), and the return temperature to the lower part of the hot water storage tank 10 is 50 ° C. During the period less than (step S442; No), the heat storage utilization heating operation with the return position as the intermediate position is continued.

During the heat storage utilization heating operation, the temperature in the heating circuit is not below the threshold value (step S436; No or step S440; No), or there is no hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S437; No). , Or step S441; No), or when the return temperature to the hot water storage tank 10 becomes 50 ° C. or higher (step S442; Yes), the heat storage utilization pump 57 is turned off and the heat storage utilization heating operation is stopped (step S443).

After that, the heating switching valve 44 is switched to the combustion side that bypasses the secondary side heat exchange pipe 52 of the water-water heat exchanger 50, and the heating combustion operation is started (step S444). When the heating operation is turned off by the remote control operation (step S445), the heating switching valve 44 is set to the combustion side, the heating pump 46 is stopped, and the heating combustion operation is stopped (step S446).

FIG. 13 shows the flow of heating operation when the control policy 4, the control policy 2, and the control policy 1 are combined. The same process as in FIG. 12 is assigned the same step number as in FIG. 12, and the description thereof will be omitted. In the process of FIG. 13, after step S434, as a process corresponding to the control policy 1, there is a step S434-01 for checking whether the fuel cell 2 has stopped power generation, and a schedule for using hot water supply by the next power generation schedule. A step S434-02 for checking whether or not there is is added. Others are the same as in FIG.

FIG. 14 shows the flow of heating operation when the control policy 4 and the control policy 3 are combined. When the heating operation is turned on by the remote controller (step S451), the control unit 60 turns on the heating pump 46, sets the heating switching valve 44 on the combustion side, and starts the heating combustion operation (step S452).

During the heating combustion operation, the required heating temperature and the temperature of the hot water in the upper part of the hot water storage tank 10 are monitored. The heating temperature is not required to be 40 ° C (60 ° C required) (step S453; No), or the heating temperature is required to be 40 ° C (step S453; Yes), but there is no hot water above 40 ° C at the top of the hot water storage tank 10 (step S454; If No), the heating combustion operation is continued.

When there is a request for a heating temperature of 40 ° C. (step S453; Yes) and there is hot water of 40 ° C. or higher above the hot water storage tank 10 (step S454; Yes), the heating combustion operation is stopped (heat for heating). Turn off the burner for the exchanger 39), turn on the heat storage utilization pump 57, switch the heating switching valve 44 to the heat storage side, switch the tank return three-way valve 55 to the lower position, and start the heat storage utilization heating operation (step S455). ..

After that, there is hot water of 40 ° C. or higher in the upper part of the hot water storage tank 10 (step S456; Yes), and the return temperature from the water-water heat exchanger 50 to the hot water storage tank 10 is less than 30 ° C. (step S457; No). While continuing, the heat storage utilization heating operation is continued with the tank return three-way valve 55 in the lower position.

When there is hot water of 40 ° C or higher at the top of the hot water storage tank 10 (step S456; Yes) and the return temperature from the water-water heat exchanger 50 to the hot water storage tank 10 is 30 ° C or higher (step S457; Yes). , The tank return three-way valve 55 is switched to the intermediate position (step S458). After that, there is hot water of 40 ° C. or higher in the upper part of the hot water storage tank 10 (step S459; Yes), and the return temperature from the water-water heat exchanger 50 to the hot water storage tank 10 is less than 40 ° C. (step S460; No). While continuing, the heat storage utilization heating operation is continued with the tank return three-way valve 55 in the intermediate position.

If there is no hot water above 40 ° C at the top of the hot water storage tank 10 (step S456; No or step S459; No), or if the return temperature from the water-water heat exchanger 50 to the hot water storage tank 10 reaches 40 ° C or higher. (Step S460; Yes), the heat storage utilization pump 57 is stopped, the heat storage utilization heating operation is stopped, and the heating switching valve 44 is further switched to the combustion side to start the heating combustion operation (step S461).

After that, when the heating operation is turned off by the remote control operation (step S462), the heating switching valve 44 is set to the combustion side, the heating pump 46 is stopped, and the heating combustion operation is stopped (step S463).

FIG. 15 shows the flow of heating operation when the control policy 4, the control policy 3, and the control policy 1 are combined. The same process as in FIG. 14 is assigned the same step number as in FIG. 14, and the description thereof will be omitted. In the process of FIG. 15, after step S454, as a process corresponding to the control policy 1, there is a step S454-01 for checking whether the fuel cell 2 has stopped power generation, and a schedule for using hot water supply by the next power generation schedule. A step S454-02 for checking whether or not there is is added. Others are the same as in FIG.

16 and 17 are diagrams showing the flow of heating operation when the control policy 4, the control policy 3, and the control policy 2 are combined. When the heating operation is turned on by the remote controller (step S471), the control unit 60 turns on the heating pump 46 (step S472). Then, it is determined whether or not the temperature of the hot water in the heating circuit is equal to or lower than a predetermined threshold value (step S473). If the temperature of the hot water in the heating circuit is not equal to or lower than a predetermined threshold value (step S473; No), the process proceeds to step S480 to perform the heating combustion operation.

If the temperature of the hot water in the heating circuit is equal to or lower than a predetermined threshold value (step S473; Yes), it is determined whether or not there is hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S474). If there is no hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S474; No), the process proceeds to step S480 to perform heating combustion operation.

If there is hot water at 60 ° C. above the hot water storage tank 10 (step S474; Yes), the heat storage utilization pump 57 is turned on, the heating switching valve 44 is set to the heat storage side, and the heat storage utilization heating operation is started (step S475). .. At this time, the tank return three-way valve 55 is set to the lower position.

During the heat storage utilization heating operation, whether or not the temperature in the heating circuit is below the threshold value (step S476), whether or not there is hot water of 60 ° C. or higher above the hot water storage tank 10 (step S477), water-. Whether or not the return temperature from the water heat exchanger 50 to the hot water storage tank 10 is 40 ° C. or higher (step S478) is monitored. The temperature in the heating circuit is below the threshold value (step S476; Yes), there is hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S477; Yes), and the return temperature to the lower part of the hot water storage tank 10 is less than 40 ° C. During that time, the heating operation using heat storage will be continued.

When the temperature in the heating circuit is not below the threshold value (step S476; No), or when the temperature of the hot water in the upper part of the hot water storage tank 10 becomes less than 60 ° C. (step S477; No), or to the lower part of the hot water storage tank 10. When the return temperature becomes 40 ° C. or higher (step S478; Yes), the heat storage utilization pump 57 is stopped and the heat storage utilization heating operation is stopped (step S479).

In step S480, the heating switching valve 44 is switched to the combustion side that bypasses the secondary side heat exchange pipe 52 of the water-water heat exchanger 50, and the heating combustion operation is started.

During the heating combustion operation, the required heating temperature and the temperature of the hot water in the upper part of the hot water storage tank 10 are monitored. The heating temperature is not required to be 40 ° C (60 ° C required) (step S481; No), or the heating temperature is required to be 40 ° C (step S481; Yes), but there is no hot water above 40 ° C at the top of the hot water storage tank 10 (step S482; If No), the heating combustion operation is continued.

When the room temperature rises and the heating temperature is required to be 40 ° C. (step S481; Yes) and there is hot water of 40 ° C. or higher above the hot water storage tank 10 (step S482; Yes), the heating combustion operation is stopped (for heating). (Turn off the burner for the heat exchanger 39), turn on the heat storage utilization pump 57, switch the heating switching valve 44 to the heat storage side, switch the tank return three-way valve 55 to the lower position, and start the heat storage utilization heating operation (step S483). ).

During the heat storage utilization heating operation, the hot water temperature at the upper part of the hot water storage tank 10 and the return temperature from the water-water heat exchanger 50 to the hot water storage tank 10 are monitored. While the hot water storage tank 10 has hot water of 40 ° C. or higher (step S484; Yes) and the return temperature from the water-water heat exchanger 50 to the hot water storage tank 10 is less than 30 ° C. (step S485; No), the state continues. , Continue heating operation using heat storage.

When there is hot water of 40 ° C or higher at the top of the hot water storage tank 10 (step S484; Yes) and the return temperature from the water-water heat exchanger 50 to the hot water storage tank 10 is 30 ° C or higher (step S485; Yes). , The tank return three-way valve 55 is switched to the intermediate position (step S486). After that, there is hot water of 40 ° C. or higher in the upper part of the hot water storage tank 10 (step S487; Yes), and the return temperature from the water-water heat exchanger 50 to the hot water storage tank 10 is less than 40 ° C. (step S488; No). While continuing, the heat storage utilization heating operation is continued with the tank return three-way valve 55 in the intermediate position.

If there is no hot water above 40 ° C at the top of the hot water storage tank 10 (step S484; No or step S487; No), or if the return temperature from the water-water heat exchanger 50 to the hot water storage tank 10 reaches 40 ° C or higher. (Step S488; Yes), the heat storage utilization pump 57 is stopped, the heat storage utilization heating operation is stopped, and the heating switching valve 44 is further switched to the combustion side to start the heating combustion operation (step S489).

After that, when the heating operation is turned off by the remote control operation (step S490), the heating switching valve 44 is set to the combustion side, the heating pump 46 is stopped, and the heating combustion operation is stopped (step S491).

18 and 19 show the flow of heating operation when the control policy 4, the control policy 3, the control policy 2, and the control policy 1 are combined. The same processes as those in FIGS. 16 and 17 are assigned the same step numbers as those in FIGS. 16 and 17, and the description thereof will be omitted. In the process of FIG. 18, after step S474, as a process corresponding to the control policy 1, there is a step S474-01 for checking whether the fuel cell 2 has stopped power generation, and a schedule for using hot water supply by the next power generation schedule. A step S474-02 for checking whether or not there is is added. In the process of FIG. 19, after step S482, as a process corresponding to the control policy 1, step S482-01 for checking whether the fuel cell 2 has stopped power generation and a schedule for using hot water supply by the next power generation schedule are scheduled. Step S482-02 to check whether or not there is is added. Others are the same as those in FIGS. 16 and 17.

FIG. 20 is a flow chart showing a heating operation when the control policy 5 and the control policy 1 are combined. When the heating operation is turned on by the remote controller (step S501), the control unit 60 turns on the heating pump 46 (step S502) and determines whether or not there is hot water of 60 ° C. or higher above the hot water storage tank 10. Determine (step S503). If there is no hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S503; No), the process proceeds to step S514 and the heating combustion operation is performed.

If there is hot water at 60 ° C. on the upper part of the hot water storage tank 10 (step S503; Yes), it is checked whether or not the fuel cell 2 has stopped power generation (step S504). If the fuel cell 2 is not stopped in power generation (step S504; No), the process proceeds to the heating and combustion operation. If the fuel cell 2 is out of power generation (step S504; Yes), it is checked whether or not there is a plan to use hot water supply by the next power generation schedule (step S505). If there is no plan to use hot water supply by the next power generation schedule (step S505; No), the process proceeds to step S514 and the heating combustion operation is performed.

If there is a plan to use hot water supply by the next power generation schedule (step S505; Yes), the heat storage utilization pump 57 is turned on, the rotation speeds of the heat storage utilization pump 57 and the heating pump 46 are set to the normal rotation speeds, and the heating switching valve 44 is set. The heating operation using heat storage is started on the heat storage side (step S506). The tank return three-way valve 55 is fixed at the lower position.

During the heat storage utilization heating operation, the return temperature from the upper part of the hot water storage tank 10 and the water-water heat exchanger 50 to the lower part of the hot water storage tank 10 is monitored. As long as there is hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S507; Yes) and the return temperature to the lower part is less than 40 ° C. (step S508; No), the heat storage utilization heating operation is continued as it is.

If there is hot water of 60 ° C or higher in the upper part of the hot water storage tank 10 (step S507; Yes) and the return to the lower part becomes 40 ° C or higher (step S508; Yes), whether or not the rotation speed of the heat storage utilization pump 57 has reached the lower limit. (Step S509). If the rotation speed of the heat storage utilization pump 57 is not the lower limit (step S509; No), the rotation speed of the heat storage utilization pump 57 is reduced by a predetermined amount (step S511), the process returns to step S507, and the heat storage utilization heating operation is continued.

If the rotation speed of the heat storage pump 57 is already the lower limit (step S509; Yes), it is checked whether or not the rotation speed of the heating pump 46 is the lower limit (step S510). If the rotation speed of the heating pump 46 is not the lower limit (step S510; No), the rotation speed of the heating pump 46 is reduced by a predetermined amount (step S512), the process returns to step S507, and the heating operation using heat storage is continued.

When the rotation speed of the heating pump 46 is the lower limit (step S510; Yes), or when there is no hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S507; No), the heat storage pump 57 is turned off. The heating operation using heat storage is stopped (step S513). Then, the heating switching valve 44 is switched to the combustion side, the rotation speed of the heating pump 46 is returned to normal, and the heating combustion operation is started (step S514).

After that, when the heating operation is turned off by the remote control operation (step S515), the heating switching valve 44 is set to the combustion side, the heating pump 46 is stopped, and the heating combustion operation is stopped (step S516).

FIG. 21 is a flow chart showing a heating operation when the control policy 5 and the control policy 2 are combined. When the heating operation is turned on by the remote controller (step S521), the control unit 60 turns on the heating pump 46 (step S522). Then, it is determined whether or not the temperature of the hot water in the heating circuit is equal to or lower than a predetermined threshold value (step S523). If the temperature of the hot water in the heating circuit is not equal to or lower than a predetermined threshold value (step S523; No), the process proceeds to step S534 to perform the heating combustion operation.

If the temperature of the hot water in the heating circuit is equal to or lower than a predetermined threshold value (step S523; Yes), it is determined whether or not there is hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S524). If there is no hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S524; No), the process proceeds to step S534 to perform heating combustion operation.

When there is hot water at 60 ° C. on the upper part of the hot water storage tank 10 (step S524; Yes), the heat storage utilization pump 57 is turned on, the rotation speeds of the heat storage utilization pump 57 and the heating pump 46 are set to the normal rotation speeds, and the heating switching valve 44 Is set to the heat storage side, and the heat storage utilization heating operation is started (step S525). The tank return three-way valve 55 is fixed at the lower position.

During the heat storage utilization heating operation, the temperature in the heating circuit, the hot water temperature at the upper part of the hot water storage tank 10, and the return temperature from the water-water heat exchanger 50 to the hot water storage tank 10 are monitored. While the temperature in the heating circuit is below the threshold (step S526; Yes), there is hot water of 60 ° C or higher above the hot water storage tank 10 (step S527; Yes), and the return temperature is less than 40 ° C (step S528; No). Continues the heating operation using heat storage as it is.

When the temperature in the heating circuit is below the threshold value (step S526; Yes) and there is hot water of 60 ° C or higher above the hot water storage tank 10 (step S527; Yes), but the return temperature to the hot water storage tank 10 becomes 40 ° C or higher. (Step S528; No), it is examined whether or not the rotation speed of the heat storage utilization pump 57 has reached the lower limit (step S529). If the rotation speed of the heat storage utilization pump 57 is not the lower limit (step S529; No), the rotation speed of the heat storage utilization pump 57 is reduced by a predetermined amount (step S531), the process returns to step S526, and the heat storage utilization heating operation is continued.

If the rotation speed of the heat storage pump 57 is already the lower limit (step S529; Yes), it is checked whether or not the rotation speed of the heating pump 46 is the lower limit (step S530). If the rotation speed of the heating pump 46 is not the lower limit (step S530; No), the rotation speed of the heating pump 46 is reduced by a predetermined amount (step S532), the process returns to step S526, and the heating operation using heat storage is continued.

When the rotation speed of the heating pump 46 is the lower limit (step S530; Yes), or when the temperature in the heating circuit exceeds the threshold value (step S526; Yes), or there is no hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10. When the state is reached (step S527; No), the heat storage utilization pump 57 is turned off and the heat storage utilization heating operation is stopped (step S533). Then, the heating switching valve 44 is switched to the combustion side, the rotation speed of the heating pump 46 is returned to normal, and the heating combustion operation is started (step S534).

After that, when the heating operation is turned off by the remote control operation (step S535), the heating switching valve 44 is set to the combustion side, the heating pump 46 is stopped, and the heating combustion operation is stopped (step S536).

FIG. 22 shows the flow of the heating operation when the control policy 5, the control policy 2, and the control policy 1 are combined. The same process as in FIG. 21 is assigned the same step number as in FIG. 21, and the description thereof will be omitted. In the process of FIG. 22, after step S524, as a process corresponding to the control policy 1, there is a step S524-01 for checking whether the fuel cell 2 has stopped power generation, and a schedule for using hot water supply by the next power generation schedule. Step S524-02 for checking whether or not there is is added. Others are the same as in FIG.

FIG. 23 shows the flow of the heating operation when the control policy 5 and the control policy 3 are combined. When the heating operation is turned on by the remote controller (step S541), the control unit 60 turns on the heating pump 46, sets the heating switching valve 44 on the combustion side, and starts the heating combustion operation (step S542).

During the heating combustion operation, the required heating temperature and the temperature of the hot water in the upper part of the hot water storage tank 10 are monitored. The heating temperature is not required to be 40 ° C (60 ° C required) (step S543; No), or the heating temperature is required to be 40 ° C (step S543; Yes), but there is no hot water above 40 ° C at the top of the hot water storage tank 10 (step S544; If No), the heating combustion operation is continued.

When there is a request for a heating temperature of 40 ° C. (step S543; Yes) and there is hot water of 40 ° C. or higher above the hot water storage tank 10 (step S544; Yes), the heat storage utilization pump 57 is turned on and the heat storage utilization pump is turned on. The rotation speed of 57 and the heating pump 46 is set to the normal rotation speed, the heating switching valve 44 is set to the heat storage side, and the heating operation using heat storage is started (step S545). The tank return three-way valve 55 is fixed at the lower position.

During the heat storage utilization heating operation, the hot water temperature at the upper part of the hot water storage tank 10 and the return temperature from the water-water heat exchanger 50 to the hot water storage tank 10 are monitored. As long as there is hot water of 40 ° C. or higher in the upper part of the hot water storage tank 10 (step S546; Yes) and the return temperature is less than 40 ° C. (step S547; No), the heating operation using heat storage is continued as it is.

If there is hot water of 40 ° C or higher at the top of the hot water storage tank 10 (step S546; Yes), but the return temperature reaches 40 ° C or higher (step S547; Yes), is the rotation speed of the heat storage pump 57 reaching the lower limit? Check whether or not (step S548). If the rotation speed of the heat storage utilization pump 57 is not the lower limit (step S548; No), the rotation speed of the heat storage utilization pump 57 is reduced by a predetermined amount (step S550), the process returns to step S546, and the heat storage utilization heating operation is continued.

If the rotation speed of the heat storage pump 57 is already the lower limit (step S548; Yes), it is checked whether or not the rotation speed of the heating pump 46 is the lower limit (step S549). If the rotation speed of the heating pump 46 is not the lower limit (step S549; No), the rotation speed of the heating pump 46 is reduced by a predetermined amount (step S551), the process returns to step S546, and the heating operation using heat storage is continued.

When the rotation speed of the heating pump 46 is the lower limit (step S549; Yes), or when there is no hot water of 40 ° C. or higher in the upper part of the hot water storage tank 10 (step S546; No), or the rotation speed of the heating pump 46 is the lower limit (step S546; No). Step S
549; Yes), the heat storage utilization pump 57 is turned off and the heat storage utilization heating operation is stopped (step S552). Then, the heating switching valve 44 is switched to the combustion side, the rotation speed of the heating pump 46 is returned to normal, and the heating combustion operation is started (step S553).

After that, when the heating operation is turned off by the remote control operation (step S554), the heating switching valve 44 is set to the combustion side, the heating pump 46 is stopped, and the heating combustion operation is stopped (step S555).

FIG. 24 shows the flow of heating operation when the control policy 5, the control policy 3, and the control policy 1 are combined. The same process as in FIG. 23 is assigned the same step number as in FIG. 23, and the description thereof will be omitted. In the process of FIG. 24, after step S544, as a process corresponding to the control policy 1, there is a step S544-01 for checking whether the fuel cell 2 has stopped power generation, and a schedule for using hot water supply by the next power generation schedule. Step S544-02 to check whether or not there is is added. Others are the same as in FIG.

25 and 26 show the flow of heating operation when the control policy 5, the control policy 3, and the control policy 2 are combined. The first half of the control is the same as steps S521 to S534 in FIG. 21, and is assigned the same step number as in FIG. The latter half of the control is the same as in steps S543 to S555 in FIG. 23, and is assigned the same step number as in FIG. 23.

27 and 28 show the flow of heating operation when the control policy 5, the control policy 3, the control policy 2, and the control policy 1 are combined. The first half of the control is the same as steps S521 to S534 (including steps 524-01 and S524-02) in FIG. 22, and is assigned the same step number as in FIG. 22. The latter half of the control is the same as in steps S543 to S555 in FIG. 24, and is assigned the same step number as in FIG. 23.

FIG. 29 is a flow chart showing a heating operation when the control policy 5, the control policy 4, and the control policy 1 are combined. When the heating operation is turned on by the remote controller (step S561), the control unit 60 turns on the heating pump 46 (step S562) and determines whether or not there is hot water of 60 ° C. or higher above the hot water storage tank 10. Determine (step S563). If there is no hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S563; No), the process proceeds to step S581 and the heating combustion operation is performed.

When there is hot water at 60 ° C. on the upper part of the hot water storage tank 10 (step S563; Yes), it is checked whether or not the fuel cell 2 has stopped power generation (step S564). If the fuel cell 2 is not stopped in power generation (step S564; No), the process proceeds to step S581. If the fuel cell 2 is out of power generation (step S564; Yes), it is checked whether or not there is a plan to use hot water supply by the next power generation schedule (step S565). If there is no plan to use hot water supply by the next power generation schedule (step S565; No), the process proceeds to step S581.

If there is a plan to use hot water supply by the next power generation schedule (step S565; Yes), the heat storage utilization pump 57 is turned on, the heating switching valve 44 is set to the heat storage side, and the tank return three-way valve 55 is set to the lower position. The heat storage utilization heating operation is started with the rotation speeds of the heat storage utilization pump 57 and the heating pump 46 as normal rotation speeds (step S566).

During the heat storage utilization heating operation, the hot water temperature at the upper part of the hot water storage tank 10 and the return temperature from the water-water heat exchanger 50 to the hot water storage tank 10 are monitored. When there is no hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S567; No), the process proceeds to step S580 to stop the heat storage utilization heating operation. While there is hot water of 60 ° C or higher in the upper part of the hot water storage tank 10 (step S567; Yes) and the return temperature to the lower part of the hot water storage tank 10 is less than 40 ° C (step S568; No), the heating operation using heat storage is continued as it is. continue.

When there is hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S567; Yes) and the return temperature to the lower part of the hot water storage tank 10 becomes 40 ° C. or higher (step S568; Yes), the rotation speed of the heat storage utilization pump 57 increases. It is checked whether or not the lower limit has been reached (step S569). If the rotation speed of the heat storage utilization pump 57 is not the lower limit (step S569; No), the rotation speed of the heat storage utilization pump 57 is reduced by a predetermined amount (step S571), the process returns to step S506, and the heat storage utilization heating operation is continued.

If the rotation speed of the heat storage pump 57 is already the lower limit (step S569; Yes), it is checked whether or not the rotation speed of the heating pump 46 is the lower limit (step S570). If the rotation speed of the heating pump 46 is not the lower limit (step S570; No), the rotation speed of the heating pump 46 is reduced by a predetermined amount (step S572), the process returns to step S567, and the heating operation using heat storage is continued.

When the rotation speed of the heating pump 46 is the lower limit (step S570; Yes), the tank return three-way valve 55 is switched to the intermediate position, and both the heat storage utilization pump 57 and the heating pump 46 are returned to the normal rotation speed (step S573). After that, the hot water temperature at the upper part of the hot water storage tank 10 and the return temperature to the middle part of the hot water storage tank 10 are monitored.

While there is hot water of 60 ° C or higher at the top of the hot water storage tank 10 (step S574; Yes) and the return temperature from the water-water heat exchanger 50 to the middle part of the hot water storage tank 10 is less than 50 ° C (step S575; No). Continues the heating operation using heat storage as it is.

When there is hot water of 60 ° C. or higher at the top of the hot water storage tank 10 (step S574; Yes) and the return temperature to the middle part of the hot water storage tank 10 reaches 50 ° C. or higher (step S575; Yes), the rotation of the heat storage utilization pump 57 Check whether the number has reached the lower limit (step S576). If the rotation speed of the heat storage utilization pump 57 is not the lower limit (step S576; No), the rotation speed of the heat storage utilization pump 57 is reduced by a predetermined amount (step S578), the process returns to step S574, and the heat storage utilization heating operation is continued.

If the rotation speed of the heat storage pump 57 is already the lower limit (step S576; Yes), it is checked whether or not the rotation speed of the heating pump 46 is the lower limit (step S577). If the rotation speed of the heating pump 46 is not the lower limit (step S577; No), the rotation speed of the heating pump 46 is reduced by a predetermined amount (step S579), the process returns to step S574, and the heating operation using heat storage is continued.

When the rotation speed of the heating pump 46 is the lower limit (step S577; Yes), or when there is no hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S574; No), the heat storage pump 57 is turned off. The heating operation using heat storage is stopped (step S580). Then, the heating switching valve 44 is switched to the combustion side, the rotation speed of the heating pump 46 is returned to normal, and the heating combustion operation is started (step S581).

After that, when the heating operation is turned off by the remote control operation (step S582), the heating switching valve 44 is set to the combustion side, the heating pump 46 is stopped, and the heating combustion operation is stopped (step S583).

FIG. 30 is a flow chart showing a heating operation when the control policy 5, the control policy 4, and the control policy 2 are combined. When the heating operation is turned on by the remote controller (step S601), the control unit 60 turns on the heating pump 46 (step S602). Then, it is determined whether or not the temperature of the hot water in the heating circuit is equal to or lower than a predetermined threshold value (step S603). If the temperature of the hot water in the heating circuit is not equal to or lower than a predetermined threshold value (step S603; No), the process proceeds to step S622 to perform the heating combustion operation.

If the temperature of the hot water in the heating circuit is equal to or lower than a predetermined threshold value (step S603; Yes), it is determined whether or not there is hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S604). If there is no hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S604; No), the process proceeds to step S622 to perform heating combustion operation.

If there is hot water at 60 ° C above the hot water storage tank 10 (step S604; Yes), the heat storage utilization pump 57 is turned on, the heating switching valve 44 is set to the heat storage side, and the tank return three-way valve 55 is set to the lower position. , The heat storage utilization heating operation is started with the rotation speeds of the heat storage utilization pump 57 and the heating pump 46 as normal rotation speeds (step S605).

During the heat storage utilization heating operation, the temperature in the heating circuit, the hot water temperature at the upper part of the hot water storage tank 10, and the return temperature from the water-water heat exchanger 50 to the hot water storage tank 10 are monitored. If the temperature in the heating circuit is not below the threshold value (step S606; No) or if there is no hot water of 60 ° C. or higher above the hot water storage tank 10 (step S607; No), the process proceeds to step S621 to perform the heat storage utilization heating operation. Stop.

The temperature in the heating circuit is below the threshold value (step S606; Yes), there is hot water of 60 ° C. or higher above the hot water storage tank 10 (step S607; Yes), and the return temperature to the hot water storage tank 10 is less than 40 ° C. (step S608). During No), the heating operation using heat storage is continued.

The temperature in the heating circuit is below the threshold value (step S606; Yes), and there is hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S607; Yes), but the return temperature to the lower part of the hot water storage tank 10 becomes 40 ° C. or higher. Then (step S608; Yes), it is examined whether or not the rotation speed of the heat storage utilization pump 57 has reached the lower limit (step S609). If the rotation speed of the heat storage utilization pump 57 is not the lower limit (step S609; No), the rotation speed of the heat storage utilization pump 57 is reduced by a predetermined amount (step 611), the process returns to step S606, and the heat storage utilization heating operation is continued.

If the rotation speed of the heat storage pump 57 is already the lower limit (step S609; Yes), it is checked whether or not the rotation speed of the heating pump 46 is the lower limit (step S610). If the rotation speed of the heating pump 46 is not the lower limit (step S610; No), the rotation speed of the heating pump 46 is reduced by a predetermined amount (step S612), the process returns to step S606, and the heating operation using heat storage is continued.

When the rotation speed of the heating pump 46 is the lower limit (step S610; Yes), the tank return three-way valve 55 is switched to the intermediate side, and both the heat storage utilization pump 57 and the heating pump 46 are returned to the normal rotation speed (step S613). After that, the temperature in the heating circuit, the hot water temperature at the upper part of the hot water storage tank 10, and the return temperature to the middle part of the hot water storage tank 10 are monitored.

The temperature in the heating circuit is below the threshold value (step S614; Yes), there is hot water of 60 ° C. or higher at the upper part of the hot water storage tank 10 (step S615; Yes), and the return temperature to the middle part of the hot water storage tank 10 is less than 50 ° C. During (step S616; No), the heating operation using heat storage is continued as it is.

The temperature in the heating circuit is below the threshold value (step S614; Yes), and there is hot water of 60 ° C. or higher above the hot water storage tank 10 (step S615; Yes), but the return temperature to the middle part of the hot water storage tank 10 is 50 ° C. or higher. (Step S616; Yes), it is checked whether or not the rotation speed of the heat storage utilization pump 57 has reached the lower limit (step S617). If the rotation speed of the heat storage utilization pump 57 is not the lower limit (step S617; No), the rotation speed of the heat storage utilization pump 57 is reduced by a predetermined amount (step 619), the process returns to step S614, and the heat storage utilization heating operation is continued.

If the rotation speed of the heat storage pump 57 is already the lower limit (step S617; Yes), it is checked whether or not the rotation speed of the heating pump 46 is the lower limit (step S618). If the rotation speed of the heating pump 46 is not the lower limit (step S618; No), the rotation speed of the heating pump 46 is reduced by a predetermined amount (step S620), the process returns to step S614, and the heating operation using heat storage is continued.

When the rotation speed of the heating pump 46 is the lower limit (step S618; Yes), or when the temperature in the heating circuit exceeds the threshold value (step S614; No), or there is no hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10. When the state is reached (step S615; No), the heat storage utilization pump 57 is turned off and the heat storage utilization heating operation is stopped (step S621). Then, the heating switching valve 44 is switched to the combustion side, the rotation speed of the heating pump 46 is returned to normal, and the heating combustion operation is started (step S622).

After that, when the heating operation is turned off by the remote control operation (step S623), the heating switching valve 44 is set to the combustion side, the heating pump 46 is stopped, and the heating combustion operation is stopped (step S624).

FIG. 31 shows the flow of heating operation when the control policy 5, the control policy 4, the control policy 2, and the control policy 1 are combined. The same process as in FIG. 30 is assigned the same step number as in FIG. 30, and the description thereof will be omitted. In the process of FIG. 31, after step S604, as a process corresponding to the control policy 1, there is a step S604-01 for checking whether the fuel cell 2 has stopped power generation, and a schedule for using hot water supply by the next power generation schedule. A step S604-02 for checking whether or not there is is added. Others are the same as in FIG.

FIG. 32 shows the flow of the heating operation when the control policy 5, the control policy 4, and the control policy 3 are combined. When the heating operation is turned on by the remote controller (step S631), the control unit 60 turns on the heating pump 46, sets the heating switching valve 44 on the combustion side, and starts the heating combustion operation (step S632).

During the heating combustion operation, the required heating temperature and the hot water temperature at the upper part of the hot water storage tank 10 are monitored. The heating temperature is not required to be 40 ° C (60 ° C required) (step S633; No), or the heating temperature is required to be 40 ° C (step S633; Yes), but there is no hot water above 40 ° C at the top of the hot water storage tank 10 (step S634; If No), the heating combustion operation is continued.

When there is a request for a heating temperature of 40 ° C. (step S633; Yes) and there is hot water of 40 ° C. or higher above the hot water storage tank 10 (step S634; Yes), the heating combustion operation is stopped (heating heat). Turn off the burner for the exchanger 39), turn on the heat storage utilization pump 57, switch the heating switching valve 44 to the heat storage side, switch the tank return three-way valve 55 to the lower side, and set the heat storage utilization pump 57 and the heating pump 46 to the normal rotation speed. It is set and the heating operation using heat storage is started (step S635).

During the heat storage utilization heating operation, the hot water temperature at the upper part of the hot water storage tank 10 and the return temperature from the water-water heat exchanger 50 to the lower part of the hot water storage tank 10 are monitored. If there is no hot water of 40 ° C. or higher in the upper part of the hot water storage tank 10 (step S636; No), the process proceeds to step S649, the heat storage utilization heating operation is stopped, and the heating combustion operation is switched to.

While there is hot water of 40 ° C or higher in the upper part of the hot water storage tank 10 (step S636; Yes) and the return temperature to the lower part of the hot water storage tank 10 is less than 30 ° C (step S637; No), the heating operation using heat storage is continued as it is. do. When there is hot water of 40 ° C. or higher in the upper part of the hot water storage tank 10 (step S636; Yes) and the return temperature to the lower part of the hot water storage tank 10 becomes 30 ° C. or higher (step S637; Yes), the rotation speed of the heat storage utilization pump 57 increases. It is checked whether or not the lower limit has been reached (step S638).

If the rotation speed of the heat storage utilization pump 57 is not the lower limit (step S638; No), the rotation speed of the heat storage utilization pump 57 is reduced by a predetermined amount (step S640), the process returns to step S636, and the heat storage utilization heating operation is continued. If the rotation speed of the heat storage pump 57 is already the lower limit (step S638; Yes), it is checked whether or not the rotation speed of the heating pump 46 is the lower limit (step S639). If the rotation speed of the heating pump 46 is not the lower limit (step S639; No), the rotation speed of the heating pump 46 is reduced by a predetermined amount (step S641), the process returns to step S6367, and the heating operation using heat storage is continued.

When the rotation speed of the heating pump 46 is the lower limit (step S639; Yes), the tank return three-way valve 55 is switched to the intermediate position, and both the heat storage utilization pump 57 and the heating pump 46 are returned to the normal rotation speed (step S642). After that, the hot water temperature at the upper part of the hot water storage tank 10 and the return temperature to the middle part of the hot water storage tank 10 are monitored.

While there is hot water of 40 ° C or higher at the top of the hot water storage tank 10 (step S643; Yes) and the return temperature from the water-water heat exchanger 50 to the middle part of the hot water storage tank 10 is less than 40 ° C (step S644; No). Continues the heating operation using heat storage as it is. There is hot water of 40 ° C or higher in the upper part of the hot water storage tank 10 (step S643; Yes), but when the return temperature to the middle part of the hot water storage tank 10 becomes 40 ° C or higher (step S644; Yes), the heat storage utilization pump 57 It is examined whether or not the rotation speed has reached the lower limit (step S645).

If the rotation speed of the heat storage utilization pump 57 is not the lower limit (step S645; No), the rotation speed of the heat storage utilization pump 57 is reduced by a predetermined amount (step S647), the process returns to step S643, and the heat storage utilization heating operation is continued. If the rotation speed of the heat storage pump 57 is already the lower limit (step S645; Yes), it is checked whether or not the rotation speed of the heating pump 46 is the lower limit (step S646). If the rotation speed of the heating pump 46 is not the lower limit (step S646; No), the rotation speed of the heating pump 46 is reduced by a predetermined amount (step S648), the process returns to step S643, and the heating operation using heat storage is continued.

When the rotation speed of the heating pump 46 is the lower limit (step S646; Yes), or when there is no hot water of 40 ° C. or higher in the upper part of the hot water storage tank 10 (step S643; No), the heat storage pump 57 is turned off. The heating operation using heat storage is stopped, the heating switching valve 44 is switched to the combustion side, the rotation speed of the heating pump 46 is returned to normal, and the heating combustion operation is started (step S649).

After that, when the heating operation is turned off by the remote control operation (step S650), the heating switching valve 44 is set to the combustion side, the heating pump 46 is stopped, and the heating combustion operation is stopped (step S651).

FIG. 33 shows the flow of the heating operation when the control policy 5, the control policy 4, the control policy 3, and the control policy 1 are combined. The same process as in FIG. 32 is assigned the same step number as in FIG. 32, and the description thereof will be omitted. In the process of FIG. 33, after step S634, as a process corresponding to the control policy 1, there is a step S634-01 for checking whether the fuel cell 2 has stopped power generation, and a schedule for using hot water supply by the next power generation schedule. A step S634-02 for checking whether or not there is is added. Others are the same as in FIG. 32.

34 and 35 show the flow of heating operation when the control policy 5, the control policy 4, the control policy 3, and the control policy 2 are combined. When the heating operation is turned on by the remote controller (step S661), the control unit 60 turns on the heating pump 46 (step S662). Then, it is determined whether or not the temperature of the hot water in the heating circuit is equal to or lower than a predetermined threshold value (step S663). If the temperature of the hot water in the heating circuit is not equal to or lower than a predetermined threshold value (step S663; No), the process proceeds to step S669 and the heating combustion operation is performed.

If the temperature of the hot water in the heating circuit is equal to or lower than a predetermined threshold value (step S663; Yes), it is determined whether or not there is hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S664). If there is no hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S664; No), the process proceeds to step S669 and the heating combustion operation is performed.

If there is hot water at 60 ° C. above the hot water storage tank 10 (step S664; Yes), the heat storage utilization pump 57 is turned on, the heating switching valve 44 is set to the heat storage side, and the heat storage utilization heating operation is started (step S665). ..

During the heat storage utilization heating operation, whether or not the temperature in the heating circuit is below the threshold value (step S666), whether or not there is hot water of 60 ° C. or higher above the hot water storage tank 10 (step S667), water-. Whether or not the return temperature from the water heat exchanger 50 to the lower part of the hot water storage tank 10 has reached 40 ° C. or higher (step S668) is monitored.

The temperature in the heating circuit is below the threshold value (step S666; Yes), there is hot water of 60 ° C. or higher in the upper part of the hot water storage tank 10 (step S667; Yes), and the return temperature to the lower part of the hot water storage tank 10 is less than 40 ° C. In the case (step S668; No), the heating operation using heat storage is continued as it is.

When the temperature in the heating circuit is not below the threshold value (step S666; No), or when the temperature of the hot water in the upper part of the hot water storage tank 10 becomes less than 60 ° C. (step S667; No), or the return to the lower part of the hot water storage tank 10. When the temperature becomes 40 ° C. or higher (step S668; Yes), the heat storage utilization pump 57 is stopped and the heat storage utilization heating operation is stopped (step S669). Then, the heating switching valve 44 is switched to the combustion side that bypasses the secondary side heat exchange pipe 52 of the water-water heat exchanger 50, and the heating combustion operation is started (step S670).

During the heating combustion operation, the required heating temperature and the temperature of the hot water in the upper part of the hot water storage tank 10 are monitored. The heating temperature is not required to be 40 ° C (60 ° C required) (step S671; No), or the heating temperature is required to be 40 ° C (step S671; Yes), but there is no hot water above 40 ° C at the top of the hot water storage tank 10 (step S672; If No), the heating combustion operation is continued.

When the room temperature rises and the heating temperature is required to be 40 ° C. (step S671; Yes), and when there is hot water of 40 ° C. or higher above the hot water storage tank 10 (step S672; Yes), the heating combustion operation is stopped (heating). (Turn off the burner for the heat exchanger 39), turn on the heat storage utilization pump 57, switch the heating switching valve 44 to the heat storage side, switch the tank return three-way valve 55 to the lower position, and switch the heat storage utilization pump 57 and the heating pump 46 to the normal position. The heating operation using heat storage is started by setting the number of rotations of (step S673).

During the heat storage utilization heating operation, the hot water temperature at the upper part of the hot water storage tank 10 and the return temperature from the water-water heat exchanger 50 to the hot water storage tank 10 are monitored. When the hot water of 40 ° C. or higher runs out in the upper part of the hot water storage tank 10 (step S674; No), the process proceeds to step S687, the heat storage utilization heating operation is terminated, and the heating combustion operation is switched to.

As long as there is hot water of 40 ° C or higher above the hot water storage tank 10 (step S674; Yes) and the return temperature to the hot water storage tank 10 is less than 30 ° C (step S675; No), the heating operation using heat storage is continued as it is. .. There is hot water of 40 ° C or higher in the upper part of the hot water storage tank 10 (step S674; Yes), but when the return temperature to the lower part of the hot water storage tank 10 becomes 30 ° C or higher (step S675; Yes), the rotation speed of the heat storage pump 57 increases. It is checked whether or not the lower limit has been reached (step S676).

If the rotation speed of the heat storage utilization pump 57 is not the lower limit (step S676; No), the rotation speed of the heat storage utilization pump 57 is reduced by a predetermined amount (step S678), the process returns to step S674, and the heat storage utilization heating operation is continued. If the rotation speed of the heat storage pump 57 is already the lower limit (step S676; Yes), it is checked whether or not the rotation speed of the heating pump 46 is the lower limit (step S677). If the rotation speed of the heating pump 46 is not the lower limit (step S677; No), the rotation speed of the heating pump 46 is reduced by a predetermined amount (step S679), the process returns to step S6674, and the heating operation using heat storage is continued.

When the rotation speed of the heating pump 46 is the lower limit (step S677; Yes), the tank return three-way valve 55 is switched to the intermediate side, and both the heat storage utilization pump 57 and the heating pump 46 are returned to the normal rotation speed (step S680). After that, the temperature of the hot water at the upper part of the hot water storage tank 10 and the return temperature to the middle part of the hot water storage tank 10 are monitored.

While there is hot water of 40 ° C or higher at the top of the hot water storage tank 10 (step S681; Yes) and the return temperature from the water-water heat exchanger 50 to the middle part of the hot water storage tank 10 is less than 40 ° C (step S682; No). Continues the heating operation using heat storage as it is. There is hot water of 40 ° C or higher at the top of the hot water storage tank 10 (step S681; Yes), but when the return temperature to the middle part of the hot water storage tank 10 reaches 40 ° C or higher (step S682; Yes), the rotation of the heat storage pump 57 Check whether the number has reached the lower limit (step S683).

If the rotation speed of the heat storage utilization pump 57 is not the lower limit (step S683; No), the rotation speed of the heat storage utilization pump 57 is reduced by a predetermined amount (step S685), the process returns to step S681, and the heat storage utilization heating operation is continued. If the rotation speed of the heat storage pump 57 is already the lower limit (step S683; Yes), it is checked whether or not the rotation speed of the heating pump 46 is the lower limit (step S684). If the rotation speed of the heating pump 46 is not the lower limit (step S684; No), the rotation speed of the heating pump 46 is reduced by a predetermined amount (step S686), the process returns to step S681, and the heating operation using heat storage is continued.

When the rotation speed of the heating pump 46 is the lower limit (step S684; Yes), or when there is no hot water of 40 ° C. or higher in the upper part of the hot water storage tank 10 (step S681; No), the heat storage pump 57 is turned off. The heating operation using heat storage is stopped, the heating switching valve 44 is switched to the combustion side, the rotation speed of the heating pump 46 is returned to normal, and the heating combustion operation is started (step S687).

After that, when the heating operation is turned off by the remote control operation (step S688), the heating switching valve 44 is set to the combustion side, the heating pump 46 is stopped, and the heating combustion operation is stopped (step S689).

36 and 37 show the flow of heating operation when the control policy 5, the control policy 4, the control policy 3, the control policy 2, and the control policy 1 are combined. In FIG. 36, the same processing as in FIG. 34 is assigned the same step number as in FIG. 34, and the description thereof will be omitted. In the process of FIG. 36, after step S664, as a process corresponding to the control policy 1, there is a step S664-01 for checking whether the fuel cell 2 has stopped power generation, and a schedule for using hot water supply by the next power generation schedule. A step S664-02 for checking whether or not there is is added. Further, in FIG. 37, the same processing as in FIG. 35 is assigned the same step number as in FIG. 35, and the description thereof will be omitted. In the process of FIG. 37, after step S672, as a process corresponding to the control policy 1, step S672-01 for checking whether the fuel cell 2 is stopped in power generation and a schedule for using hot water supply by the next power generation schedule are scheduled. A step S672-02 for checking whether or not there is is added.

Although the embodiment of the present invention has been described above with reference to the drawings, the specific configuration is not limited to that shown in the embodiment, and there are changes and additions within a range that does not deviate from the gist of the present invention. Is also included in the present invention.

The configuration of the waste heat utilization system 8 shown in FIG. 1 of the embodiment is an example, and for example, the heat source to be exhausted heat does not have to be the fuel cell 2. Further, in the hot water supply heater 30, the floor heating mat 40 is used as a radiator, but the present invention is not limited to this, and for example, a heating device installed indoors, a bathroom heating device, or the like may be used. It may be a radiator that is not intended for heating.

The water heater 30 may be provided with an automatic bath operation and a reheating function.

2 ... Fuel cell 8 ... Exhaust heat utilization system 10 ... Hot water storage tank 11 ... Water supply port 12 ... Hot water outlet 14 ... Lower intake port 15 ... Upper return port 16 ... Upper intake port 17 ... Lower return port 18 ... Intermediate return port 20 ... Exhaust Heat recovery unit 21 ... Heat exchanger for exhaust heat recovery 22 ... Circulation pump for exhaust heat recovery 24 ... Heat recovery low temperature piping 25 ... Heat recovery high temperature piping 26 ... Heat recovery low temperature side temperature sensor 27 ... Heat recovery high temperature side temperature sensor 30 ... Hot water supply heater 31 ... Water supply connection port 32 ... Hot water supply heat exchanger 33 ... Hot water supply temperature sensor 34 ... Backup heat source machine piping 35 ... Mixer 36 ... Water supply branch pipe 37 ... Tank outlet temperature sensor 38 ... Mixing temperature sensor 39 ... For heating Heat exchanger 40 ... Floor heating mat 41 ... Heating going pipe 42 ... Exhaust heat utilization pipe 43 ... Heating return piping 44 ... Heating switching valve 45 ... Exhaust heat utilization bypass pipe 46 ... Heating pump 47 ... Heating return temperature sensor 48 ... Heating going Temperature sensor 50 ... Water-water heat exchanger 51 ... Primary side heat exchange piping 52 ... Secondary side heat exchange piping 53 ... Exhaust heat utilization high temperature piping 54 ... Exhaust heat utilization low temperature piping 55 ... Tank return three-way valve 56 ... Tank intermediate return Pipe 57 ... Heat storage pump 58 ... Tank return temperature sensor 60 ... Control unit 71 ... Water supply pipe

Claims (6)

A hot water storage tank to which water is supplied from the lower part, a waste heat recovery unit for returning the water taken out from the lower part of the hot water storage tank to the upper part of the hot water storage tank after recovering the exhaust heat of a predetermined generator and raising the temperature.
The heat exchanger of the auxiliary heat source machine, the radiator, the secondary side of the water-water heat exchanger, and the heat dissipation circuit in which the heat medium fluid circulates via the first circulation pump.
A heat storage utilization circulation circuit that returns from the upper part of the hot water storage tank to the lower part of the hot water storage tank via the primary side of the water-water heat exchanger and the second circulation pump.
When the heat dissipation operation is performed by the radiator, the heat medium fluid is circulated in the heat dissipation circuit and the circulating heat medium fluid is heated by the auxiliary heat source machine, and the heat medium fluid is used in the heat radiation circuit. Is circulated and the hot water in the hot water storage tank is circulated to the heat storage utilization circulation circuit so as to return from the upper part of the hot water storage tank to the lower part of the hot water storage tank via the primary side of the water-water heat exchanger. A control unit that selects and executes one of the operations,
Equipped with
In the heat dissipation operation, the control unit selects the heat storage utilization operation if the predetermined conditions are not satisfied even when hot water having a temperature that can be used for the heat storage utilization operation exists in the upper part of the hot water storage tank. The waste heat utilization system is characterized in that the generator is stopped and the hot water is scheduled to be supplied from the hot water storage tank by the next scheduled operation time of the generator. The control unit has the first circulation pump and the first circulation pump so that the temperature of water returning to the hot water storage tank via the primary side of the water-water heat exchanger does not exceed a predetermined temperature in the heat storage utilization operation. 2 Adjust the circulation amount of either one or both of the circulation pumps.
The waste heat utilization system according to claim 1. With a hot water storage tank where water is supplied from the bottom
A waste heat recovery unit that recovers the waste heat of a predetermined generator, raises the temperature of the water taken out from the lower part of the hot water storage tank, and then returns the water to the upper part of the hot water storage tank.
The heat exchanger of the auxiliary heat source machine, the radiator, the secondary side of the water-water heat exchanger, and the heat dissipation circuit in which the heat medium fluid circulates via the first circulation pump.
A heat storage utilization circulation circuit that returns from the upper part of the hot water storage tank to the lower part of the hot water storage tank via the primary side of the water-water heat exchanger and the second circulation pump.
When the heat dissipation operation is performed by the radiator, the heat medium fluid is circulated in the heat dissipation circuit and the circulating heat medium fluid is heated by the auxiliary heat source machine, and the heat medium fluid is used in the heat radiation circuit. Is circulated and the hot water in the hot water storage tank is circulated to the heat storage utilization circulation circuit so as to return from the upper part of the hot water storage tank to the lower part of the hot water storage tank via the primary side of the water-water heat exchanger. A control unit that selects and executes one of the operations,
Equipped with
In the heat dissipation operation, the control unit selects the heat storage utilization operation if the predetermined conditions are not satisfied even when hot water having a temperature that can be used for the heat storage utilization operation exists in the upper part of the hot water storage tank. In addition, in the heat storage utilization operation, the first circulation pump and the second circulation so that the temperature of the water returning to the hot water storage tank via the primary side of the water-water heat exchanger does not exceed a predetermined temperature. Adjust the circulation volume of both pumps
A waste heat utilization system characterized by this. The waste heat utilization system according to any one of claims 1 to 3, wherein the predetermined condition includes that the temperature of the heat medium fluid in the heat dissipation circuit is equal to or lower than the predetermined temperature. The required temperature for the heat dissipation operation includes a first required temperature and a second required temperature lower than the first required temperature.
The waste heat utilization system according to any one of claims 1 to 4 , wherein the predetermined condition includes the required temperature of the heat dissipation operation being the second required temperature. The return position when returning the water after passing through the primary side of the water-water heat exchanger to the hot water storage tank in the heat storage utilization circulation circuit is set to the lower part of the hot water storage tank or above the lower part of the hot water storage tank. A return position switching part for switching whether to use the middle part of the hot water storage tank in the above is provided.
In the heat storage utilization operation, when the temperature of the water returning to the hot water storage tank via the primary side of the water-water heat exchanger is equal to or lower than the first temperature, the control unit sends the water to the lower part of the hot water storage tank. When the temperature of the returned water exceeds the first temperature, the switching unit is controlled so that the water that has passed through the primary side of the water-water heat exchanger is returned to the middle portion of the hot water storage tank. The waste heat utilization system according to any one of claims 1 to 5, which is characterized.

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