JP4160066B2 - Cogeneration system - Google Patents

Description

  The present invention relates to a cogeneration system that generates electric power according to electric power demand, stores generated power generated by the power generation, and supplies the stored thermal energy when necessary.

  Cogeneration systems are widespread. In many cogeneration systems, a power generation unit that generates power, a hot water storage tank that stores hot water, and a hot water circulation that sends the cold water in the hot water storage tank to the power generation unit and returns the hot water heated while passing through the power generation unit to the hot water storage tank. A route, a hot water supply route for sending hot water in the hot water storage tank to the hot water use location, and a heater for heating cold water (or hot water) flowing through the hot water supply route as needed are provided. When the cogeneration system performs a power generation operation, cold water is taken out from the hot water tank and sent to the power generation unit. The cold water sent to the power generation unit is heated by the generated heat generated by the power generation unit, and the heated hot water is returned to the hot water storage tank.

  Hot water stored in the hot water tank is adjusted to the required temperature when necessary, and is supplied to hot water usage points (hot water tap, bathtub, shower, etc.). If hot water having a temperature higher than the hot water temperature required at the hot water use location is stored in the hot water storage tank, the hot water sent from the hot water storage tank is mixed with tap water (cold water) to cool to the required temperature and hot water is supplied. If hot water having a temperature lower than the hot water temperature required at the hot water use location is stored in the hot water storage tank, the hot water is heated by a heater. Even when heating with a heater, the amount of heat required is smaller than when heating tap water. The cogeneration system has high overall energy efficiency and can reduce running costs for hot water supply.

  As a heater for heating a hot water supply path, there is one that uses a heat exchanger that exchanges heat between a high-temperature heat medium and hot water in a hot water supply path. Such a system includes a heat source device that heats the heat medium, a heat medium circulation path through which the heat medium circulates, and a heat exchanger that exchanges heat between the heat medium circulation path and the hot water supply path. The heat source is heated by the heat source device, and the heat medium is circulated in the heat medium circulation path to supply the high-temperature heat medium to the heat exchanger, and hot water passing through the hot water supply path is required by heat exchange with the heat medium. Heat to the desired temperature.

  In the cogeneration system that heats the hot water supply path using the heat exchanger described above, the high-temperature heat medium heated by the heat source device can be used for other purposes (such as heating and bathing). Hot water supply, heating and reheating can be performed using only one heat source machine as a heating source, and space saving of equipment can be achieved. Moreover, since the surplus heat quantity which the heat medium has at the end of hot water supply can be used for other purposes, overall energy efficiency can be improved.

  In the above-mentioned cogeneration system, when the hot water in the hot water tank is used up, hot water pumped out of the hot water tank is mixed with tap water to supply hot water whose temperature is adjusted (hereinafter referred to as heat storage hot water). The hot water pumped out from the hot water tank is switched to a state in which hot water is heated by a heater (hereinafter referred to as combustion hot water supply). When performing this switching, there is a problem that the temperature of the hot water supplied is difficult to stabilize. In combustion hot water supply, a certain amount of time is required from the start of the operation of the heat source machine until the heat medium is heated to a high temperature and the high temperature heat medium is supplied to the heat exchanger. Therefore, when the above-mentioned switching is performed, the low-temperature hot water drawn from the hot water tank is provided to the hot-water supply location without being sufficiently heated, and the hot-water temperature is temporarily lowered and the hot-water temperature is not stable. was there.

Therefore, a technology for stabilizing the hot water temperature has been developed in the cogeneration system.
Patent Document 1 discloses a cogeneration system that stabilizes a hot water supply temperature by keeping a heat medium used as a heat source for hot water supply, heating, or reheating at a predetermined temperature. In this cogeneration system, the temperature of the heat medium is constantly observed, and when the temperature of the heat medium is less than a predetermined temperature, the heat source that heats the heat medium is burned to heat the heat medium. When the temperature of the heat medium exceeds a predetermined temperature, the combustion of the heat source machine is stopped and the heating of the heat medium is ended. As a result, the temperature of the heat medium is always maintained at a predetermined temperature or higher, and the hot water pumped out of the hot water tank can be immediately heated even immediately after switching to the combustion hot water supply. It is possible to suppress the temperature drop of the heat medium due to heat radiation and to enhance the temperature rise characteristics when shifting to hot water supply, heating or reheating.
Patent Document 2 discloses a cogeneration system that stabilizes the hot water temperature by securing a heat storage amount in a hot water storage tank. In this cogeneration system, at the end of combustion hot water supply, the hot water is further heated in preparation for the next hot water supply, and the hot water obtained by continuing is supplied to the hot water storage tank. A technique is disclosed in which hot water is always stored in a hot water storage tank by storing hot hot water in the hot water storage tank in advance.

JP 2003-130448 A JP 2004-125300 A

In the technique described in Patent Document 1, the heat source device must be driven periodically in order to keep the heat medium warm even during periods when hot water supply, heating, or bathing is not performed.
In the technique described in Patent Document 2, heating by a heat source device is required to secure a heat storage amount in a hot water storage tank even after hot water supply is completed.
In any technique, it is necessary to drive the heat source unit in order to maintain the hot water temperature in a period when the hot water supply system is not used, which is not rational from the viewpoint of energy saving. We want to realize a more energy efficient system while ensuring the convenience for users by stabilizing the hot water supply temperature.
The present invention solves the above problems. The present invention provides a cogeneration system that can supply hot water at a stable hot water temperature and is excellent in energy efficiency.

The system of the present invention is a cogeneration system that generates electric power according to electric power demand, stores generated heat generated with the power generation, and supplies the stored thermal energy when necessary.
The cogeneration system includes a hot water storage tank for storing hot water, a hot water supply path for supplying hot water from the hot water storage tank to a hot water use location, a circulation path for circulating the heat medium, a heat source device for heating the heat medium flowing through the circulation path, A first temperature sensor for detecting the temperature of the heat medium flowing through the circulation path, a first heat exchanger for exchanging heat between the hot water flowing through the hot water supply path and the heat medium flowing through the circulation path, and a first for circulating the heat medium. A drive means, a power generation unit for generating power, a cooling water forward path for supplying cooling water to the power generation unit, a cooling water return path for supplying cooling water heated by the power generated by the power generation unit to the hot water storage tank, and a cooling water return path A second heat exchanger for exchanging heat between the flowing cooling water and the heat medium flowing through the circulation path; a second driving means for circulating the cooling water; and a controller for controlling the first driving means and the second driving means. Preparation There.
When the power generation unit is generating power, the controller drives the second drive means to circulate cooling water, and the temperature generated by the power generation unit and detected by the first temperature sensor is the first predetermined temperature. If the value is less than the value, the first drive means is driven to circulate the heat medium.

Said cogeneration system supplies cooling water to a power generation unit, and supplies the cooling water heated with the generated heat to a hot water storage tank. The heated cooling water is stored as hot water in a hot water tank, and the stored hot water is provided to a hot water use location when hot water is supplied.
When the temperature of the hot water stored in the hot water storage tank is low and hot water having a temperature required for not heating the hot water cannot be provided to the hot water use location, the above cogeneration system performs combustion hot water supply. At the time of combustion hot water supply, heating by the heat source device is started, the heat medium in the circulation path is circulated by the first driving means, and the heated heat medium and the hot water pumped out of the hot water storage tank are heated by the first heat exchanger. Let them exchange. As a result, the hot water pumped out of the hot water storage tank is heated to the required temperature and provided to the hot water use location.

The above cogeneration system may heat the heat medium using the heated cooling water and keep the heat medium warm before supplying the cooling water heated by the generated heat to the hot water storage tank. it can.
The temperature of the heat medium is detected by the first temperature sensor. When the temperature of the heat medium is low, the heat medium is circulated in the circulation path, and the cooling water heated by the generated heat by the second heat exchanger is used. And heat exchange with the heat medium. When the temperature of the heat medium is high, the heat medium is not circulated in the circulation path, and the cooling water heated by the generated heat is supplied to the hot water storage tank without performing heat exchange by the second heat exchanger.
In the above cogeneration system, the temperature of the heat medium is kept at a predetermined temperature. For this reason, even immediately after the start of combustion hot water supply, the hot water pumped out of the hot water tank can be immediately heated, and the hot water temperature can be stabilized.
According to the above cogeneration system, the heat medium can be kept warm using the generated heat. Since it is not necessary to drive the heat source device to keep the heat medium warm, energy saving can be realized while stabilizing the hot water temperature when the hot water runs out (when switching from heat storage hot water supply to combustion hot water supply).

  The cogeneration system includes a second temperature sensor that detects the temperature of the cooling water flowing through the cooling water return path downstream from the second heat exchanger, and a three-way valve that branches the cooling water return path downstream from the second temperature sensor; A first path for supplying the cooling water from the cooling water return path to the hot water storage tank via the three-way valve, and a second path for supplying the cooling water from the cooling water return path to the cooling water forward path via the three-way valve, In accordance with an instruction from the controller, the three-way valve communicates the cooling water return path and the first path and disconnects the cooling water return path and the second path, and communicates the cooling water return path and the second path with cooling water. The controller switches between a return path and a state in which the first path is not in communication, and the controller is configured to perform three-way operation when the power generation unit generates power and the temperature detected by the second temperature sensor exceeds the second predetermined value. Control the valve to return the cooling water to the cooling water return path When the temperature is supplied to the hot water storage tank, the power generation unit generates power, and the temperature detected by the second temperature sensor is less than the second predetermined value, the cooling water is controlled from the cooling water return path by controlling the three-way valve. It is preferable to supply to.

According to the above cogeneration system, only when the temperature of the cooling water flowing through the cooling water return path is high, the cooling water is introduced into the hot water storage tank, and when the temperature of the cooling water is low, the cooling water is supplied to the hot water storage tank. Without being allowed to flow into the cooling water.
Temperature stratification is formed inside the hot water tank, and the hot water stored in the hot water tank can be efficiently used for hot water supply by pumping out hot water from the upper part of the hot water tank during hot water supply. If low-temperature water is allowed to flow into this hot water tank, the temperature stratification will collapse, and the utilization efficiency of the heat stored in the hot water tank will be reduced.
According to the cogeneration system of the present invention, the heat stored in the hot water tank can be used efficiently by preventing the low temperature water from flowing into the hot water tank.

  In the above-mentioned cogeneration system, a part of the cooling water return path that reaches the hot water storage tank via the second heat exchanger also serves as a hot water supply path that passes from the hot water storage tank to the first heat exchanger. It is desirable that the exchanger also serves as the first heat exchanger.

  In the above cogeneration system, the cooling water heated by the power generation unit flows backward in the hot water supply path, passes through the first heat exchanger, and flows into the hot water storage tank. By setting it as such a structure, a 1st heat exchanger and a 2nd heat exchanger can be combined. The cogeneration system can be downsized.

  According to the cogeneration system of the present invention, it is possible to maintain hot water supply at a stable hot water temperature, and to realize a cogeneration system with high energy efficiency.

Hereinafter, preferred embodiments of the present invention will be described.
(Mode 1) The heat medium in the heat medium circulation path is water.
(Mode 2) The heat medium in the heat medium circulation path is used to heat the heater.
(Mode 3) For the case where the hot water temperature of the hot water storage tank is higher than the hot water temperature required at the hot water use location, a mixing unit for adjusting the temperature by mixing the hot water from the hot water tank and tap water is provided. The mixing unit is provided in the middle of the hot water supply path. The hot water supply path includes a first hot water supply path for sending hot water in the hot water storage tank to the mixing unit, and a second hot water supply path for sending the mixed water mixed in the mixing unit (hot water if not mixed) to the hot water use location.

  An embodiment embodying a cogeneration system of the present invention will be described with reference to the drawings. FIG. 1 is a system diagram of a cogeneration system 500 of the present embodiment. The cogeneration system 500 includes a power generation unit 100, a hot water supply system 10, and the like.

  The power generation unit 100 includes a fuel cell 114, a reformer 112, and a power generation heat medium circulation path 124. The fuel cell 114 has a plurality of fuel cells. The fuel cell 114 generates power by reacting the hydrogen gas supplied from the reformer 112 with oxygen in the air. When the fuel cell 114 generates power, it generates heat. The fuel cell 114 that has generated the generated heat is cooled by the heat medium passing through the power generation heat medium circulation path 124 and is maintained at an appropriate power generation temperature.

  The reformer 112 reforms the fuel gas supplied from the outside to generate hydrogen gas. The reformer 112 includes a burner 131, and reforms the fuel gas using the combustion heat of the burner 131. The generated hydrogen gas is supplied to the fuel cell 114 via the hydrogen gas path 121. High-temperature combustion gas generated by the combustion of the burner 131 is guided to the combustion gas path 126. The combustion gas path 126 is opened to the outside through the heat exchanger 116. The combustion gas guided to the combustion gas path 126 is cooled by the heat exchanger 116 and then discharged to the outside.

  The power generation heat medium circulation path 124 circulates pure water as a heat medium. The power generation heat medium circulation path 124 forms a circulation path that returns to the reserve tank 125 via the reserve tank 125, the heat medium three-way valve 122, the fuel cell 114, and the heat exchanger 118. The heating medium supplied from the reserve tank 125 is heated by the fuel cell 114, cooled by the heat exchanger 118, and returned to the reserve tank 125.

  The heat medium three-way valve 122 includes one inlet 122a and two outlets 122b and 122c. The heat medium three-way valve 122 switches between communication between the inlet 122a and the outlet 122b or communication between the inlet 122a and the outlet 122c. One end of a path 130 is connected to the outlet 122 c of the heat medium three-way valve 122. The other end of the path 130 is connected to the fuel cell 114. One end of a path 129 is connected to the outlet 122 b of the heat medium three-way valve 122. The other end of the path 129 is connected to the path 130. The heat medium (pure water) that has passed through the inlet 122a of the heat medium three-way valve 122 exits from the outlet 122b and is guided to the fuel cell 114 via the path 129 and path 130, or exits from the outlet 122c and passes the path 130. To the fuel cell 114.

  A heat medium radiator 120 is provided in the middle of the path 129. A heat medium cooling fan 119 is provided adjacent to the heat medium radiator 120. When the heat medium cooling fan 119 is operated, air is blown to the heat medium radiator 120 and the heat medium flowing through the path 129 is cooled.

  A heat medium temperature sensor 117 is connected downstream of the fuel cell 114 in the power generation heat medium circulation path 124. The heat medium temperature sensor 117 detects the temperature of the heat medium flowing through the power generation heat medium circulation path 124. The detection signal of the heat medium temperature sensor 117 is output to the controller 21 attached to the hot water supply system 10.

  When the fuel cell 114 is operated, the inlet 122a and the outlet 122c of the heat medium three-way valve 122 are communicated, and the heat medium pump 127 is driven. When the heat medium pump 127 is driven, the heat medium circulates through the power generation heat medium circulation path 124. As the heat medium circulates through the power generation heat medium circulation path 124, the generated heat is recovered from the fuel cell 114. The heat medium that has recovered the generated heat is cooled by the heat exchanger 118 and is circulated through the power generation heat medium circulation path 124 again.

  If the temperature of the heat medium detected by the heat medium temperature sensor 117 becomes too high, the heat generated by the heat medium radiator 120 is dissipated because the generated heat is not sufficiently recovered. The inlet 122a and outlet 122b of the heat medium three-way valve 122 are communicated with each other, and the heat medium cooling fan 119 is operated at the same time. When the inlet 122 a and the outlet 122 b of the heat medium three-way valve 122 communicate with each other, the heat medium flows into the path 129. The heat medium flowing into the path 129 passes through the heat medium radiator 120 and radiates heat by the air blown from the heat medium cooling fan 119. When the heat medium temperature detected by the heat medium temperature sensor 117 is lowered, the inlet 122a and the outlet 122c of the heat medium three-way valve 122 are communicated again. By repeating such switching of the heat medium three-way valve 122, the temperature of the heat medium is maintained within a predetermined range.

  The heat recovery path 128 heats water (cooling water) supplied from the hot water supply system 10 via the heat recovery forward path 128a by the heat exchanger 118 and the heat exchanger 116, and then passes through the heat recovery return path 128b. Return to hot water supply system 10.

  A power generation heat medium circulation path 124 and a heat recovery path 128 pass through the heat exchanger 118. The heat exchanger 118 exchanges heat between the heat medium in the power generation heat medium circulation path 124 and the water in the heat recovery path 128 that flow in directions opposite to each other. The water flowing through the heat recovery path 128 is heated by the heat medium in the power generation heat medium circulation path 124 by passing through the heat exchanger 118, and the temperature rises. The water flowing through the heat recovery path 128 passes through the heat exchanger 118 and is then sent to the heat exchanger 116.

  A combustion gas path 126 and a heat recovery path 128 pass through the heat exchanger 116. The heat exchanger 116 exchanges heat between the high-temperature combustion gas in the combustion gas passage 126 that flows in a direction opposite to each other and the water flowing in the heat recovery passage 128. The water flowing through the heat recovery path 128 is heated by the combustion gas flowing through the combustion gas path 126 by passing through the heat exchanger 116, and the temperature rises. The water flowing through the heat recovery path 128 passes through the heat exchanger 116 and is then sent to the heat recovery return path 128b.

  The reformer 112, the fuel cell 114, the burner 131, the heat medium three-way valve 122, the heat medium pump 127, and the heat medium cooling fan 119 described above are controlled by the controller 21 described later.

  The hot water supply system 10 includes a hot water storage tank 20, a mixing unit (mixer) 24, a burner (heat source device) 74, a cistern 63, heat exchangers 46 and 82, pumps 40, 71 and 95, a controller 21 and the like.

  A common path 26 for supplying tap water to the hot water tank 20 is connected to the bottom of the hot water tank 20. In the vicinity of the inlet 26a of the common path 26, a pressure reducing valve 28 and an opening / closing valve 28a are mounted. The pressure reducing valve 28 adjusts the feed water pressure. The on-off valve 28a is provided downstream of the pressure reducing valve 28, and is opened when water is supplied to the hot water supply system 10, and is closed when water supply is stopped.

  The downstream side of the on-off valve 28 a of the common path 26 and the water supply inlet 24 a of the mixing unit 24 are connected by a mixing unit water supply path 30. The pressure reducing valve 28 opens when the downstream pressure decreases, and tries to maintain the pressure at a predetermined pressure regulation value. When the hot water in the hot water storage tank 20 decreases or the water supply inlet 24a of the mixing unit 24 opens, the downstream pressure of the pressure reducing valve 28 decreases. For this reason, when the hot water in the hot water storage tank 20 decreases or the water supply inlet 24a of the mixing unit 24 opens, the pressure reducing valve 28 opens and tap water is supplied thereto. A heat recovery forward path 128 a is connected to the common path 26 between the on-off valve 28 a and the hot water tank 20.

  The water stored in the hot water tank 20 is adjusted to a pressure adjustment value by the pressure reducing valve 28. The hot water tank 20 is formed of a pressure resistant container that can withstand the pressure regulation value. An outlet 20a is provided at the upper part of the hot water tank 20, and a relief valve 31 is mounted thereon. The valve opening pressure of the relief valve 31 is set slightly higher than the pressure regulation value of the pressure reducing valve 28. When the pressure regulation of the pressure reducing valve 28 becomes impossible, the relief valve 31 is opened to prevent the pressure in the hot water tank 20 from exceeding the pressure resistance. One end of a pressure release path 32 is connected to the relief valve 31. The other end of the pressure release path 32 is open to the outside of the hot water tank 20.

  A drainage path 34 is disposed between the pressure release path 32 and the shared path 26 communicating with the bottom of the hot water tank 20. A drain valve 33 is inserted in the drain path 34. The drain valve 33 is controlled by the controller 21. When the drain valve 33 is opened with the on-off valve 28a closed, the water in the hot water tank 20 is drained to the outside through the common path 26, the drain path 34, and the pressure release path 32.

One end of the first hot water passage 42 is connected to the outlet 20 a at the top of the hot water tank 20. The other end of the first hot water path 42 is connected to the first inlet / outlet 48 a of the three-way valve 48.
The three-way valve 48 is controlled by the controller 21. The three-way valve 48 (1) opens the first inlet / outlet 48a and the second inlet / outlet 48b and closes the third inlet / outlet 48c, or (2) opens the second inlet / outlet 48b and the third inlet / outlet 48c and closes the first inlet / outlet 48a. Controlled by the state. How water flows in each state will be described later.

  One end of the second hot water passage 43 is connected to the second inlet / outlet 48 b of the three-way valve 48. The other end of the second hot water path 43 is connected to the hot water inlet 24 c of the mixing unit 24. The second hot water path 43 is disposed so as to pass through the heat exchanger 46. A heat recovery return path 128 b is connected to the second hot water path 43 between the heat exchanger 46 and the mixing unit 24. An exhaust heat recovery temperature sensor 45 is provided in the second hot water path 43 between the three-way valve 48 and the heat exchanger 46. The temperature detected by the exhaust heat recovery temperature sensor 45 is output to the controller 21.

  One end of the third hot water passage 44 is connected to the third inlet / outlet 48 c of the three-way valve 48. The other end of the third hot water path 44 is connected to the shared path 26.

  A pump 40 is connected to the heat recovery outward path 128a. The pump 40 is controlled by the controller 21. The three-way valve 48 is controlled to open the first port 48a and the second port 48b and close the third port 48c. When the pump 40 is driven, water flows as follows.

  Cold water is taken out from the lower part of the hot water tank 20. The extracted cold water returns from the upper part of the hot water tank 20 into the hot water tank 20 through the common path 26, the heat recovery forward path 128a, the heat recovery return path 128b, the second hot water path 43, and the first hot water path 42. That is, in this system 500, a circulation path is configured in which cold water taken out from the hot water storage tank 20 is heated while passing through the power generation unit 100, and the heated hot water returns to the hot water storage tank 20.

  The heat recovery path 128 (128a and 128b) passes through the heat exchanger 118 and the heat exchanger 116. Therefore, when the reformer 112 and the fuel cell 114 are operating, the water in the heat recovery path 128 is heated by the heat exchangers 116 and 118. The cold water taken out from the lower part of the hot water storage tank 20 is heated by the heat generated by the power generation unit 100 to raise the temperature. Then, the heated hot water is returned to the upper part of the hot water tank 20.

  As the hot water in the hot water storage tank 20 circulates through the power generation unit 100 as described above, hot hot water is stored in the hot water storage tank 20. When hot hot water is stored in the hot water tank 20, a state in which the high temperature layer is laminated on the upper part of the low temperature layer (called temperature stratification) is formed inside the hot water tank 20. The temperature difference between the high-temperature layer and the low-temperature layer forming the temperature stratification is large, and the temperature of water rapidly decreases in a portion deeper than the high-temperature layer. During power generation, when low-temperature water is sucked out from the bottom of the hot water tank 20 and high-temperature hot water continues to be returned to the top, the high-temperature layer does not cross with the low-temperature layer, and the thickness (depth) of the low-temperature layer gradually increases. It becomes smaller and the thickness (depth) of the high temperature layer becomes gradually larger. In a state where heat is completely stored in the hot water tank 20, hot hot water is stored in the entire hot water tank 20. By forming the temperature stratification, high-temperature hot water is sent out from the outlet portion 20a provided at the uppermost part of the hot water storage tank 20 even if the hot water storage tank 20 has not completely stored heat. When the hot water in the hot water tank 20 is used, hot hot water at the top of the hot water tank 20 is sucked out, and tap water enters from the bottom. In this case, the thickness (depth) of the high temperature layer is gradually reduced, and the thickness (depth) of the low temperature layer is gradually increased. When the hot water in the hot water tank 20 is used up, the hot water tank 20 is filled with tap water.

A hot water tank temperature sensor 35 is attached to a location 5 liters from the top of the hot water tank 20. The hot water tank temperature sensor 35 detects the temperature of the upper part in the hot water tank 20. Since the hot water tank temperature sensor 35 is attached to a considerably upper position, the temperature of the high temperature layer is detected unless the high temperature layer is extremely small. The detection signal of the hot water tank temperature sensor 35 is output to the controller 21. The temperature detected by the hot water tank temperature sensor 35 is used for hot water temperature control. It is also used for calculating the amount of heat stored in the hot water tank 20. The calculated heat storage amount is stored over time in a storage unit prepared in the controller 21.
In the present embodiment, only one hot water storage tank temperature sensor 35 is provided inside the hot water storage tank 20, but a temperature sensor may be further provided below the hot water storage tank temperature sensor 35. In this case, detected temperatures of a plurality of temperature sensors are used for various controls.

  The mixing unit 24 has a water supply inlet 24a, a hot water inlet 24c, a mixed water outlet 24b, a tap water temperature sensor 50, a hot water temperature sensor 51, a mixed water temperature sensor 52, a high-cut thermistor 53, a mixed water flow rate sensor 54, and a flow rate servo 55. is doing.

  Tap water flows from the mixing unit water supply path 30 into the water supply inlet 24a. The feed water inlet 24a is a flow rate adjustment valve (hereinafter also referred to as a feed water flow rate adjustment valve 24a) that can adjust the feed water flow rate by changing its opening. Hot water from the second hot water passage 43 flows into the hot water inlet 24c. The hot water inlet 24c is a flow rate adjustment valve (hereinafter sometimes referred to as a hot water flow rate adjustment valve 24c) that can adjust the hot water flow rate by changing its opening degree. The opening degree of the feed water flow rate adjustment valve 24a and the warm water flow rate adjustment valve 24c is controlled by the controller 21. The tap water flowing in from the feed water inlet 24a and the hot water flowing in from the hot water inlet 24c are mixed, and the mixed water flows out from the mixed water outlet 24b.

  The tap water temperature sensor 50 detects the temperature of tap water flowing into the feed water inlet 24a. The warm water temperature sensor 51 detects the temperature of warm water flowing into the warm water inlet 24c. The mixed water temperature sensor 52 and the high-cut thermistor 53 detect the temperature of the mixed water flowing out from the mixed water outlet 24b. The mixed water flow rate sensor 54 detects the flow rate of the mixed water flowing out from the mixed water outlet 24b. The flow rate servo 55 is a flow rate adjustment valve that can adjust the flow rate of the mixed water by changing its opening. The detection signals of the tap water temperature sensor 50, the hot water temperature sensor 51, the mixed water temperature sensor 52, the high cut thermistor 53, and the mixed water flow rate sensor 54 are output to the controller 21. The opening degree of the flow rate servo 55 is controlled by the controller 21.

  The controller 21 changes the opening degree of the hot water inlet 24c and the opening degree of the feed water inlet 24a using detection signals of the temperature sensors 35, 50, 51, 52, 75a (this thermistor will be described in detail later). When the opening degree of the hot water inlet 24c and the opening degree of the water supply inlet 24a are changed, the mixing ratio of hot water from the hot water tank 20 and tap water (cold water) is adjusted. When the mixing ratio of hot water from the hot water tank 20 and tap water is adjusted, the temperature of the mixed hot water flowing out from the mixed water outlet 24b is maintained at a predetermined value.

  When the high-cut thermistor 53 detects that the hot water greatly exceeds the predetermined value (that is, when there is a high possibility that the mixed water temperature sensor 52 or the mixing unit 24 has failed), the controller 21 24c is closed. When the hot water inlet 24c is closed, hot water having a temperature that greatly exceeds the predetermined value is prevented from being supplied.

  One end of a first mixed water path 60 is connected to the mixed water outlet 24 b of the mixing unit 24. The other end of the first mixed water path 60 is connected to the second mixed water path 61 and the third mixed water path 62.

  The third mixed water path 62 has one end connected to the first mixed water path 60 and the other end connected to the hot water tap 67. The hot water tap 67 is disposed in a bathroom, a washroom, a kitchen, or the like. In FIG. 1, the plurality of hot water taps are represented by one hot water tap 67. A remote controller 23 that can be operated by the user is provided in the vicinity of the hot water tap 67. In FIG. 1, the remote controller 23 is not disposed near the hot water tap 67 (the remote controller 23 is shown on the right side of the controller 21). The remote controller 23 is connected to the controller 21. The user can set a desired hot water temperature by operating the remote controller 23. Information input to the remote controller 23 is sent to the controller 21. The controller 21 controls the mixing unit 24, a pump 71 and a burner 74, which will be described later, so that hot water having a temperature set by the user is supplied.

  One end of the second mixed water path 61 is connected to the first mixed water path 60 and the other end is connected to the cistern 63. A makeup water valve 61 a is provided slightly upstream from the cistern 63 of the second mixed water path 61. The makeup water valve 61 a is controlled by the controller 21. The makeup water valve 61a opens and closes when a built-in solenoid is driven. When the replenishing water valve 61 a is opened, hot water from the mixing unit 24 is supplied to the cistern 63.

  The cistern 63 is a tank for storing water (hot water). In the cistern 63, water level electrodes 63a and 63b are mounted. The lower end of the water level electrode 63 a is located at the high level water level of the cistern 63. The lower end of the water level electrode 63 b is located at the low level water level of the cistern 63. The water level electrode 63a and the water level electrode 63b output a detection signal to the controller 21 when they are in contact with water. Based on the detection signals from the water level electrodes 63a and 63b, the controller 21 determines whether the water level of the cistern 63 is higher than the high level water level, between the high level water level and the low level water level, or lower than the low level water level. To do. What is appropriate as the systern 63 is a state where the water level is located between the high level and the low level. The controller 21 controls the opening and closing of the replenishing water valve 61a based on the detection signals from the water level electrodes 63a and 63b, and maintains the water level of the cistern 63 within an appropriate range.

  One end of a cistern forward path 70 is connected to the bottom of the cistern 63. A pump 71 is connected to the systern outbound path 70. The pump 71 is controlled by the controller 21. The other end of the cistern outward path 70 branches into a burner path 72 and a low temperature heating path 73.

  The burner path 72 can be heated by a gas combustion type burner 74. When the burner 74 is activated, the temperature of the water in the burner path 72 rises. A low temperature heating temperature sensor 75 a is connected to the burner path 72 upstream of the burner 74. A high temperature heating temperature sensor 75 b is connected to the burner path 72 downstream of the burner 74. These temperature sensors 75 a and 75 b detect the water temperature in the burner path 72. The temperature sensors 75 a and 75 b are connected to the controller 21. The water temperature detected by the temperature sensors 75a and 75b is taken into the controller 21.

  The other end of the burner path 72 branches into two paths 83 and 84. Below. The path 83 is called a high temperature heating path. The path 84 is called a heat exchange path.

  The high temperature heating path 83 is connected to the entrance of the high temperature heater 85. The high temperature heater 85 of the present embodiment is a bathroom heater. The high temperature heater 85 has a thermal valve 85a. The thermal valve 85a is controlled by the controller 21. When the high-temperature heater 85 is used, the thermal valve 85a is opened. While the high temperature heater 85 is not used, the thermal valve 85a is closed.

  A return path 80 is connected to the outlet of the high-temperature heater 85. Hot water that has passed through the high-temperature heater 85 flows into the return path 80.

  The return path 80 passes through the latent heat exchanger 89. The latent heat exchanger 89 is disposed in the vicinity of the burner 74 and recovers latent heat from water vapor contained in the combustion gas after the burner 74 heats the burner path 72. As the water vapor in the latent heat exchanger 89 comes into contact with the return path 80 and is condensed, the water in the return path 80 is warmed. In the present embodiment, the latent heat exchanger 89 is provided to efficiently heat. The end of the return path 80 is connected to a systern return path 77. The systurn return path 77 is connected to the bottom of the systurn 63.

  One end of the thermal valve passage 76 is connected downstream of the burner 74 of the burner passage 72. The other end of the thermal valve path 76 is connected to a systern return path 77. A thermal valve 78 is inserted in the thermal valve path 76. The thermal valve 78 is controlled by the controller 21. The thermal valve path 76 has a bypass path 76 a that bypasses the thermal valve 78. The diameter of the bypass path 76a is smaller than the diameter of the main path of the thermal valve path 76. Therefore, when the thermal valve 78 is closed, the amount of water flowing through the thermal valve path 76 is reduced.

  One end of a chasing path 79 is connected downstream of the burner 74 in the burner path 72. The other end of the tracking path 79 is connected to the return path 80. A thermal valve 81 is inserted in the tracking path 79. The thermal valve 81 is controlled by the controller 21. The tracking path 79 passes through the heat exchanger 82.

  The heat exchange path 84 passes through the heat exchanger 46. In the heat exchanger 46, heat exchange is performed between the water in the second hot water path 43 and the water in the heat exchange path 84. The end of the heat exchange path 84 is connected to the return path 80. A flow control valve 84 a is inserted in the heat exchange path 84. The flow rate control valve 84a can adjust the flow rate by changing its opening. The flow rate control valve 84a is controlled by the controller 21.

  A low-temperature heating path 73 branched from the systern outgoing path 70 is connected to an inlet of the low-temperature heater 86. The low-temperature heater 86 in this embodiment is a floor heater. A thermal valve 87 is inserted in the low temperature heating path 73. The thermal valve 87 is controlled by the controller 21. When the low-temperature heater 86 is used, the thermal valve 87 is opened. While the low-temperature heater 86 is not used, the thermal valve 87 is closed. One end of a path 88 is connected to the outlet of the low-temperature heater 86. The other end of the path 88 is connected to the return path 80.

The suction port 91 a and the supply port 91 b of the bath tub 91 are connected by a bath circulation path 90. A bath water level sensor 92, a bath water flow switch 93, a bath thermistor 94, and a pump 95 are attached to the bath circulation path 90. The bath water level sensor 92, the bath water flow switch 93, and the bath thermistor 94 output detection signals to the controller 21. The bath water level sensor 92 detects the water pressure. The controller 21 estimates the water level of hot water stretched on the bathtub 91 from the water pressure detected by the bath water level sensor 92. The bath water flow switch 92 is turned on when water flows through the bath circulation path 90. The bath thermistor 94 detects the temperature of the hot water sucked from the bathtub 91. The pump 95 is controlled by the controller 21.
The bath circulation path 90 passes through the heat exchanger 82. As described above, the reheating path 79 also passes through the heat exchanger 82, and the heat exchanger 82 performs heat exchange between the bath circulation path 90 and the reheating path 79.

  The bath circulation path 90 and the second mixed water path 61 are connected via a fourth mixed water path 64. A solenoid-driven type pouring valve 65 and a hot water filling amount sensor 66 are attached to the fourth mixed water path 64. The pouring valve 65 is controlled by the controller 21. When hot water is filled in the bathtub 91, the pouring valve 65 is opened. When the pouring valve 65 is opened, warm water flows from the second mixed water path 61 into the fourth mixed water path 64, and the warm water flowing into the fourth mixed water path 64 flows into the bath circulation path 90. The hot water flowing into the bath circulation path 90 is supplied to the bathtub 91 from the suction port 91a and the supply port 91b. Thereby, the bathtub 91 is filled with hot water. The hot water filling amount sensor 66 detects the amount of water flowing through the fourth mixed water path 64, thereby estimating how much hot water has been supplied to the bathtub 91 (hot water filling operation). The hot water filling amount sensor 66 outputs a detection signal to the controller 21.

  Next, the configuration of the controller 21 will be described with reference to FIG. The controller 21 includes a CPU 21a, a ROM 21b, a RAM 21c, an input port 21d, and an output port 21e. These elements are communicably connected by a bus line 21f.

  The CPU 21a processes a control program stored in the ROM 21b. The programs stored in the ROM 21b include a program for controlling the power generation unit 100 and a program for controlling the hot water supply system 10. The RAM 21c temporarily stores various signals input to the controller 21 and various data generated in the course of execution of processing by the CPU 21a.

  Various sensors 35 and the like and a remote controller 23 are connected to the input port 21d. Information output from the sensor 35 or the like or the remote controller 23 is input to the input port 21d. The CPU 21a takes in information input to the input port 21d. The CPU 21a executes various controls based on the input information. In FIG. 2, not all elements connected to the input port 21d are shown. For example, the sensors 66, 92, 93, 94, etc. are not shown.

  Various valves 78 and the like, various pumps 40, a burner 74 and the like are connected to the output port 21e. Various signals generated and output by the CPU 21a are input to the various valves 78, the various pumps 40, the burner 74, and the like through the output port 21e. The various valves 78 and the like open and close according to the input signal. The various pumps 40 and burners 74 start driving or stop driving according to the input signals. FIG. 2 does not show all the elements connected to the output port 21e. For example, each element of the power generation unit 100 is not illustrated. Further, the valve 61a and the like are not shown.

  Next, various processes executed by the controller 21 will be described. Here, description of processing that is not very related to the present invention is omitted. For example, the process of draining the water in the hot water tank 20 will not be described in detail.

(1) Heat storage heat The controller 21 starts the operation of the power generation unit 100 according to the power demand. When the operation of the power generation unit 100 is started, if the hot water supply location where the hot water tap 67 is installed or the hot water filling to the bathtub 91 is not performed, the controller 21 performs heat storage heat treatment.

FIG. 3 is a flowchart showing details of the heat storage heat treatment.
When the heat storage heat treatment is started in step S302, the controller 21 compares the temperature detected by the exhaust heat recovery temperature sensor 45 (hereinafter referred to as exhaust heat recovery temperature) with a threshold value in step S304. In the cogeneration system 500 of the present embodiment, the threshold value is 45 ° C. If the exhaust heat recovery temperature is less than 45 ° C. (YES in step S304), the process proceeds to step S306, the second inlet / outlet 48b and the third inlet / outlet 48c of the three-way valve 48 are communicated, and the first inlet / outlet 48a is connected. close. If the exhaust heat recovery temperature is 45 ° C. or higher (NO in step S304), the process proceeds to step S308, the first inlet 48a and the second inlet 48b of the three-way valve 48 are communicated, and the third inlet 48c is closed. .

  Thereafter, in step S310, the controller 21 drives the pump 40 to recover exhaust heat from the power generation unit 100 to the hot water supply system 10. By driving the pump 40, water is taken out from the lower part of the hot water tank 20, and the taken out water flows into the power generation unit 100 through the common path 26 and the heat recovery forward path 128a. The water that flows into the power generation unit 100 is heated by the generated heat, and then flows into the heat recovery return path 128 b and the second hot water path 43. The water temperature in the second hot water path 43 is detected as the exhaust heat recovery temperature. When the water temperature is 45 ° C. or higher, the hot water in the second hot water path 43 passes through the first hot water path 42 from the three-way valve 48. Into the upper part of the hot water tank 20. When the water temperature is less than 45 ° C., the hot water in the second hot water path 43 flows from the three-way valve 48 into the common path 26 via the third hot water path 44.

  In step S312, the controller 21 opens the flow control valve 84a to fully open and drives the pump 71. By driving the pump 71, the water in the cistern 63 circulates through a flow path that passes through the cistern forward path 70, the burner path 72, the heat exchange path 84, the return path 80, and the cistern return path 77. Hereinafter, the flow path constituted by the cis turn 63, the cis turn forward path 70, the burner path 72, the heat exchange path 84, the return path 80, and the cis turn return path 77 is simply referred to as a circulation path.

  In step S314, the controller 21 compares the temperature detected by the low-temperature heating temperature sensor 75a (hereinafter referred to as the heat medium temperature) with a threshold value. In the cogeneration system 500 of the present embodiment, the threshold value is a value obtained by adding 5 ° C. to the hot water supply temperature set in the remote controller 23 by the user (hereinafter referred to as “set temperature”). The set temperature is input to the controller 21 when the user sets the hot water supply temperature using the remote controller 23. The controller 21 obtains a set temperature by reading a previously inputted hot water supply temperature. If the heat medium temperature is equal to or higher than the threshold value (YES in step S314), the process proceeds to step S316, the controller 21 stops the pump 71, and closes the flow control valve 84a. After step S316, the process proceeds to step S322. When the heat medium temperature does not reach the threshold value (NO in step S314), the process proceeds to step S318, and the controller 21 continues to drive the pump 71 as it is. After step S318, the process proceeds to step S322.

  In step S322, the controller 21 determines whether or not the power generation in the power generation unit 100 is completed. When the power generation is completed (YES in step S322), the process proceeds to step S324 in order to end the heat storage heat treatment. If power generation has not been completed (NO in step S322), the process proceeds to step S304 to repeat the above-described process in order to continue the heat storage heat treatment.

In step S324, the controller 21 stops driving the pump 40.
In step S326, if the pump 71 is driven at this time, the controller 21 stops the driving of the pump 71. In Step S326, if the flow control valve 84a is open at this time, the controller 21 closes the flow control valve 84a.
In step S328, the controller 21 causes the first inlet / outlet port 48a and the second inlet / outlet port 48b of the three-way valve 48 to communicate with each other, closes the third inlet / outlet port 48c, and ends the heat storage process.

According to said process, heat exchange is performed between the warm water which passes the 2nd warm water path | route 43, and the water which passes the heat exchange path | route 84. FIG. The hot water passing through the second hot water path 43 is heated by the heat generated by the power generation unit 100 and has a high temperature. The water passing through the heat exchange path 84 is heated by heat exchange with the hot water passing through the second hot water path 43. Further, the hot water passing through the second hot water path 43 is cooled by heat exchange with water passing through the heat exchange path 84.
The water passing through the heat exchange path 84 circulates inside the circulation path. Due to the heat exchange in the heat exchanger 46, the water temperature in the circulation path rises. According to the above processing, each time the heat storage heat treatment is performed, the water temperature in the circulation path is detected, and if necessary, the water in the circulation path is heated by using generated heat. Can be kept warm.
If the hot water passing through the second hot water passage 43 is still hot after cooling (if the water temperature detected downstream from the heat exchanger 46 is 45 ° C. or higher), it flows into the hot water tank 20. If the temperature is low after cooling (if the water temperature detected downstream from the heat exchanger 46 is less than 45 ° C.), it flows into the common path 26.

The water temperature in the above-described circulation path is detected as the heat medium temperature. When the heat medium temperature becomes equal to or higher than the threshold value, the pump 71 is stopped, the flow control valve 84a is closed, and the circulation of water in the circulation path is stopped. The water in the heat exchange path 84 does not circulate, and heat exchange with the hot water passing through the second hot water path 43 is not performed.
According to said process, the water temperature in a circulation path is kept at the temperature about 5 degreeC higher than preset temperature. The water in the circulation path can be kept warm without making the water temperature in the circulation path higher than necessary.

According to said process, the water temperature in a circulation path is kept at the temperature about 5 degreeC higher than preset temperature. Thereby, even when the temperature of the hot water pumped out of the hot water storage tank 20 in the subsequent hot water supply operation is low, the hot water heated to the hot water temperature set by the user by the remote controller can be immediately supplied to the hot water tap 67.
In step S314 above, a value obtained by adding 5 ° C. to the set temperature is used as the threshold value of the heat medium temperature. A value may be used. For example, a value obtained by adding 10 ° C. to the set temperature may be used.

In the above heat storage heat treatment, the state of the three-way valve 48 is switched according to the temperature of the hot water flowing through the second hot water path 43. When the water temperature in the 2nd hot water path | route 43 is 45 degreeC or more, the warm water in the 2nd warm water path | route 43 is poured into the upper part of the hot water tank 20 via the 1st hot water path | route 42. FIG. Further, when the water temperature in the second hot water path 43 is less than 45 ° C., the hot water in the second hot water path 43 flows into the third hot water path and does not flow into the hot water storage tank 20.
Temperature stratification is formed in the hot water storage tank 20, and the hot water stored in the hot water storage tank 20 can be efficiently utilized for hot water supply by pumping out hot water from the upper part of the hot water storage tank 20 during hot water supply. When low-temperature water is allowed to flow into the upper part of the hot water tank 20, the temperature stratification is destroyed, and the utilization efficiency of the heat stored in the hot water tank 20 is lowered.
According to the cogeneration system 500 of the present embodiment, the heat stored in the hot water tank 20 can be used efficiently by preventing low temperature water from flowing in from the upper part of the hot water tank 20.
In step S304, the exhaust heat recovery temperature threshold is set to 45 ° C., but this is merely an example, and any value can be used as long as the temperature stratification in the hot water tank 20 is not destroyed. May be used. For example, the threshold value of the exhaust heat recovery temperature may be 50 ° C.

  In addition, said heat storage heat processing can be implemented in parallel with the low temperature heater operation process and high temperature heater operation process which are described below. In this case, since the pump 71 has already been driven for the purpose of heating operation, in steps S310, S316, and S326, only the open / closed state of the flow control valve 84a is controlled without changing the operating state of the pump 71.

(2) Low-temperature heater (floor heater) operation process When the operation of the low-temperature heater 86 is started, the controller 21 drives the pump 71. The thermal valve 87 is opened. The burner 74 is driven. When only the low-temperature heater operation process is executed, the thermal valve 78 is opened, and the thermal valve 81, the thermal valve 85a, and the flow control valve 84a are closed.
Water is taken out from the lower part of the cistern 63. The water taken out returns to the cistern 63 via the cistern outbound path 70, the low temperature heating path 73, the low temperature heater 86, the path 88, the return path 80, and the cistern return path 77.
When this processing is executed, there is a flow path in which water taken out from the cistern 63 returns to the cistern 63 via the cistern forward path 70, the burner path 72, the thermal valve path 76, and the cistern return path 77. When only the low-temperature heater operation process is executed, the thermal valve 85a and the flow rate control valve 84a are closed. For this reason, since warm water does not flow into the high-temperature heater 85 or the heat exchanger 46, it is possible to prevent wasteful use of heat.
Since the burner 74 is driven, the water in the return path 80 is heated by the latent heat exchanger 89. Moreover, the water in the burner path 72 is heated. By heating the return path 80 and the burner path 72, the water in the cistern 63 is warmed. As the hot water circulates, the low-temperature heater 86 is heated.
The controller 21 adjusts the capability of the burner 74 based on the temperature detected by the low temperature heating temperature sensor 75a. When the temperature detected by the low temperature heating temperature sensor 75a is a temperature that can sufficiently heat the low temperature heater 86, the capability of the burner 74 is set to the minimum (or the burner 74 is not driven). Conversely, when the temperature detected by the low-temperature heating temperature sensor 75a is a temperature at which the low-temperature heater 86 cannot be heated sufficiently, the capability of the burner 74 is set to the maximum.

(3) High temperature heater (bathroom dryer) operation processing The controller 21 drives the pump 71. Open the thermal valve 85a. The thermal valve 78 is closed. Further, when only the high temperature heater operation process is executed, the thermal valve 81, the thermal valve 87, and the flow rate control valve 84a are closed.
Water is taken out from the lower part of the cistern 63. The extracted water returns to the systern 63 via the systern outbound path 70, the burner path 72, the high temperature heating path 83, the high temperature heater 85, the return path 80, and the systern return path 77.
Since the burner 74 is driven, the water in the return path 80 is heated by the latent heat exchanger 89. Moreover, the water in the burner path 72 is heated. By heating the return path 80 and the burner path 72, the water in the cistern 63 is warmed. As the hot water circulates, the high-temperature heater 85 is heated.
When this processing is executed, there is a flow path in which water taken out from the cistern 63 returns to the cistern 63 via the cistern forward path 70, the burner path 72, the bypass path 76 a of the thermal valve path 76, and the cistern return path 77. . Since the diameter of the bypass path 76a is small, the amount of water circulating through this flow path is small. A lot of water circulates through this flow path, and it can be prevented that a lot of heat is radiated from the thermal valve path 76. There are the following reasons for using the bypass path 76a without completely closing the thermal valve path 76. That is, a certain amount of time is required for the thermal valve to open. Accordingly, the thermal valves 78 and 85a remain closed for a while after the high temperature heater 85 is instructed to start operation. If the bypass path 76a does not exist and the thermal valves 78 and 85a are closed, water does not circulate at all. Therefore, if the bypass path 76a does not exist, the water heated by the burner 74 will not circulate for a while from the request for operation of the high-temperature heater 85, and the water in the burner path 72 will boil. In addition, if the pump 71 operates without water circulating, the pump 71 is loaded. In order to avoid these problems, a bypass path 76a is provided. The hot water can be circulated through the bypass path 76a from the request for operation of the high-temperature heater 85 until the thermal valves 78 and 85a are opened.
The controller 21 adjusts the capability of the burner 74 based on the temperature detected by the high temperature heating temperature sensor 75b. When the temperature detected by the high temperature heating temperature sensor 75b is a temperature at which the high temperature heater 85 can be sufficiently heated, the capability of the burner 74 is set to the minimum (or the burner 74 is not driven). On the contrary, when the temperature detected by the high temperature heating temperature sensor 75b is a temperature at which the high temperature heater 85 cannot be heated sufficiently, the capability of the burner 74 is set to the maximum.

(4) Tracking process The controller 21 drives the pump 71. The burner 74 is driven. The thermal valve 81 is opened. The pump 95 is driven. When only the tracking process is executed, the thermal valve 85a, the thermal valve 87, and the flow rate control valve 84a are closed.
The water taken out from the lower part of the cistern 63 returns to the cistern 63 via the cistern outbound path 70, the burner path 72, the chase path 79, the return path 80, and the cistern return path 77. By heating the return path 80 and the burner path 72, the water in the cistern 63 is warmed. Hot water flows into the reheating path 79 and passes through the heat exchanger 82. When the bath circulation pump 95 is operated, warm water is sucked out from the suction port 91a of the bathtub 91, and the sucked warm water flows through the bath circulation path 90 and returns to the bathtub 91 from the supply port 91b. The hot water flowing through the bath circulation path 90 is heated by the heat exchanger 82 with the hot water flowing through the chasing path 79, and the hot water in the bathtub 91 is chased.

(5) Hot-water supply processing to the hot-water tap 67 Hot-water supply to the hot-water tap 67 is performed when the user opens the hot-water tap 67. Unless the heat storage heat treatment to the cistern 63 is performed, the first inlet / outlet port 48a and the second inlet / outlet port 48b of the three-way valve 48 are opened, and the third inlet / outlet port 48c is closed. When the hot water tap 67 is opened, hot water in the upper part of the hot water storage tank 20 is supplied with hot water via the first hot water path 42, the second hot water path 43, the mixing unit 24, the mixed water path 60, and the third mixed water path 62. Hot water is supplied from the stopper 67. In the case of this hot water supply, hot water is not carried by the pump. Hot water is carried by the pressure in the hot water tank 20.
The controller 21 constantly monitors whether or not hot water supply is started. When the detected value of the mixed water flow rate sensor 54 exceeds 2.7 (L / m; liter / minute), the controller 21 determines that hot water supply has started.

When the hot water supply is started, the controller 21 starts the hot water supply process shown in FIG.
When hot water supply is started in step S402, the controller 21 compares the heat medium temperature with the set temperature (step S404). If the heating medium temperature is equal to or higher than the set temperature (YES in step S404), the temperature correction amount α is set to 1 ° C. (step S406). If the heat medium temperature is less than the set temperature (NO in step S404), the temperature correction amount α is set to 5 ° C. (step S408).

  When the temperature correction amount α is set, the process proceeds to step S410, and the controller 21 compares the water temperature in the hot water tank 20 with a threshold value. The water temperature of the hot water tank 20 is detected by a hot water tank temperature sensor 35. As the threshold value, a value obtained by adding a temperature correction amount α to a hot water supply temperature (set temperature) set by the user is used. If the water temperature in hot water storage tank 20 exceeds the threshold value (YES in step S410), the process proceeds to step S412 to perform heat storage hot water supply. If the water temperature in hot water storage tank 20 is equal to or lower than the threshold value (NO in step S410), the process proceeds to step S418 to perform combustion hot water supply.

  In step S412, the mixing unit 24 is controlled. Specifically, the opening degree of the feed water flow rate adjustment valve 24a and the opening degree of the hot water flow rate adjustment valve 24c are controlled so that hot water having a set temperature is obtained. The controller 21 feed-forward-controls the opening degree of each valve 24a, 24c from the set temperature, the value of the tap water temperature sensor 50, and the value of the hot water temperature sensor 51. Further, the controller 21 feedback-controls the opening degree of the valves 24 a and 24 c based on the value of the mixed water temperature sensor 52.

  In step S414, it is determined whether or not hot water supply has been completed. When the detected value of the mixed water flow rate sensor 54 is 2.0 (L / m) or less, the controller 21 determines that the hot water supply is finished. When the hot water supply is completed (YES in step S414), the process proceeds to step S416. If hot water supply has not ended (NO in step S414), the process proceeds to step S404, and the hot water supply process is continued.

  In step S416, the mixing unit 24 is controlled, the water supply amount adjustment valve 24a is closed, and the hot water supply process is ended.

If NO is determined in step S410, the process proceeds to step S418.
At the time when the process of step S418 is executed, the amount of heat stored in the hot water storage tank 20 is insufficient, and the hot water at the set temperature cannot be supplied to the hot water tap 67 at the water temperature of the hot water storage tank 20. For this reason, tap water is not mixed with warm water by the mixing unit 24. In step S418, the opening degree of the water supply inlet 24a of the mixing unit 24 is set to zero (completely closed). If the water supply amount adjustment valve 24a is already closed at this time, the controller 21 proceeds to step S420 without performing any particular processing.
In step S420, the driving of the pump 71 is started and the flow control valve 84a is opened. The opening degree of the flow rate control valve 84a is set based on the water temperature of the hot water tank 20 detected by the hot water tank temperature sensor 35, the heat medium temperature detected by the heating low temperature thermistor 75a, and the set temperature. If the driving of the pump 71 has already started at this time, the controller 21 only adjusts the opening degree of the flow control valve 84a, and the process proceeds to step S422.
In step S422, combustion of the burner 74 is started. If combustion of the burner 74 has already started at this time, the controller 21 proceeds to step S424 without performing any particular processing.
In step S424, it is determined whether or not hot water supply has been completed. When the detected value of the mixed water flow rate sensor 54 is 2.0 (L / m) or less, the controller 21 determines that the hot water supply is finished. If hot water supply has been completed (YES in step S424), the process proceeds to step S426. If hot water supply has not ended (NO in step S424), the process proceeds to step S418, and hot water supply using the combustion heat of burner 74 is continued.

In step S426, the combustion of the burner 74 is stopped.
In step S428, the driving of the pump 71 is stopped, the flow control valve 84a is closed, and the hot water supply process is terminated.

In the cogeneration system 500 of the present embodiment, when hot water supply is started, hot water is supplied using the heat accumulated in the hot water storage tank 20.
When the amount of heat stored in the hot water storage tank 20 is small and hot water having a set temperature cannot be supplied, the hot water is supplied using the combustion heat of the burner 74.
A certain amount of time is required from the start of combustion of the burner 74 until the water temperature in the circulation path becomes high and the hot water pumped from the hot water tank 20 can be heated to the set temperature. If the water temperature in the circulation path is originally high, the hot water can be immediately heated. However, if the water temperature in the circulation path is low, it takes time to heat the warm water.
According to the cogeneration system 500 of the present embodiment, the water in the circulation path is kept warm using the heat generated by the power generation unit 100. Therefore, even when the amount of heat stored in the hot water tank 20 is small, it is possible to supply hot water that has been heated to the set temperature immediately.

In the cogeneration system 500 of the present embodiment, the timing for switching from the heat storage hot water supply to the combustion hot water supply is changed according to the detected heat medium temperature. When the temperature of the heat transfer medium is high, the combustion hot water supply is started when the water temperature of the hot water storage tank 20 falls below the set temperature + 1 ° C. Combustion hot water supply is started when it becomes below.
When the water temperature in the circulation path is high, the time required from the start of combustion of the burner 74 to the heating of the hot water pumped out of the hot water tank 20 by the heat exchanger 46 to the set temperature is short. Therefore, in the cogeneration system 500 of the present embodiment, when the detected heat medium temperature is high, the timing for switching from the heat storage hot water supply to the combustion hot water supply is delayed.
When the water temperature in the circulation path is low, it takes a long time from the start of combustion of the burner 74 to the heating of the hot water pumped out of the hot water tank 20 by the heat exchanger 46 to the set temperature. Therefore, when the detected heat medium temperature is low, the timing for switching from the heat storage hot water supply to the combustion hot water supply is advanced.
As described above, the hot water supply at a stable hot water temperature can be realized by changing the timing of switching from the regenerative hot water supply to the combustion hot water supply according to the heat medium temperature.

(6) Hot water filling process to the bathtub 91 The hot water filling process to the bathtub 91 is performed in substantially the same manner as the hot water supply process to the hot water tap 67 of (5) described above. Here, only the point different from the hot water supply processing to the hot water tap 67 of (5) will be described.
A remote controller 23 is provided in the bathroom. The user can set the hot water temperature using the remote controller 23. The remote controller 23 is provided with a switch for starting filling. When this switch is operated, the controller 21 opens the pouring valve 65. Then, the hot water in the hot water tank 20 flows through the first hot water path 42, the second hot water path 43, the first mixed water path 60, the second mixed water path 61, the fourth mixed water path 64, and the bath circulation path 90. The hot water flowing into the bath circulation path 90 flows into the bathtub 91 from both the suction port 91a and the supply port 92b.
When the hot water filling to the bathtub 91 is started, the controller 21 executes various controls according to the flowchart of the hot water supply process of FIG. The controller 21 closes the pouring valve 65 when the amount of hot water filling the bathtub 91 reaches a predetermined value (preset by the user using the remote controller 23). The amount of hot water filling the bathtub 91 can be obtained by reading the value of the bath water level sensor 92. When the pouring valve 65 is closed, a hot water filling end process is executed.
According to the present embodiment, when the water temperature of the hot water tank 20 is lower than the set temperature, the time until the hot water at the set temperature can be supplied to the bathtub 91 can be shortened.

  The cogeneration system 500 of the present embodiment has been described in detail. According to the present embodiment, when the water temperature of the hot water storage tank 20 is lower than the set temperature, it is possible to shorten the time until the hot water at the set temperature can be supplied to the hot water tap 67 or the bathtub 91. A user-friendly system 500 is implemented.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Moreover, the technique illustrated in this specification or the drawings achieves a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

FIG. 1 is a system diagram of a cogeneration system 500. FIG. 2 is a diagram simply showing the configuration of the controller 21. FIG. 3 is a flowchart of heat storage heat treatment. FIG. 4 is a flowchart of the hot water supply process.

Explanation of symbols

10: Hot water supply system 20: Hot water storage tank 20a: Outlet portion 21: Controller 21a: CPU
21b: ROM
21c: RAM
21d: Input port 21e: Output port 21f: Bus line 23: Remote control 24: Mixing unit 24a: Feed water inlet (feed water flow rate adjustment valve)
24b: Mixed water outlet 24c: Hot water inlet (warm water flow rate adjustment valve)
26: Common path 26a: Common path inlet 28: Pressure reducing valve 28a: On-off valve 30: Mixing unit water supply path 31: Relief valve 32: Pressure release path 33: Drain valve 34: Drain path 35: Hot water tank temperature sensor 40: Pump 42 : First hot water path 43: second hot water path 44: third hot water path 45: exhaust heat recovery temperature sensor 46: heat exchanger 48: three-way valve 48a: first inlet / outlet 48b: second inlet / outlet 48c: third inlet / outlet 50: Tap water temperature sensor 51: Hot water temperature sensor 52: Mixed water temperature sensor 53: High cut thermistor 54: Mixed water flow rate sensor 55: Flow rate servo 60: First mixed water path 61: Second mixed water path 61a: Makeup water valve 62: Third mixed water path 63: cistern 63a, 63b: water level electrode 64: fourth mixed water path 65: pouring valve 66: hot water amount sensor 67: hot water tap 70: sister Outward path 71: Pump 72: Burner path 73: Low temperature heating path 74: Burner 75a: Low temperature heating temperature sensor 75b: High temperature heating temperature sensor 76: Thermal valve path 76a: Bypass path 77: Systurn return path 78: Thermal valve 79: Additional Burning path 80: Return path 81: Thermal valve 82: Heat exchanger 83: High temperature heating path 84: Heat exchange path 84a: Flow control valve 85: High temperature heater 85a: Thermal valve 86: Low temperature heater 87: Thermal movement Valve 88: Path 89: Latent heat exchanger 90: Bath circulation path 91: Bath 91a: Suction port 91b: Supply port 92: Bath water level sensor 93: Bath water flow switch 94: Bath thermistor 95: Pump 100: Power generation unit 112: Modified Element 114: Fuel cell 116: Heat exchanger 117: Heat medium temperature sensor 118: Heat exchanger 119: Heat medium cooling fan 120: Heat medium radiator 121: Hydrogen gas Path 122: Heat medium three-way valve 122a: Heat medium three-way valve inlet 122b, 122c: Heat medium three-way valve outlet 124: Power generation heat medium circulation path 125: Reserve tank 126: Combustion gas path 127: Heat medium pump 128: Heat recovery path 128a : Heat recovery outward path 128b: Heat recovery return path 129, 130: Path 131: Burner 500: Cogeneration system

Claims (3)

It is a cogeneration system that generates electricity according to power demand, stores the generated heat generated with the power generation, and supplies the stored thermal energy when necessary.
A hot water storage tank for storing hot water,
A hot water supply route for supplying hot water from the hot water tank to the hot water use location;
A circulation path through which the heat medium circulates;
A heat source machine for heating the heat medium flowing through the circulation path;
A first temperature sensor for detecting the temperature of the heat medium flowing through the circulation path;
A first heat exchanger that exchanges heat between hot water flowing through the hot water supply path and a heat medium flowing through the circulation path;
First driving means for circulating the heat medium;
A power generation unit for generating power;
A cooling water outbound path for supplying cooling water to the power generation unit;
A cooling water return path for supplying cooling water heated by the power generated by the power generation unit to the hot water storage tank;
A second heat exchanger for exchanging heat between the cooling water flowing through the cooling water return path and the heat medium flowing through the circulation path;
Second driving means for circulating cooling water;
A controller for controlling the first drive means and the second drive means,
The controller is
When the power generation unit is generating power, the second drive means is driven to circulate the cooling water,
A cogeneration system, characterized in that when the power generation unit generates power and the temperature detected by the first temperature sensor is less than a first predetermined value, the first drive means is driven to circulate the heat medium. A second temperature sensor for detecting the temperature of the cooling water flowing through the cooling water return path downstream from the second heat exchanger;
A three-way valve that branches the cooling water return path downstream from the second temperature sensor;
A first path for supplying cooling water from the cooling water return path to the hot water storage tank via the three-way valve;
A second path for supplying cooling water from the cooling water return path to the cooling water outbound path via the three-way valve;
With
The three-way valve is an instruction from the controller,
A state in which the cooling water return path and the first path are communicated and the cooling water return path and the second path are not in communication;
Switching between a state where the cooling water return path and the second path are communicated and the cooling water return path and the first path are not communicated;
The controller is
When the power generation unit generates power and the temperature detected by the second temperature sensor exceeds the second predetermined value, the three-way valve is controlled to supply cooling water from the cooling water return path to the hot water storage tank,
When the power generation unit generates power and the temperature detected by the second temperature sensor is less than the second predetermined value, the three-way valve is controlled to supply the cooling water from the cooling water return path to the cooling water forward path. The cogeneration system according to claim 1. The cooling water return path from the hot water tank to the hot water storage tank via the second heat exchanger also serves as the hot water supply path from the hot water tank to the first heat exchanger,
The cogeneration system according to claim 1 or 2, wherein the second heat exchanger also serves as the first heat exchanger.

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