JP3976773B2 - Heat pump water heater - Google Patents

Description

  The present invention relates to a heat pump water heater that heats and supplies water by heat exchange with a refrigerant that circulates in a refrigerant circulation path provided with a compressor, an expander, and the like, and in particular, the energy consumption efficiency (COP) of the heat pump water heater. ).

In general, a water heating heat exchanger (corresponding to a first water heat exchanger) for heating water by heat exchange with a refrigerant circulating in a refrigerant circulation path provided with a compressor or an expander is provided, 2. Description of the Related Art A heat pump water heater that stores hot water heated by a heat exchanger for water heating in a hot water storage tank and supplies the hot water in the hot water storage tank as necessary is well known. Note that high temperature hot water heated by the water heating heat exchanger is laminated on the upper layer in the hot water storage tank, and low temperature water supplied from the water supply is laminated on the lower layer. In the heat pump water heater, a water flow path is provided so that low-temperature water stored in a lower layer of the hot water storage tank is heated by the water heating heat exchanger and then stacked on the upper layer of the hot water storage tank. ing.
In addition, the heat pump water heater may be connected to a heating circuit such as floor heating using a hot hot water stored in the hot water storage tank as a heat medium or a reheating circuit of a bath (for example, see Patent Document 1). ). In this case, hot water having a relatively low temperature (hereinafter referred to as “medium temperature water”), which is used as a heat medium in the heating circuit and lowered in temperature, flows back to the hot water storage tank. Thereby, in the heat pump water heater, heat exchange between the medium temperature water and the refrigerant is performed in the water heating heat exchanger. Therefore, the heat exchange efficiency in the water heating heat exchanger is deteriorated, resulting in a problem that the energy consumption efficiency (COP) of the heat pump water heater is deteriorated. For example, the energy consumption efficiency when heating 15 ° C. water to 65 ° C. is about 3 to 4, whereas the energy consumption efficiency when heating medium temperature water of 45 ° C. to 65 ° C. is about 1 to 2. Become.

Therefore, a water cooling heat exchanger (corresponding to the second water heat exchanger) that cools the intermediate temperature water by heat exchange with the low-temperature refrigerant flowing from the water heating heat exchanger through the expander in the refrigerant circulation path It is conceivable to provide them (for example, see Patent Document 1). In such a configuration, the intermediate temperature water is once cooled by the water cooling heat exchanger and then flowed into the water heating heat exchanger, thereby improving the heat exchange efficiency in the water heating heat exchanger. be able to.
Japanese Patent Laid-Open No. 2004-211986

However, the temperature of the refrigerant flowing from the water heating heat exchanger through the expander to the water cooling heat exchanger is so low that the water flowing from the hot water storage tank to the water heat exchanger is frozen by heat exchange. In some cases, the water flowing into the water cooling heat exchanger may freeze and damage the water cooling heat exchanger or the water flow path.
Accordingly, the present invention has been made in view of the above circumstances, and its object is to flow into a water heating heat exchanger that heats water by performing heat exchange between the refrigerant and water. An object of the present invention is to prevent freezing of water in the water cooling heat exchanger in a heat pump water heater having a water cooling heat exchanger that cools water in advance by a heat exchanger with a refrigerant.

In order to achieve the above object, the present invention provides a refrigerant circulation path through which refrigerant is circulated, a water circulation path through which water is circulated, the refrigerant discharged from a compressor in the refrigerant circulation path, and the water circulation path. A first water heat exchanger that exchanges heat with the circulating water, a hot water storage tank that stores water discharged from the first water heat exchanger, and a discharge from the first water heat exchanger An expander for expanding the generated refrigerant, an outdoor air heat exchanger for exchanging heat between the refrigerant flowing from the expander toward the compressor and outdoor air, and the expander to the compressor And a second water heat exchanger that exchanges heat between the refrigerant flowing toward the water supplied from the hot water storage tank, and the expander The temperature of the refrigerant discharged from the And A adjusts the presence and inflow of inflow of the refrigerant of the the second water heat exchanger based on the temperature of the coolant, the temperature of the detected said refrigerant, and said refrigerant and water When the temperature is such that the water is solidified by heat exchange, the heat pump water heater is configured to block the flow of the refrigerant into the second water heat exchanger . In particular, the present invention is suitable for a heat pump water heater having a heating cycle such as floor heating using hot water stored in the hot water storage tank as a heat medium.
According to the present invention configured as above, when the temperature of the refrigerant discharged from the expander is a temperature at which the water solidifies (freezes) by heat exchange between the refrigerant and water, the first By blocking the inflow of the refrigerant to the second water heat exchanger, water freezing in the second water heat exchanger can be prevented. Therefore, breakage of the second water heat exchanger, the water flow path, and the like can be prevented. Of course, when there is no possibility of water freezing in the second water heat exchanger, the water discharged from the hot water storage tank is cooled in the second water heat exchanger before the first water heat Since it can be made to flow into the exchanger, it is possible to prevent a decrease in energy consumption efficiency in the heat pump water heater .

Here, the expander discharges the refrigerant toward the outdoor air heat exchanger and the second expander discharges the refrigerant toward the second water heat exchanger. A configuration including In this case, the temperature of the refrigerant discharged from the first expander or the temperature of the refrigerant discharged from the second expander is detected, and the second water heat exchanger is detected based on the detection result. What is necessary is just to adjust the presence or absence and inflow amount of the said refrigerant | coolant inflow.
The second expander includes an electromagnetic valve that adjusts the presence or absence of the refrigerant that flows from the first water heat exchanger toward the second water heat exchanger, and A simple and inexpensive configuration including a capillary tube for expanding the refrigerant flowing toward the water heat exchanger can also be provided. In this case, the flow rate of the refrigerant flowing from the first water heat exchanger toward the second water heat exchanger is not controlled by controlling the solenoid valve, and the second water heat is not controlled. The presence or absence of the refrigerant flowing into the exchanger is controlled.

In addition, inflow of the refrigerant into the second water heat exchanger, that is, cooling of water discharged from the hot water storage tank in the second water heat exchanger is necessary when the temperature of the water is high. . Therefore, it is desirable to have a configuration including first water temperature detection means for detecting the temperature of water discharged from the hot water storage tank. Then, based on the temperature of the water detected by the first water temperature detecting means, it is conceivable to adjust the presence / absence and the amount of the refrigerant flowing into the second water heat exchanger.
Specifically, the refrigerant is caused to flow into the second water heat exchanger on the condition that the temperature of the water detected by the first water temperature detecting means is equal to or higher than a first predetermined temperature. It is conceivable to block the flow of the refrigerant into the second water heat exchanger on condition that the temperature of the water detected by the water temperature detecting means is lower than the first predetermined temperature. As a result, the water discharged from the hot water storage tank can be cooled by the second water heat exchanger as needed and then flowed into the first water heat exchanger.

Further, in order to determine whether the water discharged from the hot water storage tank is sufficiently cooled in the second water heat exchanger, a second temperature for detecting the temperature of the water flowing into the first water heat exchanger is detected. It is desirable to provide the water temperature detecting means. Further, in this case, by adjusting the presence / absence and the amount of inflow of the refrigerant into the second water heat exchanger based on the temperature of the water detected by the second water temperature detecting means, the first It is possible to appropriately adjust the temperature of the water flowing into the water heat exchanger.
Specifically, the amount of the refrigerant flowing into the second water heat exchanger is increased on condition that the temperature of the water detected by the second water temperature detecting means is equal to or higher than a second predetermined temperature. The refrigerant flowing into the second water heat exchanger on condition that the temperature of the water detected by the second water temperature detecting means is not more than a third predetermined temperature lower than the second predetermined temperature. It is conceivable to reduce the amount of.

By the way, the water flow path includes a first water flow path from the hot water storage tank through the first water heat exchanger to the hot water storage tank, a second water heat exchanger from the hot water storage tank, and the first water heat transfer tank. And a second water flow path that continues to the hot water storage tank through one water heat exchanger in order, the temperature of the water detected by the first water temperature detecting means and the second water temperature detecting means. Based on this, it is conceivable to adjust the distribution amount of the water supplied from the hot water storage tank to the first water circulation path and the second water circulation path. Even with such a configuration, the temperature of the water flowing into the first water heat exchanger can be adjusted appropriately.
Specifically, the water distributor distributes water to the second water flow path on condition that the temperature of the water detected by the first water temperature detecting means is equal to or higher than a fourth predetermined temperature. It is possible. Further, the amount of water distributed to the second water flow path by the water distributor is increased on the condition that the temperature of the water detected by the second water temperature detecting means is not less than a fifth predetermined temperature, Water to the second water flow path by the water distributor on the condition that the temperature of the water detected by the second temperature detecting means is not more than a sixth predetermined temperature lower than the fifth predetermined temperature. It is also conceivable to reduce the distribution amount.

According to the present invention, when the temperature of the refrigerant discharged from the expander is a temperature at which the water solidifies (freezes) by heat exchange between the refrigerant and water, the second water heat exchanger By blocking the flow of the refrigerant into the water, it is possible to prevent water from freezing in the second water heat exchanger. Therefore, breakage of the second water heat exchanger, the water flow path, and the like can be prevented. Of course, when there is no possibility of water freezing in the second water heat exchanger, the water discharged from the hot water storage tank is cooled in the second water heat exchanger before the first water heat Since it can be made to flow into the exchanger, it is possible to prevent a decrease in energy consumption efficiency in the heat pump water heater.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
FIG. 1 is a block diagram showing a schematic configuration of the heat pump water heater X1 according to the embodiment of the present invention, and FIG. 2 is a diagram for explaining an example of the procedure of the refrigerant flow adjustment process executed in the heat pump water heater X1. It is a flowchart of.
First, the schematic configuration of the heat pump water heater X1 according to the embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 1, the heat pump water heater X1 includes a refrigerant circuit 1 in which refrigerant is circulated (an example of a refrigerant circulation path), a hot water supply circuit 2 in which water is circulated (an example of a water circulation path), and the refrigerant. A water heating heat exchanger 3 (an example of a first water heat exchanger) that heats the water by exchanging heat between the refrigerant circulated in the circuit 1 and the water circulated in the hot water supply circuit 2. Heat exchange between the hot water storage tank 4 for storing the hot water heated by the water heating heat exchanger 3, the refrigerant circulated through the refrigerant circuit 1 and the water circulated through the hot water supply circuit 2. A water cooling heat exchanger 5 (an example of a second water heat exchanger) that cools the water and a heating cycle 6 that uses hot water stored in the hot water storage tank 4 as a heat medium (a heating cycle). And an example). The heat pump water heater X1 includes a control unit (not shown) having a CPU, a RAM, a ROM, and the like, and is comprehensively controlled by the control unit.
In the lower layer of the hot water storage tank 4, low temperature (for example, about 15 ° C.) water supplied from the water supply port via the water path 41 is stored, and the upper layer is heated by the water heating heat exchanger (high temperature ( Hot water (for example, about 65 ° C.) is stored. Hot hot water stored in the upper layer of the hot water storage tank 4 is discharged from the hot water storage tank 4 to the hot water outlet via the water path 42 when the hot water supply cock 43 provided in the water path 42 is opened.

The refrigerant circuit 1 includes a compressor 11, a water heating heat exchanger 3, an expander 12 (an example of a first expander), a refrigerant temperature sensor 13 (an example of a refrigerant temperature detecting means), and an outdoor air heat exchanger. 14, a refrigerant circuit 1a in which refrigerant is circulated in the order of the compressor 11, the compressor 11, the water heating heat exchanger 3, an expander 15 (an example of a second expander), and the water cooling heat An exchanger 5, and a refrigerant circuit 1 b in which the refrigerant is circulated in the order of the compressor 11. The expander 12 and the expander 15 may be composed of a single expander.
In the refrigerant circuit 1, the refrigerant discharged from the water heating heat exchanger 3 is distributed by the expanders 12 and 15 to the outdoor air heat exchanger 14 and the water cooling heat exchanger 5. After distribution, they merge and flow into the compressor 11. That is, the outdoor air heat exchanger 14 and the water cooling heat exchanger 5 are connected in parallel.

The expander 12 includes a flow rate adjusting mechanism that adjusts the presence or absence of the refrigerant flowing from the water heating heat exchanger 3 toward the outdoor air heat exchanger 14, and the water heating heat exchanger. And an expansion mechanism for expanding the refrigerant flowing from 3 to the outdoor air heat exchanger 14.
Similarly, the expander 15 also includes a flow rate adjusting mechanism for adjusting the presence or absence of the refrigerant flowing from the water heating heat exchanger 3 toward the water cooling heat exchanger 5, and the water amount. And an expansion mechanism that expands the refrigerant flowing from the heating heat exchanger 3 toward the water cooling heat exchanger 5.

The refrigerant temperature sensor 13 is an example of a refrigerant temperature detection unit including a thermistor and the like, and detects the temperature of the refrigerant discharged from the expander 12. Here, the temperature of the refrigerant detected by the refrigerant temperature sensor 13 is substantially equal to the temperature of the refrigerant discharged from the expander 15 and flowing into the water cooling heat exchanger 5. The temperature of the refrigerant detected by the refrigerant temperature sensor 13 is input to the control unit. The refrigerant temperature detected by the refrigerant temperature sensor 13 is used as a determination index in a refrigerant flow adjustment process (see the flowchart of FIG. 2) described later.
The refrigerant temperature sensor 13 may use an existing temperature sensor built in the outdoor air heat exchanger 14. Here, the outdoor air heat exchanger 14 includes the outdoor air blown by the blower fan 14a provided in the outdoor unit (not shown) together with the outdoor air heat exchanger, and the refrigerant discharged from the expander 12. Heat exchange between them.

In the refrigerant circuit 1, the refrigerant is circulated by driving the compressor 11 by the control unit.
At this time, in the refrigerant circuit 1a, the high-temperature and high-pressure refrigerant compressed and discharged by the compressor 11 is cooled by heat exchange with water flowing on the hot water supply circuit 2 in the water heating heat exchanger 3. After that, it expands in the expander 12. Thereafter, the low-temperature and low-pressure refrigerant expanded in the expander 12 is heat-exchanged with the outdoor air in the outdoor air heat exchanger 14 to absorb heat and vaporize, merge with the refrigerant in the refrigerant circuit 1b, and then the compressor again. 11 (in the direction of the solid arrow shown in the figure).
On the other hand, in the refrigerant circuit 1b, the high-temperature and high-pressure refrigerant compressed and discharged by the compressor 11 is cooled by heat exchange with the water flowing on the hot water supply circuit 2 in the water heating heat exchanger 3. After that, it expands in the expander 15. Thereafter, the low-temperature and low-pressure refrigerant expanded in the expander 15 is heat-exchanged with the water flowing through the hot water supply circuit 2 in the water cooling heat exchanger 5 to absorb heat and vaporize, and merges with the refrigerant in the refrigerant circuit 1a. After that, it flows again into the compressor 11 (in the direction of the broken arrow shown in the figure).
However, whether or not the refrigerant flows into the water-cooling heat exchanger 5 in the refrigerant circuit 1b and the inflow amount are determined by a refrigerant flow adjustment process (see the flowchart in FIG. 2) described later by the control unit. Adjusted.

The hot water supply circuit 2 includes a lower layer of the hot water storage tank 4, a water temperature sensor 21 (an example of a first water temperature detection means), a circulation pump 22, the water cooling heat exchanger 5, a water temperature sensor 23 (second water temperature detection means). 1), the water heating heat exchanger 3, the water temperature sensor 24, and the upper layer of the hot water storage tank 4 are connected in this order.
The water temperature sensor 21 is the temperature of water discharged from the hot water storage tank 4, the water temperature sensor 23 is the temperature of water flowing into the water heating heat exchanger 5, and the water temperature sensor 24 is the water flowing into the hot water storage tank 4. For example, a thermistor. The water temperature detected by each of the water temperature sensors 21, 23, 24 is input to the control unit.

In the hot water supply circuit 2, water is circulated by the circulation pump 22 being driven by the controller. When the circulation pump 22 is driven, water in the lower layer of the hot water storage tank 4 passes through the water cooling heat exchanger 5 and the water heating heat exchanger 3 in order in the hot water supply circuit. 4 up to the upper layer. At this time, the amount of water circulated by the circulation pump 22 is controlled by the control unit so that the water temperature detected by the water temperature sensor 24 becomes a preset temperature (for example, about 65 ° C.). In the heat pump water heater X1, the rotational speed of the compressor 11 and the rotational speed of the circulation pump 22 are controlled by the controller so that the water temperature detected by the water temperature sensor 24 becomes a preset temperature. The heating capacity of the water heating heat exchanger 3 is adjusted.
When the compressor 11 is driven in the refrigerant circuit 1 and the refrigerant is circulated through the refrigerant circuits 1a and 1b, the refrigerant is supplied from the lower layer of the hot water storage tank 4 and flows through the hot water supply circuit 2. The water to be cooled is cooled by heat exchange with the refrigerant in the water cooling heat exchanger 5 and then heated by heat exchange with the refrigerant in the water heating heat exchanger 3.
On the other hand, when the opening of the expander 15 is adjusted by the control unit to prevent the refrigerant from flowing into the water cooling heat exchanger 5 in the refrigerant circuit 1b, the hot water storage tank Water that is supplied from the lower layer 4 and flows through the hot water supply circuit 2 is not cooled by heat exchange with the refrigerant in the water cooling heat exchanger 5, and remains in the water heating heat exchanger 3 at the same temperature. It flows in and is heated by heat exchange with the refrigerant.

The hot water heated to a high temperature (for example, about 65 ° C.) by the water heating heat exchanger 3 is stacked on the upper layer of the hot water storage tank 4. The hot hot water stored in the upper layer of the hot water storage tank 4 is discharged from the hot water supply port as necessary, or used as a heat medium for realizing the heating operation in the heating cycle 6.
The heating cycle 6 includes an upper layer of the hot water supply tank 4, a water circulation pump 61, a heating heat exchanger 62, a water circulation circuit 6a in which the lower layer of the hot water supply tank 4 is connected in sequence, a brine circulation pump 63, and the heat exchange for heating. And a brine (antifreeze) circulation circuit 6b to which a heater 62 and a heater 64 are sequentially connected.
The heater 64 is a floor heater configured to include, for example, a floor heating panel, a radiation panel, a hot air fan, and the like (not shown). The heating cycle 6 is not limited to the one used for the floor heating device, and similarly applies to various devices using hot water stored in the hot water storage tank 4, such as a bath reheating device or an air conditioner. can do.

In the water circulation circuit 6 a, when the hot water circulation pump 61 is driven by the control unit, high-temperature hot water supplied from the upper layer of the hot water storage tank 4 passes through the heating heat exchanger 62 and enters the hot water storage tank 4. Reflux to the lower layer.
In the brine circulation circuit 6b, when the brine circulation pump 63 is driven by the controller, the brine is circulated through the heating heat exchanger 62 and the heater 64. Thereby, the brine circulating in the brine circulation circuit 6b absorbs heat by the heat exchange with the hot water on the water circulation circuit 6a in the heating heat exchanger 62 and dissipates heat in the heater 64.
At this time, the hot hot water supplied from the upper layer of the hot water storage tank 4 is lowered in temperature by the heat exchange with the brine in the heating heat exchanger 62 and is returned to the lower layer of the hot water storage tank 4. Here, the temperature of the hot water returned to the lower layer of the hot water storage tank 4 is lower than the hot water (for example, about 65 ° C.) stored in the upper layer of the hot water storage tank 4 (for example, about 45 ° C.). , Higher than the temperature of the water supplied from the water supply port (for example, about 15 ° C.). Hereinafter, the relatively low temperature hot water that is returned to the lower layer of the hot water storage tank 4 is referred to as intermediate hot water.

As already described, when the medium-temperature water flows into the water heating heat exchanger 3 through the hot water supply circuit 2, the heat exchange efficiency between the refrigerant and water in the water heating heat exchanger 3 deteriorates. Therefore, in the heat pump water heater X1, the control unit executes a refrigerant flow adjustment process (see the flowchart of FIG. 2), which will be described later, so that water supplied from the lower layer of the hot water storage tank 4 to the hot water supply circuit 2 is obtained. When the temperature is equal to or higher than a predetermined temperature (for example, about 35 ° C.), the water is controlled to be cooled by the water cooling heat exchanger 5 and then flowed into the water heating heat exchanger 3. The However, if the water flowing through the hot water supply circuit 2 is frozen in the water cooling heat exchanger 5, the circulation disposed on the water cooling heat exchanger 5 or the hot water supply circuit 2 will be described. There is a risk of damage to the pump 22 and the like.
However, in the heat pump water heater X1 according to the embodiment of the present invention, based on the temperature of the refrigerant flowing into the water-cooling heat exchanger 5 in the refrigerant flow adjustment process to be described later executed by the control unit. By controlling the presence / absence and amount of refrigerant flowing into the water cooling heat exchanger 5, freezing of water flowing through the hot water supply circuit 2 is prevented. Here, the control unit when executing the refrigerant flow adjusting process corresponds to the refrigerant flow adjusting means.

Hereinafter, an example of the procedure of the refrigerant flow adjustment process executed by the control unit in the heat pump water heater X1 will be described according to the flowchart of FIG. 2 with reference to FIG. In the figure, S1, S2,... Represent processing procedure (step) numbers.
The refrigerant flow adjustment process is executed by the control unit at the start of driving the compressor 11 and the circulation pump 22 in the heat pump water heater X1, and is ended when the drive of the compressor 11 and the circulation pump 2 is stopped.
First, in step S1, the expansion unit 15 is controlled by the control unit, whereby the refrigerant flow into the water cooling heat exchanger 5 in the refrigerant circuit 1b is blocked. Specifically, when the flow rate adjusting mechanism of the expander 15 is adjusted and closed, the refrigerant discharged from the water heating heat exchanger 3 is not distributed to the refrigerant circuit 1b and is not distributed to the refrigerant circuit 1a. It is distributed only to.

Next, in step S2, whether or not the temperature of the refrigerant detected by the refrigerant temperature sensor 13, that is, the temperature of the refrigerant discharged from the expander 12, is equal to or lower than a preset temperature T1 is determined. Determined by the department. As described above, the temperature of the refrigerant detected by the refrigerant temperature sensor 13 is substantially equal to the temperature of the refrigerant discharged from the expander 15 and flowing into the water cooling heat exchanger 5. In addition, when the inflow of the refrigerant to the water cooling heat exchanger 5 is not blocked, it is provided separately from the refrigerant temperature detection sensor 13 to detect the temperature of the refrigerant discharged from the expander 15. Alternatively, a temperature detected by a refrigerant temperature detection sensor (not shown) (an example of a refrigerant temperature detection means) may be used. Further, both the temperatures of the refrigerant discharged from the expanders 12 and 15 may be detected and used.
Here, the set temperature T1 is information stored in advance in the ROM or the like of the control unit, and the water is frozen by the heat exchanger between the refrigerant and water in the water cooling heat exchanger 5. It is an example of temperature. The set temperature T1 is set to about −15 ° C., for example. Whether or not the water is frozen in the water cooling heat exchanger 5 is affected by the temperature of the water flowing into the water cooling heat exchanger 5, for example, when 15 ° C. water is frozen. A configuration in which the temperature of the refrigerant is set as the set temperature T1 and the set temperature T1 is changed according to the water temperature detected by the water temperature sensor 21 is also conceivable as another embodiment.

While it is determined in step S2 that the refrigerant temperature detected by the refrigerant temperature sensor 13 is lower than the set temperature T1 (No side of S2), the determination process in step S2 is repeatedly executed. .
That is, when the temperature of the refrigerant is a temperature at which the water flowing through the hot water supply circuit 2 may be frozen (solidified), the refrigerant flows into the water cooling heat exchanger 5 in the refrigerant circuit 1b. Is interrupted and the state in which the refrigerant is circulated only in the refrigerant circuit 1a is continued.
As a result, the water supplied and circulated from the lower layer of the hot water storage tank 4 to the hot water supply circuit 2 is not cooled by the water cooling heat exchanger 5 but at the same temperature, the water heating heat exchanger 3. The water heating heat exchanger 3 is heated by heat exchange with the refrigerant circulated through the refrigerant circuit 1a. Therefore, in the heat pump water heater X1, the water flowing through the hot water supply circuit 2 in the water cooling heat exchanger 5 is not frozen, and the water cooling heat exchanger 5 and the circulation pump 22 are damaged. Can be prevented.

On the other hand, if it is determined in step S2 that the temperature of the refrigerant detected by the refrigerant temperature sensor 13 is equal to or higher than the set temperature T1 (Yes in S2), the hot water supply in the water cooling heat exchanger 5 is performed. There is no possibility that water flowing through the circuit 2 is frozen by heat exchange with the refrigerant. In this case, the process proceeds to step S3.
In the subsequent step S3, the water temperature detected by the water temperature sensor 21, that is, the water temperature of the water supplied from the lower layer of the hot water storage tank 4 to the hot water supply circuit 2 is set to a preset set water temperature t1 (first predetermined temperature). One example) The controller determines whether or not the above is true. Here, the set water temperature t1 is information stored in advance in the ROM or the like of the control unit, and is a temperature at which the heat exchange efficiency between the refrigerant and water in the heat exchanger 3 for water heating deteriorates. . The set water temperature t1 is set to about 35 ° C., for example. The set water temperature t1 is preferably changeable according to an input from an operation unit (not shown). This changing process is executed by the control unit.
Here, in step S3, when it is determined that the water temperature detected by the water temperature sensor 21 is lower than the set water temperature t1 (No side of S3), heat exchange in the water heating heat exchanger 3 is performed. The efficiency is not reduced. Therefore, it is not necessary to cool the water supplied from the hot water storage tank 4 to the hot water supply circuit 2 and then flow it into the water heating heat exchanger 3. In this case, the process proceeds to step S1, where the inflow of the refrigerant to the refrigerant circuit 1b is blocked and the state in which the refrigerant flows only into the refrigerant circuit 1a is continued.

On the other hand, when it is determined in step S3 that the water temperature detected by the water temperature sensor 21 is equal to or higher than the set water temperature t1 (Yes side of S1), the heat exchange efficiency in the water heating heat exchanger 3 is determined. Is in a state of decreasing. In this case, the process proceeds to step S4.
In subsequent step S4, the expander 15 is controlled by the control unit, whereby the refrigerant starts to flow into the water cooling heat exchanger 5 in the refrigerant circuit 1b. Specifically, the refrigerant discharged from the water heating heat exchanger 3 is distributed to the refrigerant circuit 1a and the refrigerant circuit 1b by adjusting the opening of the flow rate adjusting mechanism of the expander 15. Distributed. Thus, in the hot water supply circuit 2, the medium-temperature water supplied from the lower layer of the hot water storage tank 4 is cooled in the water cooling heat exchanger 5 and then flows into the water heating heat exchanger 3. .
Thus, in the heat pump water heater X1, the amount of refrigerant flowing into the water cooling heat exchanger 5, specifically the presence or absence of inflow, is controlled based on the temperature of the water detected by the water temperature sensor 21. The Therefore, for example, when the warming cycle 6 is used for heating operation, when the warm water is recirculated into the hot water storage tank 4, the warm water is supplied from the hot water tank 4 to the refrigerant circuit 1b. However, the heat exchange efficiency in the heat exchanger 3 for water heating is improved, and a decrease in energy consumption efficiency in the heat pump water heater X1 is prevented.
In addition, although the initial value of the inflow amount of the refrigerant to the water cooling heat exchanger 5 in the refrigerant circuit 1b is set in advance, in the refrigerant flow adjustment process, the subsequent inflow amount of the refrigerant is the subsequent step S5. It will be changed later.

  In step S5, the water temperature detected by the water temperature sensor 23, that is, the water temperature of the water flowing into the water heating heat exchanger 3 is equal to or higher than a preset set water temperature t2 (an example of a second predetermined temperature). It is determined by the control unit whether or not. Here, the set water temperature t2 is information stored in advance in the ROM or the like of the control unit, and is a temperature at which the heat exchange efficiency between the refrigerant and water in the water heating heat exchanger 3 deteriorates. . The set water temperature t2 is set to about 35 ° C., for example. That is, in step S5, it is determined whether or not the water flowing into the water heating heat exchanger 3 has been cooled to a temperature that does not lower the heat exchange efficiency in the water heating heat exchanger 3. The set water temperature t2 is preferably changeable according to an input from an operation unit (not shown). This changing process is executed by the control unit.

First, the case where it is determined that the water temperature detected by the water temperature sensor 23 is lower than the set water temperature t2 (No side of S5) will be described.
In this case, the water flowing into the water heating heat exchanger 3 is cooled to a temperature at which the heat exchange efficiency in the water heating heat exchanger 3 is not lowered. That is, the cooling performance of the water cooling heat exchanger 5 is sufficient. For this reason, the amount of refrigerant flowing into the water cooling heat exchanger 5 is not changed, and the process proceeds to the subsequent step S51.
In step S51, the control unit determines whether or not the water temperature detected by the water temperature sensor 23 is equal to or lower than a preset water temperature t3 (an example of a third predetermined temperature). Here, the set water temperature t3 is information stored in advance in the ROM or the like of the control unit, and the heat exchange efficiency between the refrigerant and water in the water heating heat exchanger 3 is good and more than necessary. This is a temperature indicating that water on the hot water supply circuit 2 is being cooled. Specifically, the set water temperature 3 is set to a temperature (for example, about 15 ° C.) lower than the set water temperature t2.
Here, when it is determined that the water temperature detected by the water temperature sensor 23 is not equal to or lower than the set water temperature t3 (No side of S51), the process proceeds to step S2 and is equal to or lower than the set water temperature t3. Is determined (Yes side of S51), the process proceeds to step S52.
In step S52, the expander 15 is controlled by the control unit, whereby the amount of refrigerant flowing into the water cooling heat exchanger 5 in the refrigerant circuit 1b is reduced by a predetermined amount. As a result, the cooling performance of the water cooling heat exchanger 5 decreases, but the amount of refrigerant flowing into the outdoor air heat exchanger 14 in the refrigerant circuit 1a increases accordingly. Therefore, since the heat exchange performance in the outdoor air heat exchanger 14 is improved, the amount of hot water supply in the heat pump water heater X1 can be increased. When step S52 is executed, the process proceeds to step S2.

Next, a case will be described in which it is determined in step S5 that the water temperature detected by the water temperature sensor 23 is equal to or higher than the set water temperature t2 (Yes side in S5).
In this case, the water flowing into the water heating heat exchanger 3 is not cooled to a temperature at which the heat exchange efficiency in the water heating heat exchanger 3 is not lowered. That is, the cooling performance in the water cooling heat exchanger 5 is not sufficient.
Therefore, in the subsequent step S6, the expander 15 is controlled by the control unit, whereby the amount of refrigerant flowing into the water cooling heat exchanger 5 in the refrigerant circuit 1b is increased by a predetermined amount. Thereby, since the cooling performance by the water cooling heat exchanger 5 is enhanced, the water flowing on the hot water supply circuit 2 can be cooled to a lower temperature before flowing into the water heating heat exchanger 3. Even if the inflow of the refrigerant to the outdoor air heat exchanger 14 is interrupted, the refrigerant circulated in the refrigerant circuit 1 is not allowed to exchange with the water on the hot water supply circuit 2 in the water cooling heat exchanger 5. Since heat can be absorbed by heat exchange between them, inflow of the refrigerant to the outdoor air heat exchanger 14 in the refrigerant circuit 1a may be blocked.

As described above, in the refrigerant flow adjustment process, the distribution amount of the refrigerant to each of the refrigerant circuit 1a and the refrigerant circuit 1b in the refrigerant circuit 1, that is, the outdoor air heat, based on the water temperature detected by the water temperature sensor 23. The amount of refrigerant flowing into each of the exchanger 14 and the water cooling heat exchanger 5 is adjusted. Therefore, the heat exchange performance in the outdoor air heat exchanger 14 and the water cooling heat exchanger 5 can be freely adjusted by arbitrarily setting the set water temperatures t2 and t3. That is, in the heat pump water heater X1, it is possible to arbitrarily adjust whether priority is given to the amount of hot water supply or energy consumption efficiency.
In addition, when the water on the hot water supply circuit 2 is likely to freeze, the refrigerant flow into the water cooling heat exchanger 5 is blocked, so that the water on the hot water supply circuit 2 is prevented from freezing. As a result, damage to the components on the water cooling heat exchanger 5 and the hot water supply circuit 2 is prevented.

FIG. 3 is a diagram showing another configuration example of the expander 15, and FIG. 4 is a flowchart for explaining another example of the refrigerant flow adjustment process.
In the present embodiment, the case where the expander 15 that can control the presence / absence and the amount of refrigerant flowing into the water-cooling heat exchanger 5 is described as an example. In the first embodiment, as shown in FIG. 3, instead of the expander 15, an electromagnetic valve that adjusts the presence or absence of refrigerant flowing from the water heating heat exchanger 3 to the water cooling heat exchanger 5. The structure provided with 15b and the capillary tube 15a which expands the said refrigerant | coolant which flows toward the said heat exchanger 5 for water cooling from the said electromagnetic valve 15b is demonstrated. The capillary tube 15a has a tube inner diameter and length set so that an appropriate flow rate of refrigerant flows so as to obtain the most efficient.
In such a configuration, the opening / closing of the electromagnetic valve 15b is controlled by the control unit, so that only the presence or absence (inflow / shutoff) of the refrigerant into the water cooling heat exchanger 5 is controlled.
That is, in the configuration provided with the expansion valve 15a and the electromagnetic valve 15b in place of the expander 15, as shown in the flowchart of FIG. 4, the refrigerant flow control process described in the embodiment (the flowchart of FIG. 2). Steps S1 to S4 in (see) are executed.
As a result, when there is a possibility that the water on the hot water supply circuit 2 is frozen, the flow of the refrigerant into the water cooling heat exchanger 5 is blocked, so that the water on the hot water supply circuit 2 is prevented from freezing. As a result, damage to the components on the water cooling heat exchanger 5 and the hot water supply circuit 2 is prevented.
In the configuration according to the first embodiment, detailed adjustment of the refrigerant flow rate is not performed as in the above-described embodiment, but the medium-temperature water can be efficiently heated with a simple and inexpensive configuration.

In the embodiment, the distribution amount of the refrigerant to each of the refrigerant circuit 1a and the refrigerant circuit 1b in the refrigerant circuit 1, that is, whether or not the refrigerant flows into the water cooling heat exchanger 5 is adjusted. Thus, the configuration adopting the method of adjusting the temperature of the water flowing into the water heating heat exchanger 3 has been described.
In the second embodiment, another method for adjusting the temperature of the water flowing into the water heating heat exchanger 3 will be described. FIG. 5 is a block diagram showing a schematic configuration of the heat pump water heater X2 according to the second embodiment of the present invention, and FIG. 6 is a flowchart for explaining an example of the procedure of the water flow rate adjustment process executed in the heat pump water heater X2. It is. 5 and 6, the same reference numerals are given to the same components and the same processing contents as those of the heat pump water heater X1 described in the embodiment, and the description thereof is omitted here.

In the heat pump water heater X2 according to the second embodiment, the water supplied from the lower layer of the hot water storage tank 4 in the hot water supply circuit 2 is supplied to the hot water supply circuit 2a (an example of a first water flow path) and the hot water supply circuit 2b (second The configuration differs from that of the heat pump water heater X1 in that a distributor 25 (an example of water distribution means) that distributes to each is provided.
The amount of water distributed by the distributor 25 can be adjusted by controlling the distributor 25 by the controller. The said control part when performing this adjustment process corresponds to a water distribution amount adjustment means here. The distributor 25 is an example of water distribution means for distributing water supplied from the hot water storage tank 4, and may be configured by combining, for example, an electromagnetic valve.

The hot water supply circuit 2 a includes a lower layer of the hot water storage tank 4, the water temperature sensor 21, the circulation pump 22, the distributor 25, the water cooling heat exchanger 5, the water temperature sensor 23, and the water heating heat exchanger 3. The water temperature sensor 24 and the upper layer of the hot water storage tank 4 are water flow paths connected in order.
The hot water supply circuit 2b includes a lower layer of the hot water storage tank 4, the water temperature sensor 21, the circulation pump 22, the distributor 25, the water temperature sensor 23, the water heating heat exchanger 3, the water temperature sensor 24, This is a water flow path in which the upper layers of the hot water storage tank 4 are sequentially connected. That is, the hot water supply circuit 2b is a flow path that bypasses the water cooling heat exchanger 5.
After the water discharged from the water cooling heat exchanger 5 in the hot water supply path 2a and the water flowing in the hot water supply path 2b bypassing the water cooling heat exchanger 5 are merged, the water heating It flows into the heat exchanger 3.
In the heat pump water heater X2 according to the first embodiment, the initial value of the water distribution amount to the hot water supply circuits 2a and 2b by the distributor 25 is set in advance, but the subsequent water distribution amount will be described later. It is changed in the water flow rate adjustment process (see the flowchart in FIG. 6).

Hereinafter, an example of the procedure of the water flow rate adjustment process executed by the control unit in the heat pump water heater X2 will be described according to the flowchart of FIG. 6 with reference to FIG. In the figure, S1, S2,... Represent processing procedure (step) numbers.
Here, only a processing procedure different from the refrigerant flow adjustment processing (see the flowchart of FIG. 2) described in the above embodiment will be described. In the water flow rate adjustment process, step S71 is executed instead of step S52 in the refrigerant flow adjustment process, and step S72 is executed instead of S6.

If it is determined in step S51 that the temperature detected by the water temperature sensor 23 is equal to or lower than the set value t3 (an example of a sixth predetermined temperature), the process proceeds to step S71 instead of step S52.
In step S71, the distributor 25 is controlled by the controller, so that the amount of water flowing into the water cooling heat exchanger 5 in the hot water supply circuit 2a is reduced by a predetermined amount. As a result, the amount of water cooled in the water cooling heat exchanger 5 decreases, so that the temperature of the water that flows from the hot water supply circuit 2a and the hot water supply circuit 2b and flows to the water heat exchanger 3 is further increased. Can do. At this time, the distributor 25 may block the flow of water into the hot water supply circuit 2a.

On the other hand, when the temperature detected by the water temperature sensor 23 is equal to or higher than the set value t2 (an example of the fifth predetermined temperature) in step S5, the process shifts to step S72 instead of step S6.
In step S72, the distributor 25 is controlled by the controller, so that the amount of water flowing into the water cooling heat exchanger 5 in the hot water supply circuit 2a is increased by a predetermined amount. As a result, the amount of water cooled in the water cooling heat exchanger 5 increases, so that the temperature of the water that flows from the hot water supply circuit 2a and the hot water supply circuit 2b and flows to the water heating heat exchanger 3 is further reduced. Can be made. At this time, the distributor 25 may block the flow of water into the hot water supply circuit 2b.

As described above, in the water flow rate adjustment process, the distribution amount of water to each of the hot water supply circuit 2a and the hot water supply circuit 2b in the hot water supply circuit 2 is adjusted based on the water temperature detected by the water temperature sensor 23. By doing so, the temperature of the water flowing into the water heating heat exchanger 3 can be appropriately adjusted. The said control part when performing this adjustment process corresponds to a water distribution amount adjustment means here.
In addition, adjusting the amount of water distribution to each of the hot water supply circuit 2a and the hot water supply circuit 2b in the hot water supply circuit 2 based on the water temperature detected by the water temperature sensor 21 is also conceivable as another embodiment. Specifically, on the condition that the temperature of the water detected by the water temperature sensor 21 is equal to or higher than a preset water temperature (an example of a fourth predetermined temperature, for example, about 35 ° C.), the distributor 25 It is conceivable to start the inflow of water into the hot water supply circuit 2a and to block the inflow of water into the hot water supply circuit 2a by the distributor 25 on condition that the temperature is lower than the set water temperature. Here, the control unit when executing such adjustment processing is also an example of the water distribution amount adjustment means.
In addition, the refrigerant flow adjustment process (see the flowchart in FIG. 2) described in the embodiment and the water flow rate adjustment process (see the flowchart in FIG. 6) described in the first embodiment may be performed simultaneously. It can be considered as an example. Specifically, it is conceivable to adjust the amounts of refrigerant and water flowing into the water-cooling heat exchanger 5 based on temperatures detected by the water temperature sensor 21 and the water temperature sensor 23.

By the way, in the structure which connects the said outdoor air heat exchanger 14 and the said water cooling heat exchanger 5 in series, the presence or absence of the inflow of the refrigerant | coolant to each of the said outdoor air heat exchanger 14 and the said water cooling heat exchanger 5 It is also possible to control the inflow amount independently.
Specifically, a refrigerant path flowing into the outdoor air heat exchanger 14 via the water cooling heat exchanger 5, and the outdoor air heat exchanger 14 bypassing the water cooling heat exchanger 5. It is conceivable to have a bypass path that flows into the flow path and a distributor that distributes the refrigerant discharged from the water heating heat exchanger 3 to the paths. The amount of refrigerant distributed by the distributor is controlled by the control unit.
According to such a configuration, by adjusting the amount of refrigerant distributed by the distributor, the amount of refrigerant flowing into each of the refrigerant path and the bypass path, that is, the outdoor air heat exchanger 14 and the water cooling It is possible to independently adjust the presence / absence and amount of refrigerant flowing into each heat exchanger 5.
Therefore, when there is a possibility that water from the hot water storage tank 4 is frozen in the water cooling heat exchanger 5, only the amount of refrigerant flowing into the water cooling heat exchanger 5 is reduced or blocked. it can.

The block diagram which shows schematic structure of the heat pump water heater which concerns on embodiment of this invention. The flowchart explaining an example of the procedure of the refrigerant | coolant flow adjustment process performed in the heat pump water heater which concerns on embodiment of this invention. The block diagram which shows the modification of the inflator 15. FIG. The flowchart explaining the other example of a refrigerant | coolant flow adjustment process. The block diagram which shows schematic structure of the heat pump water heater which concerns on Example 2 of this invention. The flowchart explaining an example of the procedure of the water flow rate adjustment process performed in the heat pump water heater which concerns on Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1b ... Refrigerant circuit 2, 2a, 2b ... Hot water supply circuit 3 ... Heat exchanger for water heating (an example of 1st water heat exchanger)
4 ... Hot water storage tank 5 ... Heat exchanger for water cooling (an example of a second water heat exchanger)
6 ... Heating cycle (an example of a heating cycle)
DESCRIPTION OF SYMBOLS 11 ... Compressor 12, 15 ... Expander 13 ... Refrigerant temperature sensor (an example of a refrigerant temperature detection means)
14 ... Outdoor air heat exchanger 15a ... Capillary tube 15b ... Solenoid valve 21 ... Water temperature sensor (an example of first water temperature detection means)
22 ... circulation pump 23 ... water temperature sensor (an example of second water temperature detection means)
24 ... Water temperature sensor 25 ... Distributor (an example of water distribution means)
41, 42 ... Water path 43 ... Hot water supply cock 6a ... Water circulation path 6b ... Brine circulation path 61 ... Water circulation pump 62 ... Heat exchanger 63 for heating ... Brine circulation pump 64 ... Heater S1, S2, ... Processing procedure (steps) )number

Claims (13)

Heat exchange is performed between the refrigerant circulation path through which the refrigerant is circulated, the water circulation path through which water is circulated, and the refrigerant discharged from the compressor in the refrigerant circulation path and the water circulated through the water circulation path. A first water heat exchanger, a hot water storage tank for storing water discharged from the first water heat exchanger, an expander for expanding the refrigerant discharged from the first water heat exchanger, Supplied from the outdoor air heat exchanger that performs heat exchange between the refrigerant flowing from the expander toward the compressor and outdoor air, the refrigerant flowing from the expander toward the compressor, and the hot water storage tank A heat pump water heater comprising: a second water heat exchanger for exchanging heat with the generated water,
Refrigerant temperature detection means for detecting the temperature of the refrigerant discharged from the expander;
Refrigerant flow adjusting means for adjusting presence / absence and / or amount of inflow of the refrigerant to the second water heat exchanger based on the temperature of the refrigerant detected by the refrigerant temperature detecting means;
Ri name with a,
When the temperature of the refrigerant detected by the refrigerant temperature detecting means is a temperature at which the water is solidified by heat exchange between the refrigerant and water, the second water heat exchanger the heat pump water heater, characterized in that it is intended to cut off the inflow of the refrigerant into.   The heat pump water heater according to claim 1, further comprising a heating cycle that uses hot water stored in the hot water storage tank as a heat medium. A first expander for discharging the refrigerant toward the outdoor air heat exchanger; and a second expander for discharging the refrigerant toward the second water heat exchanger. Comprising
The coolant temperature detecting means, any one of claims 1 or 2 is for detecting the first of said refrigerant discharged from the expander and / or the second temperature of the refrigerant discharged from the expander The heat pump water heater described in 1. The second expander adjusts the presence or absence of inflow of the refrigerant flowing from the first water heat exchanger toward the second water heat exchanger; and from the electromagnetic valve to the second A capillary tube for expanding the refrigerant flowing toward the water heat exchanger,
The refrigerant flow adjusting means adjusts presence or absence of inflow of the refrigerant flowing from the first water heat exchanger toward the second water heat exchanger by controlling the electromagnetic valve. 3. The heat pump water heater according to 3 . The heat pump water heater according to any one of claims 1 to 4 , further comprising first water temperature detecting means for detecting a temperature of water discharged from the hot water storage tank. The refrigerant flow adjusting means adjusts whether or not the refrigerant flows into the second water heat exchanger and / or the inflow amount based on the temperature of the water detected by the first water temperature detecting means. The heat pump water heater according to claim 5 . The refrigerant flow adjusting means causes the refrigerant to flow into the second water heat exchanger on condition that the temperature of the water detected by the first water temperature detecting means is equal to or higher than a first predetermined temperature, the first claim 6 temperature detected water by the water temperature detecting means is to block the inflow of the refrigerant into the second water heat exchanger on condition is less than the first predetermined temperature The heat pump water heater described in 1. The heat pump water heater according to any one of claims 1 to 7 , further comprising second water temperature detecting means for detecting a temperature of water flowing into the first water heat exchanger. The refrigerant flow adjusting means adjusts the presence or absence and / or the amount of inflow of the refrigerant into the second water heat exchanger based on the temperature of the water detected by the second water temperature detecting means. The heat pump water heater according to claim 8 . The refrigerant flow adjusting means adjusts the amount of the refrigerant flowing into the second water heat exchanger on condition that the temperature of the water detected by the second water temperature detecting means is equal to or higher than a second predetermined temperature. The water temperature is increased and flows into the second water heat exchanger on the condition that the temperature of the water detected by the second water temperature detecting means is not more than a third predetermined temperature lower than the second predetermined temperature. The heat pump water heater according to claim 9 , wherein the amount of the refrigerant is reduced. The water flow path includes a first water flow path that extends from the hot water storage tank through the first water heat exchanger to the hot water storage tank, and a second water heat exchanger from the hot water storage tank to the first water heat exchanger. A second water flow path that in turn passes through a water heat exchanger and continues to the hot water storage tank,
A water distribution means for distributing water supplied from the hot water storage tank to the first water circulation path and the second water circulation path; and the first water temperature detection means and / or the second water temperature detection means. The heat pump water heater according to any one of claims 8 to 10 , further comprising water distribution amount adjustment means for adjusting a water distribution amount by the water distribution means based on the detected water temperature. The water distribution amount adjusting means supplies water to the second water flow path with respect to the water distributor on the condition that the temperature of the water detected by the first water temperature detecting means is equal to or higher than a fourth predetermined temperature. The heat pump water heater according to claim 11 , wherein the heat pump water heater is distributed. The water distribution amount adjusting means uses the water distributor to supply water to the second water flow path on the condition that the temperature of the water detected by the second water temperature detecting means is equal to or higher than a fifth predetermined temperature. The amount of water distribution is increased, and the second temperature by the water distributor is provided on the condition that the temperature of the water detected by the second temperature detecting means is not more than a sixth predetermined temperature lower than the fifth predetermined temperature. The heat pump water heater according to claim 11 or 12 , which reduces the amount of water distributed to the water flow path.

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