JP4372762B2 - Heat pump water heater - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a heat pump type hot water heater that supplies water by heating water by heat exchange with a refrigerant circulating in a heat pump cycle provided with a compressor, an expander, and the like, and more particularly, a heat pump type having two heat pump cycles. It relates to a water heater.

2. Description of the Related Art Conventionally, a heat pump type hot water heater that supplies water by heating water by heat exchange with a refrigerant circulating in a heat pump cycle provided with a compressor, an expander, and the like is well known. The refrigerant is, for example, a carbon dioxide refrigerant or an HFC refrigerant. For example, Patent Document 1 discloses a heat pump cycle (hereinafter referred to as “CO ₂ cycle”) using a CO ₂ refrigerant (an example of a carbon dioxide refrigerant) and a heat pump cycle (hereinafter referred to as an example of an HFC refrigerant) using an R410A refrigerant. A heat pump type hot water supply system having “R410A cycle” is also shown. In the heat pump hot water supply system, the CO ₂ cycle is used when high-temperature hot water is required, and when low-temperature hot water is sufficient, the R410A cycle is used to heat the water.

By the way, since the carbon dioxide refrigerant can heat water to a high temperature (for example, about 90 ° C.) as a characteristic of the refrigerant, it is generally used for hot water storage operation in which hot water having a high temperature of about 90 ° C. is stored in a storage tank. . In addition, high temperature water of about 60 to 90 ° C. is stored in the upper layer of the storage tank, and water of about 30 to 50 ° C. (hereinafter referred to as “medium temperature water”) in which the high temperature water is cooled is stored in the lower layer of the storage tank. ”) Or about 15 ° C. water supplied from water supply or the like is stored. In the hot water storage operation, the water supplied from the lower layer of the storage tank is heated by a water heat exchanger that exchanges heat between the carbon dioxide refrigerant and water, and then returned to the upper layer of the storage tank. Is done.
Japanese Patent Laying-Open No. 2005-83585

However, the carbon dioxide refrigerant has a characteristic that the heat exchange efficiency with medium temperature water of about 30 to 50 ° C. is lower than the heat exchange efficiency with low temperature water of about 15 ° C. Therefore, when water is heated using a heat pump cycle in which the carbon dioxide refrigerant is circulated, the temperature of the water is about 30 to 50 ° C. compared to the case of heating water of about 15 ° C. The problem that the energy consumption efficiency of the said heat pump type hot water heater falls arises.
Therefore, the present invention has been made in view of the above circumstances, and the object of the present invention is that the temperature of water flowing into the water heat exchanger from the lower layer of the storage tank is a predetermined temperature (for example, about 30 ° C.). In order not to become the above, a heat pump type capable of preventing a decrease in heat exchange efficiency between the refrigerant and water in the water heat exchanger by cooling water stored in the lower layer of the storage tank in advance. The purpose is to provide a water heater.

In order to achieve the above object, the present invention provides at least a first compressor having a first refrigerant having a higher heat exchange efficiency with water having a lower temperature than a heat exchange efficiency with water having a higher temperature. And a first heat pump cycle circulated through the first expander and a second refrigerant having different characteristics from the first refrigerant are circulated through at least the second compressor and the second expander. A second heat pump cycle, a water heat exchanger for exchanging heat between the first refrigerant and / or the second refrigerant and water, and the first refrigerant and / or in the water heat exchanger. Heat exchange between a storage tank storing water to be exchanged with the second refrigerant and water stored in a lower layer of the storage tank with the first refrigerant in the water heat exchanger Tank water heating hand that heats and recirculates to the upper layer of the storage tank The temperature of water flowing into the water heat exchanger from the lower layer of the storage tank is detected, and the detected temperature of the water is predetermined. Cooling the water stored in the lower layer of the storage tank by heat exchange with the second refrigerant in the water heat exchanger and returning it to the lower layer of the storage tank on condition that the temperature is equal to or higher than the temperature It is configured as a heat pump type hot water heater characterized by For example, the first refrigerant is a carbon dioxide refrigerant, and the second refrigerant is an HFC refrigerant.
According to the present invention, when the temperature of the water flowing into the water heat exchanger from the lower layer of the storage tank becomes equal to or higher than the predetermined temperature (for example, about 30 ° C.), the water is stored in the lower layer of the storage tank. Since water is cooled, it is possible to prevent a decrease in heat exchange efficiency between the first refrigerant and water in the water heat exchanger. The predetermined temperature may be set as appropriate according to the characteristics of the first refrigerant.
Here, the tank water temperature detecting means for detecting the temperature of the water flowing into the water heat exchanger from the lower layer of the storage tank includes water in the storage tank or from the lower layer of the storage tank to the water heat exchanger. It may be arranged on the inflow path.

An indoor air heat exchanger that exchanges heat between the second refrigerant and indoor air; an outdoor air heat exchanger that exchanges heat between the second refrigerant and outdoor air; And a circulation direction switching means for switching the circulation path of the second refrigerant in the second heat pump cycle, that is, in a heat pump water heater having a function of indoor air conditioning (cooling and heating), the circulation direction switching means is controlled. Then, the second refrigerant is used in the order of the compressor, the indoor air heat exchanger, the expander, and the water heat exchanger, the compressor, the outdoor air heat exchanger, the expander, and the water. By circulating in the order of the heat exchanger, it is possible to cool water flowing from the lower layer of the storage tank by heat exchange with the second refrigerant in the water heat exchanger.
By the way, in the configuration further comprising a heating cycle such as floor heating using the water stored in the storage tank as a heat medium, the present invention is preferable because the medium temperature water radiated in the heating cycle is returned to the storage tank. is there.

  According to the present invention, the temperature of the water flowing into the water heat exchanger from the lower layer of the storage tank, the water in the storage tank or on the water inflow path from the lower layer of the storage tank to the water heat exchanger, etc. And when the temperature of the water becomes equal to or higher than the predetermined temperature (for example, about 30 ° C.), the water stored in the lower layer of the storage tank is cooled, thereby It is possible to prevent a decrease in heat exchange efficiency between the one refrigerant and water.

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 schematic configuration diagram of a heat pump type hot water heater X according to an embodiment of the present invention. FIGS. 2 and 3 are refrigerant flow paths when tank water cooling processing is performed in the heat pump type hot water heater X. FIG. 4 is a flowchart for explaining an example of a tank water cooling process executed by the control unit of the heat pump type hot water heater X.
First, the schematic configuration and basic operation of the heat pump type water heater X according to the embodiment of the present invention will be described. The heat pump water heater X preliminarily cools the water below the storage tank 31 when the temperature of water flowing into the water heat exchanger 32 from the lower layer of the storage tank 31 described later is equal to or higher than a predetermined temperature. This point has a feature, and this point will be described in detail later.
As shown in FIG. 1, the heat pump type hot water heater X includes two heat pump cycles 1 (an example of a first heat pump cycle), 2 (an example of a second heat pump cycle) in which refrigerant is circulated, and a flowing water path 30a˜ 30d, the storage tank 31, the water heat exchanger 32, the water temperature sensors 81 and 82, the circulation pump 34, the switching valves 41 to 46, and the floor heating cycle 6 (an example of a heating cycle) are schematically configured. The heat pump type water heater X 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 present embodiment, the switching valve is used as a means for switching the refrigerant and water flow paths in the heat pump type hot water heater X, but the present invention is not limited to this. For example, the switching is performed by providing a backflow prevention structure or the like. It is conceivable to omit the valve.

The water heat exchanger 32 is common to the heat pump cycles 1 and 2, and the refrigerant flowing in the pipe 14 connected to the heat pump cycle 1, the refrigerant flowing in the pipe 25 connected to the heat pump cycle 2, and Heat exchange is performed between the water flowing through the pipe 33 arranged on the flowing water path 30b from the water supply port to the hot water supply port or the flowing water path 30a returning from the lower layer of the storage tank 31 to the upper layer of the storage tank. Here, in the flowing water path 30a, the lower layer of the storage tank 31, the circulation pump 34, the switching valve 45, the water heat exchanger 32, the switching valves 43 and 46, and the upper layer or lower layer of the storage tank 31 are connected in order from the water supply port. It is a flowing water path (solid arrow) of the water. Note that the water exchanged with the refrigerant in the water heat exchanger is stored in the storage tank 31. Specifically, high temperature hot water heated by the water heat exchanger 32 is stored in the upper layer of the storage tank 31, and low temperature water supplied from the water supply port is stored in the lower layer of the storage tank 31. Is done.
The flowing water path 30b is a flowing water path (broken arrows) in which the switching valve 45, the water heat exchanger 32, the switching valve 43, and the hot water supply port are connected in order from the water supply port. The flowing water path 30c is a hot water flow path (broken arrow) from the upper layer of the storage tank 31 through the switching valve 44 to the hot water supply port, and the flowing water path 30d is connected to the switching valve 44 from the water supply port. It is the distribution channel (broken arrow) of the water which continues to the hot-water supply port.

The water temperature sensor 81 is disposed on the flowing water path 30a from the storage tank 31 to the water heat exchanger 32, and has a thermistor or the like that detects the temperature of water flowing into the water heat exchanger 32. It is an example of a tank water temperature detection means. The water temperature detected by the water temperature sensor 81 is input to the control unit and used as a determination index in a tank water cooling process (see the flowchart of FIG. 4) described later.
The water temperature sensor 82 includes a plurality of water temperature sensors 82 a to 82 d provided at predetermined intervals from the upper layer to the lower layer in the storage tank 31. The water temperature sensors 82a to 82d are a thermistor or the like that detects the temperature of water at each arrangement position. Here, the water temperature sensors 82a and 82b are provided in the upper layer of the storage tank 31, and detect the temperature of the water in the upper layer. The water temperature sensors 82c and 82d are provided in the lower layer of the storage tank 31, and detect the temperature of the water in the lower layer. The water temperature sensors 82c and 82d are an example of tank water temperature detecting means. The water temperature detected by the water temperature sensors 82c and 82d is input to the control unit and used as a determination index in the later-described (see the flowchart in FIG. 4).
In the present embodiment, a configuration in which both the water temperature sensor 81 and the water temperature sensor 82 are provided will be described. However, only one of the configurations may be provided.

In the heat pump type hot water heater X, each component is controlled by the control unit (not shown), whereby the water flowing on the flowing water path 30b is heated by the water heat exchanger 32 and directly from the hot water outlet. An instantaneous hot water supply operation for supplying hot water, a hot water storage operation in which water flowing on the flowing water path 30a is heated by the water heat exchanger 32 and stored in the storage tank 31, and the like are performed.
Here, in the instantaneous hot water supply operation, the control valves 43 and 45 are controlled by the control unit so that water supplied from the water supply port flows along the flowing water path 30b in the direction of the dashed arrow. Become. However, a sufficient amount of heating by the water heat exchanger 32 cannot be obtained for a certain time after the instantaneous hot water supply operation is started. Therefore, for a certain period of time after the start of instantaneous operation, the hot water stored in the storage tank 31 passes through the water flow path 30c and is supplied from the water supply port through the water flow path 30d in the switching valve 44. After being mixed and temperature-controlled, it is supplied to the hot water outlet. Thereby, hot water can be instantaneously supplied from the hot water supply port. And when it becomes possible to fully heat the water supplied from the water supply port by the water heat exchanger 32, the water supply to the storage tank 31 is stopped, and thereafter, the water heat is supplied from the water supply port. Instantaneous hot water supply is performed using a flowing water path 30b that passes through the exchanger 32 and continues to the hot water supply port. It is also possible to supply hot water as it is without mixing the hot water stored in the storage tank 31 with the water supplied from the water supply port.
On the other hand, in the hot water storage operation, the switching valve 43, 45, 46 is controlled by the control unit, and the circulation pump 34 is driven, so that water stored in the lower layer of the storage tank 31 flows into the flowing water path 30a. Along the direction of the solid arrow. At this time, the switching valve 46 is controlled by the control unit so that water on the flowing water path 30 a flows into the upper layer of the storage tank 31. Thereby, the hot water heated by the heat exchange with the refrigerant in the water heat exchanger 32 is returned to the upper layer of the storage tank 31. Here, the control unit for executing the process of heating the water stored in the lower layer of the storage tank 31 with the water heat exchanger 32 and returning it to the storage tank 31 is an example of tank water heating means. . In the heat pump type water heater X, the hot water in the storage tank 31 is used as a heat medium in the floor heating cycle 6.

The floor heating cycle 6 includes an upper layer of the storage tank 31, a hot water heat exchanger 62, a circulation pump 61, a hot water path 6a in which a lower layer of the storage tank 31 is connected in order, a circulation pump 63, a floor heating device 64, It has a brine (antifreeze) path 6b to which a hot water heat exchanger 62 is connected in order. The floor heating device 64 is a conventionally known floor heating device having a floor heating panel, a radiation panel, a hot air fan, etc. (not shown), and the description thereof is omitted here.
In the floor heating cycle 6, when the controller starts driving the circulation pump 61 and the circulation pump 63, the hot water stored in the storage tank 31 is circulated on the hot water path 6 a and the brine Brine is circulated through the path 6b. Thus, heat exchange is performed between the hot water and the brine in the hot water heat exchanger 62, and the brine is heated. That is, in the floor heating cycle 6, the hot water stored in the storage tank 31 is used as a heat medium. The brine heated by the hot water heat exchanger 62 flows into the floor heating device 64 to radiate heat, and then flows into the hot water heat exchanger 62 again. Thereby, floor heating in the floor heating device 64 is realized.
On the other hand, the hot water whose temperature has been lowered by heat exchange with the brine in the hot water heat exchanger 62 is returned to the lower layer of the storage tank 31. Therefore, when the floor heating cycle 6 is in operation, the water supplied from the lower layer of the storage tank 31 to the flowing water path 30a may include hot water whose temperature has been lowered in the hot water heat exchanger 62.
In the present embodiment, the floor heating cycle 6 has been described as an example of the heating cycle using the water stored in the storage tank 31 as a heat medium. However, the present invention is not limited to this, for example, reheating a bath. A cycle for performing is also considered as an example of a heating cycle.

The heat pump cycle 1 (hereinafter referred to as “CO ₂ cycle”) has a circulation path 10 in which a compressor 11, the water heat exchanger 32, an expander 12, and an outdoor air heat exchanger 13 are connected in order. . In the circulation path 10, when the compressor 11 is driven by the control unit (not shown), a CO ₂ refrigerant (an example of a first refrigerant), which is an example of a carbon dioxide refrigerant, circulates in an arrow direction shown in the drawing. Is done.
Here, the CO ₂ refrigerant has different characteristics from the R410A refrigerant described later, and can heat water to a high temperature (about 90 ° C.) as a characteristic of the refrigerant. Therefore, the CO ₂ cycle 1 is mainly used for the hot water storage operation in the heat pump type hot water heater X. However, as described above, the CO ₂ refrigerant has a characteristic that the heat exchange efficiency with low temperature water of about 15 ° C. is higher than the heat exchange efficiency with medium temperature water of about 30-50 ° C. Yes.

In the CO ₂ cycle 1, the high-temperature and high-pressure CO ₂ refrigerant compressed and discharged by the compressor 11 is cooled by heat exchange with water flowing on the flowing water path 30 a or 30 b in the water heat exchanger 32. Then, it expands in the expander 12. Thereafter, the low-temperature and low-pressure CO ₂ refrigerant expanded in the expander 12 is heat-exchanged with the outdoor air in the outdoor air heat exchanger 13 to absorb heat and vaporize, and then flows into the compressor 11 again.
In the CO ₂ cycle 1, the CO ₂ refrigerant is circulated through the circulation path 10 as described above, so that water flowing in the direction of the arrow on the flowing water path 30 a or 30 b is transferred to the water heat exchanger 32. It is heated to about 90 ° C. by heat exchange with the CO ₂ refrigerant. In addition, since the flow direction of the CO ₂ refrigerant and water in the water heat exchanger 32 is opposite, heat exchange between the CO ₂ refrigerant and water is performed efficiently.
Thereby, in the hot water storage operation, the switching valve 45 is controlled by the control unit (not shown) so as to pass through the flowing water path 30a, and the switching valve 43 is controlled by the control unit (not shown). Hot water heated in the water heat exchanger 32 is stored in the storage tank 31. In the instantaneous hot water supply operation, the switching valve 45 is controlled by the control unit (not shown) so as to pass through the flowing water path 30b, and the switching valve 43 is controlled by the control unit (not shown). Hot water heated in the water heat exchanger 32 is supplied to the hot water supply port.

On the other hand, the heat pump cycle 2 (hereinafter referred to as “R410A cycle”) includes a circulation path 20 (an example of a first circulation path) through which an R410A refrigerant (an example of a second refrigerant) that is an example of an HFC refrigerant is circulated, and A circulation path 40 (an example of a second circulation path) is included. Here, the R410A refrigerant, the CO ₂ has a refrigerant different properties, but can only heat the water compared to the CO ₂ refrigerant to a low temperature (about 65 ° C.), since the energy consumption efficiency (COP) is high , Suitable for relatively low boiling temperature. Therefore, the R410A cycle 2 is mainly used for the instantaneous hot water supply operation in the heat pump cycle X. Further, the R410A refrigerant has a characteristic that heat exchange efficiency when heating medium temperature water of about 30 to 50 ° C. is better than that of the CO ₂ refrigerant. Other examples of the R410A refrigerant include R407C / E, R404A, R507A, and R134a. Further, the two different refrigerants used in the heat pump type hot water heater X are not limited to the carbon dioxide refrigerant and the HFC refrigerant, and two refrigerants having different characteristics such as heat exchange efficiency and energy consumption efficiency may be used.

The circulation path 20 includes a compressor 21, a four-way valve 24, a switching valve 41, a water heat exchanger 32, a switching valve 42, an expander (for example, an expansion valve) 22, an outdoor air heat exchanger 23, and the four-way valve 24 in this order. Connected and configured. The outdoor air heat exchanger 23 performs heat exchange between the R410A refrigerant and outdoor air. The four-way valve 24, the switching valve 41, and the switching valve 42 are used for switching the circulation path of the R410A refrigerant in the R410A cycle 2, and correspond to refrigerant circulation path switching means.
In the circulation path 20, the R <b> 410 </ b> A refrigerant is circulated in the direction indicated by the solid arrow as illustrated in FIG. Specifically, the high-temperature and high-pressure R410A refrigerant compressed and discharged by the compressor 21 reaches the water heat exchanger 32 through the four-way valve 24 and the switching valve 41. The R410A refrigerant is cooled by heat exchange with water flowing on the flowing water path 30a or 30b in the water heat exchanger 32. Thereafter, the R410A refrigerant is expanded in the expander 22 via the switching valve 42. The low-temperature and low-pressure R410A refrigerant expanded in the expander 22 is heat-exchanged with the outdoor air in the outdoor air heat exchanger 23 to absorb heat and vaporize, and then returns to the compressor 21 again through the four-way valve 24. Inflow.
In the R410A cycle 2, as described above, the R410A refrigerant is circulated in the direction of the solid arrow in the circulation path 20, so that the water flowing in the direction of the arrow on the flowing water path 30a or 30b is transferred to the water heat exchanger 32. Is heated to about 65 ° C. by heat exchange with the R410A refrigerant. Since the flow direction of the R410A refrigerant and water in the water heat exchanger 32 is opposite, heat exchange between the R410A refrigerant and water is performed efficiently.

The water heat exchanger 32 is common to the CO ₂ cycle 1 and the R410A cycle 2, and the CO ₂ refrigerant and the R410A refrigerant circulated therethrough, the flowing water path 30a or the flowing water path. It is possible to simultaneously exchange heat with water flowing over 30b. Specifically, the water heat exchanger 32 includes the CO ₂ refrigerant pipe 14 provided in the water heat exchanger 32, the pipe 33 on the flowing water paths 30 a and 30 b, and the R410A refrigerant pipe 25. It is conceivable that the pipes 33 on the water flow paths 30a and 30b are in contact with each other. The water heat exchanger 32 is not limited to the above configuration.
In the heat pump type hot water heater X configured as described above, the CO ₂ cycle 1 and the R410A cycle 2 are operated and used at the same time, so that water can be heated with a heat exchange efficiency higher than the individual heat exchange efficiency. it can. Thereby, it is possible to increase the amount of hot water supply during the instantaneous hot water supply operation.

On the other hand, in the circulation path 40, a compressor 21, a four-way valve 24, a switching valve 41, an indoor air heat exchanger 4, a switching valve 42, an expander 22, an outdoor air heat exchanger 23 and a four-way valve 24 are sequentially connected. It is configured.
Here, the indoor air heat exchanger 4 is provided in an air conditioner (not shown) that performs indoor heating and cooling, and exchanges heat between the R410A refrigerant circulated in the circulation path 40 and room air. By doing so, the indoor air is heated or cooled.

Here, the heating operation and the cooling operation realized in the R410A cycle 2 of the heat pump type hot water heater X will be described.
(1) Heating operation When the user requests the heat pump water heater X to start a heating operation from an operation unit (not shown), in the heat pump water heater X, the control unit (not shown) The compressor 21 and the four-way valve 24 are controlled, and the circulation of the R410A refrigerant in the direction of the solid arrow in the circulation path 40 of the R410A cycle 2 is started. At this time, the illustrated solid line path is established inside the four-way valve 24.
As a result, the R410A refrigerant is circulated in the circulation path 40 in the direction of the solid arrow shown in the figure. Specifically, the high-temperature and high-pressure R410A refrigerant compressed and discharged by the compressor 21 reaches the indoor air heat exchanger 4 through the four-way valve 24 and the switching valve 41. The R410A refrigerant is cooled by exchanging heat with indoor air in the indoor air heat exchanger 4. Thereafter, the R410A refrigerant is expanded in the expander 22 via the switching valve 42. Then, the low-temperature and low-pressure R410A refrigerant expanded in the expander 22 is heat-exchanged with the outdoor air in the outdoor air heat exchanger 23 to absorb heat and vaporize, and then passes through the four-way valve 24 and again to the compressor 21. Flow into.
In the R410A cycle 2, the R410A refrigerant is circulated in the direction of the solid arrow in the circulation path 40 as described above, so that the indoor air is heated by heat exchange with the R410A refrigerant in the indoor air heat exchanger 4. Is done. That is, heating is realized by the heat pump type hot water heater X.

In the R410A cycle 2, the R410A refrigerant may be distributed to the circulation paths 20 and 40 to perform instantaneous hot water supply and heating simultaneously. However, in this case, a sufficient hot water supply temperature or hot water supply amount may not be obtained. However, in the heat pump type water heater X, when the instantaneous hot water supply and the heating are performed simultaneously, the CO ₂ refrigerant that circulates in the CO ₂ cycle 1 and the R410A that circulates in the R410A cycle 2 in the water heat exchanger 32. It is possible to heat water simultaneously with the refrigerant. Thereby, when performing instantaneous hot water supply and heating simultaneously, sufficient hot water supply temperature and amount of hot water supply can be obtained.
For example, in the heat pump type hot water heater X, when a heating operation is performed by the R410A cycle 2, when a user requests a hot water supply to an operation unit (not shown), the heat pump type hot water heater X The switching valves 41 and 42 are controlled by the control unit (not shown), and in the R410A cycle 2, the R410A refrigerant is circulated by being distributed to the circulation paths 20 and 40. At this time is driven control of the compressor 11 of the CO ₂ cycle 1 at the same time by the control unit (not shown), the circulation of the CO ₂ refrigerant in the CO ₂ cycle 1 is started.
Thereby, in the water heat exchanger 32, water is heated by heat exchange with both the R410A refrigerant and the CO ₂ refrigerant. That is, the decrease in the heating capacity of water during the simultaneous operation of instantaneous hot water supply and heating in the R410A cycle 1 is compensated by heat exchange with the CO ₂ refrigerant circulating in the CO ₂ cycle 1. Therefore, when performing instantaneous hot water supply and heating simultaneously in the R410A cycle 2, a sufficient hot water supply temperature and amount of hot water supply can be obtained.

(2) Cooling operation On the other hand, when the user requests the heat pump water heater X to start the cooling operation from an operation unit (not shown), the heat pump water heater X has the control unit (not shown). ), The compressor 21 and the four-way valve 24 are controlled, and the circulation of the R410A refrigerant in the direction of the broken line arrow is started in the circulation path 40 of the R410A cycle 2. At this time, the illustrated broken line path is established inside the four-way valve 24.
Thereby, in the circulation path 40, the R410A refrigerant is circulated in the direction of the broken arrow shown in the figure. Specifically, the high-temperature and high-pressure R410A refrigerant compressed and discharged by the compressor 21 reaches the outdoor air heat exchanger 23 via the four-way valve 24. The R410A refrigerant is cooled by exchanging heat with outdoor air in the outdoor air heat exchanger 23. Thereafter, the R410A refrigerant is expanded in the expander 22. The low-temperature and low-pressure R410A refrigerant expanded in the expander 22 is subjected to heat exchange with the indoor air in the indoor air heat exchanger 4 via the switching valve 42, and absorbs and vaporizes. It flows into the compressor 21 again through the four-way valve 24.
In the R410A cycle 2, the R410A refrigerant is circulated in the direction of the broken line arrow in the circulation path 40 as described above, so that the indoor air is exchanged with the R410A refrigerant in the indoor air heat exchanger 4. To be cooled. That is, cooling is realized by the heat pump type hot water heater X.
As described above, in the heat pump type hot water heater X, the instantaneous hot water supply operation, the hot water storage operation, and the air conditioning operation are performed by controlling the CO ₂ cycle 1 and the R410A cycle 2 by the control unit. .

By the way, as described above, the CO ₂ refrigerant circulated in the CO ₂ cycle 1 exchanges heat with medium temperature water of about 30 to 50 ° C. compared with heat exchange efficiency with low temperature water of about 15 ° C. It has the characteristic that efficiency is low. Therefore, when water is heated using the CO ₂ cycle 1, when the temperature of the water is about 30 to 50 ° C., the heat pump type hot water heater is compared with the case of heating water of about 15 ° C. There arises a problem that the energy consumption efficiency of X is lowered.
In particular, in the configuration having the floor heating cycle 6 that uses high-temperature hot water stored in the storage tank 31 as a heat medium, such as the heat pump type water heater X, the water is returned from the floor heating cycle 6 to the storage tank 31. In addition, there is a high possibility that medium-temperature water of about 30 to 50 ° C. will flow into the water heat exchanger 32.
Therefore, in the heat pump type water heater X according to the embodiment of the present invention, the control unit performs a tank water cooling process (see the flowchart of FIG. 4) described later, so that When the temperature of the water flowing into the water heat exchanger 32 is high, the water stored in the lower layer of the storage tank 31 is cooled and returned to the lower layer of the storage tank 31. The said control part when performing this process corresponds to a tank water cooling means here.

Hereinafter, an example of the procedure of the tank water cooling process executed by the control unit in the heat pump type water heater X according to the embodiment of the present invention will be described with reference to FIGS. . Here, S1, S2,... In the figure indicate processing procedure (step) numbers.
The tank water cooling process is executed constantly or every predetermined time while the heat pump type water heater X is in operation.
First, in step S1, the water temperature detected by the water temperature sensor 81 or the water temperature sensor 82d (hereinafter referred to as “detected water temperature”), that is, the temperature of the water flowing into the water heat exchanger 32 from the lower layer of the storage tank 31. Is determined by the control unit whether the temperature is 30 ° C. (an example of a predetermined temperature) or more. In the process of step S1, it is determined whether or not the heat exchange efficiency between the CO ₂ refrigerant and water in the water heat exchanger 32, that is, the energy consumption efficiency in the heat pump type hot water heater X is reduced. . In step S1, it is determined whether or not the detected water temperature is 30 ° C. or higher, but this temperature may be appropriately changed and set depending on the type of refrigerant.
In addition, as a determination index in step S1, a detected water temperature by one or both of the water temperature sensor 81 and the water temperature sensor 82d may be used. Moreover, when the water temperature sensor 82 is provided with a plurality of water temperature sensors 82a to 82d as described above, the water temperatures detected by the plurality of water temperature sensors may be used as the determination index. For example, it is conceivable to determine whether or not the average value of the detected water temperature by the water temperature sensors 82c and 82d is 30 ° C. or higher in the step S1.

When it is determined in step S1 that the detected water temperature is not 30 ° C. or higher (No side of S1), that is, the water flowing into the water heat exchanger 32 from the lower layer of the storage tank 31 is at a low temperature of less than 30 ° C. If the heat exchange efficiency between the CO ₂ refrigerant and water in the water heat exchanger 32 is good, the determination process in step S1 is repeatedly executed.
On the other hand, when medium temperature water of 30 ° C. or higher is stored in the lower layer of the storage tank 31, such as when the floor heating cycle 6 is in operation, the detected water temperature is determined to be 30 ° C. or higher. (Yes side of S1), that is, the water flowing into the water heat exchanger 32 from the lower layer of the storage tank 31 is 30 ° C. or higher, and the heat exchange efficiency between the CO ₂ refrigerant and water is poor. In this case, the process proceeds to step S2 described later.

  In step S2, the controller determines whether or not the heating operation is being performed in the R410A cycle 2. Here, when it is determined that the heating operation is being performed (Yes side of S2), the R410A refrigerant is circulated in the direction of the solid line arrow in FIG. 1 in the R410A cycle 2, and the circulation path of the R410A refrigerant Since it cannot be switched, the process returns to step S1. That is, when the heating operation is executed in the R410A cycle 2, even if the detected water temperature is 30 ° C. or higher, the water flowing from the storage tank 31 into the water heat exchanger 32 is not cooled. In addition, when heating operation is being performed in the R410A cycle 2, it is conceivable as another embodiment that the heating operation is stopped and then the process proceeds to step S3 described later.

On the other hand, when it is determined in step S2 that the heating operation is not performed (No side of S2), the process proceeds to step S3.
In step S3, the control unit determines whether or not the CO ₂ cycle 1 is operating, that is, whether or not water is being heated by the CO ₂ refrigerant.
Here, if it is determined that the CO ₂ cycle 1 is in operation (Yes in S3), the process proceeds to step S4.

In step S4, after the operation of the CO ₂ cycle 1 is stopped by the control unit, the process proceeds to step S5. Specifically, the drive of the compressor 21 is stopped. The operation of the CO ₂ cycle 1 is resumed after execution of step S10 described later, for example.
This is because when the water from the storage tank 31 is heated, it is returned to the upper layer of the storage tank 31, and when the water below the storage tank 31 is cooled as described later, the lower layer of the storage tank 31 is used. This is because these processes cannot be executed at the same time. However, each of the CO ₂ cycle 1 and the R410A cycle 2 performs heat exchange with water supplied from the storage tank 31, and the upper or lower layer of the storage tank 31 from the heat exchanger. In the configuration having the flowing water path that follows, the operation of the CO ₂ cycle 1 may not be stopped because each can operate independently.

On the other hand, when it is determined that the CO ₂ cycle 1 is not in operation (No in S3), the process proceeds to Step S5.
In step S5, the control unit determines whether or not the cooling operation is being executed in the R410A cycle 2. If it is determined that the cooling operation is not being executed (No side in S5), the process proceeds to step S61, and if it is determined that the cooling operation is being executed (Yes side in S5). In step S62, the process proceeds to step S62.
First, step S61 executed when it is determined in step S5 that the cooling operation is not being executed will be described with reference to FIG.
In step S61, the control unit operates the R410A cycle 2, and the four-way valve 24, the switching valve 41, and the switching valve 42 are controlled so that the circulation path of the R410A refrigerant in the R410A cycle 2 is established. By switching, the R410A refrigerant flows into the water heat exchanger 32. Specifically, in the R410A cycle, as indicated by a solid arrow in FIG. 2, the R410A refrigerant is converted into the compressor 21, the four-way valve 24, the outdoor air heat exchanger 23, the expander 22, and the switching. The valve 42, the water heat exchanger 32, the switching valve 41, the four-way valve 24, and the compressor 21 are circulated in this order.
As a result, in the R410A cycle 2, the low-temperature and low-pressure R410A refrigerant that is cooled by being exchanged with outdoor air in the outdoor air heat exchanger 23 and cooled and expanded in the expander 22 is transferred to the water heat exchanger 32. Will be infused.

Next, step S62 executed when it is determined in step S5 that the cooling operation is being executed will be described with reference to FIG.
In this case, the R410A cycle 2 has already been operated, and in the R410A cycle, as indicated by solid arrows in FIG. 3, the R410A refrigerant is exchanged with the compressor 21, the four-way valve 24, and the outdoor air heat exchange. The compressor 23, the expander 22, the switching valve 42, the indoor air heat exchanger 4, the switching valve 41, the four-way valve 24, and the compressor 21 are circulated in this order.
In the step S62, the switching valve 41, 42 is controlled by the control unit, whereby the circulation path of the R410A refrigerant in the R410A cycle 2 is switched and distribution to the water heat exchanger 32 is started. . Specifically, in the R410A cycle 2, as indicated by solid and dashed arrows in FIG. 3, the compressor 21, the four-way valve 24, the outdoor air heat exchanger 23, the expander 22, and the switching valve 42 are shown. The R410A refrigerant that has been circulated in order is distributed to the indoor air heat exchanger 4 and the water heat exchanger 32, and then merged by the switching valve 41, and then to the compressor 21 via the four-way valve 24. Refluxed.
Thus, in the R410A cycle 2, the low-temperature and low-pressure R410A refrigerant that is cooled by being exchanged with outdoor air in the outdoor air heat exchanger 23 and cooled and expanded in the expander 22 is converted into the indoor air heat exchanger 4. And into the water heat exchanger 32. That is, in this case, the cooling operation and the cooling of the water in the storage tank 31 are performed simultaneously.

  Thereafter, in step S7 following step S61 or step S62, the switching valve 46 is operated so that the water discharged from the water heat exchanger 32 flows into the lower layer of the storage tank 31 on the flowing water path 30a. Controlled by the control unit, the process proceeds to step S8. When the water is heated in the water heat exchanger 32 and returned to the storage tank 31, the switching valve 46 allows the water discharged from the water heat exchanger 32 to move to the upper layer of the storage tank 31. It is controlled by the controller so as to flow in.

  In Step S8, the circulation pump 34 is driven by the control unit, whereby the water stored in the lower layer of the storage tank 31 is circulated on the flowing water path 30a. Specifically, the water in the lower layer of the storage tank 31 flows into the water heat exchanger 32 from the lower layer of the storage tank 31 as indicated by solid arrows in FIGS. After being cooled by heat exchange with the low-temperature and low-pressure R410A refrigerant, it is returned to the lower layer of the storage tank 31 through the switching valves 41, 43, and 46. Thereby, the water stored in the lower layer of the storage tank 31 is cooled to about 20 ° C., for example.

Next, in step S9, the control unit determines whether or not the water temperature detected by the water temperature sensor 81 or the water temperature sensor 82d is 20 ° C. or less. In the process of step S9, it is determined whether or not the heat exchange efficiency between the CO ₂ refrigerant and water in the water heat exchanger 32, that is, the state of poor energy consumption efficiency in the heat pump type hot water heater X, has been eliminated. . In step S9, it is determined whether or not the detected water temperature is 20 ° C. or lower, but this temperature may be appropriately changed and set depending on the type of the refrigerant.
Here, when it is determined that the detected water temperature is not 20 ° C. or lower (No side of S9), that is, the water flowing into the water heat exchanger 32 from the lower layer of the storage tank 31 is higher than 20 ° C., If the state of poor heat exchange efficiency between the CO ₂ refrigerant and water in the water heat exchanger 32 has not been eliminated, the determination process of step S9 is repeatedly executed, and the water in the lower layer of the storage tank 31 is The cooling process is continued.

On the other hand, when it is determined that the water in the lower layer of the storage tank 31 has been sufficiently cooled and the detected water temperature has become 20 ° C. or lower (Yes side of S9), that is, the water heat exchanger from the lower layer of the storage tank 31 When the water flowing into the water 32 is 20 ° C. or less and the state in which the heat exchange efficiency between the CO ₂ refrigerant and water in the water heat exchanger 32 is poor, the process proceeds to step S10. .
In the step S10, the R410A cycle 2 is controlled by the control unit, whereby the circulation of the R410A refrigerant to the water heat exchanger 32 is stopped. Specifically, during the cooling operation, the switching valves 41 and 42 are controlled to end the distribution of the refrigerant to the water heat exchanger 32. When the cooling operation is not being performed, the R410A is performed. The operation of cycle 2 is stopped (compressor 21 is stopped).

In this way, in the heat pump type hot water heater X, the tank water cooling process (see the flowchart of FIG. 4) is executed by the control unit, so that it flows into the water heat exchanger 32 from the lower layer of the storage tank 31. When the temperature of the water to be increased becomes higher, the water stored in the lower layer of the storage tank 31 is cooled by heat exchange with the R410A refrigerant in the water heat exchanger 32, It returns to the lower layer of the storage tank 31.
Therefore, in the heat pump type hot water heater X, when the hot water storage operation or the instantaneous hot water supply operation is performed using the CO ₂ cycle 1, the water heat exchanger 32 preliminarily cooled to 20 ° C. or less. Since heat exchange is performed between the CO ₂ refrigerant and the CO ₂ refrigerant, the heat exchange efficiency in the water heat exchanger 32 is good, and as a result, a reduction in the energy consumption efficiency of the heat pump type hot water heater X can be prevented.

FIG. 5 is a schematic configuration diagram of the heat pump type hot water heater X1 according to the embodiment of the present invention, and FIGS. 6 and 7 show a refrigerant flow path when tank water cooling processing is performed in the heat pump type hot water heater X1. FIG. 8 and FIG. 8 are flowcharts for explaining an example of the procedure of the tank water cooling process executed by the control unit of the heat pump type water heater X1. In addition, the same code | symbol is attached | subjected about the component similar to the said heat pump type water heater X demonstrated in the said embodiment, and the same process sequence (step), and the description is abbreviate | omitted.
As shown in FIG. 5, the heat pump type hot water heater X1 has an R410A cycle 5 instead of the R410A cycle 2 of the heat pump type hot water heater X. The R410A cycle 5 is provided with switching valves 51 to 56 controlled by the control unit (not shown) and two expanders 22a and 22b. In this embodiment, the switching valve is used as means for switching the refrigerant and water flow paths in the heat pump type hot water heater X1, but the present invention is not limited to this. For example, a switching valve is provided by providing a backflow prevention structure or the like. May be omitted.
In the heat pump type water heater X1 thus configured, in the R410A cycle 5, simultaneous operation of heating and instantaneous hot water and simultaneous operation of cooling and instantaneous hot water are possible.

(1) Simultaneous operation of heating and instantaneous hot water supply During simultaneous operation of heating and instantaneous hot water supply, in the R410A cycle 5, the compressor 21, the four-way valve 24, and the switching valve 51 are controlled by the control unit (not shown). By controlling .about.56, the R410A refrigerant is circulated in the direction of the solid arrow shown in FIG.
Specifically, in the circulation path 20, the R410A refrigerant flows into the compressor 21, the four-way valve 24, the switching valve 51, the switching valve 52, the water heat exchanger 32, the expander 22a, the switching valve 53, the switching valve 54, The outdoor air heat exchanger 23, the switching valve 56, the four-way valve 24, and the compressor 21 are circulated in this order. Thereby, the water flowing on the flowing water path 30a or 30b is heated in the water heat exchanger 32.
On the other hand, in the circulation path 40, the R410A refrigerant flows into the compressor 21, the four-way valve 24, the switching valve 51, the indoor air heat exchanger 4, the switching valve 55, the expander 22b, the switching valve 54, and the outdoor air heat exchanger 23. , The switching valve 56, the four-way valve 24, and the compressor 21 are circulated in this order. Thereby, in the said indoor air heat exchanger 4, indoor air is heated and heating is performed.

(2) Simultaneous operation of cooling and instantaneous hot water supply During simultaneous operation of cooling and instantaneous hot water supply, in the R410A cycle 5, the control unit (not shown) performs the compressor 21, the four-way valve 24, and the switching valve 51-51. By controlling 56, the R410A refrigerant is circulated in the direction of the broken arrow shown in FIG.
Specifically, in the circulation path 20, the R410A refrigerant flows into the compressor 21, the four-way valve 24, the switching valve 56, the switching valve 52, the water heat exchanger 32, the expander 22a, the switching valve 53, the switching valve 55, The indoor air heat exchanger 4, the switching valve 51, the four-way valve 24, and the compressor 21 are circulated in this order. Thereby, the water flowing on the flowing water path 30a or 30b is heated in the water heat exchanger 32.
On the other hand, in the circulation path 40, the R410A refrigerant is supplied from the compressor 21, the four-way valve 24, the switching valve 56, the outdoor air heat exchanger 23, the switching valve 54, the expander 22b, the switching valve 55, and the indoor air heat exchanger 4. , The switching valve 51, the four-way valve 24, and the compressor 21 are circulated in this order. As a result, the indoor air heat exchanger 4 cools the room air by cooling it.

By the way, in the heat pump type water heater X1, when the heating operation is performed in the R410A cycle 2 (see FIG. 1), the water below the storage tank 31 cannot be cooled.
However, the heat pump type water heater X1 according to the present embodiment can cool the water below the storage tank 31 even when the heating operation is performed in the R410A cycle 5. Hereinafter, FIG. 6 and FIG. Referring to FIG. 8, an example of the tank water cooling process performed by the control unit in the heat pump type hot water heater X1 will be described according to the flowchart of FIG. In addition, about the process sequence similar to the tank water cooling process (refer the flowchart of FIG. 4) demonstrated in the said embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
In the tank water cooling process, it is determined whether or not the heating operation is performed in step S41, which is executed subsequent to step S4. Here, when it is determined that the heating operation is not performed (No side of S41), the process proceeds to Step S5, and when it is determined that the heating operation is performed (Yes side of S41). ), The process proceeds to step S42.

When it is determined in step S41 that the heating operation is being performed, the R410A cycle 2 is already in operation in the heat pump type hot water heater X1. Specifically, in the R410A cycle, as indicated by a solid arrow in FIG. 6, the R410A refrigerant is converted into the compressor 21, the four-way valve 24, the switching valve 51, the indoor air heat exchanger 4, and the switching. The valve 55, the expander 22b, the switching valve 54, the outdoor air heat exchanger 23, the switching valve 56, the four-way valve 24, and the compressor 21 are circulated in this order.
In step S42, the control unit controls the switching valve 52, the switching valve 53, the switching valve 55, and the switching valve 56, thereby switching the circulation path of the R410A refrigerant in the R410A cycle 2. At this time, the switching valve 52, the switching valve 53, the switching valve 55, and the switching valve 56 when switching the circulation path of the R410A refrigerant in the R410A cycle 5 are controlled by the control unit to switch the refrigerant path. Corresponds to means.

Specifically, in the R410A cycle 2, as indicated by solid arrows in FIG. 7, the R410A refrigerant is converted into the compressor 21, the four-way valve 24, the switching valve 51, the indoor air heat exchanger 4, and the The R410A is circulated in the order of the switching valve 55, the switching valve 53, the expander 22a, the water heat exchanger 32, the switching valve 52, the switching valve 56, the four-way valve 24, and the compressor 21. A refrigerant circulation path is formed.
As a result, in the R410A cycle 2, the low-temperature and low-pressure R410A refrigerant that is cooled by being exchanged with indoor air in the indoor air heat exchanger 4 and expanded in the expander 22a is transferred to the water heat exchanger 32. Will be infused. Therefore, when the circulation pump 34 is driven in the step 8, the water flowing into the water heat exchanger 32 from the lower layer of the storage tank 31 is transferred to the water heat exchanger 32 as indicated by solid arrows in FIG. After being cooled by heat exchange with the low-temperature and low-pressure R410A refrigerant at 32, it is returned to the lower layer of the storage tank 31.
Thus, in the heat pump type hot water heater X1, the heating operation and the cooling of the water stored in the lower layer of the storage tank 31 can be performed simultaneously. Needless to say, the cooling operation and the cooling of the water stored in the lower layer of the storage tank 31 can be performed simultaneously as described in the above embodiment.

The schematic block diagram of the heat pump type hot water heater which concerns on embodiment of this invention. The figure for demonstrating the distribution | circulation route of the refrigerant | coolant in the tank water cooling process performed in the heat pump type hot water heater which concerns on embodiment of this invention. The figure for demonstrating the distribution | circulation route of the refrigerant | coolant in the tank water cooling process performed in the heat pump type hot water heater which concerns on embodiment of this invention. The flowchart explaining an example of the procedure of the tank water cooling process performed in the heat pump type hot water heater which concerns on embodiment of this invention. The schematic block diagram of the heat pump type hot water heater which concerns on the Example of this invention. The figure for demonstrating the distribution | circulation route of the refrigerant | coolant in the tank water cooling process performed in the heat pump type hot water heater which concerns on the Example of this invention. The figure for demonstrating the distribution | circulation route of the refrigerant | coolant in the tank water cooling process performed in the heat pump type hot water heater which concerns on the Example of this invention. The flowchart explaining an example of the procedure of the tank water cooling process performed in the heat pump type water heater which concerns on the Example of this invention.

Explanation of symbols

1 ... heat pump cycle (an example of a first heat pump cycle)
2 ... Heat pump cycle (an example of a second heat pump cycle)
4 ... Indoor air heat exchanger 6 ... Floor heating cycle (an example of a heating cycle)
11, 21 ... compressors 12, 22, 22 a, 22 b ... expanders 13, 23 ... outdoor air heat exchangers 14, 25, 33 ... pipe 20 ... circulation path 40 ... circulation path 24 ... four-way valve (of the circulation path switching means) One case)
30a-30d ... Flowing water path 31 ... Reservoir tanks 41-46, 51-56 ... Switching valves S1, S2, ... Process procedure (step) numbers

Claims (5)

A first refrigerant is circulated through at least the first compressor and the first expander that has a higher heat exchange efficiency with water having a lower temperature than that with water having a higher temperature. A first heat pump cycle, a second heat pump cycle in which a second refrigerant having characteristics different from the first refrigerant is circulated through at least a second compressor and a second expander, and the first heat pump cycle. Heat exchange between the refrigerant and / or the water heat exchanger that exchanges heat between the second refrigerant and water, and the first refrigerant and / or the second refrigerant in the water heat exchanger The water stored in the storage tank in which water is stored and the water stored in the lower layer of the storage tank are heated by heat exchange between the first refrigerant in the water heat exchanger and returned to the upper layer of the storage tank A tank water heating means, A machine,
Tank water temperature detecting means for detecting the temperature of water flowing into the water heat exchanger from the lower layer of the storage tank;
On the condition that the temperature of the water detected by the tank water temperature detecting means is equal to or higher than a predetermined temperature, the water stored in the lower layer of the storage tank is heated between the second refrigerant in the water heat exchanger. Tank water cooling means for cooling by replacement and returning to the lower layer of the storage tank;
A heat pump water heater characterized by comprising:   The heat pump type hot water heater according to claim 1, wherein the first refrigerant is a carbon dioxide refrigerant, and the second refrigerant is an HFC refrigerant.   The heat pump hot water supply according to any one of claims 1 and 2, wherein the tank water temperature detection means is disposed in the storage tank and / or on a water inflow path from the storage tank to the water heat exchanger. Machine. An indoor air heat exchanger for exchanging heat between the second refrigerant and indoor air, an outdoor air heat exchanger for exchanging heat between the second refrigerant and outdoor air, and the second Circulation path switching means for switching the circulation path of the second refrigerant in the heat pump cycle,
The tank water cooling means controls the circulation direction switching means so that the second refrigerant is converted into the second compressor, the indoor air heat exchanger, the second expander, and the water heat exchange. It is what circulates in order of a unit, or in order of said 2nd compressor, said outdoor air heat exchanger, said 2nd expander, and said water heat exchanger. Heat pump water heater.   The heat pump type hot water heater according to any one of claims 1 to 4, further comprising a heating cycle that uses hot water stored in the storage tank as a heat medium.

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