JP2003232563A - Thermal storage hot water supply apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent lowering of COP of a refrigerant circuit in thermal storage in a thermal storage hot water supply apparatus using the refrigerant circuit performing a heat pump cycle operation as a heat source side part. <P>SOLUTION: Carbon dioxide is used as a refrigerant of the refrigerant circuit 2. A heat source side heat exchanger 25 performs heat exchange between the refrigerant of the refrigerant circuit 2 and water of a water circuit 20. A thermal storage means 3 of the water circuit 20 is provided with a high temperature side thermal storage material 62 for performing heat exchange with water of a high temperature side heat exchanger 63 and a low temperature side thermal storage material 66 formed of latent heat thermal storage material having a melting point lower than that of the high temperature side thermal storage material 62 for performing heat exchange with water of a low temperature side heat exchanger 67 connected in series to the high temperature side heat exchanger 63. The water circuit 20 is so constructed that at the time of thermal storage to a thermal storage means 3, water flows from the high temperature side heat exchanger 63 to the low temperature side heat exchanger 67, and water flowing out of the low temperature side heat exchanger 67 flows into the heat source side heat exchanger 25. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat storage water heater, and more particularly to a measure for improving the COP of a refrigerant circuit as a heat source side portion for performing a heat pump cycle.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open No. 2001-20
As disclosed in Japanese Patent No. 7163, a heat storage device is generally known in which the heat of the heat source side is temporarily stored in the heat storage means of the heat medium circuit and the heat of the heat storage means is supplied to the user side via the heat medium. ing. In this heat storage device, for example, a heat exchanger is provided in a heat storage means filled with a heat storage material, water as a heat medium is passed through a heat transfer tube of the heat exchanger, and water heated by the heat storage material is supplied to a user side. It is used for water heaters that supply hot water. As the heat storage material of the heat storage means, a material using a latent heat storage material is often used in order to secure as much heat storage amount as possible.

[0003]

By the way, when the heat storage device is used for a water heater, the heat source side portion is constituted by a refrigerant circuit for performing a heat pump cycle, and a heat exchanger is used to cool the refrigerant and heat of the refrigerant circuit. It is conceivable to adopt a configuration in which the heat medium of the medium circuit is heat-exchanged.

However, in the case of such a configuration,
When the temperature of the heat storage material rises during heat storage, the amount of heat exchanged in the heat exchanger decreases and the CO in the refrigerant circuit decreases.
There is a problem that P decreases. For example, when the temperature of the heat medium flowing into the heat exchanger rises, the temperature difference between the inlet temperature of the heat exchanger on the refrigerant circuit side and the inlet temperature of the heat exchanger on the heat medium circuit becomes small, and The heat exchange efficiency decreases and the heat exchange amount decreases. As a result,
The enthalpy difference between the inlet side and the outlet side of the heat exchanger is reduced, the capacity is sharply reduced, and the COP of the refrigerant circuit is reduced.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a heat storage water heater using a refrigerant circuit that performs a heat pump cycle operation as a heat source side portion during heat storage. CO in the refrigerant circuit
It is to prevent P from decreasing.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a high temperature of the heat storage means (3) when the heat medium of the heat medium circuit (20) stores heat in the heat storage means (3). After radiating heat to the side heat storage material (62), it radiates heat to the low temperature side heat storage material (66) having a lower melting point than the high temperature side heat storage material (62) and flows into the heat source side heat exchanger (25). .

Specifically, the first solution is a refrigerant circuit (2) in which a refrigerant circulates to perform a heat pump cycle operation.
A heat medium circuit (20) having a heat storage means (3) for circulating a heat medium, and a refrigerant and a heat medium circuit (2) in the refrigerant circuit (2).
Heat source side heat exchanger (2) that exchanges heat with the heat medium
Assuming a heat storage water heater for supplying hot water using the heat stored in the heat storage means (3), the heat storage means (3) includes a high temperature side heat storage material (62) and the high temperature side. Heat storage material (6
And a low temperature side heat storage material (66) made of a latent heat storage material having a melting point lower than that of 2), and the heat medium circuit (20) includes a heat medium,
When heat is stored in the heat storage means (3), heat is radiated to the high temperature side heat storage material (62) of the heat storage means (3) and then radiated to the low temperature side heat storage material (66) to flow into the heat source side heat exchanger (25). It is supposed to be flushed to.

The second solution means has a refrigerant circuit (2) for circulating a refrigerant to perform a heat pump cycle operation and a heat storage means (3), and a heat medium circuit (2) for circulating a heat medium.
0) and a heat source side heat exchanger (25) for exchanging heat between the refrigerant of the refrigerant circuit (2) and the heat medium of the heat medium circuit (20), and the heat storage means (3) stores heat. The heat storage means (3) on the premise of a heat storage water heater that uses the generated heat to supply hot water.
Is the high temperature side heat exchanger (6) connected to the heat medium circuit (20).
High temperature side heat storage material (62) that exchanges heat with the heat medium of 3)
And a latent heat storage material having a lower melting point than the high temperature side heat storage material (62), and the low temperature side heat exchanger (67) connected in series with the high temperature side heat exchanger (63) in the heat medium circuit (20). A low temperature side heat storage material (66) for exchanging heat with the heat medium of
In the heat medium circuit (20), the heat medium flows from the high temperature side heat exchanger (63) to the low temperature side heat exchanger (67) during heat storage in the heat storage means (3), and the low temperature side heat exchanger (67). ), The heat medium flowing out from the heat source side heat exchanger (25) flows into the heat source side heat exchanger (25).

A third solving means is the above first or second solving means, wherein the high temperature side heat storage material (62) of the heat storage means (3) is composed of a latent heat storage material.

The fourth solving means is the refrigerant circuit (2) according to any one of the above first to third solving means.
Are configured to compress the refrigerant above its critical pressure.

The fifth solution is that in the fourth solution, carbon dioxide is used as the refrigerant.

A sixth solving means is the high temperature side heat storage material (6) according to any one of the first to fifth solving means.
2) is sodium acetate trihydrate, melting point 50-70 ° C
Of paraffin and sugar alcohol having a melting point of 50 to 70 ° C.

A seventh solving means is the low-temperature side heat storage material (6) according to any one of the first to sixth solving means.
6) is sodium sulfate decahydrate, melting point is 20-40
It is composed of one of paraffin at a temperature of ℃ and calcium chloride.

That is, according to the first solution means, the heat source side heat exchanger (25) is used when heat is stored in the heat storage means (3).
The refrigerant in the refrigerant circuit (2) heats the heat medium in the heat medium circuit (20). The heat medium heated by the refrigerant in the refrigerant circuit (2) is used as the high temperature side heat storage material (62) of the heat storage means (3).
After radiating heat to the low temperature side heat storage material (66), the low temperature side heat storage material (66) is melted. That is, the heat radiated from the heat medium to the low temperature side heat storage material (66) is stored as latent heat. Then, this heat medium flows into the heat source side heat exchanger (25).

That is, since the low temperature side heat storage material (66) is composed of a latent heat storage material having a lower melting point than the high temperature side heat storage material (62), the temperature of the low temperature side heat storage material (66) is stable near the melting point. In this way, it is possible to suppress the temperature of the heat medium flowing into the heat source side heat exchanger (25) from rising. As a result, the amount of heat exchange between the refrigerant and the heat medium in the heat source side heat exchanger (25) can be increased without increasing the size of the heat storage means (3). Then, the enthalpy difference between the inlet side and the outlet side of the refrigerant in the heat source side heat exchanger (25) can be made large, the capacity can be increased, and the COP of the refrigerant circuit (2) decreases during heat storage. Can be prevented.

In the second solving means, the refrigerant in the refrigerant circuit (2) in the heat source side heat exchanger (25) is the heat medium in the heat medium circuit (20) when the heat is accumulated in the heat accumulating means (3). To heat. The heat medium heated by the refrigerant in the refrigerant circuit (2) flows into the high temperature side heat exchanger (63) and radiates heat to the high temperature side heat storage material (62) of the heat storage means (3). Then, the heat medium radiated to the high temperature side heat storage material (62) flows into the low temperature side heat exchanger (67) and further radiates heat to the low temperature side heat storage material (66),
The low temperature side heat storage material (66) is melted. That is, the heat radiated from the heat medium to the low temperature side heat storage material (66) is stored as latent heat. Then, the heat medium radiated to the low temperature side heat storage material (66) flows through the heat medium circuit (20) and returns to the heat source side heat exchanger (25).

That is, since the low temperature side heat storage material (66) is composed of a latent heat storage material having a lower melting point than the high temperature side heat storage material (62), the temperature of the low temperature side heat storage material (66) is stable near the melting point. In this way, it is possible to suppress the temperature of the heat medium flowing into the heat source side heat exchanger (25) from rising. As a result, the amount of heat exchange between the refrigerant and the heat medium in the heat source side heat exchanger (25) can be increased without increasing the size of the heat storage means (3). Then, the enthalpy difference between the inlet side and the outlet side of the refrigerant in the heat source side heat exchanger (25) can be made large, the capacity can be increased, and the COP of the refrigerant circuit (2) decreases during heat storage. Can be prevented.

In the third solving means, the first
Alternatively, in the second solving means, since the high temperature side heat storage material (62) is made of a latent heat storage material, heat can be stored in the heat storage means (3) with high efficiency.

Further, in the fourth solving means, the first
According to any one of the third to third means, the refrigerant is compressed to its critical pressure or higher in the refrigerant circuit (2). Then, during heat storage, the refrigerant compressed to a pressure equal to or higher than the critical pressure is stored in the heat source side heat exchanger (25) at the low temperature side heat storage material (66).
It is cooled by exchanging heat with the heat medium of the heat medium circuit (20) cooled by. That is, since the refrigerant flowing into the heat source side heat exchanger (25) is compressed to the critical pressure or higher,
The heat source side heat exchanger (25) is cooled without phase change. Therefore, the temperature difference between the refrigerant temperature and the heat medium temperature directly affects the heat exchange amount in the heat source side heat exchanger (25). As a result, the enthalpy difference between the inlet side and the outlet side of the refrigerant in the heat source side heat exchanger (25) can be made large, the capacity can be increased, and the COP of the refrigerant circuit (2) decreases during heat storage. Can be prevented.

In the fifth solving means, the fourth means is used.
In the solution, the carbon dioxide is compressed to its critical pressure or higher in the refrigerant circuit (2). Then, the carbon dioxide compressed to the critical pressure or higher is stored in the heat source side heat exchanger (2
In 5), it is cooled by exchanging heat with the heat medium of the heat medium circuit (20) cooled by the low temperature side heat storage material (66).

In the sixth solving means, the first
In any one of the fifth to fifth solving means, the high temperature side heat storage material (62) is sodium acetate trihydrate, and the melting point is 50 to 7
Since it is constituted by any one of 0 ° C. paraffin and sugar alcohol having a melting point of 50 to 70 ° C., the heat medium can be heated within the range of 50 to 70 ° C. at the time of heat storage, and the temperature is moderate. It is possible to reliably supply hot water.

In the seventh solving means, the first
In any one of the sixth to sixth means, the low temperature side heat storage material (66) is sodium sulfate decahydrate and has a melting point of 20 to
Since it is composed of one of 40 ° C. paraffin and calcium chloride, it is possible to suppress the temperature rise of the heat medium flowing into the heat source side heat exchanger (25) during heat storage. In addition, the refrigerant can be reliably cooled in the heat source side heat exchanger (25). Especially, the high temperature side heat storage material (62) is made of sodium acetate trihydrate and has a melting point of 50.
In the case of being composed of any one of paraffin of 70 ° C. and sugar alcohol having a melting point of 50 to 70 ° C., the high temperature side heat storage material (62) is heated to an appropriate temperature during heat storage,
It is possible to achieve both suppression of temperature rise of the heat medium flowing into the heat source side heat exchanger (25).

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings.

<Embodiment 1> As shown in FIG. 1, a heat storage device (1) according to Embodiment 1 includes a refrigerant circuit (2), a water circuit (20) as a heat medium circuit, and a heat storage means (3). ) And a controller (41) to form a hot water supply system.

The refrigerant circuit (2) includes a compressor (4), a heat source side heat exchanger (25) for exchanging heat between the refrigerant in the refrigerant circuit (2) and the water in the water circuit (20), and liquid-gas. A heat exchanger (7), an expansion valve (8) as a pressure reducing mechanism, and an evaporator (9) are connected in order, and are configured as a so-called vapor compression type refrigerant circuit that performs a heat pump cycle operation. An accumulator (4A) is provided on the suction side of the compressor (4). The liquid-gas heat exchanger (7) recovers heat in the refrigerant circuit (2). The liquid-gas heat exchanger (7) includes a high temperature side passage (10) through which the refrigerant flowing out of the heat source side heat exchanger (25) flows, and a low temperature side passage (10) through which the refrigerant flowing out of the evaporator (9) flows. 11), and heat exchange is performed between the refrigerant flowing through the high temperature side flow path (10) and the refrigerant flowing through the low temperature side flow path (11).

The refrigerant in the refrigerant circuit (2) is carbon dioxide (C
O ₂ ).

The water circuit (20) includes a pump (21), a high temperature side heat exchanger (63) and a low temperature side heat exchanger (67) provided in the heat storage means (3), and a three-way valve (23). And a heat source side heat exchanger (25) are sequentially connected by a water pipe (24).

The heat source side heat exchanger (25) includes a refrigerant circuit (2).
The high temperature side flow path (25a) through which the refrigerant flows and the low temperature side flow path (25b) through which the water of the water circuit (20) flows. The high temperature side flow path (25a) has one end connected to the discharge side of the compressor (4) and the other end connected to the high temperature side flow path (1) of the liquid-gas heat exchanger (7).
0) is connected. The low temperature side flow path (25b) has one end connected to the three-way valve (23) and the other end connected to the suction side of the pump (21).

A check valve (26) is provided on the discharge side of the pump (21).
Is provided. Check valve (26) and high temperature side heat exchanger (6
A hot water supply pipe (27) is connected between the above and 3).
The hot water supply pipe (27) is a supply path for supplying the hot water of the water circuit (20) to a user side (not shown). Hot water supply piping (2
A closing valve (28) is provided in 7). Between the hot water supply pipe (27) and the high temperature side heat exchanger (63), a shutoff valve (2
9) is provided.

The water circuit (20) includes a first bypass pipe (30) that bypasses the three-way valve (23). The first bypass pipe (30) is provided with a closing valve (31). Also,
The water circuit (20) includes a second bypass pipe (32).
One end of the second bypass pipe (32) is connected between the closing valve (29) and the high temperature side heat exchanger (63), and the second bypass pipe (3) is connected.
The other end of 2) is connected between the three-way valve (23) and the low temperature side flow path (25b) of the heat source side heat exchanger (25). A closing valve (33) is provided in the second bypass pipe (32). One end of the three-way valve (23) is connected to a water supply pipe (34) that supplies water to the water circuit (20). The water supply pipe (34) is provided with a closing valve (35).

The heat storage means (3) comprises a high temperature side heat storage tank (61) and a low temperature side heat storage tank (65). As shown in FIG. 2, the high-temperature side heat storage tank (61) and the low-temperature side heat storage tank (65) are located above or inside the substantially cubic container (51) divided into upper and lower parts by a partition wall (70). It is composed of the lower side. Incidentally, in FIG. 2, where the container (51) is drawn by a solid line, it is drawn by a virtual line for convenience.

The high temperature side heat storage tank (61) is filled with the high temperature side heat storage material (62). As the high temperature side heat storage material (62), for example, any one of sodium acetate trihydrate, paraffin having a melting point of 50 to 70 ° C. and sugar alcohol having a melting point of 50 to 70 ° C. can be suitably used. As this paraffin,
Paraffin # 140 (C ₂₈ H ₅₈ , melting point 61.4 ° C; Nippon Seiro
(Manufactured by Co., Ltd.) can be used.

The low temperature side heat storage tank (65) is filled with the low temperature side heat storage material (66). As the low temperature side heat storage material (66), for example, any of sodium sulfate decahydrate, paraffin having a melting point of 20 to 40 ° C., and calcium chloride can be suitably used. As this paraffin, for example, normal paraffin SCP-0028 (C ₁₈ H ₃₈ , melting point 28.1 ° C; Nippon Seiro Co., Ltd.)
Manufactured) can be used.

The high temperature side heat exchanger (63) provided in the water circuit (20) is arranged in the high temperature side heat storage tank (61). The high temperature side heat exchanger (63) includes a fin (52) and a heat transfer tube (53) penetrating the fin (52), and is configured as a so-called fin-and-tube heat exchanger. The fin (52) is configured such that a plurality of plate-shaped bodies extending in the vertical direction are arranged at equal intervals in the depth direction over substantially the entire temperature of the high temperature side heat storage tank (61). A plurality of heat transfer tubes (53) are provided, each of which has a water pipe (2) of the water circuit (20).
4) are connected in parallel to each other. Each heat transfer tube (5
3) includes a horizontal portion (54) extending in a substantially horizontal direction and a connecting portion (55) that connects the horizontal portions (54) adjacent in the substantially vertical direction to each other at their end portions in a staggered manner. (61) are arranged in a zigzag shape from the upper end to the lower end.

The low temperature side heat exchanger (67) provided in the water circuit (20) is arranged in the low temperature side heat storage tank (65). The low temperature side heat exchanger (67) includes a fin (52) and a heat transfer tube (53) penetrating the fin (52), and is configured as a so-called fin-and-tube heat exchanger. The fin (52) is configured such that a plurality of plate-shaped bodies extending in the vertical direction are arranged at equal intervals in the depth direction over substantially the entire temperature of the low temperature side heat storage tank (65). A plurality of heat transfer tubes (53) are provided, and the lower ends thereof are connected to the water pipes (24) of the water circuit (20) in parallel with each other. Each heat transfer tube (53) includes a horizontal portion (54) extending in a substantially horizontal direction,
And a connecting portion (55) that alternately connects horizontal portions (54) adjacent to each other in a substantially vertical direction at their ends, and is arranged in a zigzag shape from the upper end to the lower end of the heat storage tank (65). It is configured. The upper ends of the heat transfer tubes (53) of the low temperature side heat exchanger (67) are connected to each other.

The lower end of each heat transfer tube (53) of the high temperature side heat exchanger (63) and each heat transfer tube (5 of the low temperature side heat exchanger (67)
The upper end of 3) is connected to each other by a bridge pipe (71), and in each heat transfer pipe (53), water is stored in the high temperature side heat storage tank (61).
From the upper end to the lower end of the low temperature side heat storage tank (65) or in the opposite direction. That is, the high temperature side heat exchanger (63) and the low temperature side heat exchanger (67) are connected to the water circuit (2
0) connected in series.

As shown in FIG. 1, the controller (41) is provided with a switching control means (42) as a switching means and an additional cooking control means (43). The switching control means (42) is for the water circuit (20) during heat storage operation for storing heat in the heat storage means (3).
Water from the high temperature side heat exchanger (63) to the low temperature side heat exchanger (67)
Flow to the heat source side heat exchanger (25) and then switch to the heat source side heat exchanger (25), while the water in the water circuit (20) heats on the low temperature side during the heat storage operation in which the heat stored in the heat storage means (3) is used. The flow direction of the water in the water circuit (20) is switched so that the water flows from the exchanger (67) to the high temperature side heat exchanger (63) and is then supplied to the user side. Specifically, the switching control means (42) is configured to supply the water supply pipe (34) during the heat storage operation.
The closing valve (35), the closing valve (28) of the hot water supply pipe (27), and the closing valve (33) of the second bypass pipe (32) are closed, and the closing valve (29) and the first bypass pipe (30) are closed. ) Closure valve (31)
Is opened and the pump (21) is driven. Further, the switching control means (42) closes the closing valve (31) of the first bypass pipe (30) and the closing valve (33) of the second bypass pipe (32) during the heat storage utilization operation, and closes the closing valve (29). ), The closing valve (35) of the water supply pipe (34) and the closing valve (28) of the hot water supply pipe (27) are opened, and the pump (21) is stopped.

The additional cooking control means (43) is configured to perform a second heat storage utilization operation in which water is heated by utilizing both the heat storage of the heat storage means (3) and the heat of the refrigerant circuit (2). .
Specifically, the additional cooking control means (43) closes the closing valve (29) and the closing valve (31) of the first bypass pipe (30), and closes the closing valve (35) of the water supply pipe (34) and the second. The closing valve (33) of the bypass pipe (32) and the closing valve (28) of the hot water supply pipe (27) are opened, and the pump (21) and the refrigerant circuit (2) are driven.

The operation of each heat storage operation and heat storage utilization operation executed by the heat storage device (1) will be described below.

The heat storage operation is performed by the heat storage material (62,
This is an operation in which heat is stored in the heat storage material (62, 66) by melting 66). In the refrigerant circuit (2), the refrigerant circulates as follows. That is, carbon dioxide as a refrigerant is compressed to a critical pressure or higher in the compressor (4) and discharged. This high temperature refrigerant exchanges heat with the water in the low temperature side flow path (25b) in the high temperature side flow path (25a) of the heat source side heat exchanger (25) to be cooled. The water in the low temperature side flow path (25b) is cooled by the low temperature side heat exchanger (67) in the water circuit (20) as described later. The high temperature refrigerant flowing out of the high temperature side flow path (25a) is further cooled in the liquid-gas heat exchanger (7) by the low temperature refrigerant flowing out of the evaporator (9). In these coolings, as shown in FIG. 3, the refrigerant is cooled from 100 ° C. to 30 ° C., for example, but no phase change occurs in the refrigerant. The refrigerant flowing out of the high temperature side flow path (10) of the liquid-gas heat exchanger (7) is decompressed by the expansion valve (8) and is cooled and condensed. The refrigerant whose temperature has decreased due to the pressure reduction is evaporated in the evaporator (9). The refrigerant flowing out of the evaporator (9) is passed through the low temperature side flow path (1) of the liquid-gas heat exchanger (7).
In 1), after heat exchange with the high temperature refrigerant in the high temperature side flow path (10), it is sucked into the compressor (4) via the accumulator (4A). Then, this circulation is repeated.

In the water circuit (20), the water supply pipe (34)
Closing valve (35), hot water supply pipe (27) closing valve (28), and second bypass pipe (32) closing valve (33) are closed,
Closing valve (29) and closing valve (3) of the first bypass pipe (30)
1) is opened. The water in the water circuit (20) is supplied to the pump (21), the high temperature side heat exchanger (63) and the low temperature side heat exchanger (6).
7), and circulates in the order of the low temperature side flow path (25b) of the heat source side heat exchanger (25).

Specifically, the water in the water circuit (20) flows through the high temperature side flow path (25a) of the refrigerant circuit (2) in the low temperature side flow path (25b) of the heat source side heat exchanger (25). The coolant is heated to, for example, about 80 ° C., and becomes high-temperature hot water. After passing through the pump (21), the high temperature water flows into the high temperature side heat exchanger (63) of the heat storage means (3). And this hot water is
The flow is split and the horizontal part (54) and connection part (5) of each heat transfer tube (53)
5), heat is exchanged with the high temperature side heat storage material (62), and it is gradually cooled. Then, the cooled high temperature water flows into the low temperature side heat exchanger (67) through the bridge pipe (71). As a result, the high temperature side heat storage material (62) is heated by the high temperature water and melted sequentially from the upper part, and heat (latent heat and sensible heat) is stored in the high temperature side heat storage material (62). When the heat storage is completed, the temperature of the high temperature side heat storage material (62) is, for example, about 70 ° C. at the upper portion and about 40 ° C. at the lower portion.

Then, this water is split again in the low temperature side heat exchanger (67) and flows into each heat transfer tube (53), where it exchanges heat with the low temperature side heat storage material (66) and is gradually cooled to become low temperature water. .
As a result, the low temperature side heat storage material (66) is heated by water and melts in order from the top, and heat (latent heat and sensible heat) is stored in the low temperature side heat storage material (66). When the heat storage is completed, the temperature of the low temperature side heat storage material (66) becomes, for example, about 40 ° C. at the upper part and about 20 ° C. at the lower part.

The low temperature water flowing out of the low temperature side heat exchanger (67) has a temperature of, for example, about 25 ° C., flows out into the water pipe (24) of the water circuit (20), and flows through the first bypass pipe (30). Then, it flows into the low temperature side flow path (25b) of the heat source side heat exchanger (25). The water flowing into the low temperature side flow path (25b) of the heat source side heat exchanger (25) exchanges heat with the refrigerant in the high temperature side flow path (25a) to cool the refrigerant, and the above circulation operation is repeated.

On the other hand, the heat storage utilization operation is an operation at the time of tapping, which utilizes the heat stored in the heat storage means (3). In this heat storage device (1), as the heat storage use operation, the first heat storage use operation that uses only the heat storage of the heat storage means (3) and the heat storage means (3)
Second, which uses both the heat storage of and the heat of the refrigerant circuit (2)
The heat storage utilization operation can be selectively executed.

In the first heat storage utilizing operation, the refrigerant circuit (2) is not operated and the water circuit (20) is operated as follows.
That is, by the switching control means (42) of the controller (41), the closing valve (31) and the second valve of the first bypass pipe (30).
The closing valve (33) of the bypass pipe (32) is closed, and the closing valve (29), the closing valve (35) of the water supply pipe (34) and the closing valve (28) of the hot water supply pipe (27) are opened.

Then, the room temperature water supplied from the water supply pipe (34) flows into the low temperature side heat exchanger (67) arranged in the low temperature side heat storage tank (65). At this time, water is transferred to each heat transfer tube (53).
It splits into and flows in from the lower end side. And
This water is supplied to the horizontal portion (54) and the connecting portion (5) of the heat transfer tube (53).
It flows through 5) and exchanges heat with the low temperature side heat storage material (66) and is gradually heated. Then, the heated water passes through the bridge pipe (71) and flows into the high temperature side heat exchanger (63) arranged in the high temperature side heat storage tank (61). This water splits into the heat transfer tubes (53) again in the high temperature side heat exchanger (63) and flows. At this time, the water is further heated to about 65 ° C. by the high temperature side heat storage material (62) to become hot water.

The heated water is supplied from the upper end of the high temperature side heat exchanger (61) to the water pipe (24) of the water circuit (20).
Spill to. The hot water heated by the heat storage means (3) flows out of the high temperature side heat exchanger (63), and then is supplied from the water circuit (20) to the use side circuit (not shown) through the hot water supply pipe (27). It

In the second heat storage utilizing operation, both the refrigerant circuit (2) and the water circuit (20) are operated. The closing valve (29) and the closing valve (31) of the first bypass pipe (30) are closed,
Closing valve (35) of water supply pipe (34), second bypass pipe (32)
Shutoff valve (33) and hot water supply pipe (27) shutoff valve (2)
8) is opened. The water supplied from the water supply pipe (34) is supplied to the low temperature side heat exchanger (67) and the high temperature side heat exchanger (6).
It flows into 3) and is heated by the heat storage material (62, 66) of the heat storage means (3).

The hot water heated by the heat storage material (5) is
For example, the temperature is around 65 ° C, and the high temperature side heat exchanger (63)
Drained from. The hot water flowing out of the high temperature side heat exchanger (63) flows through the second bypass pipe (32) and flows into the low temperature side flow path (25b) of the heat source side heat exchanger (25). Low temperature side flow path (2
The hot water flowing into 5b) is heated by the refrigerant flowing through the high temperature side flow path (25a) of the heat source side heat exchanger (25) of the refrigerant circuit (2), and becomes hot water of higher temperature. The hot water has a temperature of, for example, about 75 ° C., flows out from the low temperature side flow path (25b) of the heat source side heat exchanger (25), and then flows through the hot water supply pipe (27) from the water circuit (20) to the use side. Supplied to a circuit (not shown).

As described above, in the second heat storage utilizing operation, the water heated by the heat storage means (3) is further heated by the heat source side (2), so that higher temperature hot water can be generated. That is, according to the second heat storage utilization operation, so-called reheating operation by the heat source side (2) is possible.

Next, an example of the measurement results of the inlet temperature and the outlet temperature of the heat storage means (3) during the heat storage operation will be described with reference to FIG. The inlet temperature refers to the temperature of water flowing into the high temperature side heat exchanger (63), and the outlet temperature refers to the temperature of water flowing out from the low temperature side heat exchanger (67). In this measurement, sodium acetate trihydrate is used as the high temperature side heat storage material (62), and sodium sulfate decahydrate is used as the low temperature side heat storage material (66). Further, FIG. 4 also shows the measurement results when the heat storage material of the heat storage means (3) is composed of one type of sodium acetate trihydrate for comparison. The inlet temperature is 80 ° C immediately after the start of heat storage operation.
To be stable. That is, the water in the water circuit (20) flowing into the heat storage means (3) is transferred to the heat source side heat exchanger (25) in the refrigerant circuit (2).
Since it is heated by the refrigerant of about 8
Stabilizes to 0 ° C.

On the other hand, the outlet temperature is affected by the temperature of the heat storage material. That is, when one type of heat storage material for comparison is used, the outlet temperature continues to rise until reaching the vicinity of the melting point of the heat storage material (about 50 to 60 ° C.) when the heat storage operation starts, and then the rising gradient becomes gentle. Becomes a stable region. In contrast,
When two kinds of heat storage materials are used, the outlet temperature only rises gradually after starting the heat storage operation, and near the melting point of the low temperature side heat storage material (66) (about 20 ° C) at the beginning of operation. It is in the stable area at. After that, the temperature rises and becomes a stable region near the melting point of the high temperature side heat storage material (62) (about 50 ° C.). Therefore, when using this heat storage material and a latent heat storage material having a melting point lower than that of the case where one type of heat storage material is used, it is possible to prevent the outlet temperature from increasing during heat storage operation. It is possible.

As described above, according to the heat storage device (1) of the first embodiment, during the heat storage operation, the refrigerant of the refrigerant circuit (2) in the heat source side heat exchanger (25) has the water circuit (20). )
Of water. Then, the water heated by the refrigerant in the refrigerant circuit (2) flows into the high temperature side heat exchanger (63) and radiates heat to the high temperature side heat storage material (62). The water radiated to the high temperature side heat storage material (62) flows into the low temperature side heat exchanger (67) and further radiates heat to the low temperature side heat storage material (66) to melt the low temperature side heat storage material (66). Let That is, from water to low temperature side heat storage material (66)
The heat radiated to is stored as latent heat. Then, the water radiated to the low temperature side heat storage material (66) flows through the water circuit (20) and returns to the heat source side heat exchanger (25).

That is, since the low temperature side heat storage material (66) is composed of the latent heat storage material having a lower melting point than the high temperature side heat storage material (62), the temperature of the low temperature side heat storage material (66) is stable near the melting point. However, this can prevent the temperature of the water flowing into the heat source side heat exchanger (25) from rising. As a result, the amount of heat exchange between the refrigerant and water in the heat source side heat exchanger (25) can be increased without increasing the size of the heat storage means (3). Then, the enthalpy difference between the inlet side and the outlet side of the refrigerant in the heat source side heat exchanger (25) can be made large, the capacity can be increased, and the COP of the refrigerant circuit (2) decreases during heat storage. Can be prevented.

In the refrigerant circuit (2), the refrigerant is compressed to its critical pressure or higher. During the heat storage operation, the refrigerant compressed to the critical pressure or higher is cooled by exchanging heat with the water in the water circuit (20) cooled by the low temperature side heat storage material (66) in the heat source side heat exchanger (25). To be done. That is, since the refrigerant flowing into the heat source side heat exchanger (25) is compressed to the critical pressure or higher, the heat source side heat exchanger (25) is cooled without phase change. Therefore, the temperature difference between the refrigerant temperature and the water temperature is the same as the heat source side heat exchanger (2
This will affect the amount of heat exchange in 5). As a result, the enthalpy difference between the inlet side and the outlet side of the refrigerant in the heat source side heat exchanger (25) can be made large and the capacity can be increased, and the COP of the refrigerant circuit (2) decreases during heat storage operation. Can be prevented. For example, in the configuration with one type of heat storage material, due to the temperature rise of the heat storage material (62),
While the COP of the refrigerant circuit (2) drops to 2.2, the heat storage material (66) having a lower melting point than this heat storage material (62).
By filling the low temperature side heat storage tank (65) with COP, COP can be improved up to 2.5.

Further, the high temperature side heat storage material (62) is constituted by any one of sodium acetate trihydrate, paraffin having a melting point of 50 to 70 ° C. and sugar alcohol having a melting point of 50 to 70 ° C. As a result, 50 to 7 water was added during heat storage operation.
It can be heated within the range of 0 ° C., and hot water can be reliably supplied at an appropriate temperature.

Further, since the low temperature side heat storage material (66) is constituted by any one of sodium sulfate decahydrate, paraffin having a melting point of 20 to 40 ° C. and calcium chloride, the heat source during heat storage operation. Since it is possible to prevent the temperature of the water flowing into the side heat exchanger (25) from rising, it is possible to reliably cool the refrigerant in the refrigerant circuit (2). Particularly, the high temperature side heat storage material (62) is used as sodium acetate trihydrate,
Paraffin having a melting point of 50 to 70 ° C. and melting point of 50 to 7
Since it is composed of any one of sugar alcohol at 0 ° C., the high temperature side heat storage material (62) is heated to an appropriate temperature during the heat storage operation, and water flowing into the heat source side heat exchanger (25) is used. It is possible to achieve both the suppression of temperature rise.

<Embodiment 2> As shown in FIG. 5, the heat storage device (1) according to Embodiment 2 is different from Embodiment 1 in that
The high temperature side heat storage tank (61) and the low temperature side heat storage tank (65) are arranged so as to be directly next to each other, and both heat storage tanks (61, 6)
5) is constructed integrally. In FIG. 5, the container (5
Where 1) is drawn with a solid line, it is drawn with a virtual line for convenience. Further, here, the same components as those of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

The inside of the container (51) is divided into left and right by a partition wall (70) extending in the vertical direction, one of which (see FIG. 5).
The left side in Fig. 5 is the high temperature side heat storage tank (61), and the other side (right side in Fig. 5) is the low temperature side heat storage tank (65).

The lower end of each heat transfer tube (53) of the high temperature side heat exchanger (63) and the upper end of each heat transfer tube (53) of the low temperature side heat exchanger (67) are mutually connected by a bridge pipe (71). It is connected.
As a result, the water flowing from the upper end of the high temperature side heat exchanger (63) during the heat storage operation flows through the high temperature side heat exchanger (63), then the bridge pipe (71), and then the low temperature side heat exchanger (67). ) From the lower end to the water pipe (24). Also, during the heat storage utilization operation, the water flowing from the lower end of the low temperature side heat exchanger (67) flows through the low temperature side heat exchanger (67), the bridging pipe (71), and then the high temperature side heat exchanger. (63)
It is designed to flow from this to the water pipe (24).

The high temperature side heat storage tank (61) is filled with the high temperature side heat storage material (62). As the high temperature side heat storage material (62),
For example, sodium acetate trihydrate, paraffin (52) having a melting point of 50 to 70 ° C. or sugar alcohol having a melting point of 50 to 70 ° C. can be preferably used.

The low temperature side heat storage tank (65) is filled with the low temperature side heat storage material (66). As the low temperature side heat storage material (66),
For example, sodium sulfate decahydrate, melting point 20-40 ° C
Any of paraffin (52) and calcium chloride can be preferably used.

Other configurations, operations and effects are the same as those of the first embodiment.
Is the same as.

[0065]

Other Embodiments of the Invention In each of the above embodiments, the refrigerant in the refrigerant circuit (2) is not limited to carbon dioxide. Further, the refrigerant circuit (2) is not limited to the configuration in which the refrigerant is compressed to its critical pressure or higher. For example, HF
Fluorocarbon refrigerants such as C-based refrigerants and HCFC-based refrigerants may be used. In this case, the refrigerant can be surely subcooled in the heat source side heat exchanger (25), and the COP of the refrigerant circuit (2) can be prevented from decreasing during heat storage.

[0066]

As described above, according to the inventions according to claims 1 and 2, the refrigerant and the heat medium in the heat source side heat exchanger (25) can be obtained without increasing the size of the heat storage means (3). The amount of heat exchange with can be increased. Then, the enthalpy difference between the inlet side and the outlet side of the refrigerant in the heat source side heat exchanger (25) can be made large, the capacity can be increased, and the COP of the refrigerant circuit (2) decreases during heat storage. Can be prevented.

Further, according to the invention of claim 3, since the high temperature side heat storage material (62) is composed of the latent heat storage material, heat can be stored in the heat storage means (3) with high efficiency. .

Further, according to the inventions of claims 4 and 5, since the refrigerant cooled in the heat source side heat exchanger (25) is compressed to the critical pressure or higher, the heat source side heat exchanger (25) Is cooled without phase change. Therefore, the temperature difference between the refrigerant temperature and the heat medium temperature directly affects the heat exchange amount in the heat source side heat exchanger (25).
As a result, the enthalpy difference between the inlet side and the outlet side of the refrigerant in the heat source side heat exchanger (25) can be made large, the capacity can be increased, and the COP of the refrigerant circuit (2) decreases during heat storage. Can be prevented.

According to the invention of claim 6, the heat medium can be heated within the range of 50 to 70 ° C. during heat storage, and hot water can be reliably supplied at an appropriate temperature.

Further, according to the invention of claim 7, it is possible to suppress the temperature rise of the heat medium flowing into the heat source side heat exchanger (25) during heat storage, so that the heat source side heat exchange The refrigerant can be reliably cooled in the container (25). Particularly, the high temperature side heat storage material (62) is made of sodium acetate trihydrate, paraffin having a melting point of 50 to 70 ° C., and melting point of 5
When it is composed of any one of sugar alcohols of 0 to 70 ° C., the heat of the high temperature side heat storage material (62) is heated to an appropriate temperature during heat storage and the heat flowing into the heat source side heat exchanger (25). It is possible to achieve both suppression of temperature rise of the medium.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a heat storage water heater according to a first embodiment.

FIG. 2 is a perspective view showing a configuration of heat storage means in the first embodiment.

FIG. 3 is a Mollier diagram of the refrigerant circuit according to the first embodiment.

FIG. 4 is a characteristic diagram showing changes in inlet temperature and outlet temperature of water in the heat storage means.

FIG. 5 is a perspective view showing a configuration of a heat storage unit according to a second exemplary embodiment.

[Explanation of symbols]

(2) Refrigerant circuit (3) Heat storage means (20) Water circuit (25) Heat source side heat exchanger (62) High temperature side heat storage material (63) High temperature side heat exchanger (66) Low temperature side heat storage material (67) Low temperature side heat exchanger

Claims (7)

[Claims] 1. A refrigerant circuit (2) for circulating a refrigerant to perform a heat pump cycle operation, a heat medium circuit (20) having a heat storage means (3) for circulating a heat medium, and the refrigerant circuit (2).
And a heat source side heat exchanger (25) for exchanging heat between the refrigerant and the heat medium of the heat medium circuit (20), and the heat storage means (3).
In the heat storage water heater for supplying hot water using the heat stored in the above, the heat storage means (3) comprises a high temperature side heat storage material (62) and a latent heat storage material having a lower melting point than the high temperature side heat storage material (62). The heat medium circuit (20) for radiating the heat medium to the high temperature side heat storage material (62) of the heat storage means (3) during heat storage in the heat storage means (3). After that, the heat storage water heater is characterized in that it radiates heat to the low temperature side heat storage material (66) and then flows so as to flow into the heat source side heat exchanger (25). 2. A refrigerant circuit (2) for circulating a refrigerant to perform a heat pump cycle operation, a heat medium circuit (20) having a heat storage means (3) for circulating a heat medium, and the refrigerant circuit (2).
And a heat source side heat exchanger (25) for exchanging heat between the refrigerant and the heat medium of the heat medium circuit (20), and the heat storage means (3).
In the heat storage water heater for supplying hot water using the heat stored in the heat storage means, the heat storage means (3) heats the heat medium with the heat medium of the high temperature side heat exchanger (63) connected to the heat medium circuit (20). The high temperature side heat storage material (62) to be exchanged and the latent heat storage material having a lower melting point than the high temperature side heat storage material (62) are used, and the high temperature side heat exchanger (6) is used in the heat medium circuit (20).
3) and a low temperature side heat storage material (66) for exchanging heat with the heat medium of the low temperature side heat exchanger (67) connected in series, wherein the heat medium circuit (20) comprises a heat storage means ( During heat storage in 3), the heat medium flows from the high temperature side heat exchanger (63) to the low temperature side heat exchanger (67), and the heat medium flowing out from the low temperature side heat exchanger (67) is the heat source side heat exchanger. A heat storage water heater characterized by being configured to flow into (25). 3. The heat storage water heater according to claim 1 or 2, wherein the high temperature side heat storage material (62) of the heat storage means (3) is composed of a latent heat storage material. 4. The heat storage water heater according to any one of claims 1 to 3, wherein the refrigerant circuit (2) is configured to compress the refrigerant to a pressure equal to or higher than its critical pressure. 5. The heat storage water heater according to claim 4, wherein carbon dioxide is used as the refrigerant. 6. The high temperature side heat storage material (62) according to any one of claims 1 to 5, wherein sodium acetate trihydrate, paraffin having a melting point of 50 to 70 ° C., and melting point of 50 to 70 ° C.
A heat storage water heater characterized by being constituted by any one of the above sugar alcohols. 7. The low temperature side heat storage material (66) according to claim 1, wherein the low temperature side heat storage material is any one of sodium sulfate decahydrate, paraffin having a melting point of 20 to 40 ° C., and calcium chloride. A heat storage water heater characterized by being constituted by.