JPH06281282A - Cold storage apparatus - Google Patents

Abstract

PURPOSE:To enhance cold storing velocity by effectively utilizing operating characteristics of a refrigerating cycle. CONSTITUTION:A heat exchanger for heat exchanging between refrigerant sealed in a refrigerating cycle and water of cold storage material filled in a cold storage layer 41 is connected to the cycle having a compressor 27, an outdoor heat exchanger 35, an indoor heat exchanger 37 and electronic expansion valves 45, 47. A refrigerant channel of the exchanger is disposed from an upper part to a lower part of the layer 41, and a four-way valve 39 for switching a flowing direction of refrigerant in the channel in the exchanger to a direction directed from the upper part to the lower part of the layer 41 and a direction directed from the lower part to the upper part of the layer 41 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold heat storage device used in a heat pump air conditioner using a refrigeration cycle.

[0002]

2. Description of the Related Art In a heat pump air conditioner using a refrigeration cycle, a cold storage heat storage device is used as an auxiliary heat source for reducing the air conditioning load during the cooling operation (peak shift of power usage time) and for starting the heating operation. There is something I had. FIG. 10: is a refrigerating-cycle block diagram in the heat pump air conditioner provided with the conventional cold storage heat storage apparatus. This refrigeration cycle includes a compressor 1 that discharges a refrigerant as a high-temperature / high-pressure gas, heat storage / heat storage-use heating / normal heating operation and cold storage / cooling-use cooling / normal cooling operation, and a refrigerant flow in a solid line state and a broken line state. A four-way valve 3 for switching the path, an indoor heat exchanger 5 that serves as a condenser during heating operation and serves as an evaporator during heating operation, an outdoor heat exchanger 7 that serves as an evaporator during heating and heat storage operations and serves as a condenser during heating and heat storage operations, and inside The cold storage heat storage tank 9 is provided with a heat exchanger that is filled with the cold storage heat material and exchanges heat between the cold storage heat material and the refrigerant. The heat exchanger of the cold storage heat tank 9 serves as a condenser during the heat storage and cold storage utilization operation, and serves as an evaporator during the cold storage and heat storage utilization operation. Reference numerals 11 and 13 are electronic expansion valves, reference numerals 15, 17, 19, 21, and 23 are two-way valves,
Reference numeral 25 is a one-way valve.

As the cold heat storage tank 9, a static type as shown in FIG. 11 is generally used. That is, the heat exchanger 27 configured by the pipe through which the refrigerant flows is installed in the water 29, which is a cold storage heat material, and heat is exchanged between the refrigerant and the water 29, so that heat storage / cooling storage and heat storage utilization are performed. It is configured to perform each operation of heating and cooling using cooling.
In this case, the pipes forming the heat exchanger 27 have the cold storage heat tank 9
Are evenly arranged from the top to the bottom.

[0004]

By the way, the cold storage tank 9 is used.
The refrigerant flowing through the heat exchanger 27 in the inside is connected so as to flow from the lower portion to the upper portion of the cold storage tank 9 so that the refrigerant flows from the lower portion to the upper portion. Water that occurs in the cold storage tank 9 when
The natural convection of changes the characteristics of the refrigeration cycle.

For example, the heat storage operation will be described. When the refrigerant flows from the upper part to the lower part of the cold storage heat tank 9,
When the high temperature gas flowing in from the compressor 1 gradually exchanges heat with the water 29 in the cold storage heat tank 9 and condenses, the cold storage heat tank 9
Natural convection occurs in the water 29 therein, and the temperature of the water 29 is as shown in FIG.
As shown by the solid line W in 2 (a), the upper part of the cold storage heat tank 9 is higher than the lower part.

In the temperature distribution in which the temperature on the refrigerant inlet side of the heat exchanger 27 rises in this way, as seen from the refrigeration cycle,
Although the condensing temperature becomes high and the heat storage rate becomes high, there is an adverse effect that the amount of input of the compressor required at that time becomes large.

On the other hand, when the refrigerant is made to flow from the lower part of the cold storage heat tank 9 to the upper part, heat is exchanged from the lower part of the cold heat storage tank 9 so that the water 29 in the cold heat storage tank 9 is exchanged. The temperature tends to be uniform due to the effect of natural convection, as indicated by the solid line W in FIG. Therefore, in this case, the temperature distribution of the water in the cold storage tank 9 becomes more uniform and the temperature difference between the refrigerant and the water 29 becomes smaller than in the case of flowing from the upper part to the lower part, so the heat storage rate is small. However, the input amount of the compressor 1 can be reduced.

As described above, during heat storage operation, there are merits and demerits depending on the flowing direction of the refrigerant in the cold storage tank 9, but in general, the refrigerant is directed from the upper part to the lower part for the purpose of increasing the heat storage rate. Often shed.

12 (a) and 12 (b), the alternate long and short dash line R ₁ indicates the temperature of the refrigerant in the heat exchanger 27, and this refrigerant temperature is almost the same in both FIGS. 12 (a) and 12 (b). Although constant, the temperature of the refrigerant in FIG. 12A flowing from the upper portion to the lower portion is slightly higher than that of the refrigerant in FIG. 12B flowing from the lower portion to the upper portion.

Further, when a non-azeotropic mixed refrigerant in which a high boiling point refrigerant and a low boiling point refrigerant are mixed is used as the refrigerant sealed in the refrigeration cycle, the composition of the refrigerant changes when the phase changes. , The temperature changes. FIG. 12 (a),
The broken line R ₂ in (b) is the temperature change in the cold storage tank 9 of the non-azeotropic mixed refrigerant during the heat storage operation. When the refrigerant condenses in the heat exchanger 27 as in the heat storage operation,
As can be seen from 2 (a) and 2 (b), the refrigerant is the heat exchanger 2
The temperature at the outlet is several degrees Celsius, for example, about 5 degrees Celsius lower than that at the inlet of No. 7, and when the refrigerant flows from the upper part to the lower part as shown in FIG. The tendency to be marked is further increased.

Now, let us consider the economics of utilizing the discount system for the electricity rate in the middle of the night. In order to utilize the cold storage device most economically, it is desirable to store the amount of heat necessary for the peak shift and the initial start-up in the power usage time period, that is, the amount of heat that is sufficient. The amount of heat storage is determined from the air conditioning load based on changes in the outside air temperature, the size of the air-conditioned space, and the heat insulation. Considering that there is a heat leak to the outside air, by controlling the operating frequency of the compressor and the air flow rate of the outdoor heat exchanger in the midnight time charge system, the refrigeration cycle is optimized to maximize efficiency. It is desired to drive.

Therefore, an object of the present invention is to efficiently utilize the operating characteristics of the refrigerating cycle and to make it more economical.

[0013]

In order to achieve the above object, the present invention is, firstly, a refrigeration cycle including a compressor, an outdoor heat exchanger, an indoor heat exchanger and an expansion mechanism. A heat exchanger for exchanging heat between the refrigerant filled in and the cold storage heat material filled in the container is connected, and the refrigerant passage in this heat exchanger is arranged from the upper part to the lower part of the container, The configuration is such that switching means is provided for switching the flow direction of the refrigerant in the refrigerant flow path of the heat exchanger between the direction from the upper part to the lower part of the container and the direction from the lower part to the upper part.

Secondly, in the first configuration, the switching means is configured such that the heat exchanger in the container serves as a condenser and the outdoor heat exchanger serves as an evaporator during the heat storage operation, and the temperature of the cold storage heat material and the midnight power. It is configured to be switched by the control means based on the remaining time of the charge time zone.

Thirdly, in the first configuration, the switching means is such that, at the start of the cooling operation using cold storage in which the heat exchanger in the container serves as a condenser and the indoor heat exchanger serves as an evaporator, the refrigerant is stored in the container. The control means switches the flow from the upper part to the lower part, and the control means switches the refrigerant to flow from the lower part to the upper part of the container after a predetermined time elapses after the start of the cooling operation using the cold storage.

Fourthly, in the first configuration, the switching means is configured to be switched by the control means based on the operating frequency of the compressor.

Fifth, in the first, second, third or fourth configuration, the refrigerant to be sealed in the refrigeration cycle is a non-azeotropic mixed refrigerant.

[0018]

According to the cold energy storage device configured as described above, the flow direction of the refrigerant in the refrigerant flow path of the heat exchanger in the container is
By switching between the direction from the upper part to the lower part of the container and the direction from the lower part to the upper part, the refrigeration cycle connected to the heat exchanger is efficiently operated, and the economy is further improved.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a refrigeration cycle used in a heat pump type air conditioner equipped with a cold heat storage device according to an embodiment of the present invention. This refrigeration cycle has a compressor 27 that discharges a refrigerant as a high-temperature, high-pressure gas. The compressor 27 has a heat storage / heating-use heating / normal heating / cooling / cooling-use cooling / normal cooling operation state. Three four-way valves 29 whose refrigerant flow paths are switched between a solid line state and a broken line state,
31, 33 are connected. An outdoor heat exchanger 35 is connected to the four-way valve 29, and an indoor heat exchanger 37 is connected to the four-way valve 33.

A cold storage tank 41 as a container is connected to the four-way valve 31 via a four-way valve 39. Cold storage heat tank 41
11 has a heat exchanger in which pipes are uniformly arranged from the upper part to the lower part of the cold storage heat tank 41, as in the case shown in FIG. 11, and is filled with water as a cold storage heat material. . The four-way valve 39 switches the flow direction of the refrigerant in the heat exchanger in the cold storage heat tank 41 between a state of flowing from the upper part to the lower part of the cold heat storage tank 41 and a state of flowing from the lower part to the upper part. A control circuit 43, which constitutes a control means and is composed of a microcomputer or the like, constitutes a control means.

In the heat storage operation, the control circuit 43 switches the flow direction of the refrigerant on the basis of the remaining time of the midnight power charge time zone and the temperature of water as the cold storage material. Further, the control circuit 43 switches the flow direction of the refrigerant using the temperature of water as a criterion during the cold storage operation and the operation time as a criterion during the cooling operation using the cold storage. Furthermore, the control circuit 4
3 switches the flow direction of the refrigerant with the operating frequency of the compressor 27 as a criterion. Reference numerals 45 and 47 are electronic expansion valves, reference numeral 49 is a two-way valve, and reference numerals 51, 53 and 55 are one-way valves.

2 to 5 show the flow paths of the refrigerant in each operation of heat storage, heating using heat storage, cold storage, and cooling using cold storage in a refrigeration cycle equipped with the cold storage device having such a configuration.
Is indicated by a thick line.

FIG. 6 shows the heat storage operation shown in FIG.
An example of a temperature change of the cold storage heat material (water) by switching the flow direction of the refrigerant in the cold storage heat tank 41 is shown. In FIG. 6, the solid line is according to the embodiment of the present invention, and the one-dot chain line indicates the case where the flow continues from the upper part to the lower part, and the broken line indicates the case where the flow continues from the lower part to the upper part, and the temperature T is required. The heat storage temperature. FIG. 7 is a flowchart showing the control operation of the control circuit 43 for causing the temperature change shown by the solid line in FIG.

The control operation during the heat storage operation will be described with reference to FIGS. 6 and 7. The heat storage operation is started at the start of the midnight charge of electric power (time S in FIG. 6) (step 701), and at this time, the temperature of the water is T _a . Then, the remaining time of the midnight charge time zone is determined (step 703), and the temperature of the water in the cold storage tank 41 is determined (step 705). Since the end time of the midnight charge time zone is determined together with the start time in the determination of the remaining time, the time until the end time may be measured, and the temperature of the water in the cold storage heat tank 41 is the same as that in the cold storage heat tank 41. It can be measured by a temperature sensor provided in the.

Immediately after the heat storage operation is started, the remaining time of the midnight charge exceeds the predetermined value TIM ₁ , and the temperature of the cold storage heat tank 41 is also increased.
Not exceed T _1, since by T ₁ or less, cold storage heat tank 4
In the heat exchanger in 1, the four-way valve 39 is switched so that the refrigerant flows from the lower part to the upper part (step 70).
7). As a result, the temperature of the water in the cold storage tank 41 is
Although the temperature gradually rises from the point A to the point B like this, the temperature distribution of the water in the cold storage heat tank 41 at this time is very small and the temperature difference between the refrigerant and the water becomes small, so that the heat storage Although the speed is low, the input amount of the compressor 27 can be reduced.

When the remaining time in the midnight charge time zone is small and is equal to or less than the predetermined value TIM ₁ (step 703), or when the temperature of the water in the cold storage heat layer 41 exceeds the predetermined value T ₁ (step 705). At time P in FIG. 6, the four-way valve 39 is switched (the temperature of the water at this time is T _b ), and the refrigerant flows from the upper part to the lower part of the cold storage heat tank 41 (steps 709, 71).
1). In the temperature rising process from the point B in this state, the internal temperature of the cold storage heat tank 41 is higher in the upper part than in the lower part, so that the required input amount of the compressor 27 is large, but the refrigeration cycle has a condensing temperature. Becomes higher and the heat storage rate becomes higher. Therefore, the temperature increase rate after the point B is greater than the same temperature increase rate from the start of the heat storage operation to the switching of the four-way valve 39. The switching time P of the four-way valve 39 is set to reach the heat storage temperature T required at the midnight charge end time E.

In addition to the control described above, when the required temperature of the heat storage material is high, the heat storage operation is started from the beginning and is made to flow toward the upper part or the lower part of the cold storage tank 41, and vice versa. When the temperature of the stored heat storage material is low, only the operation of flowing from the lower part to the upper part may be performed. Furthermore, the heat storage operation start time may be delayed so that the required heat storage amount can be obtained at the end of the midnight electricity rate. For these controls, for example, the outside air temperature may be used as the determination reference.

By performing the heat storage operation as described above, FIG.
To improve the operation efficiency of the cold storage heat storage device by reducing the heat leak amount by shortening the time until the start of the heat storage utilization heating operation using the heat storage shown in Fig. 1 to increase the amount of energy that can be used during the heat storage utilization operation. You can

On the other hand, during the cold storage operation shown in FIG. 4, the refrigerant flows from the upper part to the lower part of the cold storage heat tank 41 until the temperature of the water in the cold storage heat tank 41 reaches about 0 ° C., and then from the lower part. By flowing it to the upper part, it becomes possible to operate the refrigeration cycle efficiently. This is because when ice making starts in the cold storage heat storage tank 41, the temperature dependence of the density of water changes at a peak of 4 ° C., so that water having a slightly higher temperature before ice making accumulates in the lower part of the cold storage heat storage tank 41. This is because there is a tendency.

In the cooling operation using cold storage shown in FIG. 5, as in the cold storage operation, at the beginning of the operation, the refrigerant flows from the upper part to the lower part of the cold heat storage tank 41, and then from the lower part to the upper part. The control operation of the control circuit 43 in this case is shown in the flowchart of FIG. After the cooling operation using cooling storage is started (step 801), the operation time is determined (step 80).
3). The operating time can be determined by incorporating a timer circuit. Here, when the operation time does not reach the predetermined value t ₁ , that is, at the beginning of the operation, the gas refrigerant discharged from the compressor 27 flows from the upper part to the lower part of the cold storage heat tank 41 (step 805). As a result, the temperature distribution of the water in the heat storage tank 41 becomes different, the condensation temperature becomes higher, and the operation start-up time is shortened. When the operating time reaches the predetermined value t ₁ and the cooling load is reduced, the refrigerant is flowed from the lower part to the upper part (step 807). As a result, the temperature distribution of the water in the heat storage tank 41 becomes smaller, the condensation temperature becomes lower, and stable operation can be accommodated.

When the compressor 27 whose rotation speed can be changed by an inverter or the like is used, the control shown in the flowchart of FIG. 9 is performed. After the operation of the air conditioner is started (step 901), the compressor frequency is a predetermined value F ₁
If the compressor frequency is lower than the predetermined value F ₁ and the operating load is small, it is determined whether or not it is lower (step 903).
In order to raise the condensation temperature, the four-way valve 39 is switched so that the refrigerant flows from the upper part to the lower part of the cold storage tank 41 (step 905), and when the compressor frequency is equal to or higher than the predetermined value F ₁ and the operation load is large, The four-way valve 39 is switched so that the refrigerant flows from the lower part to the upper part of the cold storage heat tank 41 (step 907).

When the refrigerant to be sealed in the refrigeration cycle is a non-azeotropic mixed refrigerant in which a high boiling point refrigerant and a low boiling point refrigerant are mixed, the inlet of the heat exchanger is The temperature difference with the outlet tends to increase, and a temperature difference of several degrees Celsius occurs even during phase change. Therefore, by controlling the flow direction of the refrigerant in the heat exchanger of the cold storage tank 41 by switching control as described above, the operating characteristics of the refrigeration cycle are changed more greatly, and the characteristics of the non-azeotropic mixed refrigerant are used more effectively. Efficient operation is possible.

[0034]

As described above, according to the present invention, the heat exchanger is provided in the container filled with the cold storage material,
Since the flow direction of the refrigerant in the refrigerant flow path of the heat exchanger is switched between the direction from the upper part to the lower part of the container and the direction from the lower part to the upper part, the operating characteristics of the refrigeration cycle can be efficiently utilized. It can be made more economical.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a refrigeration cycle of a heat pump air conditioner showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a refrigerant flow path during a heat storage operation in the refrigeration cycle of FIG.

FIG. 3 is an explanatory diagram showing a refrigerant flow path during a heating operation using heat storage in the refrigeration cycle of FIG. 1.

FIG. 4 is an explanatory diagram showing a refrigerant flow path during a cold storage operation in the refrigeration cycle of FIG.

FIG. 5 is an explanatory diagram showing a refrigerant flow path during a cooling storage utilizing cooling operation in the refrigeration cycle of FIG. 1.

6 is an explanatory diagram showing a temperature change of a cold storage heat material (water) during a heat storage operation in the refrigeration cycle of FIG.

7 is a flowchart showing a control operation during a heat storage operation in the refrigeration cycle of FIG.

8 is a flowchart showing a control operation during a cooling operation using cooling storage in the refrigeration cycle of FIG.

9 is a flowchart showing a control operation depending on a difference in operating frequency of the compressor in the refrigeration cycle of FIG.

FIG. 10 is a refrigeration cycle configuration diagram of a heat pump air conditioner showing a conventional example.

11 is a schematic internal structural diagram of a cold storage heat tank in the refrigeration cycle of FIG.

FIG. 12 is an explanatory diagram showing temperature changes of the cold storage heat material, the single refrigerant, and the non-azeotropic mixed refrigerant in correspondence with the upper and lower positions of the cold storage heat tank of FIG. 11, and FIG. The case where the refrigerant flows from the upper part to the lower part of the tank, and (b) shows the case where the refrigerant flows from the lower part to the upper part.

[Explanation of symbols]

 27 Compressor 35 Outdoor Heat Exchanger 37 Indoor Heat Exchanger 39 Four-way Valve (Switching Means) 41 Cold Storage Tank (Container) 43 Control Circuit (Control Means) 45, 47 Electronic Expansion Valve (Expansion Mechanism)

Claims (5)

[Claims] 1. A refrigeration cycle including a compressor, an outdoor heat exchanger, an indoor heat exchanger, and an expansion mechanism provides heat between the refrigerant enclosed in the refrigeration cycle and the cold storage heat material filled in the container. A heat exchanger for exchange is connected, a refrigerant flow path in the heat exchanger is arranged from the upper part to the lower part of the container, and a flow direction of the refrigerant in the refrigerant flow path of the heat exchanger is changed from the upper part to the lower part of the container. A regenerator which is provided with switching means for switching between a direction toward the upper side and a direction from the lower side toward the upper side. 2. In the heat storage operation in which the heat exchanger in the container serves as a condenser and the outdoor heat exchanger serves as an evaporator, the switching means is based on the temperature of the cold storage heat material and the remaining time of the midnight power charge time zone. The regenerator according to claim 1, wherein the regenerator is switched by a control means. 3. The switching means is configured such that the refrigerant flows from the upper part to the lower part of the container at the start of the cooling operation using the cold storage in which the heat exchanger in the container serves as a condenser and the indoor heat exchanger serves as an evaporator. The heat storage device according to claim 1, wherein the heat storage device is switched by the control device, and after the predetermined time has elapsed after the start of the cooling operation using the cold storage, the control device switches so that the refrigerant flows from the lower part to the upper part of the container. . 4. The regenerator according to claim 1, wherein the switching means is switched by the control means based on the operating frequency of the compressor. 5. The regenerator of claim 1, 2, 3 or 4, wherein the refrigerant enclosed in the refrigeration cycle is a non-azeotropic mixed refrigerant.