JPH094906A - Heat storage type freezing/air conditioning apparatus - Google Patents

Abstract

PURPOSE: To provide a heat storage type freezing/air conditioning apparatus that utilizes stored heat in a heat storage tank only for keeping cold for commodities when the amount of heat stored in the heat storage tank and an air conditioning load and a cold keeping load are compared and as a result the loads are larger than the amount of stored heat or the remaining amount of stored heat is less than a predetermined value. CONSTITUTION: The consumed amount of heat stored in a heat storage tank 30 is detected by a temperature sensor, and when the consumed amount of stored heat is greater, stored heat utilization operation of an air conditioner unit 10 is interrupted. Hereby, preventing commodities contained in a show case A from being lacking in cold keeping.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat storage type refrigerating air conditioner used for air conditioning in stores such as convenience stores and for keeping cold in a showcase.

[0002]

2. Description of the Related Art Heretofore, as a heat storage type refrigerating and air-conditioning apparatus of this type, one disclosed in, for example, JP-A-62-284153 is known.

This heat storage type refrigeration air conditioner has a fan coil unit connected to a heat storage tank and a showcase for keeping the products cool, and has a structure in which a refrigerant flows from the refrigerator to the heat storage tank and the showcase.

In this heat storage type refrigerating and air-conditioning apparatus, a large amount of refrigerant is made to flow into the heat storage tank to store heat in the night when the heat insulation load of the showcase is small, and in the daytime when the heat insulation load of the showcase is large. On the contrary, while a large amount of refrigerant is flown to the showcase side to keep the products in the showcase cool, the water stored at night is circulated to the fan coil unit to cool the store.

[0005]

As described above, in the conventional heat storage type refrigerating air conditioner, the so-called heat storage utilizing operation is used in which the heat stored in the heat storage tank at night is used for product cold storage in the showcase and air conditioning in the store during the daytime. However, when the air-conditioning load in the store is very large, such as in the middle of summer, the heat stored in the heat storage tank is consumed by the air-conditioning in the store, which hinders the product cold storage that must be secured preferentially. Had.

In view of the above conventional problems, the object of the present invention is to compare the heat storage amount of the heat storage tank with the air conditioning load and the cold storage load, and when the load is large, or when the remaining heat storage amount becomes less than a predetermined value, the heat storage An object of the present invention is to provide a heat storage type refrigerating and air-conditioning apparatus that uses heat storage in a tank only for keeping products cool.

[0007]

In order to solve the above-mentioned problems, the present invention according to claim 1 provides an air-conditioning unit for air-conditioning a store, a showcase refrigerating unit for keeping products cold, and the air-conditioning unit. And a heat storage tank thermally connected to the refrigeration unit, in a heat storage type refrigeration air-conditioning apparatus performing heat storage utilization operation using the heat source of the heat storage tank as a heat source of each unit, detecting the heat storage consumption of the heat storage tank And a control means for stopping the heat storage utilization operation of the air conditioning unit based on the heat storage consumption.

According to a second aspect of the present invention, in the heat storage type refrigerating and air conditioning system according to the first aspect, the control means measures the time from the start time of the heat storage utilization operation until a predetermined heat storage amount is consumed, and the measured time is Based on this, the stop time of the heat storage utilization operation of the air conditioning unit is determined.

According to a third aspect of the present invention, in the heat storage type refrigerating air conditioner according to the first aspect, a temperature sensor for detecting the temperature of the heat storage tank is used as the detecting means, and the predetermined heat storage consumption amount is stored in the heat storage tank. The determination is made based on the temperature of the heat storage tank when the solid heat storage medium is entirely changed to the liquid heat storage medium.

According to a fourth aspect of the present invention, in the heat storage type refrigerating and air conditioning apparatus according to the first aspect, a level sensor for detecting a liquid level of the heat storage tank is used as the detecting means, and the predetermined heat storage consumption amount is stored in the heat storage tank. All the solid heat storage mediums of (1) are changed to the liquid heat storage medium by judgment based on the liquid level.

[0011]

According to the invention of claim 1, the heat storage consumption of the heat storage tank is detected by the detection means, and when the heat storage consumption is large, the heat storage utilization operation of the air conditioning unit is stopped. As a result, it is possible to prevent the product stored in the showcase from being insufficiently cooled.

According to the invention of claim 2, the time from the start time of the heat storage utilization operation to the time of consuming the predetermined heat storage amount is measured. When the measurement time is short, the air conditioning load and the refrigeration load are large. In this case, the stop time of the heat storage utilization operation of the air conditioning unit is shortened.

According to the third aspect of the present invention, the temperature of the heat storage tank is detected by the temperature sensor. When all the solid heat storage medium in the heat storage tank is melted to become the liquid heat storage medium, the temperature of the heat storage tank is increased. Rises. When the temperature of the heat storage tank is high, the remaining amount of heat stored in the heat storage tank is low. In this case, the heat storage utilization operation of the air conditioning unit is stopped.

According to the fourth aspect of the present invention, the liquid level of the heat storage tank is detected by the level sensor, and when all the solid heat storage medium in the heat storage tank is melted to become the liquid heat storage medium, the heat storage tank. The liquid level of drops. When the liquid level is low, the remaining amount of heat stored in the heat storage tank is low. In this case, the heat storage utilization operation of the air conditioning unit is stopped.

[0015]

1 to 6 show a first embodiment of a heat storage type refrigerating and air conditioning apparatus according to the present invention, and FIG. 1 shows a refrigerant circuit diagram of the heat storage type refrigerating and air conditioning apparatus.

This heat storage type refrigerating and air conditioning system comprises an air conditioning unit 10 for indoor air conditioning of a store, a refrigerating unit 20 for keeping the products stored in a showcase A cold, and a heat storage tank 30 filled with a heat storage medium, for example, water. The units 10 and 20 are thermally connected to each other via a heat storage tank 30 to perform in-store air conditioning and product cold storage.

First, the piping system of the air conditioning unit 10 will be described with reference to FIG. This air conditioning unit 10 includes a compressor 1
1, first outdoor heat exchanger 12, indoor heat exchanger 13, two expansion devices 14a, 14b, four three-way valves 15a, 15
b, 15c, 15d, two check valves 16a, 16b, an on-off valve 17a, and the heat storage tank 30 are connected by piping. Next, the piping system of the refrigeration unit 20 is also shown in FIG.
It will be described based on. The refrigerating unit 20 includes a compressor 2
1, an outdoor heat exchanger 22, an evaporator 23 for keeping the product cold in the showcase A, an expansion device 24a, and three three-way valves 25a, 2
5b and 25c, the check valve 26a, and the heat storage tank 30 are connected by piping.

To explain this refrigerant flow, in the normal cooling operation of the air conditioning unit 10 (white solid arrow), the compressor 1
1-> 3-way valve 15a-> Outdoor heat exchanger 12-> 3-way valve 15b->
The expansion device 14a, the indoor heat exchanger 13, the three-way valve 15c, and the compressor 11 are sequentially circulated, and the indoor heat exchanger 13 cools the inside of the store. Similarly, in the heat storage operation of the air conditioning unit 10 (solid line arrow), the compressor 11 → the three-way valve 15a → the outdoor heat exchanger 12 → the three-way valve 15b → the expansion device 14b → the heat storage tank 3
The heat storage tank 3 circulates in sequence from 0 → 3 way valve 15d → compressor 11
The water stored in 0 is frozen to store heat.

In the normal cooling operation of the refrigerating unit 20 (white dotted arrow), the compressor 21 → three-way valve 25a → outdoor heat exchanger 22 → three-way valve 25b → three-way valve 25c → throttle device 24a → show The evaporator 23 of the case A is sequentially circulated from the compressor 21 to cool the products in the refrigerator by the evaporator 23.

As a control for operating the air conditioning unit 10 and the refrigeration unit 20 in association with each other, a heat storage utilization operation is performed. In this heat storage utilization operation (dashed line arrow),
The air-conditioning unit 10 side is a compressor 11 → 3 way valve 15a → outdoor heat exchanger 12 → 3 way valve 15b → open / close valve 17a → heat storage tank 3
0 → 3-way valve 15d → check valve 16b → expansion valve 14a → indoor heat exchanger 13 → 3-way valve 15c → compressor 11 circulates sequentially, while the refrigeration unit side is compressor 21 → 3-way valve 25a.
→ outdoor heat exchanger 22 → 3 way valve 25b → check valve 26a → heat storage tank 30 → 3 way valve 25c → expansion valve 24a → evaporator 23 →
The compressor 21 is sequentially operated. As a result, the air conditioning unit 10
And in the refrigeration unit 20, the outdoor heat exchangers 12, 2
The refrigerant is condensed in 2, and the condensed refrigerant is further supercooled in the heat storage tank 30.

As described above, the heat storage type refrigerating air conditioner according to this embodiment has various modes of normal cooling operation, heat storage operation, normal cooling operation, and heat storage utilization operation. This is characterized by the operation control of each unit in the so-called heat storage utilization operation. The configuration will be described below based on the block diagram of the drive control circuit of FIG. 2, the flow chart of the drive control of FIG. 3, and the refrigerant circuit diagrams of various operations of FIGS. 4 to 6.

The heat storage type refrigeration air conditioner according to this embodiment has a temperature sensor 40 for detecting the temperature of the heat storage tank 30. Further, it has a CPU 41 of a microcomputer configuration having a built-in timer, and based on the detection signal of the temperature sensor 40, the air conditioning unit 10 and the refrigeration unit 20 are shown in the flowchart of FIG. Drive control is performed as shown.

When carrying out the heat storage utilization operation in the daytime, it is necessary to store heat in the heat storage tank 30 at night. Therefore, at night
The heat storage operation (solid line arrow in FIG. 4) is performed as shown in FIG. 3, and the water stored in the heat storage tank 30 is frozen to store heat as described above. On the other hand, on the side of the refrigeration unit 20, since the cold storage load does not increase much at night, the normal cooling operation (one-dot chain line outline arrow) is performed as described above.

Thus, the heat storage is completed at night, and the operation using this heat storage is started during the daytime when the air-conditioning load and the cold storage load increase (S1). Thereby, as shown in FIG. 5, the heat storage utilization operation described above is performed, and each unit 1
Store air conditioning (cooling) by storing heat in the heat storage tank 30 at 0 and 20
And product cold storage is effectively performed. When this heat storage utilization operation is started, at the same time, the temperature t of the heat storage tank 30 is measured based on the detection signal of the temperature sensor 40, while it is determined whether or not the temperature t has reached the set temperature t1 and this setting is performed. Temperature t
Measure the time to reach 1. That is, the load of the air conditioning load and the cold storage load is predicted by determining this measurement time, that is, how many hours the predetermined heat storage amount has been consumed (S2, S3).
S4). Based on this load prediction, the end time of the heat storage utilization operation on the air conditioning unit 10 side is determined (S5). That is, when it is determined that the measurement time is short and the load is large, the end time of the heat storage utilization operation on the air conditioning unit 10 side is shortened, while conversely, when it is long, the end time of the heat storage utilization operation time is delayed. . When the end time of the air conditioning unit 10 is reached based on this determination, the heat storage utilization operation of the air conditioning unit 10 is switched to the normal cooling operation as shown by the white arrow in FIG. 6 (S6, S7). As a result, the above-described normal cooling operation is performed on the air conditioning unit 10 side, while the refrigeration unit 20
On the side, heat storage utilization operation is continued.

As described above, according to the heat storage type refrigerating air conditioner of this embodiment, the stop time of the heat storage utilizing operation of the air conditioning unit 10 is controlled according to the level of the air conditioning load and the cold storage load. Excessive heat storage to the side is regulated,
The heat stored in the heat storage tank 30 can ensure the product cold storage.

FIG. 7 shows a second embodiment of the heat storage type refrigerating air conditioner according to the present invention. In this embodiment, as shown in the flowchart of FIG. 7, the heat storage utilization operation is started in each of the units 10 and 20 (S1), the temperature T of the heat storage tank 30 is detected, and the temperature T reaches the set temperature T1. It is determined whether or not (S2, S3). Here, the set temperature T1 is set to a temperature when all the ice, which is the heat storage medium of the heat storage tank 30, becomes water, and when it is determined that all the water becomes water, the heat storage utilization operation of the air conditioning unit 10 is normally performed. Switch to cooling operation (S4). This prevents shortage of product cooling.

FIG. 8 shows a third embodiment of the heat storage type refrigerating and air conditioning apparatus according to the present invention. In the first and second embodiments, the operation control is performed by detecting the temperature of the heat storage tank 30, but in this embodiment, a level sensor (not shown) is provided in the heat storage tank 30, and based on the detection signal of this level sensor. Have control.

That is, as shown in FIG. 8, each unit 1
When the heat storage utilization operation is started at 0 and 20, (S
1), the liquid level L of the heat storage tank 30 is detected and it is determined whether or not this level L has reached a set level L1 (S2).
S3). Here, the set level L1 is set to the liquid level when all the ice, which is the heat storage medium in the heat storage tank 30, becomes water, and when it is determined that all the water has become water, the heat storage utilization operation of the air conditioning unit 10 is performed. Is switched to the normal cooling operation (S4). This prevents shortage of product cooling.

As described above, in the third embodiment, when the majority of the heat storage medium is ice, the liquid level is high, and on the other hand, when the ice is melted, the liquid level is low. The operation of is switched.

[0030]

As described above, according to the inventions of claims 1 to 4, the detection means detects the heat storage consumption amount of the heat storage tank, and when the heat storage consumption amount is large, the heat storage of the air conditioning unit is stored. Since the use operation is stopped, it is possible to prevent the product stored in the showcase from being insufficiently cooled.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram of a heat storage type refrigeration air conditioner according to the present invention.

FIG. 2 is a block diagram showing a drive control circuit of a heat storage type refrigeration air conditioner according to the present invention.

FIG. 3 is a drive control flowchart according to the first embodiment.

FIG. 4 is a refrigerant circuit diagram showing a heat storage operation.

FIG. 5 is a refrigerant circuit diagram showing heat storage utilization operation.

FIG. 6 is a refrigerant circuit diagram when the heat storage utilization operation of the air conditioning unit is switched to the normal cooling operation.

FIG. 7 is a drive control flowchart according to the second embodiment.

FIG. 8 is a drive control flowchart according to the third embodiment.

[Explanation of symbols]

10 ... Air conditioning unit, 20 ... Refrigeration unit, 30 ... Heat storage tank, 40 ... Temperature sensor, 41 ... CPU, A ... Showcase.

Claims (4)

[Claims] 1. A heat source for the heat storage tank, comprising: an air conditioning unit for air-conditioning a store; a refrigeration unit for a showcase for keeping products cool; and a heat storage tank thermally connected to the air conditioning unit and the refrigeration unit. In a heat storage type refrigerating air-conditioning apparatus that performs a heat storage utilization operation using each unit as a heat source, a detection unit that detects the heat storage consumption amount of the heat storage tank is provided, and the heat storage utilization operation of the air conditioning unit is stopped based on the heat storage consumption amount. A heat storage type refrigerating and air-conditioning apparatus, characterized in that it is provided with control means for controlling the heat storage type. 2. The control means measures the time from the start time of the heat storage utilization operation until a predetermined amount of heat storage is consumed, and determines the stop time of the heat storage utilization operation of the air conditioning unit based on the measured time. The heat storage type refrigerating air conditioner according to claim 1. 3. A temperature sensor that detects the temperature of the heat storage tank is used as the detection means, and the heat storage is performed when the solid heat storage medium in the heat storage tank is phase-changed into a liquid heat storage medium. The heat storage type refrigerating and air-conditioning apparatus according to claim 1, wherein the judgment is made based on the temperature of the tank. 4. A level sensor for detecting the liquid level of the heat storage tank is used as the detecting means, and the predetermined heat storage amount is a liquid when all of the solid heat storage medium in the heat storage tank changes into a liquid heat storage medium. The heat storage type refrigerating and air-conditioning apparatus according to claim 1, wherein the judgment is made based on a surface level.