JPH0651762U - Refrigeration system - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To provide a refrigeration system capable of reducing the head loss of cooling water sent from a cooling tower and reducing the capacity and power of a water supply pump. [Composition] A refrigerating device 1 comprising a compressor 3, a condenser 4, an expansion valve 5, a cooler 6, a defrost heat exchanger 7 for gasifying liquefied refrigerant during hot gas defrosting of the cooler, and cooling for heat exchange. In the refrigeration system including the cooling tower 2 for supplying water, the cooling tower 2 and the cooling water inlet of the condenser 4 are connected by the main water supply pipe 13 including the water supply pump 12, and the main water supply pipe 13 and the defrost heat exchanger 7 are connected. Of the condenser 4 and the cooling water outlet of the defrost heat exchanger 7 are cooled by the common main return water piping 14. It is connected to the tower 2 and the discharge pressure of the water pump 12 is detected by the pressure sensor 1.
7, the capacity of the water supply pump 12 is controlled by the inverter 19 so that the required amount of cooling water can always be supplied even when water is passed through the defrost heat exchanger 7.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a hot gas defrost type refrigeration system, and more particularly to a system configured to use the heat of cooling water in a cooling tower to evaporate a liquid refrigerant after defrosting.

[0002]

[Prior art]

 FIG. 3 shows a conventional example of this type of refrigeration system. In this figure, a plurality of refrigerating apparatuses 1 arranged side by side have a compressor 3, a condenser 4, an expansion valve 5, a cooler 6 and a defrost heat exchanger 7. A pump 25 is connected to the main water supply pipe 26 extending from the cooling tower (cooling tower) 2, and a branch pipe 26a extending from the main water supply pipe 26 is connected to the cooling water inlet of each compressor 4. The cooling water outlet of the condenser 4 is connected to the cooling water inlet of the defrost heat exchanger 7 by the return water pipe 27 a, and the cooling water outlet of the heat exchanger 7 is the main return water connected to the cooling tower 2. It is connected to the pipe 27 by a pipe 27b.

In the refrigerating system configured as described above, when defrosting is required in any of the plurality of refrigerating apparatuses 1, the electromagnetic valve 8 in the corresponding refrigerating apparatus 1 is opened to open the compressor 1 The hot gas from is passed through the cooler 6 for defrosting, and the refrigerant liquefied by the defrost is guided from the cooler 6 to the defrost heat exchanger 7. Since the cooling water from the cooling tower 2 is sent to the defrost heat exchanger 7 through the condenser 4, the liquid refrigerant is gasified by exchanging heat with the cooling water, and the refrigerant gas is cooled by the compressor 3 Returned to.

[0004]

[Problems to be solved by the device]

 In the conventional refrigeration system described above, the condenser 4 and the defrost heat exchanger 7 are connected in series to the main water supply pipe 26, and since the cooling water is supplied by the serial pipe, the water is not seen from the water supply pump 25. The pressure loss under a large load increases, the pump dynamic power increases, and it is necessary to use a large pump 25.

The present invention has been proposed in order to solve the problems of such conventional techniques, and can reduce the head loss of the cooling water sent from the cooling tower and reduce the capacity and power of the water pump. An object is to provide a refrigeration system that can be reduced.

[0006]

[Means for Solving the Problems]

 In order to achieve this object, the present invention provides a compressor, a condenser, an expansion valve, a cooler, a refrigerating device including a defrost heat exchanger for gasifying liquefied refrigerant during hot gas defrosting of the cooler, and a condenser. In a refrigeration system consisting of a cooling tower and a cooling tower that supplies cooling water for heat exchange to the defrost heat exchanger, the cooling tower and the cooling water inlet of the condenser are connected by a main water supply pipe equipped with a water supply pump. An appropriate position of the water supply pipe and the cooling water inlet of the defrost heat exchanger are connected by a water supply pipe equipped with an on-off valve that opens during defrosting, and the condenser cooling water outlet and the defrost heat exchanger cooling water outlet are shared with each other. It is connected to the cooling tower by a water pipe.

Further, the refrigeration system according to the present invention is provided with a pump controller for detecting the discharge pressure of the water supply pump or receiving a defrost start signal to control the water supply capacity of the water supply pump, and to the defrost heat exchanger. When the amount of cooling water to the condenser is insufficient during water flow, the pump control unit controls the cooling tower to always deliver the required amount of cooling water.

[0008]

[Action]

 According to the configuration corresponding to claim 1 described above, the cooling water pipes to the condenser and the defrost heat exchanger are in parallel, and the opening / closing valve is opened only during defrost to allow the cooling water to flow to the defrost heat exchanger. By supplying water, the pressure loss due to the load seen from the water pump can be reduced.

According to the configuration according to claim 2, when the discharge pressure of the pump is lowered or when the defrost start signal is received, the pump control unit enhances the capacity of the water pump, so that The required amount of cooling water can be supplied from the cooling tower to the condenser and defrost heat exchanger.

[0010]

【Example】

 Hereinafter, a specific embodiment of the refrigeration system according to the present invention will be described in detail with reference to the drawings. An example of this refrigeration system is shown in the system diagram of FIG. In this figure, a plurality of refrigerating apparatuses 1 arranged in parallel are connected to a single cooling tower 2, and a compressor 3, a condenser 4, an expansion valve 5, a cooler 6 and a defrost heat which constitute each refrigerating apparatus 1 are arranged. The exchanger 7 and the cooling tower 2 constitute a freeze / freeze cycle. Explaining the connection system of the refrigerating apparatus 1, the discharge port of the compressor 3 is connected to the gas inlet of the condenser 4 by a pipeline, and a hot defrosting hot air valve having a solenoid valve 8 in the middle is provided. It is connected to the cooler 6 by a gas line 9. The refrigerant outlet of the condenser 4 is connected to the refrigerant inlet of the cooler 6 by a pipe line, and the refrigerant outlet of the cooler 6 is connected to the suction port of the compressor 3 by a pipe line provided with a solenoid valve 10 in the middle. There is. Further, the cooler 6 is connected to the refrigerant inlet of the defrost heat exchanger 7 by a defrost pipe line provided with a regulating valve 11 in the middle, and the gas outlet of the defrost heat exchanger 7 is compressed by the pipe line. It is connected to the inlet of device 3.

On the other hand, a main water supply pipe 13 equipped with a water supply pump 12 is connected to the cooling water outlet of the cooling tower 2, and a branch pipe 13 a extending from this main water supply pipe 13 is connected to the cooling water inlet of each condenser 4. Has been done. The cooling water outlet of each condenser 4 is connected to the main return water pipe 14 by a pipe 14a, and this main return water pipe 14 is connected to the cooling water return port of the cooling tower 2.

A water supply pipe 16 equipped with a solenoid valve 15 that opens at the time of defrosting branches from an appropriate position on the discharge side of the pump 12 of the main water supply pipe 13 extending from the cooling tower 2. Is connected to the cooling water inlet of each defrost heat exchanger 7. The cooling water outlet of each defrost heat exchanger 7 is connected to the main return water pipe 14 by a pipe 14b.

A pressure sensor 17 for detecting the pump discharge pressure is provided on the discharge side of the water supply pump 12 provided in the main water supply pipe 13, and the detection output of this sensor 17 is sent to the pressure detection circuit 18. To be When the pressure detection circuit 18 detects that the pump discharge pressure has dropped, the inverter 19 that serves as a pump control unit controls the water pump 12 to increase its capacity.

It is also possible to control the inverter 19 so that the capacity of the pump 12 can be enhanced at the time of defrosting by receiving the defrosting start signal.

Next, the operation of the refrigeration system configured as described above will be described. First, in the normal cooling operation, the water supply pump 12 is operated so that the cooling water from the cooling tower 2 is sent to each condenser 4 through the main water supply pipe 13 and the main return water pipe 14 to the cooling tower. Returned to 2. At this time, the high-pressure refrigerant gas discharged from the compressor 3 is liquefied by the condenser 4 in which cooling water is taken in, and the liquid refrigerant is decompressed by the expansion valve 5 and then sent to the cooler 6. As a result, the cooler 6 cools the cooled chamber 20 such as a freezer or a refrigerator. The refrigerant that has taken in heat and gasified by the refrigerating action in the cooler 6 is returned to the compressor 3 via the solenoid valve 10.

On the other hand, when it becomes necessary to perform the defrost operation in any of the coolers 6 of the plurality of refrigeration systems 1, the water supply connected to the defrost heat exchanger 7 of the corresponding refrigeration system 1 The electromagnetic valve 15 of the pipe 16 is opened based on the defrost start signal, and the cooling water from the cooling tower 2 is supplied to the heat exchanger 7 through the water supply pipe 16. The cooling water that has passed through the heat exchanger 7 is returned to the cooling tower 2 through the main return water pipe 14.

At the same time, the solenoid valve 8 of the hot gas pipe 9 is opened in response to the defrost start signal, and the hot gas discharged from the compressor 3 is passed through the cooler 6 as indicated by the dashed arrow. The defrosting of the cooler 6 is performed. The refrigerant that has lost heat by the defrost and is liquefied is sent to the defrost heat exchanger 7 via the adjusting valve 11 by closing the electromagnetic valve 10. In this defrost heat exchanger 7, the cooling water from the cooling tower 2 and the liquid refrigerant are heat-exchanged, and the gasified refrigerant is returned to the compressor 3.

During the defrosting, if the pressure detection circuit 18 to which the pressure sensor 17 is connected detects that the discharge pressure of the pump 12 has dropped, the inverter 19 increases the water supply capacity of the pump 12. The control is performed so that the condenser 4 of the other refrigeration system 1 and the heat exchanger 7 in the defrost are always supplied with the required amount of cooling water.

When the defrost ends, the electromagnetic valve 8 and the adjusting valve 11 are closed, the supply of hot gas to the cooler 6 is stopped, and the electromagnetic valve 15 is closed, so that the defrost heat from the cooling tower 2 is reduced. The supply of the cooling water sent to the exchanger 7 is stopped. This defrost operation is generally performed for each refrigeration system.

As described above, in this refrigeration system, the water supply pipe 16 is branched from the proper position of the main water supply pipe 13 for supplying the cooling water to the condenser 4, and is connected to the defrost heat exchanger 7, and the solenoid valve 15 is connected only during defrosting. Since it is opened so that the cooling water can be supplied to the defrost heat exchanger 7, the pump load is reduced, and the capacity and power of the pump 12 can be reduced.

In addition, since the capacity of the pump 12 is controlled by the inverter 19 that receives the detection signal of the pump discharge pressure, it is possible to always supply the required amount of cooling water and to pass water to the defrost heat exchanger 7. However, the amount of cooling water to the condenser 4 does not become insufficient.

FIG. 2 shows an example in which such a refrigerating system is installed in a roof 21 having a cooled room 20 of a freezing room or a refrigerating room on each floor, and a main water supply from a cooling tower 2 installed on a roof 21a. Cooling water can be supplied to the condenser 4 and the defrost heat exchanger 7 of the refrigeration system 1 by the parallel piping of the pipe 13 and the water supply pipe 16.

In the above-described embodiment, the case where a plurality of refrigerating apparatuses 1 are provided has been described, but the present invention can also be applied to a refrigerating system having one refrigerating apparatus 1.

[0024]

[Effect of device]

 As described above, according to the present invention, the cooling water can be fed from the cooling tower to the condenser and the defrost heat exchanger through the parallel piping, and the defrost heat exchanger is opened by opening the on-off valve only during defrost. Since the water can be supplied, the head loss of the cooling water is smaller than that in the conventional case where the cooling water is sent by serial piping. As a result, the capacity and power of the water pump can be reduced and energy can be saved.

Further, when the discharge pressure of the pump is reduced or the capacity of the water supply pump is increased at the time of starting defrost, the amount of cooling water to be sent to the condenser is not insufficient even when water is passed through the defrost heat exchanger. The required amount of cooling water can be sent from the cooling tower.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of a refrigeration system according to the present invention.

FIG. 2 is a system diagram showing an example in which the refrigeration system of FIG. 1 is installed in a shed provided with a freezing room or a refrigerating room on each floor.

FIG. 3 is a system diagram showing a conventional refrigeration system.

[Explanation of symbols]

 1 Refrigerator 2 Cooling Tower 3 Compressor 4 Condenser 5 Expansion Valve 6 Cooler 7 Defrost Heat Exchanger 9 Hot Gas Pipeline 12, 15 Water Pump 13 Main Water Supply Pipe 14 Main Return Water Pipe 15 Solenoid Valve 16 Water Supply Pipe 17 Pressure Sensor 18 Pressure detection circuit 19 Inverter 20 Cooled room

Claims (2)

[Scope of utility model registration request] 1. A refrigeration system comprising a compressor, a condenser, an expansion valve, a cooler, and a defrost heat exchanger for gasifying liquefied refrigerant during hot gas defrost in a cooler, and a condenser and a defrost heat exchanger. In a refrigeration system composed of a cooling tower that supplies cooling water for replacement, the cooling tower and the cooling water inlet of the condenser are connected by a main water supply pipe equipped with a water supply pump, and a proper place of this main water supply pipe and defrost heat. The cooling water inlet of the exchanger was connected by a water supply pipe equipped with an on-off valve that opens during defrosting, and the cooling water outlet of the condenser and the cooling water outlet of the defrost heat exchanger were connected to the cooling tower by a common return water pipe. A refrigeration system characterized in that 2. A pump controller for detecting the discharge pressure of the water supply pump or receiving a defrost start signal to control the water supply capacity of the water supply pump, and supplying water to the defrost heat exchanger to the condenser. 2. When the amount of cooling water is insufficient, the pump control section controls the cooling tower to constantly send the required amount of cooling water.
Refrigeration system described.