JPS6152903B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot gas defrost type refrigeration system, and particularly to the configuration of a hot gas supply path.

In a conventional hot gas defrost type refrigeration system, as shown in FIG. A valve 4 is provided, and the hot gas solenoid valve 4 is opened during defrosting operation, and the gas discharged from the compressor 1 is guided to the cooler 5 as shown by the dotted arrow.

In addition, in the figure, 6 is a dryer, 7 is a liquid feeding solenoid valve, 8 is an expansion valve, 9 is a drain pan, 10 is a fan, 11 is a suction pressure adjustment valve, 12 is a heat exchanger, 13
denotes a suction gas solenoid valve, a chain double-dashed line 14 denotes a cooling water system, solid arrows denote a refrigeration cycle, and dotted arrows denote water flowing through each refrigerant during a defrosting cycle.

However, according to this conventional configuration, during defrosting operation, a part of the discharged gas from the compressor 1 also flows toward the condenser 2 and is condensed and liquefied, so the amount of hot gas directed to the cooler 5 is reduced, and the discharged gas As the pressure decreases, the temperature of the discharged gas decreases, causing insufficient heating of the cooler 5 and incomplete defrosting.

This phenomenon is particularly noticeable when the cooling water temperature is low, such as during winter. To prevent this, conventionally, during defrosting operation, the cooling water 14 is often stopped or the cooling water temperature is adjusted so that the cooling water temperature does not become too low.

However, from the viewpoint of energy saving, during refrigeration operation, the pressure of the discharged gas should be as low as possible, that is, the cooling water temperature should be kept as low as possible.

On the other hand, at the initial stage of supplying the discharge gas during defrosting operation, the liquid refrigerant held in the condenser (or liquid receiver) self-evaporates, and this refrigerant vapor also flows into the cooler 5.
During defrosting operation, it is convenient for the refrigerant circuit between the condenser 2 and the cooler 5 to communicate with each other during defrosting operation.

In view of the above, it is an object of the present invention to provide a hot gas defrost type refrigeration system that defrosts the cooler effectively and reliably and contributes to energy saving. .

The details of the present invention will be explained below with reference to embodiments shown in the drawings. FIG. 2 shows one embodiment of the present invention.
The same reference numerals as in the figure indicate the same thing. 15 is compressor 1
This is a three-way solenoid valve as a switching valve device installed in the discharge gas refrigerant system of the compressor 1, and the discharge gas from the compressor 1 is passed through the condenser 2 through the piping 16 during cooling, and through the bypass piping 3 during the defrosting operation to the cooler. It can be switched to flow to 5. In addition to this three-way solenoid valve, for example, two two-way solenoid valves or the like can also be used as the switching valve device.

17 is the gas phase part of the condenser 2 and the three-way solenoid valve 15
The side connected to the cooler 5, that is, the bypass piping 3
This piping includes a two-way solenoid valve 18 that is opened only during defrosting operation, and a condenser 2.
A check valve 19 is provided to allow the refrigerant inside to flow only toward the bypass pipe 3 side. In addition, if a liquid receiver is provided separately from the condenser, pipe 17
is provided so as to communicate the gas phase portion of the liquid receiver with the bypass piping 3.

In this refrigeration system, ports A and B of the three-way solenoid valve 15 are in communication, the two-way solenoid valve 18 and the suction pressure regulating valve 11 are closed, and the liquid sending solenoid valve 7 and the suction gas solenoid valve 13 are open. Ru. Therefore, during refrigeration operation, the flow of refrigerant is as shown by the solid arrow, and the discharge gas from the compressor 1 is guided to the condenser 2 through ports A to B of the three-way solenoid valve 15 and the pipe 16.

On the other hand, during defrosting operation, the three-way solenoid valve 15 is switched so that ports A and C communicate with each other, and the two-way solenoid valve 18 is opened. Further, since the liquid feeding solenoid valve 7 and the suction gas solenoid valve 13 are closed and the suction pressure regulating valve 11 is opened, the refrigerant flow is as shown by the dotted arrow. That is, the discharged gas from the compressor 1 passes through ports A to C of the three-way solenoid valve 15 and flows to the cooler 5 through the bypass pipe 3. On the other hand, condenser 2
Immediately after the two-way solenoid valve 18 is opened, the liquid refrigerant in the liquid refrigerant (or liquid receiver) temporarily self-evaporates and mixes with the discharged gas passing through the bypass pipe 3 through the two-way solenoid valve 18 and the check valve 19. and flows toward the cooler 5 to defrost the cooler 5. As defrosting progresses, the discharge gas pressure increases, but the check valve 19 prevents the discharge gas from flowing into the condenser 2, so low-temperature cooling water 14 is passed through the condenser 2. Defrosting can be performed effectively and reliably without causing a drop in the temperature or pressure of the discharged gas even if left as is.

FIG. 3 shows another embodiment of the present invention, in which the present invention is applied to a refrigeration system equipped with a heat storage water tank 20, and the refrigerant circuit from the compressor 1 to the cooler 5 is as described above. It is the same as the example.

The role of such a heat storage water tank 20 is to heat the water in the heat storage water tank 20 by passing the gas discharged from the compressor 1 through the heating coil 22 through the valve device (in this example, a three-way switching valve) 21 during refrigeration operation. Then, during defrosting operation, the defrosting signal 23 is applied to the valve device 21 to switch the valve device, and the discharged gas is bypassed through the piping 24 without passing through the heating coil 22, and is routed through the suction pressure regulating valve 11. By passing the refrigerant from the cooler 5 through the heating coil 25 in the heat storage water tank 20, the refrigerant is vaporized. This device also includes a temperature controller 27 having a temperature detector 26, and when the water temperature exceeds a predetermined temperature during refrigeration operation, the valve device 21 is switched so that the discharged gas is directly guided to the condenser 2 through the pipe 24. By doing so, the water temperature is maintained at the set temperature and an excessive rise in water temperature is prevented, thereby preventing the suction gas temperature of the compressor 1 from rising excessively when switching to defrosting operation. Prevents adverse effects on the compressor. In addition, since the temperature of the heat storage water tank 20 is maintained at the set temperature, there is no need for an auxiliary heat source even in winter, contributing to energy savings. It becomes possible to use it effectively.

As described above, the refrigeration system according to the present invention has
The discharge gas refrigerant system of the compressor is provided with a switching valve device that allows the discharge gas to flow to the condenser during cooling operation and to the cooler during defrosting operation. A pipe is provided to communicate between the switching valve device and the side connected to the cooler of the switching valve device, and the pipe is equipped with a two-way solenoid valve and a check valve that are opened only during defrosting operation. Even if the cooling water temperature is low during the cold season, such as during defrosting operation, the discharged gas is not introduced into the condenser, and the refrigerant gas generated by self-evaporation of the liquid refrigerant in the condenser can also be effectively used for defrosting. The temperature and pressure of the discharged gas can be kept high, and defrosting can be performed quickly and reliably. In addition, when performing defrosting operation during the cold season, there is no need to adjust the cooling water temperature to a high temperature, and defrosting can be performed while low-temperature cooling water is flowing through the condenser. Since low-temperature cooling water can be passed through the condenser, the condensation temperature is lowered, and the refrigeration system is operated at high operating efficiency (coefficient of performance), resulting in energy savings. Note that the present invention can also be applied to an air-cooled condensing type refrigeration system.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing the configuration of a conventional hot gas defrost refrigeration system, Fig. 2 is a system diagram showing one embodiment of the present invention, and Fig. 3 is a system diagram showing another embodiment of the present invention. be. In the figure, 1... Compressor, 2... Condenser, 3... Bypass piping, 5... Cooler, 15... Three-way solenoid valve, 18... Two-way solenoid valve, 19... Check valve.

Claims (1)

[Claims] 1 The discharge gas refrigerant system of the compressor is equipped with a switching valve device that allows the discharge gas to flow to the condenser during refrigeration operation and to the inlet side of the cooler during defrost operation, and also to connect the condenser or liquid receiver to the refrigerant system. A pipe is provided that communicates the gas phase part of the switching valve device with a bypass pipe connected to the inlet side of the cooler of the switching valve device, and the pipe includes a two-way solenoid valve that is opened only during defrosting operation, and a condensing valve. 1. A refrigeration system comprising a check valve that allows refrigerant in a container or receiver to flow only to a bypass piping side.