Shanghai SUNNY-HVAC Refrigeration Equipment Co., Ltd.!
Water-cooled screw chiller freezer Air cooled box chiller
Water-cooled screw chiller freezer Air cooled box chiller
[Factors affecting the high exhaust temperature of the chiller!]
Release date:[2021/6/4] Is reading[50]次

The discharge temperature of the compressor in the chiller determines whether the operation of the equipment can be stable and efficient. The compressor is prone to excessive discharge temperature. Once this happens, it is easy to make the pressure of the chiller too high. As well as the consequences of temperature rise, excessive load, reduced chiller compressor work efficiency, and cooling capacity, other problems can also be caused. So what is the reason for the high exhaust temperature of the chiller?

1. The compression ratio is too high

The exhaust temperature is greatly affected by the compression ratio. The larger the compression ratio, the higher the exhaust temperature. Reducing the compression ratio can significantly reduce the exhaust temperature. Specific methods include increasing the suction pressure and reducing the exhaust pressure.

The suction pressure is determined by the evaporation pressure and the resistance of the suction pipe. Increasing the evaporation temperature can effectively increase the suction pressure and rapidly reduce the compression ratio, thereby reducing the exhaust temperature. Reducing the resistance of the return air line can also increase the return air pressure. The specific methods include timely replacement of the dirty return air filter, and minimizing the length of the evaporation pipe and the return air line.

In addition, insufficient refrigerant is also a factor of low suction pressure. The refrigerant must be replenished in time after leakage.

The main reason for the excessively high exhaust pressure is that the condensing pressure is too high. Insufficient heat dissipation area of the condenser, fouling, insufficient cooling air volume or water volume, too high cooling water or air temperature, etc. can cause excessive condensing pressure. It is very important to choose a suitable condensing area and maintain sufficient cooling medium flow.

2. High return air temperature

The return air temperature is relative to the evaporation temperature. In order to prevent liquid return, the return air pipeline generally requires a return air superheat of 20°C. If the return air pipe is not well insulated, the superheat will far exceed 20°C.

The higher the return air temperature, the higher the cylinder suction temperature and exhaust temperature. Every time the return air temperature increases by 1°C, the exhaust temperature will increase by 1 to 1.3°C.

3. Motor heating

For the return air cooling type refrigeration compressor, the refrigerant vapor is heated by the motor when it flows through the motor cavity, and the cylinder suction temperature is once again increased. The calorific value of the motor is affected by power and efficiency, and the power consumption is closely related to displacement, volumetric efficiency, working conditions, friction resistance, etc.

In the return air cooling type semi-hermetic compressor, the temperature rise of the refrigerant in the motor cavity is roughly between 15 and 45°C. In the air-cooled (air-cooled) compressor, the refrigeration system does not pass through the windings, so there is no motor heating problem.

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