Changes and influences of blockage pressure and temperature in refrigeration system

The stable operation of refrigeration units is crucial to maintaining a suitable temperature environment. However, in the actual operation of refrigeration systems, various blockage problems are often encountered, especially ice blockage and dirty blockage. These blockage phenomena not only affect the circulation of refrigerant, but also may cause abnormal operation of the compressor.

Take the expansion valve blockage as an example. As an important regulating component in the refrigeration system, once the expansion valve is blocked, it will block the flow channel of refrigerant from the high-pressure side to the low-pressure side. At this time, the compressor has to face the problem of increasing pressure on the high-pressure side and decreasing pressure on the low-pressure side under continuous pushing, which will cause the load and compression ratio of the compressor to increase continuously, and may eventually cause the overload protection mechanism of the compressor to start.

On the high-pressure side, due to the blockage of the expansion valve, the compressor can only slowly push the refrigerant into the condenser and the high-pressure pipe. With the accumulation of refrigerant on the high-pressure side, the condensation pressure and exhaust pressure gradually increase, and the corresponding condensation temperature also rises, and the energy consumption of the refrigeration unit increases.

On the low-pressure side, due to the blockage of the expansion valve, the refrigerant on the high-pressure side cannot flow smoothly into the evaporator. At the same time, the refrigerant in the evaporator is gradually reduced under the continuous extraction of the compressor, resulting in a continuous decrease in the pressure on the low-pressure side, a decrease in the evaporation pressure and the suction pressure, and the pressure is proportional to the temperature, so the evaporation temperature will drop, which greatly reduces the refrigeration effect in the evaporator.

Due to the reduction of refrigerant in the evaporator, the evaporated refrigerant vapor will continue to absorb heat, which will increase the superheat, thereby pushing up the suction temperature of the compressor. The increase in suction temperature will also cause the compressor exhaust temperature to rise, and the problem of carbonization of refrigeration oil.

For the compressor, the increase in high pressure, the decrease in low pressure and the increase in compression ratio caused by the blockage of the expansion valve all significantly increase the load and power consumption of the compressor. While the power consumption increases, the heat converted by the compressor also increases, causing the exhaust temperature to continue to rise, which may eventually trigger the overload protection mechanism of the compressor.

It should be noted that the blockage of the expansion valve is usually characterized by low low pressure and high high pressure, which is significantly different from the situation of insufficient refrigerant. When the refrigerant is insufficient, both the high and low pressures will be low. Therefore, when diagnosing refrigeration system problems, it is necessary to carefully distinguish between these two situations so that the correct maintenance measures can be taken.

In summary, the blockage problem of the refrigeration system cannot be ignored. In order to ensure the stable operation of the refrigeration system, we need to regularly maintain and inspect the system to promptly detect and deal with potential blockage problems. At the same time, for different types of blockage phenomena, we also need to take targeted maintenance measures to ensure the normal operation of the system and the refrigeration effect.