Air-cooling heat pump unit and anti-freezing method for plate heat exchanger

Abstract

The invention provides an air-cooling heat pump unit, which comprises a compressor, a plate heat exchanger, a pressure sensor (6) and a controller. The plate heat exchanger used as an evaporator is communicated with a first refrigerant pipeline (13) led out from an air suction port of the compressor. The pressure sensor is used for sensing refrigerant evaporation pressure of the plate heat exchanger and connected onto the first refrigerant pipeline. The controller is provided with a module which is used for outputting signals enabling the air-cooling heat pump unit to stop when sensing values of the pressure sensor are smaller than the set pressure value. The invention further provides an anti-freezing method for the plate heat exchanger, which is used for the air-cooling heat pump unit and includes anti-freezing steps: using the pressure sensor to detect the refrigerant evaporation pressure of the plate heat exchanger; and comparing the refrigerant evaporation pressure with the set pressure value, and when the refrigerant evaporation pressure is smaller than the set pressure value, stopping the air-cooling heat pump unit, otherwise, keeping the air-cooling heat pump unit in operation. By means of the air-cooling heat pump unit and the anti-freezing method for the plate heat exchanger, frost cracking of the plate heat exchanger caused by frozen water, for heat exchange with refrigerant, in the plate heat exchanger can be effectively prevented.

Description

technical field [0001] The invention relates to an air-cooled heat pump unit and an antifreeze method for a plate heat exchanger used in the air-cooled heat pump unit. Background technique [0002] For the situation where the evaporator in the air-cooled heat pump unit uses a plate heat exchanger, the air-cooled heat pump unit operates in cooling when the ambient temperature is low. Due to the small indoor load of the unit, the outlet water temperature gradually decreases. ℃, due to reasons such as small water flow and dirty water system in the water system of the plate heat exchanger, the local water flow of the plate heat exchanger is small or the water does not flow, and the water temperature will be lower than 0 ℃, freezing, resulting in local Swell, crack. [0003] The existing antifreeze measures are usually to add an outlet water temperature sensor at the water side outlet of the plate heat exchanger to protect the system outlet water temperature. When the outlet wa...

AI Technical Summary

Problems solved by technology

However, there are many factors that affect the accuracy of the outlet water temperature, so that the tested temperature cannot accurately display the actual water temperature, resulting in the outlet water temperature being lower than 0°C. For example, due to external factors such as heat preservation and heat transfer, the deviation between the temperature detected by the sensor and the actual water temperature is relatively large. Second, if the heat exchanger is a dual system or multi-system, the test outlet water temperature is the mixed water temperature, which is very different.

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