Plate heat exchanger in heat pump cycle for condenser

The plate heat exchanger used as evaporator in the refrigeration cycle of the heat pump unit is used as a condenser in the heat pump cycle. In two cases of refrigeration cycle and heat pump cycle, the flow direction of refrigerant is opposite, and the direction of flow is constant. Because the load is greater than the load of condenser evaporator, so should be considered when the plate heat exchanger as the evaporator of heat exchanger for concurrent design work, and as the condenser when used to countercurrent heat exchanger.

The determination of water temperature of cooling water inlet and outlet of plate heat exchanger should be determined according to the local meteorological conditions (mainly referring to the calculation temperature of wet bulb in summer air conditioning) and the comparison of investment and operation cost. Under normal circumstances, the cooling water inlet temperature than the local summer air conditioning wet bulb temperature is 4 degrees higher than a temperature of 6 degrees, the temperature difference of cooling water for a 6 degree of 4.

In the case of plate condenser, it is not necessary to have the same situation of condensation section and supercooling section, because the heat transfer in the cooling section is more obvious than that of the condensing section. If you need too cold, in principle, should be set alone in the cooler.

As the condensation heat transfer coefficient is generally less than the water side heat transfer coefficient, in order to make the two approaches as close as possible, the flow rate should be smaller than the water water heat exchanger, can be selected for 0.3 0.6m/s. It should be noted that the water flow rate is not too small, otherwise it will cause low turbulence, resulting in heat transfer efficiency and self-cleaning effect is not ideal.

The heat transfer in the condenser is basically caused by the condensation of the film. The refrigerant enters the plate condenser in the form of an overheated gas from the top, and then passes through the superheated cooling, condensing and leaving in the form of a supercooled liquid.

It should be pointed out that because of the small volume of the plate condenser, the liquid can not be stored, therefore, the heat pump system with a plate heat exchanger as a water side heat exchanger must be equipped with a liquid reservoir.