Structural Characteristics of Air-cooled Chillers

2021-10-13

Structural characteristics of air-cooled chillers
The air source heat pump uses outdoor air as the low temperature heat source. It has two forms: air-air heat pump and air-water heat pump.
1. Air-to-air heat pump
This type of air-cooled chiller is the most common type. Its high-temperature side and low-temperature side heat exchangers (that is, the condenser and evaporator are air-refrigerant heat exchangers are generally copper tube aluminum fin type The conversion of cooling and heating is switched through a four-way reversing valve. Heat pump room air conditioners and air-cooled heat pump unit air conditioners belong to this type.
2. Air-water heat pump
The air side heat exchanger of this air-cooled chiller is a copper tube aluminum fin heat exchanger, and the water side heat exchanger is a shell and tube heat exchanger. Air-cooled chillers are the most common form. In winter, they operate as a heating cycle and provide hot water as air conditioning heating; in summer, they operate as a refrigeration cycle and provide cold water as the cold source of non-independent air conditioning units. There are two types of heat pump chillers, integrated and combined, to switch between cooling and heating by changing the flow direction of the refrigerant by the valve. The integral air-cooled chiller consists of one or more compressors as the main engine, but only one water-side heat exchanger combined heat pump type chiller consists of multiple independent loop unit units, each unit unit has a compressor , An air-side heat exchanger and water-side heat exchanger water pipes combine several units to form an independent unit.
Three, the characteristics of air source heat pump
1) As a heat source, air can be used free of charge anytime and anywhere.
2) Suitable for mass production in the factory, site installation is relatively simple and convenient.
3) The parameters of air vary greatly with region, season and time. When the ambient temperature is below -5℃, the heating efficiency of the heat pump is already very poor, the heating is insufficient, and other heating equipment (such as electric heaters) is often needed. , Boilers and other supplementary heating.
4) Due to the small mass heat capacity of air, the heat exchange area and air volume required by the air-side heat exchanger are large, which increases the volume of the heat pump and causes a certain amount of noise.

5) The air contains water vapor. When the heat pump is working, condensation or frost will often occur on the surface of the air side heat exchanger at low temperatures. When there is a trace amount of condensation, the heat exchange effect can be improved, but the air flow resistance is increased. When frost occurs, it will reduce the effect of the switch and increase the air flow resistance. When the frost layer is thick, it must be defrosted. During defrosting, the heat pump not only cannot supply heat, but also consumes energy, which reduces the heat supply efficiency of the heat pump.

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