Capillary Tube Refrigeration - Working Principle, Construction & Applications - ElectricalWorkbook

Capillary tube is used as an expansion valve in small capacity hermetically sealed refrigeration units such as domestic refrigerators, water coolers, room air conditioners and freezers. Capillary tube is a tube of small internal diameter and of varying length, which depends upon the application. It is made up of either copper or steel.Fig. 1: Capillary tubeWorking Principle of Capillary TubeCapillary tube works as an expansion device in refrigeration system. Therefore, during flow of refrigerant through capillary tube, high pressure, low-temperature liquid refrigerant should become ow pressure, low temperature liquid refrigerant. In refrigeration system, high pressure is condenser pressure, whereas, low pressure is evaporator pressure. Thus, the function of capillary tube is “to create a pressure drop by reducing the pressure of liquid refrigerant from condenser pressure to evaporator pressure”. The amount or extent of pressure drop through capillary tube depends upon the internal diam...