Condenser
The condenser condenses the high-pressure, high-temperature refrigerant vapor from the compressor into a liquid. There are three common types of condensers: ① Water-cooled. Using water as the coolant, these include shell-and-tube condensers, double-pipe condensers, and spiral plate condensers. ② Spray type. Using both water and air as coolants, these include spray condensers (natural convection of air) and evaporative condensers (forced convection of air). ③ Air-cooled. Using air as the coolant, i.e., air condensers.
Evaporator
The evaporator, also known as a heat absorber, is a heat transfer device that cools the refrigerant or the object being cooled through the boiling and vaporization of the liquid refrigerant. Evaporators can be divided into two categories: one is liquid cooling type, used to cool liquid refrigerants, including shell-and-tube evaporators and various immersion evaporators (such as vertical tube, spiral tube, and serpentine tube types). Immersion evaporators immerse the entire heat exchange surface in a tank containing the refrigerant, with stirring to enhance heat transfer. The other type is air cooling type, used to cool air as the refrigerant, and is further divided into tube bundles and air coolers. Tube bundles consist of vertical tubes, horizontal tubes, or coiled tubes, with the refrigerant boiling inside the tubes and natural convection of air outside the tubes. Air coolers consist of a tube bundle and a fan, which forces convection of air outside the tubes.
Refrigerating Machine
A refrigerating machine is a machine that transfers heat from a cooled object at a lower temperature to the surrounding medium, thereby obtaining cooling capacity. The heat transferred from the lower temperature object is conventionally called cooling capacity. The working fluid involved in the thermodynamic process changes (energy conversion and heat transfer) within the refrigerating machine is called the refrigerant. The temperature range for refrigeration is usually above 120K; temperatures below 120K fall within the scope of cryogenic technology. Refrigerating machines are widely used in industrial and agricultural production and daily life.
