Vapor-compression chiller technology
A vapor compression chiller typically uses one of four types of compressor: Reciprocating compression, scroll compression, screw-driven compression, and centrifugal compression are all mechanical machines that can be powered by electric motors, steam, or gas turbines. Using electric motors in a semi-hermetic or hermetic configuration is the most common method of driving the compressors since electric motors can be effectively and easily cooled by the refrigerant, without requiring fuel supply or exhaust ventilation and no shaft seals are required as the motor can operate in the refrigerant, reducing maintenance, leaks, operating costs and downtime, although open compressors are sometimes used. They produce their cooling effect via the reverse-Rankine cycle, also known as vapor-compression. With evaporative cooling heat rejection, their coefficients of performance (COPs) are very high; typically 4.0 or more.
COP =Cooling power/Input power
Current vapor-compression chiller technology is based on the “reverse-Rankine” cycle known as vapor-compression. See the attached diagram which outlines the key components of the chiller system.