# Finite Time Thermodynamics of Vapour Compression Refrigeration, Airconditioning and Heat Pump Cycles

## Abstract

The experimental observations show that heat cannot be transferred from low-temperature reservoir to high-temperature reservoir without external energy input or work. The device that extracts heat from low-temperature reservoir and rejects or transfers it to high-temperature reservoir is called refrigerator (or heat pump), and the cycle followed by the device or system is called refrigeration cycle. These devices are cyclic devices, and the fluid that flows in the device is known as refrigerant. Refrigerator and heat pump are essentially the same device and follow the same thermodynamic cycle, but they differ in their objective function. Removal of heat from the space which needs to be cooled and maintained at low temperature is the main objective of refrigerator, and rejecting this heat to a higher-temperature medium is a necessity of the operation, not the objective.

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