ABSTRACT
Oliver Evans first proposed a closed cycle of refrigeration using volatile liquid in 1805. Refrigeration equipment consumes electricity that is generally produced by burning fossil fuels that emits carbon dioxide into the atmosphere. The refrigerant is drawn into the compressor and compressed into a smaller volume. In doing so, the refrigerant molecules are squeezed together, causing their temperature and pressure to be increased. When the pressure of the refrigerant is increased the boiling point also increases. The refrigerant gas enters the condenser at relatively high temperature and pressure. The refrigerant enters the expansion device as a liquid at high pressure. The function of the expansion device is to regulate the flow of the liquid refrigerant into the evaporator and thereby reduce the pressure. In flooded evaporators, the refrigerant space is largely filled with liquid. Liquid refrigerant enters the evaporator at a pressure such that it will boil readily.
