Liquid refrigerant pumping in industrial refrigeration systems

• Published in: ASHRAE journal Vol. 53; no. 8; pp. 36 - 43
• Main Authors: Jekel, Todd B, Reindl, Douglas T
• Format: Journal Article
• Language: English
• Published: New York American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. (ASHRAE) 01.08.2011; American Society of Heating, Refrigeration and Air Conditioning Engineers, Inc
• Subjects: Centrifugal pumps; Evaporating appliances; Evaporators; Leaves; Liquids; Pumps; Refrigerants; Refrigeration; Vessels; United States
• ISSN: 0001-2491; 1943-6637

Early practitioners of industrial refrigeration systems found they could increase the capacity of evaporators by supplying excess liquid refrigerant to the unit--overfeeding. In evaporators configured to operate with overfeed, the quantity of liquid refrigerant supplied is greater than the minimum amount required to meet the cooling loads as it undergoes the phase change from liquid to vapor. In this case, a mixture of low temperature liquid and vapor leaves the evaporator and returns to a vessel designed to separate the liquid from the vapor prior to the vapor being recompressed. In a mechanically pumped overfeed system, a centrifugal pump draws low temperature saturated liquid refrigerant from a vessel and raises the pressure of the liquid for delivery to one or more evaporators having a common refrigerant temperature requirement. Once pressurized by the pump, the saturated liquid becomes subcooled as it leaves the pump discharge and enters the "recirculated liquid supply line." Here, Jekel and Reindl discuss on industrial refrigeration which covers the use of centrifugal pumps to pump refrigerants.