RETA Breeze_MayJune_Final_2025

providing colder liquid, but not fast enough. A way was needed to provide cold liquid but at a higher pressure. Sub- cooled liquid, a liquid colder than its saturation point, was generated by lowering the pressure (and thus the temperature of the liquid) and then artificially increasing the pressure. Initially, this need was met with subcool ers. Subcoolers are more a type of heat exchanger than a storage vessel. A topic for another day. PUMPED RECEIVERS (PR) Pumped receivers are sometimes referred to as recirculators. Pumped recirculators allowed designers to overcome the low feed rate at low liquid temperature problem. High-pressure liquid is fed into the pumped recirculator. The pressure within the vessel is much lower than the supply liquid pressure. Vapor is drawn off by the com- pressor in order to maintain pressure within the pumped receiver. As the name implies the pumped receiver uses mechanical (or pressure) pumps to

increase the liquid pressure as it exits the pumped receiver without changing the liquid refrigerant temperature. This sub- cooled refrigerant is then fed to the evaporator. This allows the evaporator to be more efficient (because there is no flash gas) at lower temperatures than achievable with the controlled pressure liquid from the controlled pressure receiver. There are other benefits of the recircula tor, as well. These include the ability to overfeed evaporators, as well as the elimination of an additional vapor separation vessel. It will be interesting to see the next gener ation of receivers. Vern M. Sanderson is Senior Manager of PSM (and amateur recruiter) at SFC Global Supply Chain Inc., where he eats a lot of Red Baron® pizza. The article is Vern’s personal work and does not reflect the view of SFC Global Supply Chain or any affiliated companies or brands. If you have correc tions to the article or memories of the conference, please email them to Vern at Vern.Sanderson@Schwans.com.

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