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Portable Chiller Systems Glossary: R

Ramp

Ramp is a term used in temperature generation to describe the amount of time it takes for the system to reach Set Point. This Ramp Speed can be set in the programming of the system to be more or less rapid, according to the needs of the application.

Refrigerant

Refrigerants (Primary Fluids) are used in compression refrigeration cycles that require compression, condensation, expansion and evaporation sequences to phase transition from a liquid to a gas and back again, thereby removing heat from the load. They are direct expansion fluids that evaporate in the portion of the process that requires refrigeration/cooling. Refrigerant types include chlorofluorocarbons and non-halogenated hydrocarbons.

RTD (Resistance Temperature Detector)

Resistance Temperature Detectors (RTD) are Temperature Sensing Probes constructed of finely wound platinum wire in which temperature changes produce corresponding, predictable linear resistance changes; Resistance Increases as the Temperature Rises. RTDs are a common device used in Chillers to obtain the Output and DUT temperatures readings necessary for precise temperature programming, generation and control. RTDs are superior to Thermocouples in that their readings are more accurate, stable, and more repeatable, and receive more robust signals. They are substantially more expensive than Thermocouples, however, leading to a cost vs. accuracy/durability decision when choosing which type of temperature sensing device is appropriate for a particular chiller.