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Refrigerant. A refrigerant is a working fluid used in the refrigeration cycle of air conditioning systems and heat pumps where in most cases they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are heavily regulated because of their toxicity and flammability and the contribution of CFC and HCFC ...
Variable refrigerant flow ( VRF ), also known as variable refrigerant volume ( VRV ), is an HVAC technology invented by Daikin Industries, Ltd. in 1982. [ 1] Similar to ductless mini-split systems, VRFs use refrigerant as the primary cooling and heating medium, and are usually less complex than conventional chiller -based systems.
Thermodynamic heat pump cycles or refrigeration cycles are the conceptual and mathematical models for heat pump, air conditioning and refrigeration systems. A heat pump is a mechanical system that transmits heat from one location (the "source") at a certain temperature to another location (the "sink" or "heat sink") at a higher temperature. [ 1]
e. A heat pump is a device that consumes work (or electricity) to transfer heat from a cold heat sink to a hot heat sink. Specifically, the heat pump transfers thermal energy using a refrigeration cycle, cooling the cool space and warming the warm space. [ 1] In cold weather, a heat pump can move heat from the cool outdoors to warm a house (e.g ...
Refrigeration. Refrigeration is any of various types of cooling of a space, substance, or system to lower and/or maintain its temperature below the ambient one (while the removed heat is ejected to a place of higher temperature). [ 1][ 2] Refrigeration is an artificial, or human-made, cooling method. [ 1][ 2] Refrigeration refers to the process ...
Thermodynamics. The Brayton cycle, also known as the Joule cycle, is a thermodynamic cycle that describes the operation of certain heat engines that have air or some other gas as their working fluid . It is characterized by isentropic compression and expansion, and isobaric heat addition and rejection, though practical engines have adiabatic ...
Vapor-compression uses a circulating liquid refrigerant as the medium which absorbs and removes heat from the space to be cooled and subsequently rejects that heat elsewhere. Figure 1 depicts a typical, single-stage vapor-compression system. All such systems have four components: a compressor, a condenser, a metering device or thermal expansion ...
The process of heat transfer from one place to another place without the movement of particles is called conduction, such as when placing a hand on a cold glass of water—heat is conducted from the warm skin to the cold glass, but if the hand is held a few inches from the glass, little conduction would occur since air is a poor conductor of heat.