Chapter 8 - RefrigerationKEY TERMS AND CONCEPTSAbsorption refrigeration: a refrigeration cycle that uses gas as an energy resource to operate the generator. It is used for food chillers and freezers.Absorber: a component of a refrigeration cycle (absorption cycle) that contains a salt solution that absorbs a vapor refrigerant, then the refrigerant releases its latent heat of vaporization.American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE): the organization that hasdeveloped non-CFC refrigerant standards; they have developed a new 400 series of refrigerants that are blends of approved halocarbon refrigerants.Appliance heat load: the heat gain from electric lamps or fan motors in a food chiller or freezer.Chiller: a food storage area (walk-in or reach-in) that maintains a 40-45F (4.4-7.2C) temperature.Chlorofluorocarbon refrigerant (CFC): the group of refrigerants that when released to the atmosphere destroy the protective ozone layer around the earth. These are currently banned around the world, and must be replaced with substitute safe refrigerants.Compressed air refrigeration: a cooling technique that increases the pressure on air, and then quickly releases the pressure of the air allowing it to expand, thus absorbing heat.Compressor: a component of a refrigeration cycle that increases the refrigerant pressure. Normal compressors are rotary, centrifugal, and reciprocating and are usually driven by electric motors.Condenser: a component of a refrigeration cycle that releases the heat absorbed by the refrigerant to the environment. Condensers are usually air or water cooled.Defrosting: the removal of ice from an evaporator used in food chillers and freezers. May be hot-gas or electric resistance defrost. The hot-gas system circulates high pressure refrigerant gas from the compressor to the evaporator.Drier: a device used on a refrigeration cycle that removes water from the refrigerant.Energy Management System (EMS): a computer controlled (full computer or microprocessor - computer chip) energymanagement system, that monitors and controls energy and energy measurement terms.Environmental Protection Agency (EPA): an agency of the US Federal government that develops, tests, establishes,and regulates environment protection standards.Evaporative cooler: see swamp cooler.Evaporator: a component of a refrigeration cycle that is located in a space that is to be cooled. The evaporator absorbs heat from the space through a refrigerant.Expansion valve: a component of a refrigeration cycle that reduces refrigerant pressure and regulates refrigerant flowto the evaporator.Forced convection evaporator/condenser: evaporators/condensers equipped with fans or pumps to circulate the environment coolant (air or water) over the condenser, or cooled space environment over the evaporator.Freezer: a food storage area (reach-in or walk-in) that maintains a temperature below the freezing point of food. It is usually maintained between -10 and +10F (-23.3-12.2C).Generator: a component of a refrigeration cycle (absorption cycle) that heats a salt solution driving off the refrigerant contained in the salt solution as a vapor or gas.Halocarbon refrigerants: a family of safe and essentially non-toxic refrigerants.Hermetic unit: a rotary compressor. Both the compressor and its driving motor are housed as one basic component, hence if either fails, the entire unit (compressor and motor) are replaced.Infiltration heat load: the heat gain by air movement through an open door or around a closed door in a food freezer or chiller. Infiltration may be reduced when using plastic door strips.Lithium bromide absorption refrigeration cycle: a mechanical system that will remove heat from a space or products contained in that space. Such a system has four basic components: evaporator, absorber, generator, and condenser. The normal energy source to operate the cycle is steam which is supplied to the generator.Oil separator: a device used on a refrigeration cycle that removes oil from the refrigerant.Product heat load: the heat gain from products placed in food chillers (sensible heat) and freezers (sensible and latent heat if the products are frozen in the unit).Radiative cooling: a solar cooling system in which water absorbs building heat which is then circulated to devices thatare exposed to the cool outside night air. The heated water is allowed to cool.Refrigerant: a substance that has a low boiling point, hence it is capable of absorbing its latent heat of vaporization at a low temperature.Refrigeration: the removal of heat from a space or products using electro-mechanical systems, such as a vapor compression refrigeration system.Solar absorption cycle: similar to the lithium bromide absorption refrigeration cycle. Solar energy is used to generate steam which is fed to the generator.Solar vapor compression cycle: similar to the vapor compression refrigeration cycle. Solar energy is used to drive the compressor by either a steam engine or by the direct conversion of solar energy to electric power.Strong brine: an absorbent used in an absorption refrigeration cycle, usually lithium bromide.Swamp cooler: similar to a water cooling tower. A device that sprays water into air thus cooling the air which is blown into a space to be cooled. These devices work very well in a hot-dry climate. It is also called an evaporative cooler.Transmission heat load: the heat gained through walls, ceiling, floor, and doors of a walk-in or reach-in chiller or freezer.Underwriters Laboratories (UL): a non-profit and non-government organization that develops equipment and productsafety standards. The emphasis in this chapter is with the development of safe refrigerant and refrigeration cycle component standards.Vapor compression refrigeration cycle: a mechanical system that will remove heat from a space or products contained in that space. Such a system has four basic components: evaporator, compressor, condenser, and expansion valve.Water cooling tower: a device that releases condenser or absorber heat to the environment. Generally, water absorbsheat at the condenser or absorber and is sprayed into an environment. This spraying cools the water.Vapor Compression Refrigeration CycleQ: what are the 4 main parts to a vapor compression cycle?Q: what blows cold air?Q: what blows hot air?Q: what has high pressure?Q: what happens during high pressure?Q: what has low pressure? Q: what happens during low