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ASHRAE Terminology

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ASHRAE Terminology

ASHRAE Terminology, a free resource, is a comprehensive online glossary of more than 3700 terms and definitions related to the built environment, with a focus on heating, ventilating, air conditioning, and refrigeration (HVAC&R), as well as building envelope, electrical, lighting, water and energy use, and measurement terms.

This searchable glossary was designed for use by engineering professionals but is also useful for architects, building owners and operators, educators, public officials, and homeowners.

The terms in ASHRAE Terminology have been assembled and defined and are updated on an ongoing basis by ASHRAE Technical Committee (TC) 1.6, Terminology. TC 1.6 is concerned with terminology, nomenclature, definitions, abbreviations, symbols, and the International System (SI) and Inch-Pound (I-P) units used in the fields of heating, ventilating, air conditioning, water heating, and refrigeration.

Also see the ASHRAE SI Guide for HVAC&R >>

Popular Search Terms

Recently, users have been interested in finding more information about these search terms:

dry-bulb temperature - temperature of air indicated by an ordinary thermometer shielded from solar and long wave radiation

dry-bulb temperature (DBT) - (1) temperature of air indicated by an ordinary thermometer shielded from solar and long wave radiation. (2) in general, any thermometer that indicates the temperature of air (or other fluids); distinguished from a wet-bulb thermometer.

direct-expansion (DX) refrigeration systems - (1) system in which the cooling effect is obtained directly from the expansion of the liquid refrigerant into a vapor. (2) common term applied to an air-conditioning or refrigeration system that utilizes the vapor-compression refrigeration cycle. In a vapor-compression refrigeration cycle, the refrigerant removes heat in the evaporator by directly expanding the entering liquid refrigerant into vapor as it leaves the evaporator. The vapor is then compressed and piped to a condenser where the heat removed by the evaporator and the heat of compression are rejected to another medium so that the gaseous refrigerant is condensed to a liquid. The liquid is then piped to a pressure reducing device/metering device to be supplied to the evaporator.

global warming potential (GWP) - an index developed to provide a simplified means of describing the relative ability of a chemical compound to affect radiative forcing, if emitted to the atmosphere, over its lifetime in the atmosphere, and thereby to affect the global climate. Radiative forcing reflects the factors that affect the balance between the energy absorbed by the earth and the energy emitted by it in the form of longwave infrared radiation. The GWP is defined on a mass basis relative to carbon dioxide. The GWP for a compound must be calculated up to a particular integrated time horizon, for example, 20, 100, or 500 years. The time horizon most widely accepted is 100 years.

ASHRAE Publications

You may be interested in these ASHRAE publications: