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Viewing results 0 - 10 of 318 matches for "D" Back   |   Next
daily range
difference between high and low temperatures for a typical day. Used in HVAC load calculations.
Dalton’s law
each constituent of a mixture of gases behaves thermodynamically as if it alone occupied the space. The sum of the individual pressures of the constituents equals the total pressure of the mixture.
damp building
a building that has a persistent and excessive accumulation of moisture which will, if allowed to persist, shorten the intended useful life of the building’s contents, materials, structural fasteners, or systems.
damper
element inserted into an air-distribution system or element of an air-distribution system permitting modification of the air resistance of the system and consequently changing the airflow rate or shutting off the airflow.
damper actuator
device that provides the necessary force to position a damper.
damping
(1) progressive diminution with time of certain quantities characterizing a phenomenon. (2) reducing the amplitude of vibrations by dissipating the corresponding mechanical energy to some suitable absorbing sink.
darcy unit
measure of permeability. At one darcy, a material will pass a fluid of one centipoise viscosity through a section of one square centimeter at a rate of one cubic centimeter per second, with a drop in pressure of one standard atmosphere.
data
(1) general term used to denote any or all facts, numbers, letters, and symbols that refer to or describe an object, idea, condition, situation, or other factors. (2) information obtained by experimental means, assumed to be in numerical form; recorded values of the variables; readings.
data bank
any electronic depository of data.
data base
ordered and named collection of data, particularly for use in computerized information systems.
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About 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, and air conditioning (HVAC), as well as refrigeration, 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.

To request a free electronic file of the complete list of terms and definitions, email ashraetermseditor@ashrae.org.