Air Balance Terms

Air balance terms speaks to an air balance glossary and air balance terminology commonly used in the air balance industry are as listed.This the vernacular mostly used by people in the industry.

Ambient air - the air in the room.

Air change - the number of times the air is changed in a room based on the rate air exhausted from a room as compared to the volume of the room.

Dry air - in air balance terms, air without water vapor in it.

Outdoor air - air drawn in from outside.

Recirculated air - return air moved through the air system before being supplied to the conditioned space.

Reheated air - it air that is that being reheated before being supplied to the conditioned space.

Return air- air being returned from the conditioned space.

Saturated air - air which has all the moisture it can hold in it.

Air cleaner - a device or filters which remove air borne particles.

Air conditioning system - it is an assembly of mechanical equipment for the conditioning of air controlling cleanliness, temperature and humidity to meet space requirements.

Algae - a minute fresh water plant growth which forms a scum on the surfaces of water interfering with fluid flow and heat transfer.

Belt driven - in air balance terms it is equipment which has motor and fan pulleys and is belt driven.

Blower - a common term for a fan used to force air under pressure.

Boiler - a closed vessel in which a liquid is heated or converted to steam

BTU - the heat required to raise the temperature of a lb of water 1 degree F.

Ceiling outlet - a round, square, rectangular or linear air diffuser located in a ceiling

Change of State - change from one state such as solid, liquid or gas to another.

Chill - to apply refrigeration moderately without freezing.

Coefficient of performance - the rate of heat delivered to the rate of energy input.

Coil - a cooling or heating element made of pipe or tubing.

Comfort Chart - shows effective temperatures with dry bulb temperatures and humidity by which the effects of various air conditions on human comfort may be compared.

Comfort zone - the average range of effective temperatures over which the majority of adults feel comfortable.

Condensation - the process of changing a vapor into liquid by the extraction of heat.

Condenser - in air balance terms it is a heat exchanger in which the refrigerant compressed to a suitable pressure is condensed by rejection of heat to an external cooling medium.

Control - any device for the regulation of components or systems in normal operation.

Cooling coil - an arrangement of pipe or tubing which transfers heat from air to a refrigerant.

Cooling element - heat transfer surface containing refrigerating fluid in location where refrigerating effect is desired.

Cooling medium - any substance whose temp is such that it is used, with or without a change of state, to lower the temp of other bodies or substances.

Cooling water - water used for condensation of refrigerant; condenser water.

Critical velocity - the velocity above which air flow becomes turbulent.

Chimney effect - the tendency of air or gas in a duct or other vertical passage to rise when heated.

Damper - a valve or plate used to regulate the flow of air.

Degree day - a unit, based upon difference and time, used in estimating fuel consumption and specifying nominal heating load of a building in winter. For any one day, when the mean temp is less than 65 F, there exist as many degree days as there are F degrees difference in temp between the mean temp for the day and 65 F.

Dehumidification - in air balance terms it refers to the removal of water from air by cooling the air below the dew point or removal of water vapor from air by chemical or physical means.

Direct connected - fan and motor direct connected, no pulleys or belts.

Duct - a passageway made of sheet metal or other material not necessarily leak tight, used for conveying air.

Evaporation - change of state from liquid to vapor.

Air flow outward through a wall or membrane.

Fan centrifugal - a fan rotor or wheel with a scroll type housing, including driving mechanisms to support a belt drive or direct connection.

Fan propeller - a propeller or disc type wheel within a mounting ring or plate, including driving mechanism supports for belt drive or direct connection.

Fan tube axial - a propeller or disc type wheel within a cylinder, including drive mechanism supports for belt drive or direct connection.

Fan vane axial - in air balance terms it is a disc type wheel within a cylinder, a set of air guide vanes located either before or after the wheel, including drive mechanism supports for belt drive or direct connection.

Specific gravity - density compared to density of water or air.

Latent heat - heat as a result of a change of state.

Sensible heat - heat as a result of a change of state.

Horsepower - in air balance terms it is the unit of power for motors.

Humidifier - a device which humidifies air to be circulated through ducts in an air conditioning system.

Hydrometer - an instrument which indicated the specific gravity of the liquid in which it floats.

Hygrometer - an instrument responsive to relative humidity of the air.

Louvre an assembly of sloping vanes intended for air to pass through and to inhibit transfer of water droplets.

Outside air opening - any opening used as an entry for air from outside.

Pneumatic - operated by air pressure.

Psychrometer - an instrument for measuring relative humidity by means of wet and dry bulb temperatures.

Return air - air returned from conditioned space.

Thermometer - an instrument for measuring temperature.

Thermostat - an automatic control device actuated by temperature and designed to be responsive to temperature.

Ton of refrigeration - a useful refrigerating effect equal to 12,000 Btu/hr.

Vapor barrier - a moisture impervious layer applied to a surface enclosing a humid space to prevent moisture from traveling to a point where it may condense due to a lower temperature.

Ventilation - the process of supplying or removing air by natural or mechanical means, to or from any space.

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