The total of the indicated gage pressure plus the atmospheric pressure. Abbreviated "psia" for pounds per square inch absolute.

 

Temperature measured from absolute zero using an absolute temperature scale (e.g. Kelvin).

 

Temperature at which all molecular motion ceases (-460 °F, -273.15 °C, and 0 K.)

 

The number of times that air in a house is completely replaced with outdoor air in one hour.

 

Act of combining substance with air.

 

The ratio of annual output of useful energy or heat to the annual energy input to the furnace.

 

The inside part of the A/C system that contains the blower, cooling (evaporator) coil, and heater.

 

The amount of air required to completely replace the air in a room or building; not to be confused with re-circulated air

 

Coil on some types of heat pumps used either as an evaporator or condenser.

 

Equipment that conditions air by cleaning, cooling, heating, humidifying, or dehumidifying it. A term often applied to comfort cooling equipment.

 

A process that maintains comfort conditions in a defined area.

 

Mechanism designed to lower temperature of air passing through it.

 

Air distribution outlet or grille designed to direct airflow into desired patterns.

 

Distribution of the air in a space, called the treated space, by means of devices, called air terminal devices, in a manner so as to meet certain specified conditions, such as air change rate, pressure, cleanliness, temperature, humidity, air velocity and noise level.

 

The transportation of a specified air flow to or from the treated space or spaces, generally by means of ductwork.

 

The space between magnetic poles or between rotating and stationary assemblies in a motor or generator.

 

Fan/blower, filter and housing parts of a system.

 

Leakage of air into rooms through cracks, windows doors and other openings.

 

A device that registers changes in air conditions such as pressure, velocity, temperature, or moisture content.

 

Heat pumps or air conditioners that uses the outdoor air to transfer heat to and from the refrigerant in the unit.

 

A device located in an opening provided at the boundaries of the treated space to ensure a predetermined motion of air in this space.

 

A fitting used to vent air manually or automatically from a system.

 

Heat of compression, plus the heat of absorption, is transferred from refrigerant within coil to surrounding air, either by convection or fan or blower.

 

The volume of air moving through a blower or duct. Units of measure are cubic feet per minute (CFM), liters per second (LPS) or cubic meters per hour (m³h).

 

An instrument used to measure air velocities.

 

Air-Conditioning and Refrigeration Institute is a nonprofit, voluntary organization comprised of heating, air conditioning and refrigeration manufacturers. ARI publishes standards for testing and rating heat pumps and air conditioners to provide you with a standardized measure of comparison. So, ARI ensures a level of performance within the industry.

 

The U.S. Federal Government and some states have set standards for acceptable levels of asbestos fibers in indoor air. Many common building materials used before 1975 contain asbestos, such as some floor tiles, ceiling tiles, taping muds, pipe wrap, mastics and other insulation materials. Normally significant releases of asbestos fiber do not occur unless the building materials are disturbed, especially by sanding, drilling or building remodeling. There are particularly stringent regulations applicable to schools and residences. Inhalation of asbestos fibers over long exposure times is associated with increased incidence of lung cancer.

 

A leading HVAC/R Association - American Society of Heating, Refrigerating and Air Conditioning Engineers - http://www.ashrae.org/

 

American Society for Testing and Materials.

 

Controls that react to a change in conditions to cause the condition to stabilize.

 

A refrigerant control valve that maintains a constant pressure in an evaporator.

 

The pressure exerted upon the earth's surface by the air because of the gravitational attraction of the earth. Standard atmosphere pressure at sea level is 14.7 pounds per square inch (psi). Measured with a barometer.

 

A device that propels air in an axial direction.

 

The lowest outdoor temperature at which the refrigeration cycle of a heat pump will supply the heating requirements without the aid of a supplementary heat source.

 

Process of adjusting the flow of air in duct systems, or water flow in hot-water heating systems.

 

An instrument for measuring atmospheric pressure.

 

An enclosed air-moving device which redirects the airflow by 90 degrees towards one or more exit points.

 

Quantity of heat required to raise the temperature of one pound of water one degree Fahrenheit.

 

A device used to prepare and burn fuel.

 

Carbon Dioxide is a surrogate for indoor pollutants emitted by humans and correlates with human metabolic activity. Carbon dioxide at levels that are unusually high indoors may cause occupants to grow drowsy, get headaches, or function at lower activity levels. Humans are the main indoor source of carbon dioxide. Indoor levels are an indicator of the adequacy of outdoor air ventilation relative to indoor occupant density and metabolic activity. To eliminate most Indoor Air Quality complaints, total indoor carbon dioxide should be reduced to below 600 ppm (parts per million) above outdoor levels.  ASHRAE recommends that carbon dioxide levels not exceed 700 ppm above outdoor ambient levels.

 

A colorless, odorless, highly poisonous gas produced when carbon burns without sufficient air nearby.

CM is one of the most acutely toxic indoor air contaminants is carbon monoxide (CO), a colorless, odorless gas that is a byproduct of incomplete combustion of fossil fuels. Common sources of carbon monoxide are tobacco smoke, space heaters using fossil fuels, defective central heating furnaces and automobile exhaust. By depriving the brain of oxygen, high levels of carbon monoxide can lead to nausea, unconsciousness and death.

 

A device that draws air in axially and discharges it radially.

 

A class of refrigerants. Generally refers to the Chlorofluorocarbon family of refrigerants. Sometimes called Freon.

 

A standard measurement of airflow that indicates how many cubic feet of air pass by a stationary point in one minute. The higher the number, the more air is being forced through the system.

 

Amount of refrigerant placed in a refrigerating unit.

 

A device that opens an electric circuit when an overload occurs.

 

A reaction called rapid oxidation or burning produced with the right combination of a fuel, oxygen, and heat.

 

The range of temperatures, humidities and air velocities at which the greatest percentage of people feel comfortable.

 

Pump of a refrigerating mechanism which draws a low pressure on cooling side of refrigerant cycle and squeezes or compresses the gas into the high pressure or condensing side of the cycle.

 

The moisture collected on an evaporator coil.

 

A small pump used to pump condensate to a higher level.

 

Part of the outdoor portion of a split-system air conditioner or heat pump. By converting refrigerant that is in a gas form back to a liquid, the coil transfers heat carried by the refrigerant to the outside air.

 

The temperature at which a vapor changes to a liquid.

 

Part of a refrigerating mechanism which pumps vaporized refrigerant from the evaporator, compresses it, liquefies it in the condenser and returns it to the refrigerant control.

 

The transfer of heat through a solid material.

 

Material coating to protect fan from harsh environmental conditions.

 

The movement of heat by fluid flow(e.g. air, water).

 

COP compares the heating capacity of a heat pump to the amount of electricity required to operate the heat pump in the heating mode.

 

Crankcase or Crankcase heater

A crankcase is the housing for the compressor's crankshaft.  The crankcase heater

Crankcase heaters are used to overcome the problem of migration and condensation of
refrigerant in the crankcases of compressors used in air conditioning and heat pump systems. They are designed to keep the crankcase oil at a temperature higher than the coldest part of the system to prevent migration.

A device that is located in ductwork to adjust air flow.

 

Dry Bulb Temperature

 

A decibel describes the relative loudness of a sound on a logarithmic scale.

 

The process of removing ice or frost buildup from the outdoor coil during the heating season.

 

The reduction of water vapor in air by cooling the air below the dew point; removal of water vapor from air by chemical means, refrigeration, etc.

 

The exact temperature at which moisture begins to form.

 

The burner fires directly in the air stream being heated, rather than through a heat exchanger. 100% of available BTUs are delivered to the heated space because no flue or heat exchanger is required. This results in no wasted energy.

 

The Department of Energy is a federal agency in charge of setting industry efficiency standards and monitoring the consumption of energy sources.

 

A drum-kicker is a slang term for a water treatment salesman.  They are easily recognized by their complete lack of service and knowledge of water treatment.  The definition of a 'Drum-Kicker's Water treatment program is as follows:

1. Go see the customer.

2. B.S. for about two hours with customer until he makes you leave.

3. Kick the drum of water treatment chemicals.

4. If drum falls over, sell the customer more chemicals.

5. If the drum stands firm after kick, then go sell the customer more chemicals anyway.

6. Repeat process next month.

A pipe or closed conduit made of sheet metal, fiberglass board, or other suitable material used for conducting air to and from an air handling unit.

 

A ratio calculated by dividing the cooling capacity in Btu's per hour (Btuh) by the power input in watts at any given set of rating conditions, expressed in Btuh per watt (Btuh/watt). EER & SEER can not be compared equally. Air source equipment is rated by SEER and geothermal equipment is rated by EER. EER changes with the inside and outside conditions, falling as the temperature difference between inside and outside gets larger.

 

A rating on comfort equipment is similar to the miles per gallon rating on your car.

 

This device preheats incoming outside air during the winter and pre-cools incoming air during the summer to reduce the impact of heating and or cooling the indoor air.

 

Environmental Protection Agency - http://www.epa.gov/

 

The condition that occurs when heat is absorbed by liquid and it changes to vapor.

 

Part of a split-system air conditioner or heat pump located indoors. The evaporator coil cools and dehumidifies the air by converting liquid refrigerant into a gas, which absorbs the heat from the air. The warmed refrigerant is then carried through a tube to the outdoor unit (condenser coil).

 

Uncontrolled air leakage out of a building.

 

The air flow leaving the treated space.

 

An online magazine is a magazine that is delivered in an electronic form. An online magazine may be online-only, or may be the online version of an otherwise print-published magazine. Today, most online magazines are Internet websites.  Most online magazines that cater to a niche or special interest subject matter, i.e. a zine, is referred to as an ezine (usually pronounced "ee-zeen").

The temperature scale that places the boiling point of water at 212°F and the freezing point at 32°F.

 

A device that produces a pressure difference in air to move it.

 

The use of a pressure control to turn a condenser fan on and off to maintain a correct pressure within the system.

 

A family of mathematical relationships that allows the calculation of new operating characteristics from known system conditions.

 

A device for removing dust particles from air or unwanted elements from liquids.

 

A dimensionless parameter relation air velocity to fan tip velocity. It's used to determine approximate fan width for centrifugal impellers.

 

The production of chill water without operating the chillers. Free cooling is not really free as the chilled and tower water pumps and the tower fan(s) must operate. However, the pumps and fans operate with very little energy consumption as compared to the centrifugal chiller

 

An instrument for measuring pressure.

 

Heat pumps that uses the ground to transfer heat to and from the refrigerant in the unit. The unit circulates water through a heat exchanger in the to a closed loop buried in the ground or by pumping water from a well through the unit.

 

Greendom

A word totally made up by Jimmy V., but by his definition Greendom is total 'Green Building' euphoria.  A place where one's building has reached it's total 'Green' potential where drastic improvements have been made to lower energy consumption and an environment created that would make Al Gore himself 'Green' with envy.  Greendom's Registered Trademark is Pending

A class of refrigerants. Generally refers to Halogenated Chlorofluorocarbon family of refrigerants.

 

This is a device that enables furnaces to transfer heat from combustion safely into breathable air. The primary heat exchanger transfers heat from combustion gases to the air blowing through the ductwork.

 

The amount of heat gained, measured in BTU's, from a space to be conditioned, at the local summer outdoor design temperature and a specified indoor design condition.

 

The amount of heat lost, measured in BTU's from a space to be conditioned, at the local winter outdoor design temperature and a specified indoor design condition.

 

Compression cycle system used to supply heat to a temperature controlled space. Same system can also remove heat from the same space.

 

This device bring fresh, outside air into a home while simultaneously exhausting stale indoor air outside. In the process of doing this, an HRV removes heat from the exhaust air and transfers it to the incoming air, pre-heating it.

 

A class of refrigerants. Generally refers to Hydrofluorocarbon family of refrigerants

 

A device that adds moisture to warm air being circulated or directed into a space.

 

A device designed to regulate humidity input by reacting to changes in the moisture content of the air.

 

The amount of moisture in the air. Air conditioners remove moisture for added comfort.

 

Heating, Ventilating and Air Conditioning

 

A unit of air pressure measurement equal to the pressure exerted by a column of water 1 inch high.

 

Indoor Air Quality

 

Insulated Gate Bipolar Transistor.

 

The resistance or opposition to airflow in a system. Same as back pressure or static pressure.

 

The component of a fan assembly that is composed of a number of contoured blades.

 

Process by which the primary air sets into motion an air volume, called secondary air, in the room.
 

Kilowatt, equals 1000 Watts.

 

Kilowatt hour is the amount of kilowatts of electricity used in one hour of operation of any equipment.

 

The net amount of moisture added to the inside air by plants, people, cooking, infiltration, and any other moisture source. The amount of moisture in the air can be calculated from a combination of dry-bulb and wet-bulb temperature measurements.

 

Heat, that when added or removed, causes a change in state - but no change in temperature.

 

Legionellosis or Legionnaire's Disease is caused by a waterborne bacterium, which is probably the most common serious health threat to building interiors, since mortality is high in infected patients. The number of instances of this disease is higher than commonly understood. The bacterium itself thrives on warm moist substrates and hence is usually associated with a plumbing miss-design or malfunction.

 

A unit of measurement. The velocity of the air.

 

An instrument that measures air pressure differences between locations. Tubes are usually attached to a manometer and run to the spaces where pressures are measured. Essentially a U-tube partly filled with a liquid, usually water, mercury or a light oil. The pressure exerted on the liquid is indicated by the liquid displaced. A manometer can be used as a differential pressure gage.

 

These biological agents can arise from a host of means, but there are two common classes: (a) moisture induced growth of mold colonies and (b) natural substances released into the air such as animal dander and plant pollen. Moisture buildup inside buildings may arise from water penetrating compromised areas of the building skin, from plumbing leaks, from condensation due to improper ventilation, or from ground moisture penetrating a building slab. Indoors, mold growth can be inhibited by keeping humidity levels between forty and sixty percent and by eliminating leaks or moisture condensation and accumulation. Source: www.wikipedia.org

A device that converts electrical energy into mechanical energy. A motor can operate on direct current (DC) or alternating current (AC) voltage supply, not both.

 

Printed Circuit Board.

 

A small unit of air pressure.

 

A sensing device used to measure total pressures in a fluid stream. It was invented by a French physicist, Henri Pitot, in the 1700's.

 

An air flow passage.

 

A dimensionless parameter relating the static pressure potential of a fan to its tip velocity pressure equivalent. It's used to determine approximate fan diameter.

 

The transfer of heat directly from one surface to another. (No intermediate air acting as a transfer mechanism required).

 

Radon is the invisible, radioactive atomic gas that results from radioactive decay of some forms of uranium that may be found in rock formations beneath buildings or in certain building materials themselves. Radon is probably the most pervasive serious hazard for indoor air in the United States and Europe, probably responsible for tens of thousands of lung cancer deaths per annum. There are relatively simple tests for radon gas, but these tests are not commonly done, even in areas of known systematic hazards. Radon is a very heavy gas and thus will tend to accumulate at the floor level. Source: www.

 

Substance used in refrigerating mechanism. It absorbs heat in evaporator by change of state from a liquid to a gas, and releases its heat in a condenser as the substance returns from the gaseous state back to a liquid state.

 

Refrigeration

The process of removing heat from an enclosed space, or from a substance, and rejecting it elsewhere for the primary purpose of lowering the temperature of the enclosed space or substance and then maintaining that lower temperature. To satisfy the Second Law of Thermodynamics, mechanical work must be performed to accomplish this.

Relative Humidity

 

Revolutions per minute, the measurement of fan blade speed.

 

The rotating part of the motor which includes the propeller assembly.

 

Also referred to as the boiling point or the condensing temperature. This is the temperature at which a refrigerant will change state from a liquid to a vapor or visa versa.

 

The total cooling of a central unitary air conditioner or unitary heat pump in BTU's during its normal annual usage period for cooling divided by the total electric energy input in watt-hours during the same period.

 

The heat gain of the home due to conduction, solar radiation, infiltration, appliances, people, and pets. Burning a light bulb, for example, adds only sensible load to the house. This sensible load raises the dry-bulb temperature.

 

Heat, that when added or removed, causes a change in temperature but not in state.

 

Components which are inserted into the air distribution system and designed to reduce airborne noise which is propagated along the ducts.

 

A dimensionless parameter based on fan rotational speed, flow rating and pressure rating. It's a tool used to select the type of fan for a specific application. Each Different fan type achieves peak efficiency at a unique specific speed range.

 

Refrigeration or air conditioning installation, which places condensing unit outside or away from evaporator. These unit are connected together by a supply and return refrigerant lines.

 

The volumetric rate of airflow at standard air conditions.

 

A measure of an air mover's efficiency based on its air horsepower in terms of flow and static pressure vs. required shaft input power.

 

The difference in air pressure between the suction side and pressure side of the blower. Unit of measure is inches of water column (in. wc) or Pascals (Pa).

 

The part of the motor that is fixed, typically found in the hub of the fan.

 

Liquid refrigerant which is cooled below its saturation temperature.

 

Refrigerant vapor which is heated above its saturation temperature. If a refrigerant is superheated, there is no liquid present.

 

The resistance to air flow when moving air through an airflow system. Examples: air filters, air grilles and abrupt changes in flow direction.

 

The point of operation of the air mover on its air performance curve. It is described by an airflow and static pressure point. The operating point is that point on the air mover performance curve where the system resistance curve crosses the air performance curve.

 

An instrument used to detect differences in the level of heat.

 

A device that senses temperature change and changes some dimension or condition within to control an operating device.

 

A unit of measure for cooling capacity. One ton = 12,000 BTUs per hour.

 

A measure of an air movers efficiency based on its air horsepower in terms of flow and total pressure vs. required shaft input power.

 

(VFD) Variable Frequency Drive

An ac motor drive that controls motor speed by changing the current frequency fed to the motor.

Water treatment describes a process used to make water more acceptable for a desired end-use. These can include use as drinking water, industrial processes, medical and many other uses. The goal of all water treatment process is to remove existing components in the water, improving it for subsequent utilization. In the mechanical industry water treatment is a method used to optimize most water-based mechanical and industrial processes, such as: heating, cooling, processing, cleaning, and rinsing, so that operating costs and risks are reduced. 

Wet Bulb

 

Common measure of air pressure used in HVAC systems.

 

When a wet wick is placed over a standard thermometer and air is blown across the surface, the water evaporates and cools the thermometer below the dry-bulb temperature. This cooler temperature (called the wet-bulb temperature) depends on how much moisture is in the air.