- Absolute Humidity - The amount of water vapor per square foot.
- Absorption Cycle - Absorption cycle utilizes a thermal or chemical process to produce the refrigeration effect.
- Accumeter - An accumeter is a flow control device within a carrier centrifugal chiller. It feeds the cooler with liquid refrigerant, which has a greater cooling capacity than a gas refrigerant.
- Accurator - An accurator is a metering device that provides the correct amount of liquid refrigerant into the evaporator.
- Air Change - The volume of air necessary to completely replace the air in an enclosed space.
- Air Conditioner - Equipment that controls air temperature, relative humidity, purity, and motion.
- Air Cooled - Removes indoor heat by moving heat from a condenser coil to the outdoors with the use of a fan.
- Air-Cooled System - Utilizes refrigerant and air as a condensing medium.
- Air Diffuser - Equipment that directs airflow into a desired pattern.
- Air Flow - Movement of air.
- Air Handler - The part of a central air conditioner that moves cooled air through the duct system.
- Annual Fuel Utilization Efficiency (AFUE) - A rating that measures the amount of heat per dollar the heating equipment provides. This rating is calculated in accordance with the Department of Energy test procedures.
- Atmospheric Pressure - The measure in weight of a 1 square inch column of the atmosphere.
- Auto Changeover - Automatic switch to a back up air conditioning system in the event of a failure.
- Balance Point - Between 30 and 40 degrees, an outdoor temperature that equals the heating needs of the home without the need for supplemental electric resistance heat.
- Bimetal - Used to open or close a switch or valve, bimetal is comprised of two metals with different rates of expansion that are secured together. When heated or cooled, they will warp and open the valve/switch.
- Blower - Device that moves air in a distribution system.
- Boiling Point - Temperature in which a liquid will turn to a vapor.
- BTU (British Thermal Unit) - The rate that measures the amount of heat needed to raise the temperature of a pound of water by one degree Fahrenheit.
- BTU/hr - The rate of measurement that raises the temperature of one pound of water by one degree Fahrenheit per hour.
- Capacity - The amount of space a heating or cooling system can heat or cool. Heating ability is expressed in BTUs and cooling ability is expressed in tons.
- Carbon Monoxide - Colorless, odorless gas produced from burning any fuel.
- Central Air Conditioner System - Air is cooled at a central point and distributed through fans and ducts.
- Centrifugal Compressor - A compressor that uses a rotating impeller to compress the refrigerant vapor. The vapor is drawn into the impeller axially, energy is added to the vapor, and then it is discharged.
- Centigrade (Measure of Temperature) - A temperature scale that measures the boiling point at 100 degrees and the freezing point at 0 degrees (sea level).
- CFM (Cubic Feet per Minute) - Cubic feet per minute – the measurement for the rate of air flow in an air conditioner.
- Charge - The charge is the total refrigerant in a system.
- Chilled Water System - Utilizes a separate chiller that houses the refrigerant. It cools the water and pipes it to the air conditioner.
- Comfort Air Conditioning - Designed for the comfort of people. People generate humid heat. Comfort air conditioning systems remove 60-70% dry/sensible heat and 30-40% of humidity.
- Compressor - Cycles refrigerant from the indoor evaporator to the outdoor condenser and back to the evaporator.
- Compression - Mechanically reduces the volume of vapor or gas.
- Compression Ratio - Discharge pressure divided by suction pressure.
- Condensation - Through heat removal, gas is changed into a liquid.
- Condensation Point - If the temperature were reduced below this point it would change the vapor to a liquid.
- Condenser - A condenser disposes of unwanted heat. The three types of condensers are air-cooled, water-cooled, and evaporative.
- Condenser Coil - A network of tubes filled with refrigerant. It removes heat to make the gaseous refrigerant a liquid again.
- Condensing Unit - A refrigerant mechanism that pumps vaporized refrigerant from the evaporator, compresses it, liquefies it and returns it to the refrigerant control.
- COP (Coefficient of Performance) - The COP measures how energy efficient a chiller operates.
- Cooling Anticipator - A heater that is parallel to the cooling circuit and shortens the off cycle.
- Cooling Capacity - Measures the ability of a unit to remove heat from a room or building.
- Cooling Load - Based on an engineering space analysis, the amount of conditioned air needed to cool a space.
- Damper - Movable plates within the ductwork that are used in zoning to regulate airflow to certain rooms.
- Defrost Cycle - During the heating season, the procedure to remove frost/ice build up from the outdoor coil.
- Dehumidification - Removal of water vapor from the air by either cooling the air below dew point or by chemical means.
- Department of Energy (DOE) - A government department dedicated to monitoring energy use and setting industry efficiency standards.
- Direct Expansion Systems - A type of basic cooling media that uses Freon for cooling and dehumidification; the three most common methods of heat rejection are air cooled, water cooled, and glycol cooled.
- Direct Vent - Uses outside air for combustion and then vents the resulting gases back outside.
- Downflow - Used most often in computer rooms and modern office spaces, a type of precision air conditioning system that discharges air directly beneath a raised floor.
- Downflow Furnace - A furnace that inhales return air from the top and exhales warm air at the bottom.
- Duct - A closed, sheet metal, fiberglass board, or other material conduit used for conducting air to and from an air handling unit.
- Ductwork - Channels used to move air throughout a building.
Glossary Items starting with "E"
- Economizer - In terms of HVAC, an economizer is a mechanical device that is used to reduce energy consumption.
- Efficiency - The cooling and heating equipment rating that judges the cost-efficiency of the system.
- Electronic Air Cleaner - Equipment that filters particles and contaminants from indoor air.
- Emergency Heat (Supplemental or Auxillary Heat) - Supplementary heat in a heat pump system, used in an emergency situation.
- Energy Efficiency Ratio (EER) - Ratio of the cooling capacity of an air conditioner in BTUs to electrical input in watts (API-specified test conditions).
- Enthalpy - The total heat contained in a refrigerant at any given temperature.
- Evaporator - Absorbs heat and moves it outside the refrigerated area.
- Evaporator Coil - A series of refrigerant filled tubes that take heat and moisture out of indoor air.
Glossary Items starting with "F"
- Fahrenheit (Represented as degrees "F") - United States of America’s unit of temperature measurement.
- Filter - Removes dust/particles from the air to reduce the load on the respiratory systems and HVAC equipment.
- Free Cooling System - Water cooled or glycol cooled system with an added coil the provides chilled water cooling when the outdoor temperature is cold.
- Free Delivery - A system that doesn’t use ducts.
- Freon - Describes a group of halogenated simple hydrocarbons containing fluorine, chlorine, or bromine (used as refrigerants).
- Furnace - Equipment that convert gas, oil, electricity, or other fuel into heat.
Glossary Items starting with "G"
- Generator - The container in which the lithium bromide solution is boiled and re-concentrated.
- Glycol-Cooled System - An air conditioning system that uses Freon as a refrigerant and water/glycol as a condensing medium.
- Ground Water-Source - Underground well water is used as a heat source for a heat pump.
Glossary Items starting with "H"
- Heat Exchanger - Transfers heat energy from the source to the medium.
- Heat Gain - The amount of heat that enters an indoor area during the air conditioning season, measured in BTUs.
- Heat Loss - The amount of heat that is lost from an indoor area during the heating season, measured in BTUs.
- Heat Pump - A system that has a valve that allows it to alternate between heating and cooling.
- Heat Source - The heat source that the heating system uses to warm an indoor area.
- Heat Transfer - The movement of heat from one area to another.
- Heat Capacity - The rating that judges how much heat a device can provide.
- Heating Seasonal Performance Factor (HSPF) - Total heat pump output in BTUs divided by total electrical input in watt-hours during normal usage period.
- Horizontal Furnace - A furnace that pulls return air in on one side and expels warm air on the other side.
- HVAC - Heating, Ventilation, and Air Conditioning.
- Humidification - The method of adding moisture to the air.
- Humidistat - Equipment that regulates humidity input by reacting to moisture changes in the air.
- Humidity - Humidity is the amount of moisture in the air.
Glossary Items starting with "I"
- Indoor Unit -
Contains the indoor coil, fan, motor, and filtering device.
- Indoor Coil -
Tubing containing refrigerant.
- Infiltration -
Air flow leaks into a living space.
- Insulation -
Slows down the transfer of heat.
- Integrally Controlled Motor (ICM) -
An efficient, variable-speed motor.
- Isolation Valves -
Valves that transfer and isolate refrigerate charge in the cooler or condenser.
Glossary Items starting with "J"
- Item Title - This is a sentence about this item.
Glossary Items starting with "K"
- (K) Factor -
(k) Factor is the insulating value.
- Kilowatt (kW) -
A unit of electrical consumption that equals 1,000 watts.
Glossary Items starting with "L"
- Latent Cooling Capacity -The capability of an air conditioner to remove moisture from the air.
- Latent Heat -The amount of heat energy needed to change a substance from a liquid to a gas.
- LCD -Liquid Crystal Display
- Load Calculation -A design tool that measures the heat gain and loss in a building; it helps determine the proper air conditioning/heating equipment size.
Glossary Items starting with "M"
- Matched System -
A heating/cooling system that is equipped with products that have been certified to perform optimally together.
- Microprocessor Controls -
Uses computer logic to operate and monitor air conditioning systems.
Glossary Items starting with "N"
- Natural-Draft Furnace -
A furnace that utilizes the natural flow of air around the furnace to provide air to support combustion.
- NFPA -
National Fire Protection Association.
Glossary Items starting with "O"
- Operating Cost -
The cost of running the air conditioner/heater in a space.
- Outdoor Coil/Condensing Unit -
Collects heat and moves it to the outdoor air.
Glossary Items starting with "P"
- Package System -
A system where all air conditioning and heating equipment is located in one cabinet.
- Packaged Unit -
A self-contained heating and/or air conditioning system.
- Payback Analysis -
It is a measure of value of a home comfort system; combining your purchase price and operating cost, the payback analysis determines how many years it takes to offset the purchase price.
- Precision Air Conditioning -
Pre-packaged systems designed to cool electronic equipment.
- Purge Device -
Equipment that removes air and water vapor from the refrigerant of a negative pressure designed chiller.
Glossary Items starting with "Q"
- Item Title - This is a sentence about this item.
Glossary Items starting with "R"
- Refrigerant -
A substance that provides a cooling effect by expanding or vaporizing.
- Refrigerant Lines -
The connection between an outdoor and indoor unit made of two copper lines.
- Register -
Covers an air opening or the end of an air duct; it is a combination of a grille and damper.
- Relative Humidity -
Given a certain temperature, the amount of vapor in the air divided by the largest amount of vapor that could be contained in the air.
- Return Air -
The air drawn into the heating unit after circulating from the heater’s output supply.
- Reversing Valve -
The device within a heat pump that reverses the refrigerant flow and switches the equipment from cooling to heating.
Glossary Items starting with "S"
- SEER (Seasonal Energy Efficiency Ratio) -
The Seasonal Energy Efficiency Ratio measures the energy efficiency of air conditioning equipment.
- Sensible Cooling Capacity -
The air conditioner’s ability to remove heat from an area.
- Sensible Heat -
Heat energy that changes the temperature of a gas, liquid, or solid when added or removed.
- Setpoint -
The ideal thermostat temperature.
- Single Package -
A year-round heating and air conditioning system that is contained in a single package.
- Split System -
The most common system installed in homes, it is a central air conditioner that contains a compressor and condenser installed outdoors and a non-compressor installed inside the building.
- Storage Tank -
The refrigerant temporarily is stored here while being serviced.
- Supercooled Liquid -
Liquid refrigerant cooled below its saturation point.
- Subcooler -
Some condensers contain this section, which reduces the temperature of the condensed refrigerant liquid, improving energy efficiency.
- Subcooling -
Removes sensible heat from a refrigerant liquid by dropping the temperature.
- Superheated Vapor -
Refrigerant vapor heated beyond its saturation point.
- Superheating -
Adds heat energy to a refrigeration vapor by creating a rise in temperature.
- Supplementary Heat -
Emergency heat, available at temperatures below a heat pump’s balance point.
- Switchover -
Equipment that switches the heat pump from cooling to heating by changing the flow of refrigerant.
Glossary Items starting with "T"
- Temperature -
The measure of heat matter contains.
- Thermidistat -
A sophisticated thermostat that measures the outdoor temperature, indoor air temperature, and indoor relative humidity. A microprocessor communicates with the temperature control equipment to determine the most efficient method of achieving an optimal temperature.
- Thermostat -
A temperature control device that monitors the control functions of temperature control equipment.
- Tonnage -
In cooling systems, the unit of measurement that describes the cooling capacity.
Glossary Items starting with "U"
- Upflow -
An air conditioner that discharges cool air through a top-mounted discharge plenum or overhead duct.
- Upflow Furnace -
A type of furnace that expels warm air at the top and expels return air at the bottom.
Glossary Items starting with "V"
- Vacuum Pump -
Removes air and water vapor from a refrigeration system below atmospheric pressure.
- Vapor Barrier -
A moisture-proof layer, preventing the travel of water vapor.
- Vapor Seal -
A vapor seal is a critical component of sealing moisture out of a sensitive room. The seal barricades air, moisture, and contaminants from moving through small cracks or pores in the walls, floor, or ceiling into the contaminant-sensitive area.
- Ventilation -
Adding or removing air by either natural or mechanical means to or from any space.
- Ventilator -
Removes stale indoor air and transfers it to fresh incoming air.
Glossary Items starting with "W"
- Water Cooled System -
An indoor cooling unit that utilizes Freon and water as a condenser. Water is piped to the unit from a suitable source.
- Water Source -
Water is a heat source for the heat pump.
- Watt -
A unit of power.
Glossary Items starting with "X"
Glossary Items starting with "Y"
- Year-Round -
A gas or oil fueled air conditioner.
Glossary Items starting with "Z"
- Zone System -
A system that divides a space into zones and provides the ability to control the temperature for each zone separately.
- Zoning -
The act of providing independent heating and cooling options to different zones of a structure. This practice uses a system controller, zoning dampers, and a bypass damper.