Compressor

The heart of any refrigeration system that pumps the refrigerant (absorption systems that use ammonia or lithium bromide do not have compressors). Compressors can be reciprocating, rotary, scroll, disc, or screw.  Part of a split system heat pump or air conditioner's outdoor unit that controls the pressure applied to the refrigerant, necessary for taking in heat to warm your home or getting rid of heat to keep your home cool.

Compressor Erosion/Corrosion

Damage to the bearings and impeller caused by poor lubrication, low oil levels or operating conditions such as liquid refrigerant carryover into the compressor system.

Compressor Motor Amps

The energy used to power the refrigerant cycle in a chiller system. The input energy is dependent upon the pressure increase in the compressor. The head pressure divided by the suction pressure or the condenser pressure divided by the evaporator pressure determines it.

Compressor Oil Temperature

Compressor oil temperature is the temperature of the oil in the compressor bearing lubrication system. This temperature is predetermined by manufacturers specifications.

Concealed Heating

See radiant heating.

Concealed Nail Method

Application of roll roofing in which all nails are driven into the underlying course of roofing and covered by a cemented, overlapping course. Nails are not exposed to the weather.

Concrete

A hard, stone-like material formed by mixing sand, an aggregate, e.g., crushed stone, gravel and cement with water and allowing the mixture to harden.

Concrete Basement Walls

Concrete is not a good insulator. Concrete walls above grade and up to two feet below grade lose about as much heat as a double-pane window. Since the basement area is often finished for additional living space, insulating these walls results in substantial energy savings and improved comfort. Basement walls are generally insulated on the interior with either batt insulation or foam products.

Concrete Block

Concrete compressed into a block, hardened and used as a structural masonry unit.

Condensation

The change of water from a gaseous state to a liquid one when warm, moisture-laden air comes in contact with a cold surface.  The process a vapor goes through to change phase from vapor to a liquid.  The precipitation of liquid from its vapor phase resulting from the lowering of temperature at constant pressure especially the deposition of water from moist, warm air onto a relatively cold surface or between two surfaces such as within a cavity wall.  The deposit of water vapor from the air on any cold surface whose temperature is below the dew point, such as a cold window glass or frame that is exposed to humid indoor air.

Condenser/ Condenser Coil

The part of a refrigeration system that gives up heat from the refrigerant and changes the refrigerant from a vapor to a liquid. Condensers can be either water cooled or air cooled. Heat exchanger where the system heat is rejected and the refrigerant condenses into a liquid. The condenser is where hot pressurized refrigerant vapors in the compressor are cooled and liquefied by cooling tower water circulating through the tubes of the condenser. The condenser side is commonly referred to as the open recirculation system or open loop;  The outdoor portion of a heating or cooling system that either releases or collects heat from the outside air, depending on the time of year. The condenser coil is connected directly to the home's air handler and is also known as the outdoor coil.  Part of a split-system air conditioner or heat pump. By converting refrigerant that is in a gas form back to a liquid, the coil sends heat carried by the refrigerant to the outside.

Condenser Pressure

The head pressure produced in the condenser dependent on the entering condenser water temperature and the saturated refrigerant temperature. The condenser pressure can affect the refrigerant cycle and heat transfer. The pressure correlates to saturated refrigerant temperature on a pressure/temperature chart for each refrigerant type.

Condenser Refrigerant Approach Temperature

The refrigerant temperature minus the leaving water temperature. The refrigerant temperature can be determined by locating the condenser (head) pressure on a pressure/temperature chart, or if the chiller control panel provides this information.

Condenser Water

The open recirculating system connects the chiller condenser to the cooling tower system and the atmosphere. Condenser water is subject to evaporation, debris/contamination, fouling/scaling and microbio growth.

Condensing Unit

Outdoor unit of an air conditioning system which contains compressor, propeller fan, circuit board, and heat exchange coil. Pumps refrigerant to evaporator.

Conditioned Air

Air that has been heated, cooled, humidified, or dehumidified to maintain an interior space within the ""comfort zone."" (sometimes referred to as ""tempered"" air.).

Conditioned Fluid

The fluid being acted upon by the working fluid. Example: in an air conditioning system the air is conditioned by the refrigerant (refrigerant is the working fluid).

Condominium

A structure of two or more units, the interior spaces of which are individually owned the balance of the property (both land and building) is owned in common by the owners of the individual units. The size of each unit is measured from the interior surfaces (exclusive of paint or other finishes) of the exterior walls, floors and ceiling. The balance of the property is called the common area.

Conduction

Heat transfer through a solid material by contact of one molecule to the next. Heat flows from a higher-temperature area to a lower-temperature one.

Conductivity

Conductivity is the measure of conduction within a material. The conductivities of materials vary widely, being greatest for metals, less for nonmetals, still less for liquids and least for gases. Any material that has a low conductivity may be considered an insulator.

Constant Air Volume System

An air handling system that provides a constant airflow while varying the temperature to meet heating and cooling needs.

Constant Speed Drive

Constant speed drives are the most common type of chiller compressor motor. They have limited ability to adjust speed based on part load conditions.

Contaminant

Any physical, chemical, biological, or radioactive substance that can adversely affect air, water or soil.