Air conditioner
Equipment that conditions air by cleaning, cooling,heating, humidifying,dehumidifying. A term applied to comfort cooling equipment.
Air conditioning
A process that maintains comfort conditions in a defined area.
Ambient temperature
Surrounding air temperature.
Atmospheric pressure
The weight of the atmosphere's gasses pressing down on the earth. Approximately 14.696 psi at sea level.
Boiling point
The temperature level of a liquid at which it begins to change to a vapor. The boiling temperature is controlled by the vapor pressure above the liquid.
Btu
The amount of heat required to raise one pound of water 1degree.
Celsius scale
A temperature scale with 100-degree graduations between the freezing point 0 degrees C. And the boiling point 100 C of water.
Change of state
The condition that occurs when a substance changes from one physical state to another such as ice to water or water to steam.
Cold
The word used to describe heat at lower levels of intensity.
Condensing pressure(Saturation)
The pressure that corresponds to the condensing temperature in a refrigeration system.
Condensing Temperature
The temperature at which vapor changes to a liquid.
Conduction
heat transfer from one molecule to another within a substance. Or from one substance to another.
Conductivity
The ability of a substance to conduct electricity from one substance to another.
Controlled Environment
The conditioned space the HVAC system is trying to maintain.
Convection
Heat transfer from one place to another using a fluid.
Crank Case Pressure Regulator
A refrigerant control device located in the suction line that controls the maximum suction pressure allowed to a compressor by reducing refrigerant flow.
Density
The weight per unit of volume of a substance.
Dew Point Temperature
The exact temperature at which moisture begins to form.
Dry-Bulb Temperature
The temperature Measured using a regular thermometer.
Energy
The capacity for doing work.
Enthalpy
The amount of heat a substance contains from a predetermined base or point.
Evaporation
The condition that occurs when heat is absorbed by liquid and it changes to vapor.(Evaporation is a cooling process.)
Evaporator Pressure Regulator
A refrigerant control device, located in the suction line, that limits the minimum pressure of an evaporator coil by reducing refrigerant flow.
Fahrenheit Scale
The temperature scale that places the boiling point of water at 212F. And the freezing point at 32F
Gas
The vapor state of matter.
Heat
Energy that causes molecules to be in motion and to raise the temperature of a substance.
Heat Transfer
The transfer of heat from a warmer substance to a colder substance.
Hidden Heat
Latent heat
High Temperature Refrigeration
A Refrigeration temperature range starting with evaporator temperatures no lower than 35Fahrenheit. A range usually associated with air conditioning.
humidity
Moisture in the air.
Kelvin Scale
A Temp Scale that has the same graduations as the Celsius scale but has absolute zero as a starting point or o (460 below)
Kilowatt
A unit of power = to 1000 watts.
Latent Heat
Heat energy absorbed or rejected when a substance changes state and there is no change In temperature.
Latent Heat Of Condensation
The latent heat given off when a gas condenses to a liquid.
Latent Heat Of Condensation
The latent Heat Given off when a gas changes to a liquid.
Latent Heat Of Vaporization
The latent heat absorbed when a liquid changes to a vapor
Low Temperature Refrigeration
A refrigeration range starting with evaporator temps no higher than 0 F. Commonly used for storing frozen foods.
Mass
Matter held together to the extent that it is considered one body.
Matter
A substance that takes up space and has weight.
Medium Temp Refrigeration
Refrigeration range where the evaporator temperatures are above 32 degrees F. Normally used for preserving fresh food.
Melting Point
The temperature at which a substance will change from a solid to a liquid.
Molecular Motion
The movement of molecules within a substance.
Natural Convection
The natural movement of a gas or fluid caused by differences in temperature.
Power
The rate at which work is done.
Pressure
Force per unit of area.
Pressure Temperature Relationship
refers to the relationship of a liquid and vapor in a closed container. If the temp increases, the pressure will increase. If the temp is lowered, the pressure will decrease.
PSI
Pounds per square inch
PSIa
Pounds per square Inch absolute
PSIg
Pounds per square inch gage
Radiant Heat
Heat that passes through air, heating solid objects that in turn heat the surrounding area.
Rankin
The absolute Fahrenheit scale with 0 at the point where all molecular motion stops.
Refrigerant
THe fluid in a refrigeration system that changes from a liquid to a vapor and back to a liquid at practical pressures.
Refrigeration
The process of removing heat from a place where it's not wanted and transferring that heat to a place where it makes little or no difference.
Relative Humidity
The amount of moisture contained in the air as compared to the amount the air could hold at that temperature.
Saturated Vapor
The refrigerant when all of the liquid has just changed to a vapor.
Saturation
A term used to describe a substance when it contains all of another substance it can hold.
Saturation Temperature
The temp at which both liquid and vapor exist.
Sensible Heat
Heat that causes change in temperature
Solid
Molecules of a solid are highly attracted to each other forming a mass that exerts all of it's weight downward.
Specific Gravity
The weight of a substance compared to the weight of an equal volume of water.
Specific Heat
The amount of heat required to raise the temperature of 1lb of a substance 1degree F.
Specific Volume
The volume occupied by 1lb of fluid.
Standard Atmosphere of Standard Conditions
Air at sea level at 70 degrees F, when the atmosphere's pressure is 14.696. PSIa(29.92in.hg). Air at sea level has a volume of 13.33ft squared/lb.
Steam
The vapor state of water.
Subcooled
The temperature of a liquid when it's cooled below it's condensing temperature.
Super heat
The temp of a liquid when it's above it's saturation(change of state) temp.
Temperature
A word used to describe the level of heat or molecular activity, expressed in Fahrenheit,Rankin,Celsius, or Kelvin units.
Temperature Difference(air-conditioning)
The difference between the air entering the evaporator coil and the air leaving the evaporator coil.
Temperature Difference(Refrigeration)
The difference between the saturated suction temperature and the temperature of the conditioned space.
Temperature/Pressure Relationship
This refers to the temperature/pressure relationship of a liquid and vapor in a closed container. If the temp increases, the pressure will increase. If the temp is lowered the pressure will decrease.
Ton Of Refrigeration
The amount of heat required to melt a ton of ice at 32 degrees F. In 24hrs, 288,000 btu/24. 12btu an hour.
Vapor
The gaseous state of a substance.
Vapor Pressure
The pressure exerted on top of a saturated liquid.
Vaporization
The changing of a liquid to a gas or vapor.
Watt
A unit of power applied to electron flow. 1Watt= 3.414BTU
Weight
The force that matter (liquid,solid,or gas)applies to a supporting surface when it is at rest.
Wet Bulb Temperature
A wet bulb temperature of air is used to evaluate the humidity in the air. It is obtained with a wet thermometer bulb to record the evaporation rate with an air stream with an air stream passing over the bulb to help in evaporation.
Boyles Law
The volume of gas varies inversely with the absolute pressure,provided the temperature remains constant.
Charles Law
At a constant pressure, the volume of gas varies directly with the absolute temperature, and at a constant volume ,the pressure of a gas varies directly with the absolute temperature.