Sait Refrigeration Theory Definitions, 1St Year

Front 1

Absolute Pressure

Back 1

A system of pressure measurement with a starting point in a perfect vacuum. (psi) (kpa)

Front 2

Absolute Temperature

Back 2

A system of temperature measurement based on a starting or zero point where there is no heat and molecular motion theoretically stops. (0°R) (-46°F)

Front 3

Absorb

Back 3

A process where one substance attracts and holds another substance.

Front 4

Ambient Temperature

Back 4

The average temperature of the media that surrounds a point.

Front 5

Atmospheric Pressure

Back 5

The force per unit area due to gravity applied to the air surrounding the earth. (14.7 PSIA) (101.3 kpaa)

Front 6

Back Pressure

Back 6

The low side of a refrigeration system. Also called low side pressure, suction pressure and evaporator pressure.

Front 7

Barometer

Back 7

An instrument that measures atmospheric pressure.

Front 8

Boyle's Law

Back 8

A decrease in the volume of an ideal gas that has constant temperature, results in a proportional increase in pressure of that gas.

Front 9

British Thermal Unit (BTU)

Back 9

The amount of heat required to raise the temperature of one pound of water by one Fahrenheit degree.

Front 10

Change Of State

Back 10

The dynamic process of form transfer.

Front 11

Charles' Law #1

Back 11

A change in temperature of an ideal gas at constant pressure, results in proportional volume change in that gas.

(Constant Pressure)

Front 12

Charles'Law #2

Back 12

A change in absolute pressure of an ideal gas at a constant volume, results in a proportional absolute temperature change for that gas.

(Constant Volume)

Front 13

Condensate

Back 13

The moisture gained from a condensing process.

Front 14

Condensation

Back 14

A state or phase changing from a vapor to a liquid.

Front 15

Condensor

Back 15

A heat exchanger, most often in the form of a coil or shell and tubes, used to reject heat from a refrigeration system while condensing refrigerant within it confines.

Front 16

Condenser pressure

Back 16

The head pressure produced in the condenser at saturated conditions.

Front 17

Convection

Back 17

Heat transfer through fluids by the movement of currents.

Front 18

Counter flow

Back 18

Two fluids flowing near each other in opposite directions.

Front 19

Cross flow

Back 19

Two fluids flowing near each other at right angles to each other.

Front 20

Cycle

Back 20

One complete Revolution or execution through a repeatable process.

Front 21

Dalton's law of partial pressures

Back 21

The total pressure of a mixture of gases is the sum of the individual pressures of each gas.

Front 22

Density

Back 22

The ratio of mass to volume.

M/V

Front 23

Dry bulb temperature

Back 23

The sensible temperature of the air determined with a dry thermometer.

Front 24

Energy

Back 24

The ability to perform work.

Front 25

Enthalpy

Back 25

The heat in one pound (lb) or kilogram (kg) of a substance from a zero base point at -40°F.

Front 26

Entropy

Back 26

A measurement of energy transfer where the energy is moved but not used to do work.

Front 27

Force

Back 27

The creator of motion or acceleration.

Front 28

Head pressure

Back 28

The high pressure side of a normal refrigeration system, also called high side, condenser or discharge pressure.

Front 29

Horsepower

Back 29

A unit of work. 1 horsepower equals 33000 lbs moved at distance of feet per minute.

1Hp = 745.7 watts

Front 30

Humidity

Back 30

The total water content of a specified air sample.

Front 31

Hydrometer

Back 31

An instrument that measures the specific gravity of a liquid.

Front 32

Hydrostatic pressure

Back 32

The force applied by a liquid over an area.

Front 33

Kinetic energy

Back 33

Energy based in motion

Front 34

Laminar flow

Back 34

The smooth undisturbed flow of a fluid within a duct or pipe.

Front 35

Latent heat

Back 35

Heat gained or lost with no temperature change.

Front 36

Low side

Back 36

The low pressure side of a refrigeration system. It also is called low side, suction or evaporator pressure.

Front 37

Manometer

Back 37

A pressure measuring instrument that is based on liquid movement due to applied gas pressure.

Front 38

Mass

Back 38

The quality that gives an object shape and gravitational weight.

Front 39

Micron

Back 39

One millionth of a meter.

Front 40

Pascal's law

Back 40

Pressure applied to a fluid is equal in all directions.

Front 41

Potential energy

Back 41

Energy based on position.

Front 42

Pressure

Back 42

Force applied over an area.

Front 43

Radiation

Back 43

Heat transfer through vacuums.

Front 44

Reclaim

Back 44

Returning recovered refrigerant to design characteristics by a refrigerant manufacturer.

Front 45

Recovery

Back 45

The removal of refrigerant from mechanical refrigeration or air-conditioning systems.

Front 46

Recycle

Back 46

The process of cleaning recovered refrigerant in a portable recycling unit on a job site or in a shop.

Front 47

Refrigerant

Back 47

A liquid that absorbs heat while evaporating and expels heat while condensing, both at useful temperatures.

Front 48

Relative humidity

Back 48

The ratio of moist air to dry air in a given area.

Front 49

Saturated liquid

Back 49

A liquid that contains as much of a vapor of the same substance as it can hold.

Front 50

Saturated vapor

Back 50

A vapor that contains as much of a liquid of the same substance as it can hold.

Front 51

Saturation pressure

Back 51

At a given temperature, the pressure at which vapor and liquid can exist in equilibrium.

Front 52

Saturation temperature

Back 52

At a given pressure, the temperature at which vapor and liquid can exist in equilibrium.

Front 53

Sensible heat change

Back 53

A change in a mass' heat quantity caused by a rise or fall in temperature of that mass.

Front 54

Specific density

Back 54

The ratio of a substances mass to the density of a given reference substance (usually water) at a given volume.

(lbs/ft3)

Front 55

Specific gravity

Back 55

A ratio of a substance's density devided by water density at 39°F (4°C)

Front 56

Specific heat

Back 56

The amount of heat required to change a specified mass of a substance one degree.

Front 57

Specific volume

Back 57

The amount of space required for a unit mass of a substance.

(ft3/lb)

Front 58

Static pressure

Back 58

The pressure exerted by stationary air.

Front 59

Subcool

Back 59

To lower the temperature of a liquid while it remains at its condensing or saturated pressure.

Front 60

Subcooling

Back 60

the difference between the temperature at which a liquid is formed from vapor and the measured temperature of that liquid if it remains at its condensing or saturated pressure.

Front 61

Sublimation

Back 61

A change of state from a solid directly to a vapor without having a liquid state.

Front 62

Suction pressure

Back 62

The low pressure of a refrigeration system. Also called back pressure and evaporator pressure.

Front 63

Suction side

Back 63

The low pressure of a refrigeration system. Also called low Pressure, back pressure and evaporator pressure.

Front 64

Superheat

Back 64

Heat added to a vapor at it saturated pressure.

Front 65

Superheating

Back 65

Increasing the temperature of a vapor above it saturated pressure.

Front 66

Temperature

Back 66

Average level of molecular motion.

Front 67

Ton of refrigeration

Back 67

A measurement of refrigeration capacity based on the melting of one ton of ice in one day. One ton of refrigeration equals 288,000 btu/24hrs, 12,000 bthu/hr or 200/btu/min.

Front 68

Turbulent flow

Back 68

The chaotic flow of a fluid within a duct or pipe.

Front 69

Vacuum

Back 69

a pressure below atmospheric pressure. A perfect vacuum occurs when all liquids and vapors have been removed from a space and it's pressure is zero absolute.

Front 70

Volume

Back 70

The space taken up by an object or substance with mass.

Front 71

Wet-bulb temperature

Back 71

The latent based temperature of the air determined with a wet thermometer.

Front 72

Work

Back 72

The result of applying a force through a distance.