HVAC Study Review 2026 with Solutions
Moves from one substance to another as well as between
Heat Transfer
molecules of a substance, temperature is the driving force
The level of heat or heat intensity, measured with ther-
Temperature
mometers
Is the motion of molecules, and travels from a warm sub-
Heat
stance to a cold substance
Energy travelling from one molecule to another, involves
Conduction
direct contact
Passes through air and heats the first solid object it comes
Radiation
in contact with
Heat transfer that results in the change of temperature of
Sensible Heat
a substance
Used to move heat from one location to another, and is
Convection energy travelling through a fluid from one substance to
another
Results in the change in state of a substance, its energy is
Latent Heat stored when a liquid turns to gas, and released when a
gas turns to a liquid.
The amount of heat necessary to raise the temperature of
Specific Heat
1lb of a substance 1 degree F.
A substance that occupies space and has mass, and is
Matter
made up of atoms
Is the property of matter that responds to gravitational
Mass
attraction.
Density Describes a substance's mass to volume relationship
Is a unitless number because it is the density of a sub-
Specific Gravity stance divided by the density of water. Water is used as
a comparison. The density of water is 62.4 lb/ft^3 which
, HVAC Study Review 2026 with Solutions
equals 1, anything greater than 1 will sink anything less
will sink.
Indicates the volume that each pound of a gas occu-
pies,when air is heated it volume increases and whens its
Specific Volume
cooled its volume decreases, one pound of clean dry air
has a total volume of 13.33 ft^3.
States that energy is neither created or destroyed but can
Law of conservation of energy
be converted from one form to another.
Is the amount of heat required to melt 1 ton of ice in a 24
One ton of refrigeration
hour period
Correlates the vapor pressure and the boiling point of wa-
Temperature/Pressure Relationship
ter and is the basis for controlling a system's temperature.
The boiling point of water can be changed and controlled
Refrigeration Process
by controlling the vapor pressure above the water
A liquid under pressure above its boiling point without
vaporization, is found my subtracting the evaporator outlet
temp by the evaporator saturation temp. Low superheat
Superheated
means overfed coil high superheat means starved coil.
should be 8-12 degrees of overall temprature for outlet
inlet should be 10-20 degrees F.
When the change of state is occurring and when the
Saturated refrigerant is at equilibrium, and both liquid and gas are
present.
Liquid cooler than the condensing saturation tempera-
Subcooled
ture.
A substance that can be changed easily to a vapor by
Refrigerant
boiling it and then changed to a liquid by condensing it
Evaporator
Moves from one substance to another as well as between
Heat Transfer
molecules of a substance, temperature is the driving force
The level of heat or heat intensity, measured with ther-
Temperature
mometers
Is the motion of molecules, and travels from a warm sub-
Heat
stance to a cold substance
Energy travelling from one molecule to another, involves
Conduction
direct contact
Passes through air and heats the first solid object it comes
Radiation
in contact with
Heat transfer that results in the change of temperature of
Sensible Heat
a substance
Used to move heat from one location to another, and is
Convection energy travelling through a fluid from one substance to
another
Results in the change in state of a substance, its energy is
Latent Heat stored when a liquid turns to gas, and released when a
gas turns to a liquid.
The amount of heat necessary to raise the temperature of
Specific Heat
1lb of a substance 1 degree F.
A substance that occupies space and has mass, and is
Matter
made up of atoms
Is the property of matter that responds to gravitational
Mass
attraction.
Density Describes a substance's mass to volume relationship
Is a unitless number because it is the density of a sub-
Specific Gravity stance divided by the density of water. Water is used as
a comparison. The density of water is 62.4 lb/ft^3 which
, HVAC Study Review 2026 with Solutions
equals 1, anything greater than 1 will sink anything less
will sink.
Indicates the volume that each pound of a gas occu-
pies,when air is heated it volume increases and whens its
Specific Volume
cooled its volume decreases, one pound of clean dry air
has a total volume of 13.33 ft^3.
States that energy is neither created or destroyed but can
Law of conservation of energy
be converted from one form to another.
Is the amount of heat required to melt 1 ton of ice in a 24
One ton of refrigeration
hour period
Correlates the vapor pressure and the boiling point of wa-
Temperature/Pressure Relationship
ter and is the basis for controlling a system's temperature.
The boiling point of water can be changed and controlled
Refrigeration Process
by controlling the vapor pressure above the water
A liquid under pressure above its boiling point without
vaporization, is found my subtracting the evaporator outlet
temp by the evaporator saturation temp. Low superheat
Superheated
means overfed coil high superheat means starved coil.
should be 8-12 degrees of overall temprature for outlet
inlet should be 10-20 degrees F.
When the change of state is occurring and when the
Saturated refrigerant is at equilibrium, and both liquid and gas are
present.
Liquid cooler than the condensing saturation tempera-
Subcooled
ture.
A substance that can be changed easily to a vapor by
Refrigerant
boiling it and then changed to a liquid by condensing it
Evaporator
