Test Review Flashcards
What are the units used to measure heat?
BTUs
When matter is in a gaseous state, it has…
No size or definite shape
What best defined heat?
Molecular motion
What are three forms of heat transfer?
Conduction
Convection
Radiation
The state of matter is determined by what two things?
Temperature and pressure
What is the process called when a substance goes from a solid to a gas?
Sublimation
What are the stages of refrigeration?
Compression
Condensation
Expansion
Evaporation
What are the three physical states of matter?
Solid, liquid, gas
What is the zero point of the enthalpy of water?
32*F
Name four common heat transfer components in the plant.
Transformer cooling radiator
Surface air coolers
Oil tub cooling coil
Compressor after/intercooler
What can we use to cool the condenser?
Liquid and air
When heat is applied to a substance, the density will…
Decrease
At what temperature is water the most dense?
39*F
The heat that causes a change of state without temperature change is…
Latent heat
True or False:
A fluid that picks up heat by evaporating at low temperature and pressure, and gives up heat by condensing at a high temperature and pressure is called a refrigerant compound.
True
The amount of BTUs required to change the temperature of a substance of 1lb by 1 degree is called its…
Specific heat
Does a refrigerant give up heat when it evaporates?
No. It absorbs heat.
The theoretical temperature at which molecules have no movement is…
Absolute zero
Temperature is the measure of the ______ of heat.
intensity
The heat required to change the state of water to vapor is called…
Latent heat of vaporization
What are the two kinds of dry steam?
Saturated and superheated
Steam in its purest form is…
invisible, odorless, nonpoisonous, and relatively noncorrosive
The temperature at which a refrigerant changes from liquid to vapor, or a vapor to liquid is called…?
Saturation temperature
Water vapor that is heated above its saturation point and no longer in the presence of water is…
Superheated steam
The ability of a substance to conduct heat or the rate of conduction is called…
Thermal conductivity
The transfer of heat from a place where it is unwanted to a place where it is unobjectionable is called…
Refrigeration
Where does the temperature of air that blows through a heat exchanger decrease from a high temperature to a low temperature?
At the evaporator
What component is on the low side of the refrigeration system?
Evaporator
When adding or removing heat causes a change in the temperature of a material, the heat is called ______.
sensible heat
