Refrigeration Machine Operator Course
– Turner QUESTIONS AND ANSWERS
What is refrigeration - ANSWER>>Refrigeration is the removing of heat from an
object or mass and then dissipating that same heat in a place where it's presence
will not be objectionable. "Refrigeration systems move heat"
The refrigeration process is made possible by - ANSWER>>Boiling a refrigerant
BTU "British Thermal Unit" - ANSWER>>A BTU is the quantity of heat needed to
raise one pound of water one degree Fahrenheit.
Specific Heat - ANSWER>>The specific heat of a substance is the number of BTU's
required to raise the temperature of one pound of that substance 1 degree
Fahrenheit.
Temperature - ANSWER>>Temperature is the intensity of heat.
Fahrenheit to Centigrade - ANSWER>>F = (1.8 x C) +32
Changes of state are accompanied by - ANSWER>>The removal of heat
Sensible Heat - ANSWER>>Heat which is associated with a change in temperature
Latent Heat - ANSWER>>Heat which is associated with a change in state.
Latent heat of fusion - ANSWER>>Heat energy needed to change the state of a
substance without a change in temperature from a liquid to a solid or a solid to a
liquid. In the case of water, from a solid, ice to water or vice-versa.
Latent heat of vaporization - ANSWER>>Heat energy added to change the state of
a substance without a change in temperature from a liquid to a vapor, or in the
,case of water, from a liquid to steam (vapor). In the case of refrigerants, it is a
change from liquid to gas (in the evaporator).
Latent heat of condensation - ANSWER>>heat energy removed to change the
state of a substance without a change in temperature from a vapor to a liquid.
Superheat - ANSWER>>Superheat is heat added to steam or refrigerant gas
(vapor), to raise the temperature above its boiling point. Each additional degree
above the boiling temperature is a degree of superheat.
Sublimation - ANSWER>>Sublimation is a process whereby a substance changes
from a solid to a vapor without passing through the liquid state. Ex: Dry ice.
Conduction - ANSWER>>Conduction is heat transfer by contact.
Convection - ANSWER>>Convection is heat transfer by the movement of a fluid,
usually water or air.
Radiation - ANSWER>>Radiation is heat movement through space by shining, just
as light is radiated. Ex: The sun.
One Ton - ANSWER>>2000lbs
2000 lbs x 144 btu/lbs - ANSWER>>288,000 BTUs
One ton of refrigeration - ANSWER>>based on the cooling capacity produced by a
2000 block of ice.
144 BTUs - ANSWER>>must be removed from one lb of water (at 32F) to form one
lb of ice.
One Ton of refrigeration - ANSWER>>capable of moving 288,000 BTUs/Day
(24hrs)
,288,000 BTUs (day) /24 hrs (day) - ANSWER>>12,000 BTUs hr
12,000 BTUs (hour)/ 60 (minutes per hour) - ANSWER>>200 BTUs minute
Pressure - ANSWER>>The force exerted by a fluid (liquid or vapor) which has been
uniformly distributed over a surface and is measured per unit area.
p=f/a - ANSWER>>Pressure
Barometer - ANSWER>>A device for predicting weather changes.
29.92 - ANSWER>>The earth's pressure at sea level.
29.92 converted to "pounds per square inch" - ANSWER>>14.7 psi
PSIG - ANSWER>>Pounds per square inch gauge.
Pressure Gauge - PSIG - ANSWER>>Indicates values of pressure above
atmospheric pressure. Value starts at 0.
HG - ANSWER>>Inches of Mercury
Vacuum Gauge - HG - ANSWER>>Indicates values of pressure below atmospheric
pressure. The values of pressure on a vacuum gauge descend down to 29.92Hg,
indicating that virtually no pressure is exerted (perfect vacuum)
PSIA - ANSWER>>Pounds per square inch absolute - Absolute pressure values are
based on a perfect vacuum.
Pressure Gauge - 0 Psig-300Psig above atm - ANSWER>>Installed on the discharge
side of a compressor
, Vacuum Gauge - ANSWER>>0hg - 30hg below atmospheric pressure (inches of
mercury)
Compound Gauge - 30 hg - 100 psig - ANSWER>>psig above atm & vacuum below
atm, Installed on the suction side of a compressor.
Gauge Manifold - ANSWER>>Makes it possible for a service mechanic or
operating engineer to determine both the high and low side operating pressures
in a system that is not equipped with permanently installed pressure gauges.
Used while adding or removing refrigerant from a system.
Gauge Size - ANSWER>>Generally, the more accurate gauges are larger and more
costly.
Gauge Case and Housing - ANSWER>>Stainless steel, black, ABS, painted steel,
brass and fiberglass reinforced thermoplastic are standard case materials.
Stainless, brass or ABS cases are recommended for outdoor service.
Psig to psia - ANSWER>>Psia = psig + 14.7
Psia to Psig - ANSWER>>Psig = psia - 14.7
Vacuum pressure to Psia - ANSWER>>Psia = (30-Hg)/2
Barometric Pressure to Psia - ANSWER>>Psia - = Hg x .491
Charles Law - ANSWER>>There is a direct relationship between the pressure,
temperature and volume of a vapor or gas.
Dalton's Law of partial pressures - ANSWER>>Dalton's law states that more than
one gas placed in a container will exert a pressure that is an accumulation of the
pressures that each gas exerts.
– Turner QUESTIONS AND ANSWERS
What is refrigeration - ANSWER>>Refrigeration is the removing of heat from an
object or mass and then dissipating that same heat in a place where it's presence
will not be objectionable. "Refrigeration systems move heat"
The refrigeration process is made possible by - ANSWER>>Boiling a refrigerant
BTU "British Thermal Unit" - ANSWER>>A BTU is the quantity of heat needed to
raise one pound of water one degree Fahrenheit.
Specific Heat - ANSWER>>The specific heat of a substance is the number of BTU's
required to raise the temperature of one pound of that substance 1 degree
Fahrenheit.
Temperature - ANSWER>>Temperature is the intensity of heat.
Fahrenheit to Centigrade - ANSWER>>F = (1.8 x C) +32
Changes of state are accompanied by - ANSWER>>The removal of heat
Sensible Heat - ANSWER>>Heat which is associated with a change in temperature
Latent Heat - ANSWER>>Heat which is associated with a change in state.
Latent heat of fusion - ANSWER>>Heat energy needed to change the state of a
substance without a change in temperature from a liquid to a solid or a solid to a
liquid. In the case of water, from a solid, ice to water or vice-versa.
Latent heat of vaporization - ANSWER>>Heat energy added to change the state of
a substance without a change in temperature from a liquid to a vapor, or in the
,case of water, from a liquid to steam (vapor). In the case of refrigerants, it is a
change from liquid to gas (in the evaporator).
Latent heat of condensation - ANSWER>>heat energy removed to change the
state of a substance without a change in temperature from a vapor to a liquid.
Superheat - ANSWER>>Superheat is heat added to steam or refrigerant gas
(vapor), to raise the temperature above its boiling point. Each additional degree
above the boiling temperature is a degree of superheat.
Sublimation - ANSWER>>Sublimation is a process whereby a substance changes
from a solid to a vapor without passing through the liquid state. Ex: Dry ice.
Conduction - ANSWER>>Conduction is heat transfer by contact.
Convection - ANSWER>>Convection is heat transfer by the movement of a fluid,
usually water or air.
Radiation - ANSWER>>Radiation is heat movement through space by shining, just
as light is radiated. Ex: The sun.
One Ton - ANSWER>>2000lbs
2000 lbs x 144 btu/lbs - ANSWER>>288,000 BTUs
One ton of refrigeration - ANSWER>>based on the cooling capacity produced by a
2000 block of ice.
144 BTUs - ANSWER>>must be removed from one lb of water (at 32F) to form one
lb of ice.
One Ton of refrigeration - ANSWER>>capable of moving 288,000 BTUs/Day
(24hrs)
,288,000 BTUs (day) /24 hrs (day) - ANSWER>>12,000 BTUs hr
12,000 BTUs (hour)/ 60 (minutes per hour) - ANSWER>>200 BTUs minute
Pressure - ANSWER>>The force exerted by a fluid (liquid or vapor) which has been
uniformly distributed over a surface and is measured per unit area.
p=f/a - ANSWER>>Pressure
Barometer - ANSWER>>A device for predicting weather changes.
29.92 - ANSWER>>The earth's pressure at sea level.
29.92 converted to "pounds per square inch" - ANSWER>>14.7 psi
PSIG - ANSWER>>Pounds per square inch gauge.
Pressure Gauge - PSIG - ANSWER>>Indicates values of pressure above
atmospheric pressure. Value starts at 0.
HG - ANSWER>>Inches of Mercury
Vacuum Gauge - HG - ANSWER>>Indicates values of pressure below atmospheric
pressure. The values of pressure on a vacuum gauge descend down to 29.92Hg,
indicating that virtually no pressure is exerted (perfect vacuum)
PSIA - ANSWER>>Pounds per square inch absolute - Absolute pressure values are
based on a perfect vacuum.
Pressure Gauge - 0 Psig-300Psig above atm - ANSWER>>Installed on the discharge
side of a compressor
, Vacuum Gauge - ANSWER>>0hg - 30hg below atmospheric pressure (inches of
mercury)
Compound Gauge - 30 hg - 100 psig - ANSWER>>psig above atm & vacuum below
atm, Installed on the suction side of a compressor.
Gauge Manifold - ANSWER>>Makes it possible for a service mechanic or
operating engineer to determine both the high and low side operating pressures
in a system that is not equipped with permanently installed pressure gauges.
Used while adding or removing refrigerant from a system.
Gauge Size - ANSWER>>Generally, the more accurate gauges are larger and more
costly.
Gauge Case and Housing - ANSWER>>Stainless steel, black, ABS, painted steel,
brass and fiberglass reinforced thermoplastic are standard case materials.
Stainless, brass or ABS cases are recommended for outdoor service.
Psig to psia - ANSWER>>Psia = psig + 14.7
Psia to Psig - ANSWER>>Psig = psia - 14.7
Vacuum pressure to Psia - ANSWER>>Psia = (30-Hg)/2
Barometric Pressure to Psia - ANSWER>>Psia - = Hg x .491
Charles Law - ANSWER>>There is a direct relationship between the pressure,
temperature and volume of a vapor or gas.
Dalton's Law of partial pressures - ANSWER>>Dalton's law states that more than
one gas placed in a container will exert a pressure that is an accumulation of the
pressures that each gas exerts.
