Refrigeration and Airconditioning Exam
Questions with Correct Answers
refrigeration - Answer-A branch of science that deals with process of cooling of a space
or substance below the environmental temperature.
refrigeration system - Answer-An assembly of four major components, namely the
compressor, condenser, expansion valve, evaporator through which a very low boiling
point substance flow in a cycle and absorbs heat from the immediate surroundings,
thereby producing the cooling effect.
refrigeration cycle - Answer-A sequence of thermodynamic processes whereby heat is
withdrawn from a cold body and expelled to a hot body.
mechanical refrigeration - Answer-The removal of heat by utilizing a refrigerant
subjected to cycles of refrigerating thermodynamics and employing a mechanical
compressor.
compressor - Answer-The heart of the vapor compression system.
condenser - Answer-Receives superheated refrigerant from the compressor, remove
the superheat and then liquefy the refrigerant.
expansion valve - Answer-It reduces the pressure of the liquid refrigerant and regulates
the flow of the refrigerant to the evaporator.
evaporator - Answer-A heat exchanger which transfers heat from the substance being
cooled to a boiling refrigerant.
cascade refrigeration system - Answer-Combines two vapor-compression units, with the
condenser of the low temperature system discharging its heat to the evaporator of the
high temperature system.
steam jet refrigeration - Answer-A refrigeration cycle in which water is used as the
refrigerant; high velocity steam jets provide a high vacuum in the evaporator, causing
the water to boil at low temperature and at the same time compressing the flashed
vapor up to the condenser pressure level.
absorption refrigeration system - Answer-The refrigerant gas evolved in the evaporator
is taken up in an absorber and released in a generator upon the application of heat.
float valve - Answer-A type of expansion valve which maintains the liquid at a constant
level in a vessel or an evaporator.
, R-11 - Answer-trichloromonofluoromethane (CCl3F)
R-12 - Answer-dichlorodifluoromethane
R-13 - Answer-monochlorotrifluoromethane
R-22 - Answer-monochlorodifluoromethane
R-40 - Answer-methyl chloride
R-113 - Answer-trichloritrifluoroethane
R-114 - Answer-dichlorotetrafluoroethane
R-50 - Answer-methane
R-170 - Answer-ethane
R-270 - Answer-propane
R-717 - Answer-ammonia
R-718 - Answer-water refrigerant
R-729 - Answer-air refrigerant
R-744 - Answer-carbon dioxide
R-764 - Answer-sulfur dioxide
Azeotrope - Answer-A liquid mixture of two or more substances that has its own
constant boiling point, different from the boiling points of its constituents. The vapor of
this unique mixture has the same composition as the liquid state, making it difficult to
separate the constituents.
air conditioning - Answer-Process of treating air so as to control simultaneously its
temperature, humidity, cleanliness, and distribution to meet the requirements of the
conditioned space.
ventilation - Answer-The process of supplying or removing air by natural or mechanical
means to or from any space.
psychrometry - Answer-The study of the properties of mixtures of air and water vapor.
psychrometer - Answer-An instrument used in the study of the properties of air.
Questions with Correct Answers
refrigeration - Answer-A branch of science that deals with process of cooling of a space
or substance below the environmental temperature.
refrigeration system - Answer-An assembly of four major components, namely the
compressor, condenser, expansion valve, evaporator through which a very low boiling
point substance flow in a cycle and absorbs heat from the immediate surroundings,
thereby producing the cooling effect.
refrigeration cycle - Answer-A sequence of thermodynamic processes whereby heat is
withdrawn from a cold body and expelled to a hot body.
mechanical refrigeration - Answer-The removal of heat by utilizing a refrigerant
subjected to cycles of refrigerating thermodynamics and employing a mechanical
compressor.
compressor - Answer-The heart of the vapor compression system.
condenser - Answer-Receives superheated refrigerant from the compressor, remove
the superheat and then liquefy the refrigerant.
expansion valve - Answer-It reduces the pressure of the liquid refrigerant and regulates
the flow of the refrigerant to the evaporator.
evaporator - Answer-A heat exchanger which transfers heat from the substance being
cooled to a boiling refrigerant.
cascade refrigeration system - Answer-Combines two vapor-compression units, with the
condenser of the low temperature system discharging its heat to the evaporator of the
high temperature system.
steam jet refrigeration - Answer-A refrigeration cycle in which water is used as the
refrigerant; high velocity steam jets provide a high vacuum in the evaporator, causing
the water to boil at low temperature and at the same time compressing the flashed
vapor up to the condenser pressure level.
absorption refrigeration system - Answer-The refrigerant gas evolved in the evaporator
is taken up in an absorber and released in a generator upon the application of heat.
float valve - Answer-A type of expansion valve which maintains the liquid at a constant
level in a vessel or an evaporator.
, R-11 - Answer-trichloromonofluoromethane (CCl3F)
R-12 - Answer-dichlorodifluoromethane
R-13 - Answer-monochlorotrifluoromethane
R-22 - Answer-monochlorodifluoromethane
R-40 - Answer-methyl chloride
R-113 - Answer-trichloritrifluoroethane
R-114 - Answer-dichlorotetrafluoroethane
R-50 - Answer-methane
R-170 - Answer-ethane
R-270 - Answer-propane
R-717 - Answer-ammonia
R-718 - Answer-water refrigerant
R-729 - Answer-air refrigerant
R-744 - Answer-carbon dioxide
R-764 - Answer-sulfur dioxide
Azeotrope - Answer-A liquid mixture of two or more substances that has its own
constant boiling point, different from the boiling points of its constituents. The vapor of
this unique mixture has the same composition as the liquid state, making it difficult to
separate the constituents.
air conditioning - Answer-Process of treating air so as to control simultaneously its
temperature, humidity, cleanliness, and distribution to meet the requirements of the
conditioned space.
ventilation - Answer-The process of supplying or removing air by natural or mechanical
means to or from any space.
psychrometry - Answer-The study of the properties of mixtures of air and water vapor.
psychrometer - Answer-An instrument used in the study of the properties of air.
