Marine Refrigeration Test 1 - USCG questions with correct answers, Exams of Marine Engineering

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Marine Refrigeration Test 1 - USCG

questions

'respiratory heat' is a term applied primarily to which of the following cargoes? - ✔✔fresh vegetables a one ton air conditioning system has which of the listed operating characteristics? - ✔✔it has the cooling capacity equivalent to melting 2,000 lbs. of ice per day an air conditioning system, required to remove from 33,000 to 35, BTU per hour, should have a minimum capacity of what tonnage? - ✔✔3.0 tons How many BTUs must be added to one pound of water at 32 F to raise the temperature to 212 F? - ✔✔180 BTUs how much heat per hour can a 5 ton refrigeration unit remove from a refrigerated space? - ✔✔60,000 BTU/hr if a refrigerated space has associated with it a heat load of 60, BTU/hour, what size refrigeration unit would be required? - ✔✔5 ton

if a refrigeration system extracted 48,000 BTU per hour from the refrigerated space, what would be the equivalent tonnage of the unit? - ✔✔4 tons If an air conditioning system were rated at 24,000 BTU, what would be the equivalent tonnage of the unit? - ✔✔2 tons in a refrigeration system, the heat normally producing the flash gas at the thermostatic expansion valve, is obtained by what means? - ✔✔the portion of liquid refrigerant which does not flash in a small appliance using HFC-134a you would expect to see the greatest temperature drop across what system component? - ✔✔condenser (or TXV, TXV more likely) in a typical refrigeration system, refrigerant leaving the receiver will then flow to what system component? - ✔✔liquid line strainer in a typical refrigeration system, where is the temperature of the refrigerant gas at the highest? - ✔✔at the compressor discharge in a vapor compression refrigeration cycle, the temperature of the liquid refrigerant experiences its greatest decrease flowing through what component? - ✔✔expansion valve

refrigerant is circulated through a refrigeration system by the action of what component? - ✔✔compressor refrigerant leaving the metering device in a refrigeration system is in which of the following conditions? - ✔✔saturated liquid/vapor mixture the component of a refrigerating system in which the refrigerant vaporizes and absorbs heat is known as what? - ✔✔evaporator the definition of superheat refers to the amount of heat a substance contains and applies to I. vapors II. solids - ✔✔I only the heat gained per pound of refrigerant in the evaporator is known as what? - ✔✔refrigerating effect the heat removed from the refrigerant in the condenser of a refrigeration plant is known as what? - ✔✔heat of compression the low pressure refrigerant leaves the evaporator of a refrigeration system in what condition? - ✔✔superheated vapor

the only means of removing latent heat of condensation from a refrigerant in the normal refrigeration cycle is by performing what process? - ✔✔condensing refrigerant in the system condenser the rate of heat transfer from a hot region to a cold region is affected most by the - ✔✔temperature difference between the regions the refrigerant gas returning to the compressor should be in what condition? - ✔✔superheated the temperature of the refrigerant in the evaporator coil depends mostly upon what factor? - ✔✔refrigerant pressure in the evaporator under normal conditions, the refrigerant enters the compressor in an operating refrigeration system in what condition and/or state? - ✔✔superheated vapor what is the equivalent tonnage of a refrigeration system rated at 48,000 BTU per hour? - ✔✔ 4 what term is defined as the amount of heat required to convert a unit mass of a substance from a liquid to a vapor at a constant temperature and pressure? - ✔✔latent heat of vaporization

which of the listed refrigeration system components keeps the refrigerant circulating through the system? - ✔✔compressor which of the listed statements describes specific heat - ✔✔the amount of heat required to change the temperature of one pound of a material, one degree Fahrenheit which of the listed statements is correct concerning refrigeration system heat removal capacity is true? - ✔✔one refrigeration ton is equivalent to the removal of 12,000 btu per hour