Short horizontal lines on pressure-enthalpy chart show__________________?
(A) constant pressure lines
(B) constant temperature lines
(C) constant total heat lines
(D) constant entropy lines
(D) constant volume lines
One ton of the refrigeration is_________________?
(A) the standard unit used in refrigeration problems
(B) the cooling effect produced by melting 1 ton of ice
(C) the refrigeration effect to freeze 1 ton of water at 0°C into ice at 0°C in 24 hours
(D) the refrigeration effect to produce 1 ton of ice at NTP conditions
(D) the refrigeration effect to produce 1 ton of ice in 1 hour time
For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphere is high, then_________________?
(A) bigger cabinet should be used
(B) smaller cabinet should be used
(C) perfectly tight vapour seal should be used
(D) refrigerant with lower evaporation temperature should be used
(D) refrigerant with high boiling point must be used
The advantage of dry compression is that________________?
(A) it permits higher speeds to be used
(B) it permits complete evaporation in the evaporator
(C) it results in high volumetirc and mechanical efficiency
(D) all of the above
(D) none of the above
The suction pipe diameter of refrigerating unit compressor in comparison to delivery side is_________________?
(A) bigger
(B) smaller
(C) equal
(D) smaller/bigger depending on capacity
(D) unpredictable
Under-cooling in a refrigeration cycle_________________?
(A) increases COP
(B) decreases COF
(C) COP remains unaltered
(D) other factors decide COP
(D) unperdictable
The coefficient of performance is the ratio of the refrigerant effect to the_________________?
(A) heat of compression
(B) work done by compressor
(C) enthalpy increase in compressor
(D) all of the above
(D) none of the above
Vertical lines on pressure-enthalpy chart show constant_______________?
(A) pressure lines
(B) temperature lines
(C) total heat lines
(D) entropy lines
(D) volume lines
One of the purposes of sub-cooling the liquid refrigerant is to________________?
(A) reduce compressor overheating
(B) reduce compressor discharge temperature
(C) increase cooling effect
(D) ensure that only liquid and not the vapour enters the expansion (throttling) valve
(D) none of the above
In a refrigeration system, heat absorbed in comparison to heat rejected is_________________?
(A) more
(B) less
(C) same
(D) more for small capacity and less for high capacity
(D) less for small capacity and more for high capacity