Description : Air refrigeration cycle is used in (a) domestic refrigerators (b) commercial refrigerators (c) air conditioning (d) gas liquefaction
Last Answer : Ans: d
Description : Most of the domestic refrigerators work on the following refrigeration system (a) vapour compression (b) vapour absorption (c) carnot cycle (d) electrolux refrigerator
Last Answer : Ans: a
Description : Air refrigeration operates on (a) Carnot cycle (b) Reversed Carnot cycle (c) Rankine cycle (d) Brayton cycle.
Description : In a refrigeration cycle, the super heating……..C.O.P (a)decreases (b)does not change (c) increases (d)none of the above
Description : The change in evaporator temperature in a refrigeration cycle, as compared to change in condenser temperature, influences the value of C.O.P. (a) more (b) less (c) equally. (d) unpredictable
Description : The C.O.P. of a refrigeration cycle with lowering of condenser temperature, keeping the evaporator temperatureconstant, will (a) increase (b) decrease (c) may increase or decrease depending on the type of refrigerant used (d) remain unaffected
Description : Reducing suction pressure in refrigeration cycle (a) lowers evaporation temperature (b) increases power required per ton of refrigeration (c) lowers compressor capacity because vapour is lighter (d) all of the above.
Description : The C.O.P of a refrigeration cycle with increase in evaporator temperature, keeping condenser temperature constant, will (a) increase (b) decrease (c) remain unaffected (d) may increase or decrease depending on the type of refrigerant used
Description : Under-cooling in a refrigeration cycle (a) increases COP (b) decreases COF (c) COP remains unaltered (d) other factors decide COP
Description : Superheating in a refrigeration cycle (a) increases COP (b) decreases COP (c) COP remains unaltered (d) other factors decide COP
Last Answer : Ans: b
Description : The lower horizontal line of the refrigeration cycle plotted on pressure-enthalpy-diagram represents (a) condensation of the refrigerant vapour (b) evaporation of the refrigerant liquid (c) compression of the refrigerant vapour (d) metering of the refrigerant liquid
Description : In a refrigeration cycle, the flow of refrigerant is controlled by (a) compressor (b) condenser (c) evaporator (d) expansion valve
Description : A refrigeration cycle operates between condenser temperature of + 27°C and evaporator temperature of- 23°C. TheCarnot coefficient of performance of cycle will be (a) 0.2 (b) 1.2 (c) 5 (d) 6
Last Answer : Ans: c
Description : Highest temperature encountered in refrigeration cycle should be (a) near critical temperature of refrigerant (b) above critical temperature (c) atcritica. temperature (d) much below critical temperature
Description : Ammonia-absorption refrigeration cycle requires (a) very little work input (b) maximum work input (c) nearly same work input as for vapour compression cycle (d) zero work input
Description : Vapour compression refrigeration is some what like (a) Carnot cycle (b) Rankine cycle (c) reversedCamot cycle (d) reversed Rankine cycle
Last Answer : Ans: C
Description : Refrigeration in aeroplanes usually employs the following refrigerant (a) Co2 (b) Freon-11 (c) Freon-22 (d) Air
Description : Domestic refrigerator working on vapour compression cycle uses the following type of expansion device (a) electrically operated throttling valve (b) manually operated valve (c) thermostatic valve (d) capillary tube
Description : In refrigerators, the temperature difference between the evaporating refrigerant and the medium being cooled should be (a) high, of the order of 25° (b) as low as possible (3 to 11°C) (c) zero (d) any value
Description : Domestic refrigerator usually works on the __________ refrigeration cycle. (A) Carnot (B) Air (C) Absorption (D) vapour-ejection
Last Answer : (C) Absorption
Description : The refrigeration effect in a dry evaporator compared to flooded evaporator in a similar plant is (a) same (b) more (c) less (d) more or less depending on ambient conditions
Description : The general rule for rating refrigeration systems (excepting for CO2 system) is to approximate following h.p. per ton of Refrigeration (a) 0.1 to 0.5 h.p. per ton of refrigeration (b) 0.5 to 0.8 h.p. per ... (c) 1 to 2 h.p. per ton of refrigeration (d) 2 to 5 h.p. per ton of refrigeration
Description : Moisture in freon refrigeration system causes (a) ineffective refrigeration (b) high power consumption (c) freezing automatic regulating valve (d) corrosion of whole system
Description : For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphereis high, then (a) bigger cabinet should be used (b) smaller cabinet should ... tight vapour seal should be used (d) refrigerant with lower evaporation temperature should be used
Description : 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 ... ice at 0°C in 24 hours (d) the refrigeration effect to produce 1 ton of ice at NTP conditions
Description : Mass flow ratio of NH3 in comparison to Freon-12 for same refrigeration load and same temperature limits is of the orderof (a) 1 : 1 (b) 1 : 9 (c) 9 : 1 (d) 1 : 3
Description : The leaks in a refrigeration system using Freon are detected by (a) halide torch which on detection produces greenish flame lighting (b) sulphur sticks which on detection gives white smoke (c) using reagents (d) sensing reduction in pressure.
Description : Aqua ammonia is used as refrigerant in the following type of refrigeration system (a) compression (b) direct (c) indirect (d) absorption
Description : Highest pressure encountered in a refrigeration system should be (a) critical pressure of refrigerant (b) much below critical pressure (c) much above critical pressure (d) near critical pressure
Description : In vapour compression refrigeration system, refrigerant occurs as liquid between (a) condenser and expansion valve (b) compressor and evaporator (c) expansion valve and evaporator (d) compressor and condenser
Description : In a flooded evaporator refrigerator, an accumulator at suction of compressor is used to (a) collect liquid refrigerant and prevent it from going to compressor (b) detect liquid in vapour (c) superheat the vapour (d) increase refrigeration effect
Description : In a refrigeration system, heat absorbed in comparison to heat rejected is (a) more (b) less (c) less for small capacity and more for high capacity. (d) more for small capacity and less for high capacity
Description : In S.J. unit, one ton of refrigeration is equal to (a) 210 kJ/min (b) 21 kJ/min (c) 3.5 kJ/min (d) 2.4 kJ/min
Description : One ton of refrigeration is equal to the refrigeration effect corresponding to melting of 1000 kg of ice (a) in 1 hour (b) in 1 minute (c) in 24 hours (d) in 12 hours
Description : An important characteristic of absorption system of refrigeration is (a) noisy operation (b) quiet operation (c) very little power consumption (d) its input only in the form of heating.
Last Answer : Ans: D
Description : The C.O.P. of a domestic refrigerator in comparison to domestic air conditioner will be (a) same (b) more (c) less (d) dependent on weather conditions
Description : Air standard cycle uses ____ as a working medium. a. Perfect gas b. Real gas c. Ideal gas d. Natural gas
Last Answer : ANSWER a. Perfect gas
Description : Consider the following statements 1. Large cold storage plants use ammonia as refrigerant while domestic refrigerators use chlorofluorocarbons. 2. Ammonia can be liquefied at ambient temperatures and at low pressures. 3. Chlorofluorocarbons are ... 3 only (b) 2 and 3 only (c) 1, 2 and 3 (d) 3 only
Last Answer : Ans:(a)
Description : The bank of tubes at the back of domestic refrigerator are (a) condenser tubes (b) evaporator tubes (c) refrigerant cooling tubes (d) capillary tubes
Description : The domestic refrigerator uses following type of compressor (a) centrifugal (b) axial (c) miniature sealed unit (d) piston type reciprocating
Description : The COP of a domestic refrigerator (a) is less than 1 (b) is more than 1 (c) is equal to 1 (d)depends upon the weather conditions.
Description : Rating of a domestic refrigerator is of the order of (a) 0.1 ton (b) 5 tons (c) 10 tons (d) 40 tons
Description : Identify modes of heat transfer involved applications with brief explanation. (1) Radiator of automobile (2) Condenser of domestic refrigerator.
Last Answer : Modes of heat transfer Automobile radiator-A radiator is a type of heat exchanger. It is designed to transfer heat from the hot coolant that flows through it to the air blown through ... of heat transfer plays very important deciding factor transferring heat from condenser tube to atmosphere.
Description : The ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency is called a. net efficiency b. efficiency ratio c. relative efficiency d. overall efficiency
Last Answer : ANSWER c. relative efficiency
Description : An engine working on air standard Otto cycle has a cylinder diameter of 10 cm and stroke length of 15 cm. The ratio of specific heats for air is 1.4. If the clearance volume is 196.3 cc and the heat supplied per kg of air per ... kg of air is a. 879.1 kJ/ b. 890.2 kJ c. 895.3 kJ d. 973.5 kJ
Last Answer : ANSWER d. 973.5 kJ
Description : A diesel engine is usually more efficient than a spark ignition engine because a. Diesel being a heavier hydrocarbon, release more heat per kg than gasoline b. The air standard efficiency of diesel ... an Spark ignition engine d.Self ignition temperature of diesel is higher than that of gasoline.
Last Answer : ANSWER c. The compression ratio of a diesel engine is higher than that of an S.I engine
Description : For an engine operating on air standard Otto cycle, the clearance volume is 10% of the swept volume. The specific heat ratio of air is 1.4. The air standard cycle efficiency is a. 38.3 % b. 39.8 % c. 60.2 % d. 61.7 %
Last Answer : ANSWER d. 61.7%
Description : An ideal air standard Otto cycle has a compression ratio of 8.5. If the ratio of the specific heats is 1.4, then what is thermal efficiency (in percentage) of the Otto cycle? a. 57.5% b. 45.7% c. 52.5% d. 95%
Last Answer : ANSWER a. 57.5%
Description : The air standard Otto cycle comprises a two constant pressure processes and two constant volume processes b two constant pressure and two constant entropy processes c. two constant volume processes and two constant entropy processes d. none of the above.
Last Answer : ANSWER (c) two constant volume processes and two constant entropy processes
Description : Claude's liquefaction process employs the cooling of gases by (A) Expansion in an engine (B) Following a constant pressure cycle (C) Throttling (D) None of these
Last Answer : A) Expansion in an engine