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 ton of refrigeration (c) 1 to 2 h.p. per ton of refrigeration (d) 2 to 5 h.p. per ton of refrigeration

1 Answer

Answer :

Ans: c

Related questions

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.

Last Answer : Ans: d

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

Last Answer : Ans: a

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

Last Answer : Ans: c

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

Last Answer : Ans: c

Description : Rating of a domestic refrigerator is of the order of (a) 0.1 ton (b) 5 tons (c) 10 tons (d) 40 tons

Last Answer : Ans: a

Description : Refrigeration in aeroplanes usually employs the following refrigerant (a) Co2 (b) Freon-11 (c) Freon-22 (d) Air

Last Answer : Ans: d

Description : If the evaporator temperature of a plant is lowered, keeping the condenser temperature constant, the h.p. of compressorrequired will be (a) same (b) more (c) less (d) more/less depending on rating

Last Answer : Ans: b

Description : COP of a refrigerator drawing 1 kW of power per ton of refrigeration is about (A) 0.5 (B) 3.5 (C) 4.5 (D) 8.5

Last Answer : (B) 3.5

Description : In a refrigeration cycle, the super heating……..C.O.P (a)decreases (b)does not change (c) increases (d)none of the above

Last Answer : Ans: a

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

Last Answer : Ans: a

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

Last Answer : Ans: a

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

Last Answer : Ans: a

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 : 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 : Moisture in freon refrigeration system causes (a) ineffective refrigeration (b) high power consumption (c) freezing automatic regulating valve (d) corrosion of whole system

Last Answer : Ans: c

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.

Last Answer : Ans: a

Description : Aqua ammonia is used as refrigerant in the following type of refrigeration system (a) compression (b) direct (c) indirect (d) absorption

Last Answer : Ans: d

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

Last Answer : Ans: b

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

Last Answer : Ans: c

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

Last Answer : Ans: b

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 : Air refrigeration cycle is used in (a) domestic refrigerators (b) gas liquefaction (c)commercial refrigerators (d) Chillers

Last Answer : Ans: b

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

Last Answer : Ans: c

Description : Under-cooling in a refrigeration cycle (a) increases COP (b) decreases COF (c) COP remains unaltered (d) other factors decide COP

Last Answer : Ans: a

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

Last Answer : Ans: c

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 : 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

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

Last Answer : Ans: b

Description : In a refrigeration cycle, the flow of refrigerant is controlled by (a) compressor (b) condenser (c) evaporator (d) expansion valve

Last Answer : Ans: d

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

Last Answer : Ans: a

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

Last Answer : Ans: d

Description : Air refrigeration cycle is used in (a) domestic refrigerators (b) commercial refrigerators (c) air conditioning (d) gas liquefaction

Last Answer : Ans: d

Description : Air refrigeration operates on (a) Carnot cycle (b) Reversed Carnot cycle (c) Rankine cycle (d) Brayton cycle.

Last Answer : Ans: d

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

Last Answer : Ans: a

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 : The normal heptane(C7H16) is given a rating of ____________ octane number. a) 0 b) 50 c) 100 d) 120

Last Answer : Answer: a Explanation: None.

Description : For the best results of efficient combustion, high speed diesel engines need an approximate cetane number of a. 100 b. 50 c. 10 d. 5

Last Answer : ANSWER b. 50

Description : The specific fuel consumption of a petrol engine compared to diesel engine of same H.P is A. same B.more C. less D. unpredictable

Last Answer : ANSWER : B

Description : A 40 kW engine has a mechanical efficiency of 80 %. If the frictional power is assumed to be constant with load, what is the approximate value of the mechanical efficiency at 50 % of the rated load? (a) 45% (b) 55 % (c) 65% (d) 75%

Last Answer : Ans :c

Description : A fuel of an octane number rating of 75 matches in knocking intensity as a mixture of a) 75% iso-octane and 25% normal heptane b) 75% normal heptane and 25% iso-octane c) 75% petrol and 25% diesel d) 75% diesel and 25% petrol

Last Answer : Answer: a Explanation: None.

Description : If the performance of diesel engine of different sizes, cylinder dimensions and power rating are to be compared, which of the following parameters can be used for such comparison? (a) Swept volume (b) Air fuel ratio (c) Specific brake fuel consumption (d) Volumetric efficiency

Last Answer : Ans :c

Description : The two reference fuel used for cetane rating are (a) Cetane and iso octane (b) Cetane and tetra ethyl lead (c) Cetance and n-heptane (d) Cetane and α- methyl naphthalene

Last Answer : Ans : d

Description : Reference fuels for knock rating of SI engine fuels would include (a) Iso octane alpha methyl naphthalene (b) Normal octance and aniline (c) Isooctance and n octane (d) N heptane and iso octane

Last Answer : Ans : d

Description : Use of gasoline blend like tetraethyl lead in internal combustion engine a. increases the octane rating of the fuel b. allows engine to operate at higher compression ratio c. avoids auto-ignition of fuel d. all of the above

Last Answer : ANSWER d. all of the above

Description : The benchmarking parameter for a vapour compression refrigeration system is a) kW / kg of refrigerant used b) kcal / m3 of chilled water c) BTU / Ton of Refrigeration d) kW / Ton of Refrigeration

Last Answer : d) kW / Ton of Refrigeration

Description : One ton of refrigeration is not equivalent to the heat removal rate of (A) 200 BTU/minute (B) 50 kcal/minute (C) 50 kJ/sec (D) 3.5 KW

Last Answer : (C) 50 kJ/sec

Description : Which of the following refrigerants has lowest freezing point (a) Freon-12 (b) NH3 (c) CO2 (d) Freon-22

Last Answer : Ans: d

Description : In a petrol engine, which of the following gas gets exhausted out without burning and without transformation? a. CO2 b. CO c. O2 d. N2

Last Answer : ANSWER d. N2

Description : Pick out the wrong statement. (A) A refrigeration cycle violates the second law of thermodynamics (B) Refrigeration cycle is normally represented by a temperature vs. entropy plot (C) In a refrigerator, ... (D) One ton of refrigeration is equivalent to the rate of heat absorption equal to 3.53 kW

Last Answer : (A) A refrigeration cycle violates the second law of thermodynamics

Description : One ton of refrigeration capacity is equivalent to the heat removal rate of (A) 50 kcal/hr (B) 200 BTU/hr (C) 200 BTU/minute

Last Answer : (C) 200 BTU/minute