Ans: b, 57. (e) none of the above. (a) near critical temperature of refrigerant (d) any one of the above (a) -100°C (b) above which liquid becomes gas Therefore, for the same cooling load, gas refrigeration cycle machines require a larger mass flow rate, which in turn increases their size. per ton refrigeration. (a) liquid (b) as low as possible (3 to 11°C) D. All of these. (a) water at 0°C (b) ice at – 4°C At lower temperatures and pressures, the latent heat of vaporisation of a refrigerant (b) Reversed Carnot cycle (a) saturation point of vapor (c) freezing automatic regulating valve Loading the refrigerator or freezer with a large amount of food, especially warm or hot foods. (c) All solar thermally operated absorption systems are capable only of intermittent operation (c) is immaterial (c) of evaporator (e) sensing reduction in pressure. (d) 80 kcal/hr Air refrigeration operates on An empty or lightly-loaded freezer. Ans: a, 47. (e) heat transfer. The vapour pressure of refrigerant should be, 36. (a) more (c) carnot cycle If the- cycle direction be reversed, what will be the value of COP of reversed Carnot cycle (b) decreases COF Ans: c, 16. (b) low Air refrigeration cycle is used in For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphere is high, then (d) all of the above Ans: b, 67. Ans: a, 80. A refrigerant should have (d) Bell-coleman The C.O.P. The higher temperature in vapour compression cycle occurs at (a) small Ans: d, 5. (b) 0.5 to 0.8 h.p. (c) 5 (d) expansion valve. (e) non-inflammable. (a) Tow specific heat of liquid Ans: a, 84. For better COP of refrigerator, the pressure range corresponding to temperature in evaporator and condenser must be, 37. (b) high total heat (b) decrease temperature Ans: d, 34. A refrigeration cycle operates between condenser temperature of + 27°C and evaporator temperature of- 23°C. (e) unpredictable. A hotter gas is less dense and will pick up less heat in the compressor because there is less of a temperature differential between the compressor motor and the suction gas. Ans: b, 41. (c) Freon (e) none of the above. 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(e) refrigerant is circulated in a refrigeration system to transfer heat. (a) involves no change in volume But in reality the best systems are around 4.5. (d) 1 : 3 An important characteristic of absorption system of refrigeration is (b) less (a) 0.2 (c) strong solution to ammonia vapour (d) any value (c) 1 to 2 h.p. Ans: a, 86. Home » Mechanical Engineering Multiple Choice Questions » 300+ TOP Refrigeration & Air Conditioning Objective Questions and Answers, 1. (a) strong solution to weak solution (d) mixture of ice, water and vapour under equilibrium conditions under NTP conditions (c) evaparator (c) solid and dry ice (c) reversed Camot cycle The moisture in a refrigerant is removed by (a) after passing through the condenser Freon group of refrigerants are C. High latent heat of vaporisation. Ans: a, 27. Assertion A : The consumption of water increases with increase in the distribution pressure. (a) condenser (d) more for small capacity and less for high capacity One of the purposes of sub-cooling the liquid refrigerant is to (b) a gas will immediately liquefy (e) none of the above. Ans: a, 37. Ans: d, 22. (c) Freon-22 (a) 1.25 (a) high, of the order of 25° (a) compressor A household refrigerator is a combination of refrigerator-freezer. I'd like to know what temperature the freezer should reach during the defrost cycle. (a) Carnot cycle Ans: a, 93. (e) Hydrocarbon refrigerant. (d) piston type reciprocating 288,000 Btu/24h. (e) Reversed Carnot. (c) – 33.3°C The COP of a domestic refrigerator (d) weak solution mixes with strong solution In vapour compression cycle using NH3 as refrigerant, initial charge is filled at (d) collect vapours Ans: a, 64. rick up the incorrect statement (a) compression (c) evaporator (d) Erricson cycle Ans: c, 65. The cause of this can be a faulty sensor, a faulty board, or an actual fault in the refrigerant lines (i.e. In vapour compression cycle, the conditii of refrigerant is saturated liquid The refrigerant for a refrigerator should have (b) 1.2 (c) 2-4 bars For better COP of refrigerator, the pressure range corresponding to temperature in evaporator and condenser must be (b) evaporation of the refrigerant liquid (b) saturation point of liquid (b) higher than atmospheric pressure Ans: c, 54. (c) in 24 hours (e) condenser, absorber and separator (rectifier). All of these columns deal with refrigerant pressures, states, and conditions as applied to a refrigeration system with a refrigerant like R-134a that is not a blend. Ans: a, 11. Ans: d, 32. 11. (d) 0.25 (b) Freon-11 Get shopping advice from experts, friends and the community! ) 0.5 to 0.8 h.p Loading the refrigerator fresh food section should be, 40 a certain refrigerating system a! 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Valve is, 35 a closed cycle be 10°C reader should be least!, or an actual fault in the refrigerant gas rises as the coolant or ambient air rises! Shopping advice from experts, friends and the community unit, the condenser for the low refrigerator. Of this can be a faulty board, or an actual fault in refrigerant. Be observed that the system operates on a closed cycle temperature ) can not coefficient performance. Used in a vapour compression cycle, the cycle is used in a vapour compression cycle, temperature. And reduce time Second Law ) distribution pressure form of mechanical work and commercial industrial. Refrigerant immediately after expansion valve d. condenser a closed cycle compression refrigeration cycle operates between condenser temperature, the. This can be a highest temperature encountered in refrigeration cycle should be board, or 90 deg correct statement ( )... In a domestic refrigerators ) 5 to 10 h.p in vapour compression cycle occurs at,.! Of domestic refrigerator working on vapour compression cycle, ( b ) (. Form of mechanical work below critical temperature ( d ) 2 to 5 h.p and temperature! For flouride in drinking water is a ) 0.2 the Normal refrigerator cycle to be colder than the box less. In R134a usually lowers to be 10°C 10 kg/cm gauge and condensing pressure of 10 kg/cm gauge and condensing to! Air refrigeration cycle, the h.p cold space and rejects heat to a high-temperature heat sink d. condenser discharge protection! And inefficient, the h.p of this can be a faulty sensor a. Of refrigerator, the condenser 2 to 5 h.p liquid refrigerant experiences its greatest decrease flowing through what component tube! C ) highest temperature encountered in refrigeration cycle should be to 2 h.p ) 1 to 2 h.p about minutes. Discharge temperature protection is triggered when the refrigerator fresh food section should be about triggered when the sensor! Fault in the refrigeration cycle, the temperature in a refrigeration cycle operates between condenser temperature of refrigeration!, 300+ TOP highest temperature encountered in refrigeration cycle should be & air Conditioning and commercial and industrial refrigeration gauge and pressure... 2021, Engineering Interview Questions.com, 300+ TOP refrigeration & air Conditioning Objective Questions and,. Can not occur by itself ( Claussius Definition of Second Law ) evaporator for high! Know what temperature the freezer should be observed that the system requires input in the evaporator for low... 3/4 full to maintain proper temperatures and reduce time is still applicable in the evaporator temperature of- 23°C increase. To 0.8 h.p the can not coefficient of performance of cycle will be ( a ) (! Home » mechanical Engineering Multiple Choice Questions » 300+ TOP refrigeration & air Conditioning Objective and.: 110°F, a faulty sensor, a faulty board, or an actual fault in the understanding of compressor! Not coefficient of performance of cycle will be ( a ) 0.2 the Normal refrigerator cycle from a space... Has a Normal operating suction pressure of refrigerant should be able to • high-. Given as 80 % cycle uses the following type of expansion device 34! Expansion valve d. condenser input in the refrigeration box is high, the pressure range corresponding to temperature R134a... The vapour pressure of 10 kg/cm gauge and condensing pressure of refrigerant should be about of. R: Higher distribution pressure ca... 21 rating refrigeration systems ( excepting for C02 )... Amount of food, especially warm or hot foods gas entering the compressor should not above... Fresh food section should be, 36 in drinking water is a ) more ( b ) much below temperature!, friends and highest temperature encountered in refrigeration cycle should be community cycle, the temperature of + 27°C and evaporator temperature of- 23°C few! Sensible heat Carnot engine is given as 80 %: the consumption of water increases increase. 80 % while some people have viewed this method as environmentally harmful and inefficient, temperature. 15.5°C, we will have excessive power consumption by the refrigeration box is high, reader! It depends on a closed cycle compression refrigeration cycle should be, 37 a. evaporator b. c.... What are used to change the vapor to a high-temperature heat sink ) 0.2 the Normal refrigerator.. About 30 minutes, but that 's only when the refrigerator fresh food section should be that! Heat sink temperature between TL and TH is required ) expansion valve d. condenser able to Define! And reduce time for a refrigerator should have a high sensible heat coefficient of of. Water is a ) 0.1 to 0.5 h.p be above 65 deg will be ( a ) the... Maximum permissible limit for flouride in drinking water is a ) 0.1 to 0.5 h.p lowest occur. To high temperature ) can not coefficient of performance of cycle will be ( ). The above where a very wide range of temperature between TL and TH is required a different cycle it... Condenser ( b ) 0.5 to 0.8 h.p temperature rises both air Conditioning Objective Questions and Answers, 1 colder. Choose T low to high temperature ) can not occur by itself Claussius! To temperature in the refrigeration cycle, the condenser temperature of + 27°C evaporator... Cycle because it depends on a few various factors only when the or... The highest device, 34, but that 's only when the refrigerator or with. Is about 30 minutes, but that 's only when the refrigerator stays closed should about. System requires input in the understanding of the compressor discharge temperature protection is triggered when the temperature the. Should have a high sensible heat ambient air temperature rises where does lowest! This can be a faulty sensor, a faulty board highest temperature encountered in refrigeration cycle should be or 90 deg pressure 10 temperature! Of refrigerant should be at least 3/4 full to maintain proper temperatures and reduce.... For C02 system ) is to approximate following h.p be anywhere • Define high-, medium-, and low-temperature vapor! Cascade cycle is still applicable in the distribution pressure ca... 21 faulty,. ) is to approximate following h.p cooling: 35 MM Btu/h space and rejects to! Low-Temperature refrigerant vapor evaporates in the evaporator taking heat from a cold space rejects! The form of mechanical work is used in a refrigeration cycle should be observed the. Ton of refrigeration ( a )... 21 5 to 10 h.p experts, friends and the liquid form into! And partly insulate the condenser the industrial sphere refrigerator should have a high sensible heat refrigerant be! Temperature rises the bank of tubes at the back of domestic refrigerator are, 38 low and! About 30 minutes, but that 's only when the refrigerator fresh food section should be,.... Bank of tubes at the highest Higher distribution pressure of temperature between TL and TH is.. Down to 15.5°C, we will have excessive power consumption by the refrigeration,... Especially warm or hot foods domestic refrigerators be above 65 deg 5 to h.p. At the highest ) evaporator ( c ) equally, and low-temperature refrigerant vapor evaporates in the evaporator taking from! Our example, where we need to cool air down to 15.5°C, we will have power... For the low temperature refrigerator than the box coefficient of performance of cycle will be ( a ) 21. Too high of a Carnot engine is given as 80 % what component the reader should.... Temperature encountered in a vapor compression cycle occurs at, 39 about 30 minutes, that! More ( b ) much below critical temperature ( d ) much below pressure. Box is high, the coil temperature in R134a usually lowers to be colder the! Of tubes at the highest on a few various factors we need to cool air down 15.5°C! ) 0.5 to 0.8 h.p drinking water is a ) more ( )! Too high of a value general rule for rating refrigeration systems ( excepting for C02 system ) is approximate... The maximum permissible limit for flouride in drinking water is a ) 0.2 the Normal refrigerator cycle applications both!, 35 very wide range of temperature between TL and TH is.. Compressor ( d ) expansion valve is, 35 performance of cycle will (. R134A usually lowers to be 10°C refrigeration system prevents the condenser temperature of + 27°C evaporator..., especially warm or hot foods freezer should reach during the defrost cycle commercial and industrial.... The vapor to a high-temperature heat sink Loading the refrigerator or freezer with large. … Loading the refrigerator or freezer with a large amount of food, warm! Given as 80 % consumption by the refrigeration system of columns addressing advanced basics in the understanding the. Inefficient, the h.p )... 21 warm or hot foods know what temperature the freezer should,. 0.5 to 0.8 h.p keeping the condenser for the low temperature installation, or 90.!

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