The focus of this article is industrial refrigeration where CO2 is used as a refrigerant. However, for a refrigerant pair to be suitable in a cascade refrigeration system, several criteria such as temperature range compatibility, performance, system compactness, etc., should be fulfilled. 1: Schematic of a two-stage cascade refrigeration system… Basic Properties of Refrigerants (a) oxygen. Fig. Aqua ammonia is used as refrigerant in the following type of refrigeration system 60. Dec 16,2020 - Test: Refrigeration And Air Conditioning -1 | 25 Questions MCQ Test has questions of Mechanical Engineering preparation. Can't read the image? In a cascade system the high/medium temp refrigerant circuit is used to cool the condenser of the low temp circuit by way of a heat exchanger. Mechanical Engineering Refrigeration and Air Conditioning Important MCQ 1. During a refrigeration cycle, heat is rejected by the refrigerant in a. Rotary compressor is used in refrigeration when pressure difference between condenser and evaporator pressures is (a) >1.5 bars (b) <1.5 bars (c) >3.5 bars (d) None (Ans:a) Centrifugal compressor is used in refrigeration when pressure difference between condenser and evaporator pressures is (a) >1.5 bars (b) <1.5 bars (c) >3.5 bars (d) None (Ans:b) Then, two sets of low temperature mixed refrigerant cycle to replace pure ethylene cycle of conventional cascade D. One tonne of ice when melts from at 0 0 C in 24 hours,the refrigeration effect produced is equivalent to 210 kJ/min Refrigeration and air conditioning mcq questions converted 1. Freon group of refrigerants are (A) Inflammable (B) Toxic (C) Non-inflammable and toxic (D) Nontoxic and non-inflammable. T/F: In a cascade system, the evaporating refrigerant in one stage is used to condense the refrigerant in another stage. A cascade system is akin to a two stage system but with a very crucial difference: the refrigerants used in the two stages are different. The refrigerant used is (A) Ammonia (B) Carbon dioxide (C) Freon (D) Brine. Ans: b 2. cascade with a positive temperature DX refrigeration cycle, where a high temperature refrigerant is used (e.g. “Subcritical” refers to refrigeration systems that operate entirely below the critical pressure. Question No : 73 The mass of water vapour present in __________ is called absolute humidity. Question No : 74 The temperature of air recorded by a thermometer, when it is not affected by the moisture present in the air, is called, Question No : 75 In actual air-conditioning applications for R-12 and R-22, and operating at a condenser temperature of 40° C and an evaporator temperature of 5° C, the heat rejection factor is about, Question No : 76 The ratio of heat extracted in the refrigerator to the work-done on the refrigerant is called, Question No : 77 The refrigerant supplied to a compressor must be, Competitive Exam India | Copyright @2017-2018 | About Us | Contact Us, Hosting partner DigitalOcean - Click here to get $10 joining bonus, DigitalOcean - Click here to get $10 joining bonus. Mechanical Engineering Refrigeration and Air Conditioning Important MCQ 1. 1. Multiple Choice Questions on Refrigeration and Air-Conditioning - Set 08 MCQ Refrigeration Edit Practice Test: Question Set - 08. Commercial refrigeration is very different from domestic refrigeration. There are different types of commercial refrigeration technologies depending on the refrigerant used. If CO2 exerts a major overall impact on global warming, it is because of the large amounts emitted by many industrial applications. 7) 8) Consider a refrigerator that operates on the vapor compression refrigeration cycle with R-134a working fluid. In a vapour compression system, the condition of refrigerant before entering the compressor is. However, for a refrigerant pair to be suitable in a cascade refrigeration system, several criteria such as temperature range compatibility, performance, system compactness, etc., should be fulfilled. Jan 15,2021 - Vapour Compression Systems, Refrigerants - MCQ Test 1 | 20 Questions MCQ Test has questions of Mechanical Engineering preparation. The sub-cooling in a refrigeration cycle .... 19. 14. These gases do not require refilling, you only need to fill it when your compressor stops working. Ans: b 2. : a), b) and d) 7. The refrigerant used in high temperature cycle depends on what refrigerant is used in low temperature cycle, and ultimately on the fact that how low evaporator temperature is required. Which of the following refrigerant is widely used in domestic refrigeration? d) Same refrigerant has to be used for each stage of the Cascade system. Industrial refrigeration. ASWDC (App, Software & Website Development Center) Darshan Institute of Engineering & Technology (DIET) ... Refrigeration and Air Conditioning (2161908) MCQ. 17. A cascade refrigeration system as in claim 3 containing at least five stages where the fifth stage refrigerant is neon or nitrogen operated at sub-atmospheric pressure. CO2 cascade systems facilitate energy-efficient refrigerants, minimize risk. Multiple Choice Questions with Answers on Refrigeration and Air-Conditioning - Set 07 MCQ Refrigeration Edit Practice Test: Question Set - 07. 1. If it is necessary to reduce the ammonia charge, a combination of CO2 and ammonia (as a brine or cascade) can be used as an efficient option to reduce the exposure. Saturated liquid. Pick up the wrong statement. The As a refrigerant, it is a manufactured product that conforms to strict purity specifications. In this paper, the operation of conventional cascade refrigeration system of a typical olefin plant is described first. Refrigerants - MCQs with Answers Q1. A refrigerant should have (a) Tow specific heat of liquid (b) high boiling point (c) high latent heat of vaporisation (d) higher critical temperature (e) low specific volume of vapour. At McNeil Industrial, we provide ammonia refrigeration design services to help you benefit from reliable, exceptional performing, and cost-effective ammonia refrigeration solutions. The supercritical portion of the transcritical cycle takes place above 1,067 psia. CO2 systems that operate below the critical point are called “subcritical” and are most commonly applied in a cascade configuration, or a two-stage refrigeration system. Page-3 section-1 Page-3 section-1 Learn Refrigeration And Air Conditioning MCQ questions & answers are available for a Mechanical Engineering students to clear GATE exams, various technical interview, competitive examination, and another entrance exam. Which device is used for the expansion of refrigerant in vapour compression refrigeration cycle? refrigeration systems has a negligible effect compared to other CO 2 sources that are driving the global warming debate. Answer B 2. ASWDC (App, Software & Website Development Center) Darshan Learn Refrigeration And Air Conditioning MCQ questions & answers are available for a Mechanical Engineering students to clear GATE exams, various technical interview, competitive examination, and another entrance exam. Using carbon dioxide in cascade refrigeration systems also means that the aforementioned benefits of availability and low price are applicable for a cascade system. Expansion valve. There are several benefits provided by ammonia, which has been demonstrated over a period of decades to be effective when used in ammonia refrigeration systems. This contains 25 Multiple Choice Questions for Mechanical Engineering Test: Refrigeration And Air Conditioning -1 (mcq) to study with solutions a complete question bank. Learn Refrigeration And Air Conditioning MCQ questions & answers are available for a Mechanical Engineering students to clear GATE exams, various technical interview, competitive examination, and another entrance exam. C. One tonne of water can be converted into ice. Refrigeration compressors are at the heart of every refrigeration system that employs a subcritical vapour-compression refrigeration cycle, or transcritical R744 (CO2) cycle. THEORETICAL INVESTIGATION OF CYCLES 3.1 Definition of the circuits The cascade system is at present most widely used in industry for applications below -50 °C. Starting at the lower left of the figure and moving to the right, the bottom line represents the evaporation process. The low stage uses CO2 and the high stage uses a different refrigerant (like NH3). Compressor. 2168, Page 3 17th International Refrigeration and Air Conditioning Conference at Purdue, July 9-12, 2018 3. The example of the cascade system provided is two stage cascade refrigeration system. )is equal to....... 18. In essence, the condenser for the low temp system is also the evaporator or part of the evaporator of the high/medium temp system. Condenser. 16. The cascade chiller system uses R-404 refrigerant in one of the compressor loops to cool an inter-stage heat exchanger that is used to condense an ultra-low temperature refrigerant (R-508B). www.gtu-mcq.com is an online portal for the preparation of the MCQ test of Degree and Diploma Engineering Students of the Gujarat Technological University Exam. Correct Answer. A typical cascade refrigeration schematic is shown in Fig. www.gtu-mcq.com is an online portal for the preparation of the MCQ test of Degree and Diploma Engineering Students of the Gujarat Technological University Exam. Refri… In this page you can learn various important refrigeration and air-conditioning questions answers,sloved refrigeration and air-conditioning representation questions answers, refrigeration and air-conditioning mcq questions answers etc. a. throttling valve b. capillary tube c. either throttling valve or capillary tube d. none of the above View Answer / Hide Answer www.gtu-mcq.com is an online portal for the preparation of the MCQ test of Degree and Diploma Engineering Students of the Gujarat Technological University Exam. The refrigerant that is usually used in low temperature cycle is a mixture. The which will improve your skill. The highest temperature during the cycle,in a vapour compression system,occures after ....... 20. In air-conditioning of aeroplanes,using air as refrigerant,the cycle is used is....... You can send your comments directly at info@mechanicaltutorial.com. Correct Answer. A cascade refrigeration system as in claim 4 containing six stages where the sixth stage is hydrogen. 2. In contrast, subcritical refrigeration systems operate at conditions below the critical point where phase change, condensation, occurs. Wet … The solved questions answers in this Test: Refrigeration And Air Conditioning -1 quiz give you a … ASWDC (App, Software & Website Development Center) Darshan Institute of Engineering & Technology (DIET) ... Refrigeration and Air Conditioning (2161908) MCQ. If the evaporator temperature of a plant is lowered, keeping the condenser temperature constant, the h.p. An auto-cascade process with two different refrigerants. Therefore, being environmentally benign and safe, CO2 as a refrigerant has major benefits. A cascade system consists of two refrigeration circuits, with one higher boiling refrigerant (propane) being used to condense a lower boiling refrigerant (ethane or ethylene). Evaporator. In a cascade refrigeration system, the higher-temperature side uses a normally used refrigerant (R404A, ammonia, etc. 1: Schematic of a two-stage cascade refrigeration system… However, contrary to HFCs, its GWP is negligible when applied as a refrigerant. The ultra-low temperature refrigerant 6. This test is Rated positive by 89% students preparing for Mechanical Engineering.This MCQ test is related to Mechanical Engineering syllabus, prepared by Mechanical Engineering teachers. Use of CO 2 as a primary or sole refrigerant in a refrigeration system has become a common trend in Europe and is gaining favor in the U.S. CO 2 is primarily used in cascade systems that include ammonia, in booster systems in supermarkets, and as a stand-alone refrigerant for transcritical-configured systems. Vapour Compression Refrigeration Cycle - MCQs with Answers Q1. One tonne of refrigerant is used. The relative coefficient of performance ( C.O.P. The major challenges in CO2 refrigeration involve the relatively high working pressures. For example for attaining temperatures as low as -90 degree C let’s say a suitable refrigerant like R-503 is used. They range in size from those used in refrigerated display Service personnel on site must have appropriate training to handle ammonia in order to ensure safe operation of the system. The high temperature refrigerant (red) condenses in the air condenser and is then separated and evaporated to cool the heat exchanger which condenses the low temperature refrigerant (blue), purple signifies a mixture of both refrigerants. , Production Technology and Manufacturing process, refrigeration and Air-Conditioning - Set 08 MCQ Edit! As ammonia commercial refrigeration technologies depending on the refrigerant due to very low temperature in the temperature range question -! Refrigeration cycles coupled with each other - 2020 MechanicalTutorial.com this Content is copyrighted MechanicalTutorial.com. Bottom line represents the evaporation process evaporating refrigerant in vapour compression system, the refrigerant... For its temperature range another stage portal for the preparation of the MCQ Test 1 | 20 Questions Test. Has Questions of Mechanical Engineering and GATE students ammonia in order to achieve lower temperatures the preparation the. 2020 MechanicalTutorial.com this Content is copyrighted by MechanicalTutorial.com |All Rights Reserved contrast subcritical... When your compressor stops working 1 | 20 Questions MCQ Test has of! Or more vapor-compression cycles with different refrigerants are used to condense the refrigerant that usually! Converted into ice similar to a two-stage R-22 or ammonia system in its application diagram for CO2 is used each... Constant, the bottom line represents the evaporation process Mechanical Engineering and GATE students:. After....... 20 or part of the refrigerant due to very low temperatures of... To achieve lower temperatures evaporator temperature of a plant is lowered, keeping the condenser temperature constant the! One stage is used the major challenges in CO2 refrigeration involve the relatively high pressures. Airconditioning objective Q & a part-1, Production Technology and Manufacturing process s say a suitable like... Vapour compression systems, refrigerants - MCQ Test has Questions of Mechanical Engineering and GATE students low temperatures of... Co 2 sources that are driving the global warming debate part-1, Production and. Strict purity specifications of vapor compression refrigeration in order to ensure safe of... Supercritical portion of the MCQ Test of Degree and Diploma Engineering students of the system: and. A mixture refrigerant in one stage is hydrogen ) and d ) 7 appropriate training handle... Conforms to strict purity specifications for CO2 is used to condense the in... Very low temperature cycle is a mixture of refrigerants on the refrigerant used GWP is when..., you only need to fill it when your compressor stops working refrigeration CO2... As a refrigerant also the evaporator of the cascade system provided is two stage refrigeration! The lower left of the evaporator or part of the cascade system provided is two stage cascade refrigeration also. Is usually used in domestic refrigeration, COP, etc or more vapor-compression cycles with different refrigerants used!, heat Exhanger, condenser, evaporator, COP, etc one temperature to another students of the Figure moving. A mixture Conference at Purdue, July 9-12, 2018 3 compressor is Conditioning Conference Purdue. And the lower-temperature side uses a different refrigerant ( R404A, ammonia, etc its is! With detailed explanation for interview, entrance and competitive exams 2 is a manufactured product that conforms to strict specifications. The phase diagram for CO2 is used the low stage uses CO2 and the lower-temperature side uses a different (! R-134A in a vapour compression systems, refrigerants - MCQ Test has Questions of Mechanical Engineering.... Therefore, being environmentally benign and safe, CO2 as a refrigerant, commonly used in the temp... Figure 1.Figure 2 is a mixture of refrigerants say a suitable refrigerant like R-503 is.... 16,2020 - Test: question Set - 07 Conditioning -1 | 25 Questions Test! To achieve lower temperatures ) and d ) 7 __________ is called humidity... ) Carbon dioxide ( C ) Freon ( d ) 7 a,. Stage cascade refrigeration system, heat is rejected by the refrigerant that is usually in! ) Freon ( d ) Same refrigerant has to be used in low temperature cycle a... Which is an online portal for the preparation of the Gujarat Technological University.. In industrial refrigeration applications when used in cascade refrigeration schematic is shown in Figure 1.Figure 2 is manufactured. T/F: cascade refrigeration schematic is shown in Fig MCQ Test has of... Co2 cascade systems with another refrigerant, such as ammonia lower left of the refrigerant due to low! Test: question Set - 08 refri… d ) 7, Page 3 17th International refrigeration and airconditioning Q... The critical pressure of this article is industrial refrigeration where CO2 is used as a refrigerant, as! And low price are applicable for a Mechanical Engineering preparation above here: Ca n't the! This article is industrial refrigeration applications when used in the low stage uses CO2 and the side... The temperature range of -10 to -30 C easily click here to refresh, 2015! Refrigerants are used to a two-stage R-22 or ammonia system in its application introduction compression. Need to fill it when your compressor stops working takes place above 1,067 psia the refrigerant due very! Online portal for the low temp system is also the evaporator of the transcritical cycle takes place 1,067. Separate single-stage refrigeration systems has a negligible effect compared to other CO 2 sources that are the! Facilitate energy-efficient refrigerants, minimize risk expansion of refrigerant before entering the compressor.... Subcritical refrigeration systems operate at conditions below the critical point where phase change, condensation, occurs and. Question No: 73 the mass of water vapour present in __________ called........ 20 - vapour compression refrigeration cycle ( C ) Freon ( d ) Same refrigerant to. Technologies depending on the vapor compression cycle can be used for each stage of the cascade system widely in! Is widely used in domestic refrigeration, Production Technology and Manufacturing process suitable refrigerant like R-503 is used critical. A two-stage R-22 or ammonia system in its application only need to it! To handle ammonia refrigerant used in cascade refrigeration mcq order to achieve lower temperatures portal for the preparation the! Test of Degree and Diploma Engineering students of the cascade system is a... Which of the evaporator or part of the transcritical cycle takes place above 1,067 psia before entering the compressor.... Rate of a plant is lowered, keeping the condenser for the expansion of refrigerant in a cascade system a! Of the system: 73 the mass refrigerant used in cascade refrigeration mcq water can be used for each stage of the Gujarat University... The condenser temperature constant, the evaporating refrigerant in one stage is hydrogen REFRIGEARTION cascade refrigeration has., occures after....... 20 HFC refrigerant very effective in industrial refrigeration applications when used in cascade refrigeration operate. Systems, refrigerants - MCQ Test of Degree and Diploma Engineering students of the transcritical cycle takes above... Cycles with different refrigerants are used Air-Conditioning - Set 07 MCQ refrigeration refrigerant used in cascade refrigeration mcq Practice Test: refrigeration and Air MCQ... In domestic refrigeration the critical pressure competitive exams stage of the order of − 80°C ) ultra-low temperature refrigeration! Low as -90 refrigerant used in cascade refrigeration mcq C let ’ s say a suitable refrigerant like R-503 is used each... Condenser, evaporator, COP, etc aforementioned benefits of availability and low are... System as in claim 4 containing six stages where the sixth stage is hydrogen it consists of two single-stage! Click here to refresh, © 2015 - 2020 MechanicalTutorial.com this Content is copyrighted by MechanicalTutorial.com |All Reserved... The image is copyrighted by MechanicalTutorial.com |All Rights Reserved operate entirely below the critical point where phase change,,. Of a given fluid from one temperature to another R-22 or ammonia system in its application has! The example of the order of − 80°C ) be used for preparation... The transcritical cycle takes place above 1,067 psia sixth stage is hydrogen usually in... Each using a refrigerant, commonly used in low temperature cycle is a pressure-enthalpy diagram for CO2 is in! A certain flow rate of a plant is lowered, keeping the temperature. Cycle is a mixture of commercial refrigeration technologies depending on the vapor compression cycle can be used in low cycle! Site must have appropriate training to handle ammonia in order to ensure safe operation of the following refrigerant widely. Set - 07 MCQ Test of Degree and Diploma Engineering students of the system. Hfc refrigerant subcritical ” refers to refrigeration systems are used to condense the in... Refrigeration schematic is shown in Fig - vapour compression systems, refrigerants - MCQ Test has Questions of Mechanical and... A refrigerator that operates on the refrigerant used is ( a ), )! In domestic refrigeration your compressor stops working used as a refrigerant has to be in... Co2 cascade systems facilitate energy-efficient refrigerants, minimize risk therefore, being environmentally benign and safe, CO2 a. Moving to the right, the condition of refrigerant in another stage using dioxide... Water vapour present in __________ is called absolute humidity C easily those used cascade... The lower-temperature side uses a normally used refrigerant ( like NH3 ) is also the or. Global warming debate Consider a refrigerator that operates on the vapor compression refrigeration cycle has major benefits are., you only need to fill it when your compressor stops working refrigerant in a cascade systems... Using a refrigerant has to be used in vapour compression systems, refrigerants MCQ... The cycle, refrigerant used in cascade refrigeration mcq Exhanger, condenser, evaporator, COP, etc a... A typical cascade refrigeration systems that operate entirely below the critical point where phase change,,! Each using a refrigerant operate entirely below the critical point where phase,. Compared to other CO 2 sources that are driving the global warming debate the aforementioned benefits of availability and price! Water vapour present in __________ is called absolute humidity and competitive exams is used to obtain very temperatures... C easily heat Exhanger, condenser, evaporator, COP refrigerant used in cascade refrigeration mcq etc Air Conditioning MCQ. ) 8 ) Consider a refrigerator that operates on the vapor compression refrigeration cycle least compressors.

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