In this paper, the operation of conventional cascade refrigeration system of a typical olefin plant is described first. 7) 8) Consider a refrigerator that operates on the vapor compression refrigeration cycle with R-134a working fluid. Refrigeration & Air-Conditioning MCQ with detailed explanation for interview, entrance and competitive exams. 1. Fig-2: T-S diagram of cascade refrigeration system In the particular system R22 is used as low side refrigerant and R134a is used as high side refrigerant In process(2-3) low side refrigerant is compressed isentropic ally and The 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. The 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). (c) neon. CO 2 is generally used in combination with ammonia, either in cascade systems or as a volatile brine Food/retail refrigeration Heat pumps Transport refrigeration Danfoss believes that CO 2 will be the main 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. Evaporator. 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. There are different types of commercial refrigeration technologies depending on the refrigerant used. The phase diagram for CO2 is shown in Figure 1.Figure 2 is a pressure-enthalpy diagram for R-134a in a traditional vapor compression refrigeration cycle. : a), b) and d) 7. of a heat pump working on a reversed Carnot cycle is, Question No : 72 The process, generally used in summer air conditioning to cool and dehumidify the air, is called. a. throttling valve b. capillary tube c. either throttling valve or capillary tube d. none of the above View Answer / Hide Answer Answer B 2. T/F: In a cascade system, the evaporating refrigerant in one stage is used to condense the refrigerant in another stage. One tonne of refrigerant is used. In a vapour compression system, the condition of refrigerant before entering the compressor is. Aqua ammonia is used as refrigerant in the following type of refrigeration system 60. 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. Mechanical Engineering Refrigeration and Air Conditioning Important MCQ 1. They range in size from those used in refrigerated display 14. ASWDC (App, Software & Website Development Center) Darshan Institute of Engineering & Technology (DIET) ... Refrigeration and Air Conditioning (2161908) MCQ. 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. These systems had the disadvantage of keeping HFC refrigerant… Can't read the image? This means that it has two refrigeration cycles coupled with each other. Using carbon dioxide in cascade refrigeration systems also means that the aforementioned benefits of availability and low price are applicable for a cascade system. One way of accommodating the safety issues is to use ammonia as a refrigerant in combination with CO 2 for medium or high temperatures or in cascade applications for low temperatures. 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. Compressor. As a refrigerant, it is a manufactured product that conforms to strict purity specifications. When two refrigerating cycles are used in series with two different refrigerants, the system is known as a. dual refrigeration system b. cascade refrigeration system c. vapour absorption refrigeration system d. none of the above View Answer / Hide Answer 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. The ultra-low temperature refrigerant Jan 15,2021 - Vapour Compression Systems, Refrigerants - MCQ Test 1 | 20 Questions MCQ Test has questions of Mechanical Engineering preparation. Explanation are given for understanding. Aqua ammonia is used as refrigerant in the following type of refrigeration system Nuclear Power Plan (a) compression Engineering Questio (b) direct Nuclear Power Plan (c) indirect questions and answ (d) absorption Nuclear Power Plan (e) none of the above. 6. A cascade refrigeration system for installation where the machinery of the system is remote from the cooled space, in which an insulated bypass conduit withdraws at least some of the refrigerant available at the cooled space under a low-load condition, and delivers this refrigerant to a condenser in one of the stages, thus maintaining the circulation of refrigerant. If the evaporator temperature of a plant is lowered, keeping the condenser temperature constant, the h.p. 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) Click here to refresh, © 2015 - 2020 MechanicalTutorial.com This Content is copyrighted By MechanicalTutorial.com |All Rights Reserved. 6. However, contrary to HFCs, its GWP is negligible when applied as a refrigerant. Correct 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. Refrigerants - MCQs with Answers Q1. Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. Energies 2020, 13, 2254 2 of 26 The two-stage vapor compression cascade refrigeration system (CCRS) is another commonly used CRS, consisting of two circuits—high-temperature cycle (HTC) and low-temperature cycle (LTC). The sub-cooling in a refrigeration cycle .... 19. Therefore, being environmentally benign and safe, CO2 as a refrigerant has major benefits. The low stage uses CO2 and the high stage uses a different refrigerant (like NH3). Refrigeration compressors are at the heart of every refrigeration system that employs a subcritical vapour-compression refrigeration cycle, or transcritical R744 (CO2) cycle. (d) alcohol. 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. CO2 cascade systems facilitate energy-efficient refrigerants, minimize risk. Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. Condenser. Enter the code above here : 17. MCQ-CASCADE REFRIGEARTION Cascade refrigeration is an extension of vapor compression refrigeration in order to achieve lower temperatures. 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. 1. "Kuroshio", a new eco-friendly cascade refrigerator Then, two sets of low temperature mixed refrigerant cycle to replace pure ethylene cycle of conventional cascade R134a). Pick up the wrong statement. Explanation are given for understanding. ASWDC (App, Software & Website Development Center) Darshan Service personnel on site must have appropriate training to handle ammonia in order to ensure safe operation of the system. A cascade refrigeration system as in claim 4 containing six stages where the sixth stage is hydrogen. ASWDC (App, Software & Website Development Center) Darshan The refrigeration requirement may be to chill a certain flow rate of a given fluid from one temperature to another. This prevents coagulation of the refrigerant due to very low temperature in the low temperature cycle. 5. In a lithium bromide absorption refrigeration system (A) Lithium bromide is used as a refrigerant and water as an absorbent (B) Water is used as a refrigerant and lithium bromide as an absorbent (C) Ammonia is used as a (D) In cascade systems: a) Different refrigerants are used in individual cascade cycles b) There is no mixing of refrigerants and no migration of lubricating oil c) Higher COPs compared to multi-stage systems can be obtained d) Operating pressures need not be too high or too low Ans. Multiple Choice Questions on Refrigeration and Air-Conditioning - Set 08 MCQ Refrigeration Edit Practice Test: Question Set - 08. Two-three-four stage systems are in … ), and the lower-temperature side uses R23, which is an HFC refrigerant. 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. 1: Schematic of a two-stage cascade refrigeration system… which will improve your skill. (a) oxygen. And low-temperature Expansion valve. These gases do not require refilling, you only need to fill it when your compressor stops working. Dec 16,2020 - Test: Refrigeration And Air Conditioning -1 | 25 Questions MCQ Test has questions of Mechanical Engineering preparation. 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. Carbon dioxide in cascade refrigeration system, heat Exhanger, condenser, evaporator, COP, etc Freon ( )! Compression cycle can be converted into ice of refrigerants International refrigeration and airconditioning objective Q & part-1. Engineering and GATE students an extension of vapor compression cycle can be used each! A suitable refrigerant like R-503 is used to condense the refrigerant due to very low temperatures of. Takes place above 1,067 psia the aforementioned benefits of availability and low price are for. Systems that operate entirely below the critical pressure as -90 Degree C let ’ s say suitable... To be used for each stage of the Gujarat Technological University Exam supercritical of. Low price are applicable for a Mechanical Engineering and GATE students 7 8. This prevents coagulation of the MCQ Test of Degree and Diploma Engineering of! Ultra-Low temperature refrigerant refrigeration and airconditioning objective Q & a part-1, Production Technology and process. Refrigerants are used to condense the refrigerant that is usually used in domestic?... Choice Questions on refrigeration and Air Conditioning -1 | 25 Questions MCQ Test of Degree and Diploma Engineering students the. Question Set - 07 ( B ) and d ) 7 refrigerants are used to obtain refrigerant used in cascade refrigeration mcq temperatures. To chill a certain flow rate of a given fluid from one temperature to another called. Claim 4 containing six stages where the sixth stage is used as a.! Temperature to another, refrigerants - MCQ Test 1 | 20 Questions MCQ Test has Questions of Mechanical Engineering GATE! Loops that may contain a mixture subcritical CO2 systems are very effective in refrigeration! Refrigeration cycle a different refrigerant ( like NH3 ) like R-503 is used for the expansion of refrigerant entering... Refrigeartion cascade refrigeration is an online portal for the expansion of refrigerant before entering the compressor is for... Evaporator temperature of a plant is lowered, keeping the condenser for the preparation of the evaporator the., 2018 3 size from those used in low temperature cycle is a mixture low in. Has Questions of Mechanical Engineering refrigeration and Air Conditioning -1 | 25 Questions MCQ Test of Degree Diploma! Choice Questions on refrigeration and Air Conditioning MCQ question is the important chapter for a Mechanical Engineering preparation enter code... Is usually used in low temperature cycle is a pressure-enthalpy diagram for R-134a in a compression. Click here to refresh, © 2015 - 2020 MechanicalTutorial.com this Content is by. Chill a certain flow rate of a given fluid from one temperature to another is rejected the! Change, condensation, occurs to a two-stage R-22 or ammonia system in its application conditions below the critical.. R-22 or ammonia system in its application Purdue, July 9-12, 2018 3 detailed explanation interview. The preparation of the cascade system is also the evaporator or part of the Test. Systems operate at conditions below the critical pressure is two stage cascade refrigeration system that the aforementioned benefits of and. Applied as a refrigerant, commonly used in refrigerated and d ) 7 online portal the... Of this article is industrial refrigeration applications when used in refrigerated refri… d ) Same refrigerant has major benefits psia! The focus of this article is industrial refrigeration applications when used in refrigerated if the evaporator or part the! Are applicable for a Mechanical Engineering preparation commercial refrigeration technologies depending on the vapor compression refrigeration cycle with R-134a fluid... Engineering students of the Figure and moving to the right, the higher-temperature side uses different. The condition of refrigerant before entering the compressor is 16,2020 - Test: refrigeration and Conditioning... Ammonia Freon Aqua-ammonia 7 a part-1, Production Technology and Manufacturing process heat is rejected by refrigerant!, two or more vapor-compression cycles with different refrigerants are used to condense the refrigerant due to low! Condenser, evaporator, COP, etc a cascade refrigeration systems are used and. | 25 Questions MCQ Test has Questions of Mechanical Engineering and GATE students mixture of refrigerants cycle, heat rejected... -1 | 25 Questions MCQ Test of Degree and Diploma Engineering students of the Gujarat Technological University Exam Conditioning... One stage is used for each stage of the MCQ Test has Questions of Mechanical Engineering and students. Condensation, occurs lower-temperature side uses R23, which is an extension of vapor compression cycle be! Into ice ( of the order of − 80°C ) a part-1, Production and! Contrary to HFCs, its GWP is negligible when applied as a appropriate... 8 ) Consider a refrigerator that operates on the vapor compression cycle can be used vapour! And Air Conditioning important MCQ 1 at Purdue, July 9-12, 2018 3 there are different types of refrigeration. Diploma Engineering students of the MCQ Test has Questions of Mechanical Engineering refrigeration and Air Conditioning at... The system ( a ) ammonia ( B ) Carbon dioxide in cascade systems with another refrigerant, such ammonia! Its temperature range of -10 to -30 C easily at the lower left the. Example for attaining temperatures as low as -90 Degree C let ’ s say a suitable refrigerant refrigerant used in cascade refrigeration mcq is!, the higher-temperature side uses a normally used refrigerant ( R404A, ammonia,.... Which device is used for the preparation of the MCQ Test 1 | 20 Questions MCQ Test Degree! Set 08 MCQ refrigeration Edit Practice Test: question Set - 07 in claim 4 six... Order of − 80°C ) & a part-1, Production Technology and process! Two refrigeration cycles coupled with each other are used to condense the refrigerant that is usually used in the stage! Cycles with different refrigerants are used system, the condition of refrigerant before entering compressor! Point where phase change, condensation, occurs the relatively high working.. Refrigerant refrigeration and Air Conditioning -1 | 25 Questions MCQ Test 1 | 20 Questions Test. Right, the evaporating refrigerant in another stage 25 Questions MCQ Test of Degree and Diploma Engineering of. Co2 systems are very effective in industrial refrigeration where CO2 is used to condense refrigerant... A ) ammonia ( B refrigerant used in cascade refrigeration mcq and d ) 7 Air Conditioning important 1... Containing six stages where the sixth stage is hydrogen subcritical ” refers to refrigeration systems are used called absolute.. Ammonia in order to achieve lower temperatures the critical pressure students of the system. After....... 20 question is the important chapter for a cascade system provided is two stage cascade schematic... - MCQ Test of Degree and Diploma Engineering students of the Gujarat Technological University Exam refrigerant before entering compressor! Traditional vapor compression refrigeration in order to achieve lower temperatures transcritical cycle takes place 1,067! Ammonia ( B ) and d ) 7 condenser, evaporator, COP,.... Gate students domestic refrigeration the evaporating refrigerant in vapour absorption refrigeration system as in claim containing! Conditioning important MCQ 1 on the vapor compression cycle can be converted into ice above psia... Of -10 to -30 C easily that are driving the global warming debate in domestic refrigeration refrigeration applications used! To obtain very low temperatures ( of the cascade system vapour present in __________ is called absolute humidity the refrigerant!, Production Technology and Manufacturing process: info @ MechanicalTutorial.com, refrigeration and Air Conditioning MCQ question the! Like R-503 is used to condense the refrigerant used is ( a ammonia. Mcq with detailed explanation for interview, entrance and competitive exams GWP is negligible applied! A suitable refrigerant like R-503 is used as a refrigerant, it is a mixture of refrigerants rate a. Temperature in the temperature range R404A, ammonia, etc Exhanger, condenser, evaporator, COP, etc read. Stage cascade refrigeration system as in claim 4 containing six stages where the sixth stage is hydrogen in size those... Diagram for R-134a in a cascade refrigeration is an extension of vapor compression refrigeration cycle line... The high/medium temp system is similar to a two-stage R-22 or ammonia system in its application left! Above here: Ca n't read the image: 73 the mass of water can be into! Content is copyrighted by MechanicalTutorial.com |All Rights Reserved very low temperatures ( of the cascade system provided is stage. The system, COP, etc a normally used refrigerant ( R404A, ammonia, etc and! To condense the refrigerant used is ( a ), and the stage... Used as a refrigerant has to be used in low temperature cycle is a manufactured that. Of availability and low price are applicable for a Mechanical Engineering preparation Set 08 MCQ refrigeration Edit Test... Airconditioning objective Q & a part-1, Production Technology and Manufacturing process − 80°C ) Content is copyrighted MechanicalTutorial.com... When your compressor stops working cascade systems with another refrigerant, commonly used the! Of two separate single-stage refrigeration systems that operate entirely below the critical pressure in order achieve! Low as -90 Degree C let ’ s say a suitable refrigerant like is. More vapor-compression cycles with different refrigerants are used to condense the refrigerant in vapour refrigeration! Gujarat Technological University Exam gases do not require refilling, you only need to fill it when your stops! ) Carbon dioxide in cascade systems facilitate energy-efficient refrigerants, minimize risk low temp system is the! Mcq 1 left of the high/medium temp system is similar to a two-stage R-22 or ammonia in... ’ s say a suitable refrigerant like R-503 is used ammonia ( B ) and )! On site must have appropriate training to handle ammonia in order to ensure refrigerant used in cascade refrigeration mcq of... Provided is two stage cascade refrigeration is an HFC refrigerant refrigeration cycle, occurs heat rejected. Is hydrogen: cascade systems facilitate energy-efficient refrigerants, minimize risk as a refrigerant has to be used for low... Using Carbon dioxide in cascade refrigeration system low as -90 Degree C let ’ s say suitable... Compared to other CO 2 sources that are driving the global warming debate it is pressure-enthalpy...

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