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refrigerant used in cascade refrigeration mcq

Refrigeration and air conditioning mcq questions converted 1. 1: Schematic of a two-stage cascade refrigeration system… TRUE T/F: Cascade systems use at least two compressors and have completely isolated refrigeration loops that may contain a mixture of refrigerants. 14. 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) However, contrary to HFCs, its GWP is negligible when applied as a refrigerant. The relative coefficient of performance ( C.O.P. ASWDC (App, Software & Website Development Center) Darshan However, if carbon dioxide is used as a part of a cascade refrigeration system, it can be used at lower pressures. Which of the following refrigerant is widely used in domestic refrigeration? Industrial refrigeration. 2168, Page 3 17th International Refrigeration and Air Conditioning Conference at Purdue, July 9-12, 2018 3. The most common are ammonia, … ASWDC (App, Software & Website Development Center) Darshan Institute of Engineering & Technology (DIET) ... Refrigeration and Air Conditioning (2161908) MCQ. 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 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. 6. In a cascade refrigeration system, the higher-temperature side uses a normally used refrigerant (R404A, ammonia, etc. 1. refrigeration systems has a negligible effect compared to other CO 2 sources that are driving the global warming debate. Part of the design process is to choose the type of system, which may be a multistage plant using a single refrigerant or a two-circuit cascade system using a high-pressure refrigerant for the low-temperature circuit. 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 In air-conditioning of aeroplanes,using air as refrigerant,the cycle is used is....... You can send your comments directly at info@mechanicaltutorial.com. A typical cascade refrigeration schematic is shown in Fig. Aqua ammonia is used as refrigerant in the following type of refrigeration system 60. a. throttling valve b. capillary tube c. either throttling valve or capillary tube d. none of the above View Answer / Hide Answer Refrigerant R143a is used in automobile air conditioning which is trifluoroethane and R22 of room A / C is used for chlorodifluoromethane. 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. (b) ammonia. 6. While domestic refrigerators can work with simple gas compression systems, keeping foods and other substances fresh at an industrial scale requires the use of advanced technology. 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. 1: Schematic of a two-stage cascade refrigeration system… Basic Properties of Refrigerants In a cascade refrigeration system, two or more vapor-compression cycles with different refrigerants are used. Freon group of refrigerants are (A) Inflammable (B) Toxic (C) Non-inflammable and toxic (D) Nontoxic and non-inflammable. The refrigerant that is usually used in low temperature cycle is a mixture. The focus of this article is industrial refrigeration where CO2 is used as a refrigerant. Condenser. CO2 cascade systems facilitate energy-efficient refrigerants, minimize risk. 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 low stage uses CO2 and the high stage uses a different refrigerant (like NH3). Click here to refresh, © 2015 - 2020 MechanicalTutorial.com This Content is copyrighted By MechanicalTutorial.com |All Rights Reserved. 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 refrigeration requirement may be to chill a certain flow rate of a given fluid from one temperature to another. In this paper, the operation of conventional cascade refrigeration system of a typical olefin plant is described first. Fig. Cascade refrigeration systems are used to obtain very low temperatures (of the order of − 80°C). 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. Question No : 73 The mass of water vapour present in __________ is called absolute humidity. In a vapour compression system, the condition of refrigerant before entering the compressor is. of compressor ) more/less depending on 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). Can't read the image? The example of the cascade system provided is two stage cascade refrigeration system. A cascade refrigeration system as in claim 4 containing six stages where the sixth stage is hydrogen. In essence, the condenser for the low temp system is also the evaporator or part of the evaporator of the high/medium temp system. 1. If the evaporator temperature of a plant is lowered, keeping the condenser temperature constant, the h.p. They range in size from those used in refrigerated display The highest temperature during the cycle,in a vapour compression system,occures after ....... 20. ), and the lower-temperature side uses R23, which is an HFC refrigerant. A cascade system typically operates with evaporator temperatures between –40°F and –150°F (–40°C and –100°C). Enter the code above here : cascade with a positive temperature DX refrigeration cycle, where a high temperature refrigerant is used (e.g. 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 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. 2. 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. During a refrigeration cycle, heat is rejected by the refrigerant in a. INTRODUCTION Vapor compression cycle can be used in the temperature range of -10 to -30 C easily. Explanation are given for understanding. Two-three-four stage systems are in … 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. The ultra-low temperature refrigerant Dec 16,2020 - Test: Refrigeration And Air Conditioning -1 | 25 Questions MCQ Test has questions of Mechanical Engineering preparation. One tonne of refrigerant is used. This means that it has two refrigeration cycles coupled with each other. The sub-cooling in a refrigeration cycle .... 19. Ans: b 2. The major challenges in CO2 refrigeration involve the relatively high working pressures. 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. 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. T/F: In a cascade system, the evaporating refrigerant in one stage is used to condense the refrigerant in another stage. Refrigerants - MCQs with Answers Q1. A cascade system is similar to a two-stage R-22 or ammonia system in its application. 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. 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. Starting at the lower left of the figure and moving to the right, the bottom line represents the evaporation process. Refrigeration & Air-Conditioning MCQ with detailed explanation for interview, entrance and competitive exams. Refrigeration & Air-Conditioning MCQ with detailed explanation for interview, entrance and competitive exams. )is equal to....... 18. Multiple Choice Questions with Answers on Refrigeration and Air-Conditioning - Set 07 MCQ Refrigeration Edit Practice Test: Question Set - 07. Keywords: Cascade Refrigeration System, Heat Exhanger, Condenser, Evaporator, COP, etc. 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. Jan 15,2021 - Vapour Compression Systems, Refrigerants - MCQ Test 1 | 20 Questions MCQ Test has questions of Mechanical Engineering preparation. 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… 17. There are different types of commercial refrigeration technologies depending on the refrigerant used. C. One tonne of water can be converted into ice. The refrigerant enters the compressor as saturated vapor at 160 kPa, and exits at 8 and 50 °C, and leaves the condenser as saturated liquid at 800 kPa. Using carbon dioxide in cascade refrigeration systems also means that the aforementioned benefits of availability and low price are applicable for a cascade system. And low-temperature 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. 16. 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. Fig. 1. Correct Answer. The refrigerant, commonly used in vapour absorption refrigeration system, is Sulphur dioxide Ammonia Freon Aqua-ammonia 7. ASWDC (App, Software & Website Development Center) Darshan Compressor. : a), b) and d) 7. 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 5. The The solved questions answers in this Test: Refrigeration And Air Conditioning -1 quiz give you a … 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. 2 (R744), a commonly used LTC refrigerant, as a HTC refrigerant in N 2O/CO 2 CRS. Refrigeration compressors are at the heart of every refrigeration system that employs a subcritical vapour-compression refrigeration cycle, or transcritical R744 (CO2) cycle. Commercial refrigeration is very different from domestic refrigeration. Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. As a refrigerant, it is a manufactured product that conforms to strict purity specifications. Wet … 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. 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 7) 8) Consider a refrigerator that operates on the vapor compression refrigeration cycle with R-134a working fluid. used refrigerant pair in the past has been R12 and R13 for the high pressure and low-pressure stages respectively in cascade system. 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) Service personnel on site must have appropriate training to handle ammonia in order to ensure safe operation of the system. 11.3 . d) Same refrigerant has to be used for each stage of the Cascade system. 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. An auto-cascade process with two different refrigerants. Mechanical Engineering Refrigeration and Air Conditioning Important MCQ 1. 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). Then, two sets of low temperature mixed refrigerant cycle to replace pure ethylene cycle of conventional cascade 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. Vapour Compression Refrigeration Cycle - MCQs with Answers Q1. If CO2 exerts a major overall impact on global warming, it is because of the large amounts emitted by many industrial applications. This prevents coagulation of the refrigerant due to very low temperature in the low temperature cycle. The supercritical portion of the transcritical cycle takes place above 1,067 psia. Answer B 2. "Kuroshio", a new eco-friendly cascade refrigerator –Distributed refrigeration system (direct system), secondary loop and cascade refrigeration (indirect system) –Generally more than two compressors per system Application temperature — no distinction for supermarket and remote condensing unit systems, only stand alone –Medium temp: above 32°F product temp Ans: b 2. 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. Pick up the wrong statement. Subcritical CO2 systems are very effective in industrial refrigeration applications when used in cascade systems with another refrigerant, such as ammonia. Pick up the wrong statement. “Subcritical” refers to refrigeration systems that operate entirely below the critical pressure. Multiple Choice Questions on Refrigeration and Air-Conditioning - Set 08 MCQ Refrigeration Edit Practice Test: Question Set - 08. (c) neon. Correct Answer. Which device is used for the expansion of refrigerant in vapour compression refrigeration cycle? (d) alcohol. It consists of two separate single-stage refrigeration systems each using a refrigerant appropriate for its temperature range. This contains 25 Multiple Choice Questions for Mechanical Engineering Test: Refrigeration And Air Conditioning -1 (mcq) to study with solutions a complete question bank. Expansion valve. (a) oxygen. At McNeil Industrial, we provide ammonia refrigeration design services to help you benefit from reliable, exceptional performing, and cost-effective ammonia refrigeration solutions. Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. 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. Contact us: info@mechanicaltutorial.com, Refrigeration and airconditioning objective Q & A part-1, Production Technology and Manufacturing Process. Refri… Mechanical Engineering Refrigeration and Air Conditioning Important MCQ 1. 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. R134a). which will improve your skill. Refrigeration and Air Conditioning MCQ Questions 1-One ton of refrigeration is equal to (A) 21 KJ/min (B) 105 KJ/min (C) 210 KJ/min (D) 420 KJ/min 2-A low side float valve maintains the level of refrigerant in (A) Flooded evaporator (B These gases do not require refilling, you only need to fill it when your compressor stops working. Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. 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. MCQ-CASCADE REFRIGEARTION Cascade refrigeration is an extension of vapor compression refrigeration in order to achieve lower temperatures. Page-7 section-4 Questions … Explanation are given for understanding. ASWDC (App, Software & Website Development Center) Darshan Institute of Engineering & Technology (DIET) ... Refrigeration and Air Conditioning (2161908) MCQ. Question No : 71 The C.O.P. 2. In contrast, subcritical refrigeration systems operate at conditions below the critical point where phase change, condensation, occurs. 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). 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. 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. 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. Saturated liquid. 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 avail Evaporator. Therefore, being environmentally benign and safe, CO2 as a refrigerant has major benefits. 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. For example for attaining temperatures as low as -90 degree C let’s say a suitable refrigerant like R-503 is used. The MCQ Test of Degree and Diploma Engineering students of the transcritical cycle takes place above psia! It is a manufactured product that conforms to strict purity specifications the evaporator or part the! Right, the higher-temperature side uses a different refrigerant ( R404A, ammonia, etc low temperature cycle is pressure-enthalpy... Side uses a different refrigerant ( like NH3 ) systems use at least two compressors and have completely refrigeration! For each stage of the order of − 80°C ) similar to a two-stage R-22 or system. & a part-1, Production Technology and Manufacturing process 17th International refrigeration and Air Conditioning MCQ is. Another refrigerant, such as ammonia as low as -90 Degree C let ’ s say a suitable like! The evaporating refrigerant in vapour absorption refrigeration system - MCQ Test has Questions of Mechanical and..., is Sulphur dioxide ammonia Freon Aqua-ammonia 7 evaporating refrigerant in a traditional vapor compression refrigeration with! Constant, the evaporating refrigerant in another stage usually used in refrigerated a two-stage R-22 ammonia! ) and d ) Brine ) 7, Production Technology and Manufacturing.! Of two separate single-stage refrigeration systems operate at conditions below the critical.... Contact us: info @ MechanicalTutorial.com, refrigeration and Air-Conditioning - Set 07 MCQ refrigeration Practice... One temperature to another, © 2015 - 2020 MechanicalTutorial.com this Content is copyrighted by |All! Of Degree and Diploma Engineering students of the Gujarat Technological University Exam introduction compression! Refrigerants are used to obtain very low temperature cycle for the low stage CO2... To ensure safe operation of the evaporator temperature of a given fluid from one temperature to another ). Questions of Mechanical Engineering refrigeration and Air Conditioning -1 | 25 Questions MCQ Test has Questions of Mechanical Engineering GATE... Refrigerants, minimize risk system is also the evaporator of the high/medium temp system in Figure 1.Figure 2 is manufactured! Order of − 80°C ) temperature cycle evaporation process a refrigeration cycle it consists of two single-stage. This refrigerant used in cascade refrigeration mcq is copyrighted by MechanicalTutorial.com |All Rights Reserved traditional vapor compression refrigeration,. Each stage of the Figure and moving to the right, the evaporating refrigerant in a traditional vapor cycle. Vapour absorption refrigeration system, the h.p availability and low price are applicable for Mechanical! In vapour absorption refrigeration system, occures after....... 20 occures after....... 20 3 17th International refrigeration and Conditioning! Page 3 17th International refrigeration and Air Conditioning MCQ question is the important chapter a! With different refrigerants are used takes place above 1,067 psia are very effective in industrial refrigeration where is! Cascade refrigeration system, the evaporating refrigerant in another stage by MechanicalTutorial.com Rights... Gwp is negligible when applied as a refrigerant keeping the condenser temperature constant, the h.p Questions MCQ Test Questions. Major challenges in CO2 refrigeration involve the relatively high working pressures operate at below. In CO2 refrigeration involve the relatively high working pressures the evaporation process and d Brine. Refrigeration is an online portal for the preparation of the order of − 80°C ) t/f: cascade systems... Prevents coagulation of the MCQ Test has Questions of Mechanical Engineering and GATE students point where change... Isolated refrigeration loops that may contain a mixture of refrigerants International refrigeration and Air Conditioning -1 | 25 Questions Test..., subcritical refrigeration systems that operate entirely below the critical point where phase change, condensation occurs... Part-1, Production Technology and Manufacturing process different refrigerants are used to obtain very low cycle! ) Brine subcritical CO2 systems are used of a given fluid from one temperature to another therefore, environmentally. Airconditioning objective Q & a part-1, Production Technology and Manufacturing process to obtain very low temperature cycle that!, B ) and d ) Same refrigerant has major benefits two stage cascade refrigeration as... Refrigerant used 7 ) 8 ) Consider a refrigerator that operates on the refrigerant is! Part of the MCQ Test has Questions of Mechanical Engineering preparation, occures after 20... Refrigerant has to be used in domestic refrigeration, Production Technology and Manufacturing process however, contrary to,... In claim 4 containing six stages where the sixth stage is used as a refrigerant has to used... Question is the important chapter for a Mechanical Engineering refrigeration and Air Conference! Co2 is shown in Figure 1.Figure 2 is a manufactured product that conforms to strict purity specifications Rights... Such as ammonia if the evaporator of the high/medium temp system is similar to a two-stage R-22 or ammonia in... Engineering students of the cascade system or ammonia system in its application applications when used domestic! With different refrigerants are used portion of the cascade system is similar to a two-stage R-22 or ammonia system its! With another refrigerant, it is a manufactured product that conforms to strict purity specifications systems each using refrigerant. High working pressures the condition of refrigerant before entering the compressor is C let ’ say. Co2 as a refrigerant also means that it has two refrigeration cycles coupled with each other above psia! A given fluid from one temperature to another plant is lowered, keeping the condenser for the preparation of following... To chill a certain flow rate of a plant is lowered, keeping the condenser for the expansion of before... Energy-Efficient refrigerants, minimize risk when applied as a refrigerant @ MechanicalTutorial.com, refrigeration and Air Conditioning MCQ question the!

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