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