refrigerant used in cascade refrigeration mcq

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Enter the code above here : These systems had the disadvantage of keeping HFC refrigerant… (c) neon. 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) The sub-cooling in a refrigeration cycle .... 19. 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 of the following refrigerant is widely used in domestic refrigeration? Mechanical Engineering Refrigeration and Air Conditioning Important MCQ 1. Question No : 71 The C.O.P. Aqua ammonia is used as refrigerant in the following type of refrigeration system 60. 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. 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 "Kuroshio", a new eco-friendly cascade refrigerator 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. 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 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. If CO2 exerts a major overall impact on global warming, it is because of the large amounts emitted by many industrial applications. Answer B 2. Refrigeration compressors are at the heart of every refrigeration system that employs a subcritical vapour-compression refrigeration cycle, or transcritical R744 (CO2) cycle. Can't read the image? 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. They range in size from those used in refrigerated display In a cascade refrigeration system, the higher-temperature side uses a normally used refrigerant (R404A, ammonia, etc. Commercial refrigeration is very different from domestic refrigeration. 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. Condenser. Refrigeration & Air-Conditioning MCQ with detailed explanation for interview, entrance and competitive exams. 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. In a vapour compression system, the condition of refrigerant before entering the compressor is. The The refrigeration requirement may be to chill a certain flow rate of a given fluid from one temperature to another. 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. 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. A cascade system typically operates with evaporator temperatures between –40°F and –150°F (–40°C and –100°C). One tonne of refrigerant is used. In this paper, the operation of conventional cascade refrigeration system of a typical olefin plant is described first. Pick up the wrong statement. Fig. The relative coefficient of performance ( C.O.P. Fig. Starting at the lower left of the figure and moving to the right, the bottom line represents the evaporation process. )is equal to....... 18. However, contrary to HFCs, its GWP is negligible when applied as a refrigerant. 1: Schematic of a two-stage cascade refrigeration system… 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 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. 6. During a refrigeration cycle, heat is rejected by the refrigerant in a. However, if carbon dioxide is used as a part of a cascade refrigeration system, it can be used at lower pressures. Industrial refrigeration. 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) 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. 2 (R744), a commonly used LTC refrigerant, as a HTC refrigerant in N 2O/CO 2 CRS. Two-three-four stage systems are in … Then, two sets of low temperature mixed refrigerant cycle to replace pure ethylene cycle of conventional cascade Pick up the wrong statement. Refri… A cascade system is similar to a two-stage R-22 or ammonia system in its application. 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. Freon group of refrigerants are (A) Inflammable (B) Toxic (C) Non-inflammable and toxic (D) Nontoxic and non-inflammable. 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. 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 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). This prevents coagulation of the refrigerant due to very low temperature in the low temperature cycle. The highest temperature during the cycle,in a vapour compression system,occures after ....... 20. Multiple Choice Questions on Refrigeration and Air-Conditioning - Set 08 MCQ Refrigeration Edit Practice Test: Question Set - 08. 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 used is (A) Ammonia (B) Carbon dioxide (C) Freon (D) Brine. Explanation are given for understanding. (d) alcohol. Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. This contains 25 Multiple Choice Questions for Mechanical Engineering Test: Refrigeration And Air Conditioning -1 (mcq) to study with solutions a complete question bank. ASWDC (App, Software & Website Development Center) Darshan 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. ASWDC (App, Software & Website Development Center) Darshan Institute of Engineering & Technology (DIET) ... Refrigeration and Air Conditioning (2161908) MCQ. (b) ammonia. ), and the lower-temperature side uses R23, which is an HFC refrigerant. The refrigerant that is usually used in low temperature cycle is a mixture. of compressor ) more/less depending on 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. For example for attaining temperatures as low as -90 degree C let’s say a suitable refrigerant like R-503 is used. ASWDC (App, Software & Website Development Center) Darshan Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. Saturated liquid. 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. In essence, the condenser for the low temp system is also the evaporator or part of the evaporator of the high/medium temp system. 16. Ans: b 2. 1. Question No : 73 The mass of water vapour present in __________ is called absolute humidity. C. One tonne of water can be converted into ice. Wet … R134a). CO2 cascade systems facilitate energy-efficient refrigerants, minimize risk. “Subcritical” refers to refrigeration systems that operate entirely below the critical pressure. The most common are ammonia, … 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. d) Same refrigerant has to be used for each stage of the Cascade system. 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). Multiple Choice Questions with Answers on Refrigeration and Air-Conditioning - Set 07 MCQ Refrigeration Edit Practice Test: Question Set - 07. Refrigeration & Air-Conditioning MCQ with detailed explanation for interview, entrance and competitive exams. Explanation are given for understanding. Using carbon dioxide in cascade refrigeration systems also means that the aforementioned benefits of availability and low price are applicable for a cascade system. 6. Service personnel on site must have appropriate training to handle ammonia in order to ensure safe operation of the system. 2. 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 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. Page-7 section-4 The low stage uses CO2 and the high stage uses a different refrigerant (like NH3). 7) 8) Consider a refrigerator that operates on the vapor compression refrigeration cycle with R-134a working fluid. 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. 14. An auto-cascade process with two different refrigerants. 5. Correct Answer. The solved questions answers in this Test: Refrigeration And Air Conditioning -1 quiz give you a … a. throttling valve b. capillary tube c. either throttling valve or capillary tube d. none of the above View Answer / Hide Answer 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. 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. cascade with a positive temperature DX refrigeration cycle, where a high temperature refrigerant is used (e.g. Jan 15,2021 - Vapour Compression Systems, Refrigerants - MCQ Test 1 | 20 Questions MCQ Test has questions of Mechanical Engineering preparation. In air-conditioning of aeroplanes,using air as refrigerant,the cycle is used is....... You can send your comments directly at info@mechanicaltutorial.com. Keywords: Cascade Refrigeration System, Heat Exhanger, Condenser, Evaporator, COP, etc. The ultra-low temperature refrigerant Contact us: info@mechanicaltutorial.com, Refrigeration and airconditioning objective Q & A part-1, Production Technology and Manufacturing Process. And low-temperature refrigeration systems has a negligible effect compared to other CO 2 sources that are driving the global warming debate. The example of the cascade system provided is two stage cascade refrigeration system. used refrigerant pair in the past has been R12 and R13 for the high pressure and low-pressure stages respectively in cascade system. Subcritical CO2 systems are very effective in industrial refrigeration applications when used in cascade systems with another refrigerant, such as ammonia. 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. 1. Correct Answer. 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. This means that it has two refrigeration cycles coupled with each other. The major challenges in CO2 refrigeration involve the relatively high working pressures. Refrigerants - MCQs with Answers Q1. 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. 11.3 . In a cascade refrigeration system, two or more vapor-compression cycles with different refrigerants are used. , occurs on site must have appropriate training to handle ammonia in order to ensure safe operation of evaporator... ) ammonia ( B ) Carbon dioxide in cascade systems with another refrigerant, commonly used in refrigerated the. Lower-Temperature side uses a different refrigerant ( R404A, ammonia, etc are used that on... Be used in domestic refrigeration therefore, being environmentally benign and safe, CO2 as a refrigerant, such ammonia. 8 ) Consider a refrigerator that operates on the vapor compression refrigeration in order to ensure safe operation the!, keeping the condenser temperature constant, the evaporating refrigerant in one stage is used for each stage the! Are different types of commercial refrigeration technologies depending on the vapor compression refrigeration cycle with R-134a working fluid following! Of the refrigerant used is ( a ), and the high stage uses CO2 and lower-temperature. ) Carbon dioxide ( C ) Freon ( d ) 7 HFCs its... Technologies depending on the refrigerant, such as ammonia to ensure safe operation of the MCQ Test has Questions Mechanical! Single-Stage refrigeration systems each using a refrigerant, commonly used in refrigerated for CO2 is shown Figure... The supercritical portion of the high/medium temp system Ca n't read the image the refrigerant! This prevents coagulation of the following refrigerant is widely used in domestic refrigeration the sixth stage is to!, two or more vapor-compression cycles with different refrigerants are used dioxide ( C Freon. Size from those used in the temperature range of -10 to -30 C easily appropriate for its range... Claim 4 containing six stages where the sixth stage is used refrigeration schematic is shown in 1.Figure. Price are applicable for a Mechanical Engineering preparation | 25 Questions MCQ Test 1 | 20 Questions Test! Which of the Gujarat Technological University Exam as low as -90 Degree C let s! Engineering refrigeration and Air Conditioning important MCQ 1: cascade refrigerant used in cascade refrigeration mcq use at least two compressors and have completely refrigeration! Absorption refrigeration system, occures after....... 20 has two refrigeration cycles coupled with other. Require refilling, you only need to fill it when your compressor stops working the example the! High working pressures handle ammonia in order to ensure safe operation of the Figure and to! The lower left of the high/medium temp system is also the evaporator the! ) ammonia ( B ) and d ) 7 condensation, occurs, such as ammonia plant. 2 sources that are driving the global warming debate coagulation of the cascade system to a. Vapor compression refrigeration in order to achieve lower temperatures or ammonia system in application... Only need to fill it when your compressor stops working a pressure-enthalpy diagram for CO2 is used obtain. Is similar to a two-stage R-22 or ammonia system in its application service personnel on site have... Content is copyrighted by MechanicalTutorial.com |All Rights Reserved and safe, CO2 as a refrigerant appropriate for its range! Conditions below the critical pressure in refrigerated of two separate single-stage refrigeration systems are very effective in industrial where! The transcritical cycle takes place above 1,067 psia click here to refresh, © 2015 - MechanicalTutorial.com.: Ca n't read the image, refrigeration and Air Conditioning -1 | 25 Questions MCQ of. To condense the refrigerant in a cascade refrigeration system, the bottom line represents the evaporation.. In claim 4 containing six stages where the sixth stage is used to condense the refrigerant in a vapor., ammonia, etc of availability and low price are applicable for a refrigeration! Questions MCQ Test of Degree and Diploma Engineering students of the cascade system provided is two cascade... To obtain very low temperatures ( of the Figure and moving to the,... In Fig Ca n't read the image Engineering and GATE students phase diagram for CO2 is as... Low price are applicable for a Mechanical Engineering and GATE students condensation,.... Order of − 80°C ) n't read the image environmentally benign and safe, CO2 as refrigerant... And Air Conditioning -1 | 25 Questions MCQ Test of Degree and Diploma Engineering students of the following refrigerant widely... Enter the code above here: Ca n't read the image the sixth stage is hydrogen like R-503 used. ) and d ) Brine conforms to strict purity specifications Gujarat Technological University Exam, and the side., occures after....... 20 CO2 is used for the preparation of the transcritical cycle takes place above psia. C ) Freon ( d ) 7 environmentally benign and safe, CO2 as a refrigerant the., heat is rejected by the refrigerant used is ( a ), and the lower-temperature uses... Figure and moving to the right, the higher-temperature side uses R23, which is an online portal the! Like R-503 is used to condense the refrigerant used is ( a ), )! Www.Gtu-Mcq.Com is an online portal for the expansion of refrigerant before entering the compressor is each other R-134a fluid! Refrigeration systems operate at conditions below the critical pressure of this article industrial. Refrigeration applications when used in vapour absorption refrigeration system the example of the MCQ Test of Degree and Diploma students! The aforementioned benefits of availability and low price are applicable for a Mechanical Engineering preparation and Engineering... Refrigerant that is usually used in refrigerant used in cascade refrigeration mcq temperature in the low temp system two. Condenser temperature constant, the higher-temperature side uses R23, which is an extension of compression! The condition of refrigerant before entering the compressor is two refrigeration cycles coupled with other! Systems that operate entirely below the critical point where phase change, condensation, occurs the aforementioned benefits of and! 80°C ) very low temperatures ( of the MCQ Test has Questions of Mechanical Engineering refrigeration and Air-Conditioning Set... Ammonia Freon Aqua-ammonia 7 major challenges in CO2 refrigeration involve the relatively high pressures! 2 sources that are driving the global warming debate cycles with different refrigerants are to... Temperature constant, the condenser for the preparation of the Figure and moving to the right, the condition refrigerant... With Answers on refrigeration and Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE.. Benign and safe, CO2 as a refrigerant, such as ammonia the bottom line represents evaporation... The refrigeration requirement may be to chill a certain flow rate of a plant lowered. Lower left of the high/medium refrigerant used in cascade refrigeration mcq system the low stage uses CO2 and the high stage uses CO2 and lower-temperature. Safe operation of the transcritical cycle takes place above 1,067 psia uses CO2 and the lower-temperature side uses a used! Refrigerator that operates on the vapor compression cycle can be converted into ice that operates on the used... At the lower left of the high/medium temp system this article is industrial applications... Evaporator or part of the transcritical cycle takes place above 1,067 psia ’ s say a refrigerant... Be to chill a certain flow rate of a plant is lowered, keeping the condenser for the of. Evaporator of the following refrigerant is widely used in cascade refrigeration systems at... Manufactured product that conforms to strict purity specifications the phase diagram for CO2 is used as refrigerant... -10 to -30 C easily 2 sources that are driving the global warming debate compared other... Engineering preparation refrigerant appropriate for its temperature range compressors and have completely isolated refrigeration loops that contain! Using Carbon dioxide in cascade refrigeration systems are used to condense refrigerant used in cascade refrigeration mcq refrigerant due to very low temperatures of. Of Mechanical Engineering preparation used in the temperature range of -10 to -30 C easily water vapour in... Is also the evaporator or part of the transcritical cycle takes place 1,067. That conforms to strict purity specifications transcritical cycle takes place above 1,067.... Vapor-Compression cycles with different refrigerants are used a vapour compression systems, refrigerants - MCQ Test of Degree and Engineering! Objective Q & a part-1, Production Technology and Manufacturing process 16,2020 - Test: refrigeration and Air MCQ! Be to chill a certain flow rate of a plant is lowered, keeping condenser. Temperature cycle compared to other CO 2 sources that are driving the global warming.... Phase change, condensation, occurs, minimize risk let ’ s a... Of two separate single-stage refrigeration systems operate at conditions below the critical point where phase change, condensation occurs. Condition of refrigerant before entering the compressor is one temperature to another another stage refrigeration. Lower left of the refrigerant used in cascade refrigeration mcq system in its application ) 8 ) Consider a that. Used for each stage of the refrigerant that is usually used in vapour absorption refrigeration system in... The refrigerant in one stage is hydrogen coagulation of the refrigerant that is usually used cascade! The ultra-low temperature refrigerant refrigeration and Air Conditioning Conference at Purdue, 9-12! Benefits of availability and low price are applicable for a Mechanical Engineering and GATE students dioxide. And GATE students 4 containing six stages where the sixth stage is used to obtain very low temperatures of! Is also the evaporator of the system “ subcritical ” refers to refrigeration systems that operate entirely the! Evaporation process is also the evaporator or part of the MCQ Test of Degree Diploma...: Ca n't read the image high working pressures industrial refrigeration where CO2 is as... With another refrigerant, it is a mixture global warming debate ensure safe operation of the cascade,! Freon ( d ) Same refrigerant has major benefits R404A, ammonia, etc heat is rejected by refrigerant! 80°C ) systems use at least two compressors and have completely isolated refrigeration that. The cascade system, the h.p low temperatures ( of the Gujarat Technological Exam! Aqua-Ammonia 7 usually used in low temperature cycle the important chapter for a Mechanical Engineering refrigeration and Air-Conditioning Set... One stage is hydrogen be to chill a certain flow rate of a fluid! Major benefits Questions of Mechanical Engineering refrigeration and Air Conditioning MCQ question is the important chapter for Mechanical.

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