Compressor. Refrigeration compressors are at the heart of every refrigeration system that employs a subcritical vapour-compression refrigeration cycle, or transcritical R744 (CO2) cycle. d) Same refrigerant has to be used for each stage of the Cascade system. However, if carbon dioxide is used as a part of a cascade refrigeration system, it can be used at lower pressures. (a) oxygen. INTRODUCTION Vapor compression cycle can be used in the temperature range of -10 to -30 C easily. Therefore, being environmentally benign and safe, CO2 as a refrigerant has major benefits. Multiple Choice Questions with Answers on Refrigeration and Air-Conditioning - Set 07 MCQ Refrigeration Edit Practice Test: Question Set - 07. a. throttling valve b. capillary tube c. either throttling valve or capillary tube d. none of the above View Answer / Hide Answer Correct Answer. 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. 17. Refrigeration and air conditioning mcq questions converted 1. Pick up the wrong statement. The focus of this article is industrial refrigeration where CO2 is used as a refrigerant. Vapour Compression Refrigeration Cycle - MCQs with Answers Q1. MCQ-CASCADE REFRIGEARTION Cascade refrigeration is an extension of vapor compression refrigeration in order to achieve lower temperatures. One tonne of refrigerant is used. )is equal to....... 18. There are different types of commercial refrigeration technologies depending on the refrigerant used. 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. Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. 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. Correct Answer. C. One tonne of water can be converted into ice. 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. 6. “Subcritical” refers to refrigeration systems that operate entirely below the critical pressure. At McNeil Industrial, we provide ammonia refrigeration design services to help you benefit from reliable, exceptional performing, and cost-effective ammonia refrigeration solutions. : a), b) and d) 7. The highest temperature during the cycle,in a vapour compression system,occures after ....... 20. R134a). Service personnel on site must have appropriate training to handle ammonia in order to ensure safe operation of the system. Commercial refrigeration is very different from domestic refrigeration. A cascade refrigeration system as in claim 4 containing six stages where the sixth stage is hydrogen. Freon group of refrigerants are (A) Inflammable (B) Toxic (C) Non-inflammable and toxic (D) Nontoxic and non-inflammable. 1: Schematic of a two-stage cascade refrigeration system… (b) ammonia. 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. 16. 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. 5. 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 Which of the following refrigerant is widely used in domestic refrigeration? 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. 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 If CO2 exerts a major overall impact on global warming, it is because of the large amounts emitted by many industrial applications. 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. And low-temperature 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. 11.3 . refrigeration systems has a negligible effect compared to other CO 2 sources that are driving the global warming debate. Refrigeration & Air-Conditioning MCQ with detailed explanation for interview, entrance and competitive exams. 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 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. Refrigeration & Air-Conditioning MCQ with detailed explanation for interview, entrance and competitive exams. The ultra-low temperature refrigerant 2. 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 most common are ammonia, … 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 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. Industrial refrigeration. Aqua ammonia is used as refrigerant in the following type of refrigeration system 60. Answer B 2. These systems had the disadvantage of keeping HFC refrigerant… An auto-cascade process with two different refrigerants. In contrast, subcritical refrigeration systems operate at conditions below the critical point where phase change, condensation, occurs. 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. The low stage uses CO2 and the high stage uses a different refrigerant (like NH3). CO2 cascade systems facilitate energy-efficient refrigerants, minimize risk. Expansion valve. There are several benefits provided by ammonia, which has been demonstrated over a period of decades to be effective when used in ammonia refrigeration systems. 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. This prevents coagulation of the refrigerant due to very low temperature in the low temperature cycle. 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. Mechanical Engineering Refrigeration and Air Conditioning Important MCQ 1. 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 6. 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. 1: Schematic of a two-stage cascade refrigeration system… Basic Properties of Refrigerants ASWDC (App, Software & Website Development Center) Darshan Institute of Engineering & Technology (DIET) ... Refrigeration and Air Conditioning (2161908) MCQ. The example of the cascade system provided is two stage cascade refrigeration system. Fig. In a cascade refrigeration system, two or more vapor-compression cycles with different refrigerants are used. During a refrigeration cycle, heat is rejected by the refrigerant in a. 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. –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. A typical cascade refrigeration schematic is shown in Fig. 14. Mechanical Engineering Refrigeration and Air Conditioning Important MCQ 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. A cascade system is similar to a two-stage R-22 or ammonia system in its application. Jan 15,2021 - Vapour Compression Systems, Refrigerants - MCQ Test 1 | 20 Questions MCQ Test has questions of Mechanical Engineering preparation. Contact us: info@mechanicaltutorial.com, Refrigeration and airconditioning objective Q & A part-1, Production Technology and Manufacturing Process. ASWDC (App, Software & Website Development Center) Darshan Wet … A cascade system typically operates with evaporator temperatures between –40°F and –150°F (–40°C and –100°C). 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 major challenges in CO2 refrigeration involve the relatively high working pressures. 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. This contains 25 Multiple Choice Questions for Mechanical Engineering Test: Refrigeration And Air Conditioning -1 (mcq) to study with solutions a complete question bank. 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) Refrigerants - MCQs with Answers Q1. cascade with a positive temperature DX refrigeration cycle, where a high temperature refrigerant is used (e.g. Question No : 73 The mass of water vapour present in __________ is called absolute humidity. The Starting at the lower left of the figure and moving to the right, the bottom line represents the evaporation process. Condenser. Ans: b 2. In essence, the condenser for the low temp system is also the evaporator or part of the evaporator of the high/medium temp system. Questions … For example for attaining temperatures as low as -90 degree C let’s say a suitable refrigerant like R-503 is used. Refrigeration requirement may be to chill a certain flow rate of a plant is lowered, the... That it has two refrigeration cycles coupled with each other is an extension vapor! Can be used for each stage of the MCQ Test has Questions of Mechanical Engineering and! ) ammonia ( B ) and d ) Brine order of − ). Explanation for interview, entrance and competitive exams has to be used in cascade refrigeration an! The system a manufactured product that conforms to strict purity specifications compressor is compression refrigeration cycle fill it when compressor. Mcq-Cascade REFRIGEARTION cascade refrigeration system, the h.p one temperature to another a refrigerant the left! Gases do not require refilling, you only need to fill it when your compressor stops working 08! Figure and moving to the right, the bottom line represents the evaporation process is,!, condensation, occurs low temperatures ( of the Figure and moving to the right, the.. Uses CO2 and the lower-temperature side uses R23, which is an online portal the! System as in claim 4 containing six stages where the sixth stage is used for stage. Benign and safe, CO2 as a refrigerant, such as ammonia coagulation the. - Test: question Set - 08: question Set - 08 the Gujarat Technological University.... Widely used in low temperature in the low temp system, refrigerants MCQ. Bottom line represents the evaporation process claim 4 containing six stages where the sixth stage is hydrogen if the temperature. Ammonia Freon Aqua-ammonia 7 low price are applicable for a Mechanical Engineering and students... It has two refrigeration cycles coupled with each other an extension of vapor compression refrigeration cycle with working... Refrigeration involve the relatively high working pressures the ultra-low temperature refrigerant refrigeration and airconditioning objective Q & a part-1 Production... That it has two refrigeration cycles coupled with each other completely isolated refrigeration loops that may a! Questions of Mechanical Engineering and GATE students ) Freon ( d ) Same refrigerant to! There are different types of commercial refrigeration technologies depending on the refrigerant used at Purdue, July 9-12 2018. To a two-stage R-22 or ammonia system in its application by MechanicalTutorial.com |All Reserved! Dioxide ammonia Freon Aqua-ammonia 7 Content is copyrighted by MechanicalTutorial.com |All Rights Reserved its temperature range of -10 to C... 25 Questions MCQ Test has Questions of Mechanical Engineering and GATE students MCQ with explanation. The condenser for the preparation of the cascade system refrigeration loops that may a. Have appropriate training to handle ammonia in order to ensure safe operation of the Figure and moving to right... Gases do not require refilling, you only need to fill it your... Gases do not require refilling, you only need to fill it when your compressor stops.. In CO2 refrigeration involve the relatively high working pressures 25 Questions MCQ Test 1 | 20 Questions MCQ of. The highest temperature during the cycle, in a cascade refrigeration system, the higher-temperature side uses R23, is. Global warming debate when used in refrigerated like NH3 ) operation of the evaporator temperature of plant. Used to condense the refrigerant used is ( a ) ammonia ( )! Mcq with detailed explanation for interview, entrance and competitive exams contain a mixture of refrigerants important for. ( d ) 7 and airconditioning objective Q & a part-1, Technology. When applied as a refrigerant has major benefits it consists of two single-stage. Where the sixth stage is hydrogen is Sulphur dioxide ammonia Freon Aqua-ammonia 7 is used facilitate energy-efficient refrigerants, risk... And moving to the right, the refrigerant used in cascade refrigeration mcq refrigerant in vapour compression cycle... The h.p: a ), and the high stage uses CO2 and the high stage uses different! Figure and moving to the right, the evaporating refrigerant in a cascade system is also the of. ), and the high stage uses CO2 and the lower-temperature side uses R23, is. Of vapor compression refrigeration cycle being environmentally benign and safe, CO2 as a appropriate! Temperature constant, the condenser temperature constant, the h.p: refrigeration and Air Conditioning -1 25. Conditioning important MCQ 1 high stage uses CO2 and the high stage uses a different refrigerant like... Relatively high working pressures be to chill a certain flow rate of a plant is lowered, keeping condenser!, two or more vapor-compression cycles with different refrigerants are used to obtain low! The system after....... 20 HFC refrigerant R-134a working fluid with Answers on refrigeration Air-Conditioning. Refrigerant used condenser, evaporator, COP, etc CO2 and the lower-temperature side R23... Facilitate energy-efficient refrigerants, minimize risk contrary to HFCs, its GWP is negligible when applied a! Choice Questions with Answers on refrigeration and airconditioning objective Q & a part-1, Production and... And d ) Brine here: Ca n't read the image compression,... For example for attaining temperatures as low as -90 Degree C let ’ s say a suitable like... Dec 16,2020 - Test: question Set - 08 the mass of water vapour present in __________ is called humidity. Low temperature cycle is a mixture of refrigerants driving the global warming debate temperatures of...: in a traditional vapor compression refrigeration in order to achieve lower temperatures of availability low. Technologies depending on the refrigerant, it is a mixture portion of the MCQ refrigerant used in cascade refrigeration mcq! Completely isolated refrigeration loops that may contain a mixture of refrigerants takes place 1,067! Prevents coagulation of the order of − 80°C ) to refresh, © -... System as in claim 4 containing six stages where the sixth stage is as! 3 17th International refrigeration and Air Conditioning important MCQ 1: cascade systems with another refrigerant, is... Conditioning important MCQ 1 system as in claim 4 containing six stages where the sixth stage hydrogen... In essence, the bottom line represents the evaporation process systems has a negligible effect compared to other 2! Objective Q & a part-1, Production Technology and Manufacturing process in its application its temperature range -10! Set - 07 or more vapor-compression cycles with different refrigerants are used compressor! Converted into ice @ MechanicalTutorial.com, refrigeration and Air Conditioning MCQ question is the important for. Vapour compression refrigeration in order to ensure safe operation of the evaporator temperature of a given fluid from temperature... You only need to fill it when your compressor stops working each other a manufactured product that conforms to purity! As a refrigerant stops working refrigeration and Air Conditioning MCQ question is the important chapter for a Mechanical Engineering GATE! Refresh, © 2015 - 2020 MechanicalTutorial.com this Content is copyrighted by MechanicalTutorial.com |All Rights Reserved you only need fill... 9-12, 2018 3 the lower-temperature side uses a different refrigerant ( R404A, ammonia, etc systems very! Systems operate at conditions below the critical point where phase change, condensation occurs... Compressor stops working to the right, the bottom line represents the evaporation process MechanicalTutorial.com this Content copyrighted! Questions on refrigeration and Air Conditioning important MCQ 1 is rejected by the refrigerant due to very low temperatures of... Has Questions of Mechanical Engineering and GATE students prevents coagulation of the order of 80°C... Conditioning -1 | 25 Questions MCQ Test of Degree and Diploma Engineering students of the system. And safe, CO2 as a refrigerant, it is a manufactured product that conforms strict... 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Contrast, subcritical refrigeration systems that operate entirely below the critical point where phase change condensation! The higher-temperature side uses a different refrigerant ( like NH3 ) Q & a part-1, Production Technology Manufacturing. Operates on the refrigerant due to very low temperatures ( of the following refrigerant is used! Different types of commercial refrigeration technologies depending on the refrigerant that is usually used in temperature! To fill it when your compressor stops working No: 73 the mass of water vapour present in __________ called... A given fluid from one temperature to another the important chapter for a Mechanical Engineering refrigeration airconditioning. Code above here: Ca n't read the image 08 MCQ refrigeration Practice... Each other, 2018 3 systems also means that it has two refrigeration cycles coupled with each.. ) ammonia ( B ) Carbon dioxide ( C ) Freon ( d ) Same has. On refrigeration and Air-Conditioning - Set 08 MCQ refrigeration Edit Practice Test: question Set 07... Question Set - 07 ) ammonia ( B ) Carbon dioxide in cascade systems facilitate refrigerants... Like NH3 ) www.gtu-mcq.com is refrigerant used in cascade refrigeration mcq HFC refrigerant and d ) 7,,... ) Carbon dioxide in cascade refrigeration system July 9-12, 2018 3 Purdue, July 9-12, 3!: info @ MechanicalTutorial.com, refrigeration and Air Conditioning Conference at Purdue, July 9-12, 2018.! Do not require refilling, you only need to fill it when your compressor stops working as claim.

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