© Chary Publications Pvt. If an expansion tank was installed as part of the retrofit from the original CFC to R-23, the charge amount will have to be adjusted accordingly. It should not make the materials unfit of consumption in the event of leakage. MCQ_REFRIGERANTS Refrigerant in a refrigeration system is lie blood circulation in the human body. D. There is 1 refrigerant circuit and only 1 type of refrigerant. Transcritical or subcritical CO2 refrigeration systems are common in Europe and Asia, and they’re gaining popularity in the Americas. Set 02. Mechanical Engineering Refrigeration and Air Conditioning Important MCQ 1. R-23 conversions to Suva 95 There are 2 refrigerant circuits and only 1 type of refrigerant. R-23 could be and has been used alone, but Suva 95, an azeotrope of R-23 and R-116, has superior properties. Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. (Ans:b), Pressure of refrigerant in the evaporator should be particular refrigerant s are used due there suitable difference in boiling point for the desirable outcome from the system. Thus, a cascade of two refrigeration systems is used and called cascade system. A cascade refrigeration cycle is a multi-stage thermodynamic cycle. Refrigerants - MCQs with Answers Q1. The expansion tank will not have to be replaced. (a) Refrigerant – 22 Ans: b 2. (k) Freon-22 In a Carnot vapor refrigeration cycle refrigerant R - 134a is used as the working fluid. (b) Cooled in the evaporator Example: at –120°F (–84°C), the suction pressure for R-23 will be 3.9 in Hg vacuum (90 kPa). 2. (d) None Note: If the system contains a cap tube that is difficult to access, it may not make economic sense to convert to Suva 95 – if the cap tube has to be adjusted or replaced. (d) None This system is employed to obtain temperatures of -40 to -80°C or ultra-low temperatures lower than them. Natural refrigerants with relatively small amount of charge can be used as a refrigerant in the autocascade refrigeration system. COP for Refrigerants using Economiser and Cascade cycles 1Moiz Mansur Bookwala , 2Sonali Bhattacharjee 3Arvind Prasad 1,2.3 Department of Chemical Engineering, DJ Sanghvi College of Engineering, Mumbai 400056, India Abstract: Refrigeration is one of the most commonly used unit operations in the chemical industry. (a) Cooled by the water Solutions for CO 2 in industrial refrigeration. (Ans:c), Latent heat is highest for If a POE lubricant is being used with the R-23, it does NOT have to be replaced when converting to Suva 95. Industrial refrigeration is the first area where CO 2 has made a successful comeback. For the low-temperature circuit, a high-pressure refrigerant with a high vapour density (even at low temperatures) is chosen. 1. (c) Equal to the temperature required (Ans:b), Which is the tertiary refrigerant in central air conditioning plant Also, the service technician should have a thorough understanding of the system design and operation. Wet compression is _____. Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. B. It should not make the materials unfit of consumption in the event of leakage. Home MCQ Refrigeration Multiple Choice Questions with Answers on Refrigeration and Air-Conditioning ... Water is used as a refrigerant and lithium bromide as an absorbent (C) Ammonia is used as a refrigerant and lithium bromide as an absorbent (D) None of the above. View All Answers. (a) Heated in the evaporator Q. it must be cheap and available in abundance. Due to the higher operating pressure of Suva 95, the dump valve setting should be increased to about 290 psig. (d) None (c) Freon-22 (a) Greater than the temperature required Cascade refrigeration is a term you will hear more and more over the coming years, and while some of the systems may be very complex, the concept is actually pretty simple. The pressure for Suva 95 will be 3 psig (122 kPa). The most commonly used refrigeration cycle is the ‘Vapour … mcq for refrigeration and air conditioning, mcq in refrigeration and air conditioning, mcq on refrigeration and air conditioning, ... may increase or decrease depending on the type of refrigerant used (d) remain unaffected (e) unpredictable. Suva 95 should also be considered for replacing R-23 in existing systems. (c) Cooled by the primary refrigerant A.Open cycle B.Closed cycle C.Mixed cycle D.Hybrid cycle . The objective of this article is to provide general retrofit guidelines and items for consideration when planning a conversion to Suva 95. Refrigerant should be non-corrosive, non decomposable, non-toxic and inert to the materials of construction. Dec 16,2020 - Test: Refrigeration And Air Conditioning -1 | 25 Questions MCQ Test has questions of Mechanical Engineering preparation. In process (2-3) low side refrigerant is compressed isentropic ally and increases the temperature and pressure. Reciprocating compressors are used with refrigerants with high pressure and small volumes of suction vapour. Q2. which will improve your skill. T-S diagram of cascade refrigeration system In the particular system HC is used as low side refrigerant and R134a is used as high side refrigerant. 14. (c) < Cv of air Some refrigerants are well suited for high and medium temperature applications, and some are better suited and for a lower temp applications. C. There is 1 refrigerant circuit and 2 different refrigerants. (a) Equal to the atmospheric pressure (l) None (d) None (Ans:c), Which is the secondary refrigerant in central air conditioning plant (a) Water Solutions for CO 2 in industrial refrigeration. Set 08. 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. Pick up the wrong statement. Cascade Refrigeration Three-Stage Refrigeration of methane Two-Stage Refrigeration of ethylene Three-Stage Refrigeration of propane Multi-Stage Cascade Refrigeration Cycle & Results 02/33. (b) Water (b) Ammonia … Cascade systems are often unique and sometimes complex in their design. These two systems are thermally connected by a cascade condenser in which the condenser of the lower system becomes the evaporator of the higher system as the higher system’s evaporator takes on the heat released from the lower system’s condenser. It is tertiary in a central air conditioning, Refrigerant used should be such that its normal boiling point is (Ans:c), Specific heat at constant pressure is highest A high pressure ratio implies high discharge and oil temperatures and low volumetric efficiencies and, hence, low COP values. The compressor discharge temperature is significantly lower than the discharge temperature of compressors using R-23. (Ans:c) (Ans:d), Secondary refrigerant is one which is As most of you know each refrigerant has its upsides and downsides. Gong et. Suva 95 offers excellent operating characteristics when compared with R-503 and R-13. One Stop Solution Service Provider for all kind of Refrigerant Gas & Motor Capacitor Products. (b) Ammonia Ltd., Vashi, Navi Mumbai | All rights reserved, Cooling India Monthly Business Magazine on the HVACR Business | Green HVAC industry | Heating, Ventilation, Air conditioning and Refrigeration News Magazine Updates, Articles, Publications on HVACR Business Industry | HVACR Business Magazine, PROPANE-OPTIMISED CONDENSER FROM ALFA LAVAL, EFFICIENT ENERGY’S LARGER-CAPACITY WATER-ONLY eCHILLER120, Quality Cooling and Sustainable Performance, Residential HVAC Market: Recovery route from COVID-19, Aircuity introduces AQaaS for safer building re-openings, Facilio and Belimo for IoT-driven Connected Building Environments. It consists of two separate single-stage refrigeration systems each using a refrigerant appropriate for its temperature range. (i) Mercury A cascade system consists of two separate single-stage refrigeration systems – each using a refrigerant appropriate for its temperature range. Thus, a cascade of two refrigeration systems is used and called cascade system. This test is Rated positive by 86% students preparing for Mechanical Engineering.This MCQ test is related to Mechanical Engineering syllabus, prepared by Mechanical Engineering teachers. Refrigerant in a refrigeration system is lie blood circulation in the human body. So, natural refrigerants are increasing used in low temperature refrigeration system. (Ans:b), Which is the secondary refrigerant in an window air conditioner Two systems comprise a lower system that maintains lower evaporating temperatures and a higher system that operates at higher evaporating temperatures. The most commonly used refrigerant in refrigerators is R 134a which is tetrafluoroethylene, which does not deteriorate ozone layers. (d) None These gases do not require refilling, you only need to fill it when your compressor stops working. (k) Air Refrigeration and Air Conditioning, Mechanical Engineering Multiple Choice Questions / Objective type questions, MCQ's, with question and answers, download free PDF, Mechanical Engineering, Multiple Choice Questions, Objective type questions, Mechanical … (b) Cooled by the air (c) Freon- 22 Ans: a; Which of the following refrigerants has lowest freezing point (a) Freon-12 (b) NH3 (c) C02 (d) Freon-22 (e) S02. The cascade refrigeration system is a freezing system that uses two kinds of refrigerants having different boiling points, which run through their own independent freezing cycle and are joined by a heat exchanger. Suva 95 offers higher capacity and efficiency and significantly lower compressor discharge temperature. C. One tonne of water can be converted into ice. A cascade system typically operates with evaporator temperatures between –40°F and –150°F (–40°C and –100°C). Set 09. CO 2 in industrial refrigeration is used either as the low-stage refrigerant in cascade installations, or as a secondary coolant. (a) > Cv of air (Ans:c), Click to share on Twitter (Opens in new window), Click to share on Facebook (Opens in new window). Alternatively, refrigeration capacity per unit volume of suction vapour may be used to estimate how large is the compressor required for same refrigeration capacity for different refrigerants. Numbers of researchers have evaluated the thermodynamic performance of the two stage cascade refrigeration systems. Which one acts as a primary, secondary as well as a tertiary refrigerant   It causes cooling by latent heat of vaporization. If the system is equipped with liquid injection, the valves will need to be ‘throttled back’ to reduce the flow. Refrigerant should be non-corrosive, non decomposable, non-toxic and inert to the materials of construction. (c) Neither heated in evaporator nor cooled in condenser 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 (Ans:d), Which one acts as a primary, secondary as well as a tertiary refrigerant (Ans:a), Which is the secondary refrigerant in an ice plant The thermodynamic properties for the refrigerant are given below. Set 04. Refrigerant R143a is used in automobile air conditioning which is trifluoroethane and R22 of room A / C is used for chlorodifluoromethane. 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. CO 2 in industrial refrigeration is used either as the low-stage refrigerant in cascade installations, or as a secondary coolant. (d) None (b) Vapor Ammonia Set 10. 15. (k) Freon-22 December 25, 2019 BILAL KHATTAK 0 . (d) None (h) None In a cascade refrigeration system, two or more vapor-compression cycles with different refrigerants are used. (Ans:c), Specific heats at constant pressure and at constant volume are equal Vapour Compression Refrigeration Cycle - MCQs with Answers Q1. Ltd. | Cooling India Magazine on HVACR Industry | Powered by: 360digital Hub Pvt. In a domestic vapour compression refrigerator, the refrigerant commonly used is (A) CO ₂ (B) Ammonia (C) R-12 (D) All of these. (j) Brine solution (d) None This refrigerant is then passed The refrigerant enters the condenser as saturated vapor at 28 0 C and leaves as saturated liquid. (j) Water [17] conducted comprehensive thermodynamic analyses on mixed-gases refrigeration cycles including the autocascade refrigeration cycle, and indicated that the mixed refrigerant is the most important designing parameter in the design of such … (Ans:d), Which is the secondary refrigerant in an ice plant The schematic view and the P-h diagram of this system are shown below. ANSWER: c. either throttling valve or capillary tube . Set 01. Q4 : A cascade refrigeration system is designed to supply 10 tonnes of refrigeration at an evaporator temperature of -40°C and a condenser temperature of 36°C. (b) Ammonia (d) None The application of transcritical R-744 systems is one example and another example is the cascade system. In addition, Suva 95 will maintain a positive suction pressure at lower evaporator temperatures than R-23. Typical refrigerants for the high-temperature system include R-22, and R-404A. It consists of two separate single-stage refrigeration systems each using a refrigerant appropriate for its temperature range. (a) Air (c) Freon-22 (i) Air R-503, R-13, and R-23 performance parameters are shown for comparison. Parekh et al., (2012) CASCADE REFRIGERATION SYSTEM WITH ALTERNATIVE REFRIGERANTS Mr. PARTHIBAN KASI Assistant Professor, Department of Mechanical Engineering, Velammal Institute of Technology, Chennai, India ABSTRACT The main aim of this project is to analyses the cascade refrigeration system by employing various alternative refrigerant pairs and choosing the best pair for higher temperature … (a) Water Set 07. (c) Greater than the atmospheric pressure (c) Water vapors 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 (b) Air One tonne of refrigerant is used. 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Is often employed for devices such as ULT freezers one tonne of water can be converted ice! To environment and GWP and ODP is negligible and do not violate the kyoto protocol know each refrigerant its... ( 90 kPa ) temperatures, single-stage compression systems with reciprocating compressors are used azeotrope R-23! For chlorodifluoromethane researchers have evaluated the thermodynamic properties for the refrigerant is also considering due to environmental safety their.! The discharge temperature is significantly lower than them MCQ_REFRIGERANTS refrigerant in refrigerators is R 134a which trifluoroethane. For all kind of refrigerant Gas & Motor Capacitor Products MCQs with Answers Q1 R-23 will 3... Is significantly lower than the discharge temperature of compressors using R-23 tube d. none of the system and... Suction vapour lie blood circulation in the human body in process ( 2-3 ) low refrigerant... Non-Toxic and inert to the materials of construction will need to fill when! Gate students most commonly used refrigerant in a Carnot vapor refrigeration cycle - MCQs with Answers Q1 refrigeration is for... Will be 3.9 in Hg vacuum ( 90 kPa ) on mobile ) the cascade cycle given. Parameters are shown in Table 1, but Suva 95 has about 25 higher...