EduRev is a knowledge-sharing community that depends on everyone being able to pitch in when they know something. Only liquid is then passed to evaporator and the vapors will be passed to the compressor directly. View Answer. In a mechanical refrigeration system the refrigerant occurs as liquid (or very wet vapour) between ; The condition of refrigerant before and after the expansion or throttle valve in a vapour compression system is ; Post navigation. This flash chamber between the condenser and evaporator is known as flash intercooling. A part of the high-pressure liquid … 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. b. to reduce the mass of vapour formed during expansion process, c. to reduce vapour bubbles which obstruct the flow of liquid refrigerant. Which of the following statement is true for a condenser? The values of enthalpy at the beginning of compression, at the end of compression and at the end of condensation are 185 kJ/kg, 210 kJ/kg and 85 kJ/kg respectively. Ans: a. The highest temperature during the cycle, in a vapour compression system, occurs after. The most common is the soap-bubble method. Vapour Compression Refrigeration System: Analysis of simple vapour compression Refrigeration cycle by p-h and T-S diagram. Q13. As fluid flow through capillary its velocity increase as per continuity eqation (AV=const).hence conversion of pressure energy into kinetic energy takes place. Throttling process can be done by capillary tube.Working fluid is flow through capillary tube. Compression. Explanation: These are a group of halogenated hydrocarbons. Under the MYCOM brand, Mayekawa’s compressors are used worldwide in industrial refrigeration and freezing, heat pumps, and gas markets. Which device is used for the expansion of refrigerant in vapour compression refrigeration cycle? Refrigerants , are chemical compounds that are alternately compressed and condensed into a liquid and then permitted to expand into a vapor or gas as they are pumped through the mechanical refrigeration system to cycle. b) genetron (D) all of the above, Q25.The process of undercooling is generally brought about by Question: P Flag Question In Compound Vapor Compression Refrigeration System, Complete Desuperbeating Of The Vapor Is Not Possible In Case Of Select One: Vapor Refrigerant Intercooling Liquid Subcooling Liquid Refrigerant Intercooling Water Intercooling c) large installations use air-cooled condenser Since for isentropic compression process. In this video I explained the MCQ, true false type MCQ with solution and description of answer for a chapter Air refrigeration system of refrigeration and air conditioning. Explanation: Here C is the clearance and p1,p2 are pressures. In refrigeration systems, two or more compressors are connected in series, figure 3-11. Effect of operating conditions 5 Multiple Evaporator and compressor system: Application, air compressor system, Individual compressor, compound compression, cascade system. The refrigeration compressor in a water cooled refrigeration system is short cycling on the high pressure cutout switch. Q22.The most widely used refrigerants are Both the gills and the lung are present in which of these. Answer: d (D) any of the above What is the principle of refrigeration? Question 49. What is the result of superheating of vapour at the evaporator outlet? During a refrigeration cycle, heat is rejected by the refrigerant in a, 2. A standard ice point temperature corresponds to the temperature of (a) water at 0°C (b) ice … Using SCORG on refrigeration and air-conditioning compression alone and reducing their energy consumption by up to 6%, can lead to a potential saving of at least 1.5% of US total energy consumption. 4.The amount of heat exchanged in condenser and evaporator are equal under steady conditions. MCQ No - 1. Reduces work done per kg of air C. Reduces cost of compressor D. Gives more uniform torque E. All of the above The multi stage compression as compared to single stage compression..... A. View Answer. Edit. 15. The required input is the work input, W ref. 5. c) (p1*p2)/(p1+p2) Only liquid is then passed to evaporator and the vapors will be passed to the compressor directly. The pumping work in the former is negligible since specific volume of strong liquid solution is small. All such systems have four components: a compressor, a condenser, an expansion valve (also called a throttle valve or meteric device) and an evaporator. The latter uses an absorber while former uses a generator. While a 65° return vapor temperature may be satisfactory for high-temperature applications and, perhaps, some medium-temperature … We also offer a full lineup of environmentally-friendly compressors that use natural refrigerants. 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 Engineering short notes, rapid fire notes, best theory d. none of the above The Following Section consists Multiple Choice Questions on Basic Mechanical Engineering. In a vapour compression system, the condition of refrigerant before entering the compressor is. a. no liquid droplets will travel to the compressor, b. the compressor discharge temperature increases. In a vapour compression system, the lowest temperature during the cycles occurs after, 5. The result is … So for same heat transfer temperature difference will be high, The power required for the compressor in kw is, Explanation : Since power is required for compressor in refrigeration is in compression cycle (1-2), Hence, Power required = m (h2 -h1) = mo (h2 -hf). 2. - ∆KE= 0 ( velocity will change but it is negligible). This reduced pressure will produce flash evaporation and some part of refrigerant will evaporate by its own heat energy. Name the essential parts of … No. MCQs of Vapour Compression System. c. either throttling valve or capillary tube, ANSWER: c. either throttling valve or capillary tube, a. more dangerous than the dry compression in vapour compression refrigeration system, b. less dangerous than the dry compression in vapour compression refrigeration system, c. equally preferable in vapour compression refrigeration system, ANSWER: a. more dangerous than the dry compression in vapour compression refrigeration system. (A) improve overall heat transfer coefficient 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. US2140415A US140534A US14053437A US2140415A US 2140415 A US2140415 A US 2140415A US 140534 A US140534 A US 140534A US 14053437 A US14053437 A US 14053437A US 2140415 A US2140415 A US 2140415A Authority US United States Prior art keywords oil compressors compressor conduit crankcase Prior art date 1937-05-03 Legal status (The legal status is an assumption and is not … The coefficient of performance is quite high. If compression or expansion of gas takes place with no flow of heat energy either into or out of the gas , the process is said to be isentropic process and it is reversible in nature . So, During the throttling process, heat absorption capacity at a cons. This arrangement provides the means for cooling of fluid between stages, and thus compression work is reduced. Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. 4. Q9. Answer: d Part 1: List for questions and answers of Refrigeration and Air Condi tioning. A large percentage of compressor failures in low-temperature vapor-compression refrigeration system applications originate from overheating. Oil separator is NOT required in refrigeration system if: Refrigerant and oil are immiscible at all pressures and temperatures, Refrigerant and oil are immiscible at condensation pressure and temperature, Refrigerant and oil are miscible at all pressures and temperatures. Freon 12 is a compound consisting of stoms of: A. Adsorption refrigeration is regarded as because it can be driven by low-grade heat and use natural refrigerants. Mechanical Engineering Handbook. ANSWER: b. throttle valve, Q12. a) p1*p2 Q10. c) both of the mentioned Desirable Properties of an ideal Refrigerant. When the exhaust pressure is higher than 2.5MAPa, two compressors can be adopted, which are driven by two main motors. Q1. Subject: Refrigeration and Air Conditioning 1. Mechanical Engineering MCQ Question Papers: DRDO, ISRO, Interview . The main components are shown in Fig. Ribas et al. Dry saturated liquid. E). The correct sequence of vapour compression (VC), vapour absorption (VA) and steam ejector (SE) refrigeration cycles in increasing order of the COP is: The correct sequence of VC, VA and SE in increasing order of COP is VA, SE and VC, the Value being of the order of 0.3 to 0.4 0.5 to 0.8 and 4 to 5 respectively. Module 6 Vapour Absorption Refrigeration System Lesson 22 … Which of the following refrigerant is highly toxic and flammable? Explanation: Because of these reasons we have to use multistage compression with intercooling. How is the condensation process in vapour compression refrigeration cycle carried out? MCQ … Refrigeration and Air Conditioning Multiple Choice Questions :-1. Reason (R): It is almost impossible for Freon-12 leakage to attain a fatal concentration. a) it increases the pressure of refrigerant Match List-I (Refrigerant) with List-II (Designation) and select the correct answer using the codes given below the lists: Theoretical vapour compression refrigeration cycle is represented on a T-s diagram as. Air cooling is used for freon compressors whereas water jacketing is adopted for cooling ammonia compressors. View Answer. Air-Conditioning and Refrigeration. It improves the volumetric efficiency for the given pressure ratio.. A flash chamber is a device which separates liquid from vapors. Expansion valve: c. Evaporator: d. Compressor: Check my answer! Of accumulation of lubricating oil in condenser. 4BEngineers allows students to be thorough with their choice of streams or subjects, by enabling them to learn at their comfortable time without losing out on sessions and conveniently access sessions from any given place. The general rule for rating refrigeration systems (excepting for C02 system) is to approximate following h.p. a. to increase volumetric efficiency of of compressor, b. to allow the system to operate between higher pressures, c. to reduce risk of damage to refrigerant. This contains 30 Multiple Choice Questions for Mechanical Engineering Vapour Compression Systems, Refrigerants - MCQ Test 2 (mcq) to study with solutions a complete question bank. Heating, ventilation, and air conditioning (HVAC) is the technology of indoor and vehicular environmental comfort. Download Full PDF Package. In this video I explained the MCQ, true false type MCQ with solution and description of answer for a chapter vapour compression refrigeration system. It can be employed over a large range of temperatures. The heat required to melt 1 tonne of ice in 12 hours is equivalent to. Answer: c Q1. Of the larger superheat horn of ammonia compression cycle. READ PAPER. 9. Pick up the wrong statement. Compressor manufacturers can tell you what the maximum compression ratio is for a specific compressor, but an accepted rule is no more than a 10:1 compression ratio. 2. b) larger units Answer: b Take the Quiz and improve your overall General Knowledge. As can be seen, the liquid leaving the condenser is cooled by passing through the throttle valve, where the pressure drops, resulting in partial vaporisation of the refrigerant and a significant reduction in temperature. Enhancement of vapour compression refrigeration system (VCR) performance using greenhouse gas mixtures Saikesh Erramshettya#Barmavatu Praveenb* Venkata Manikanta Ankema Yesu Raju Uppea aMaster's in Renewable Energy Systems, Hochschule Nordhausen - University of Applied Sciences, Nordhausen, Germany-99734. How it works : Energy equation for refrigerant, (h + KE +PE )of inlet + Q - W = (h +KE +PE)of outlet. Refrigeration and Air Conditioning Mcqs for Preparation of Fpsc, Nts, Kppsc, Ppsc, and other test. Answer: d Carbon, hydrogen and fluorine: B. Q2. Multiple Choice Questions (MCQ) and Answers on Chemical Engineering Thermodynamics Question 1 : The co-efficient of performance (COP) of a refrigerating system, which is its index of performance, is defined as the ratio of useful refrigeration to the net work. 3. a) capillary tubes Please read all the important question of that chapter because the MCQ comes from only this important topic. However, in such system no subcooling of the liquid for delivery purposes is provided. c) 1 – C + C(p2/p1)^(1/n) The vapour compression refrigerator employs the following cycle This arrangement is adopted for very high compression ratio to avoid difficulties occurred in single stage compressor. Q23.1. The work done per kg of refrigerant is reduced in compound compression with intercooler as compared to single stage compression for the same delivery pressure. 7. For premium access Login / Register. In addition to this, the temperature of refrigerant gas after compression is at lower temperature in case of multi-stage compression as compared to single stage compression system. The sub-cooling in a refrigeration cycle, 6. c) both of the mentioned 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. 15. StudySite.org, Best online Subjective, Objective questions, MCQ's solution, best for any competitive examination provide best online coaching. pressure of a unit mass of refrigerant remains the same, ie. The other is the halide torch method used with fluorocarbons. Hey Readers on the off chance that you are searching for the free download Thermal Engineering R S Khurmi And J K Gupta Book Pdf then you each the ideal spot.Today group ebooksfree4u.com share with you Thermal Engineering R S Khurmi And J K Gupta Book Pdf.This book will help you in Your scholarly examination or focused examinations. Q16.For an expansion device, which of the following is true? per ton of refrigeration Vapour-compression refrigeration or vapor-compression refrigeration system (VCRS), in which the refrigerant undergoes phase changes, is one of the many refrigeration cycles and is the most widely used method for air-conditioning of buildings and automobiles. Air-Conditioning and Refrigeration. MCQ In vapor compression refrigeration system, at entrance to which component the working fluid is superheated vapor? The units of _____ and COP are the same. In milk chilling plants, the usual secondary refrigerant is: A single-stage vapour compression refrigeration system cannot be used to produce ultralow temperatures because, Refrigerants for ultra-low temperatures are not available, Lubricants for ultra-low temperatures are not available, Volumetric efficiency will decrease considerably, Heat leakage into the system will be excessive, The vapour compression refrigeration cycle is an inherently irreversible cycle, because, The condensation process is not isothermal, Of the use of expansion valve instead of an expansion engine. For entropy s = 0.95 the enthalpy h = 276.45 kJ /kg, Large latent heat of vaporisation and low operating pressures, Small latent heat of vaporisation and high operating pressures, Large latent heat of vaporisation and large operating pressures, Small latent heat of vaporisation and low operating pressures. c) the refrigerant is damaged In system A vapour are superheated by 10°C in the evaporator while in system B vapour are superheated by 10°C in a liquid vapour regenerative heat exchanger, other conditions being the same. Match List-I (T-s diagram) with List-II (P-h diagrams) of vapour compression refrigeration cycles and select the correct answer using the codes given below the lists: Replacing a water-cooled condenser with an air-cooled one in a vapour compression refrigeration system with constant evaporator pressure results in, Heat transfer co-efficient of gas very small compared to water hwater >> hair. Both A and R are individually true and R is the correct explanation of A, Both A and R are individually true but R is not the correct explanation of A. Mechanical refrigeration, is the utilization of mechanical components arranged in a "refrigeration system" for the purpose of transferring heat. d) all of the mentioned In a refrigeration cycle, the desired output is Q C, because the goal is to remove heat from the cold reservoir. Discuss the use of flash tank for flash gas removal only (Section 12.5) 7. The most common refrigeration system in use for refrigerated food transport applications today is the vapour compression system. 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