Major modification required to produce temperature of – 200?C in a vapour compression refrigeration system using Freon 12 as refrigerant, is, In a vapour absorption refrigeration system the power is required for vapour compressor as compared to that in vapour compression cycle is, Agriculture Ecology and General Silviculture Mcqs, Agriculture Genetics Plant Breeding and Biotechnology Mcqs, Fluid Mechanics and Hydraulic Machines Mcqs, Forest Types and Geographical Distribution Mcqs, Temperature Distribution and Ocean Salinity Mcqs. d) none of the mentioned What is the condition of refrigerant at the exit of evaporator in aqua-ammonia absorption system? 6. In the aqua-ammonia absorption system, 1. Even though water (R718) is one of the oldest refrigerants, state of the art technology is required to use water as a refrigerant in compression refrigeration plants with turbo compressors.  Quiet in operation, low maintenance cost. Vapour Absorption refrigeration system || Chapter-3 || RAC || Rgpv Important Theory & Mcq Questions, (Rgpv online exam important questions & answers 2020 )|| Chp-2|| RAC ), Important Questions Chapter wise All subject playlist:-, Vapour Absorption refrigeration system || Important Theory Questions. Refrigeration and Air Conditioning Multiple Choice Questions :-1. What is the value of the … What is the condition of refrigerant at the exit of evaporator … Vapour Compression Refrigeration Cycle - MCQs with Answers Q1. b) absorbent A.To cool the vapour leaving the analyzer B.To separate ammonia and water C.To dissolve ammonia in water D.To add energy from external source E.None of the above. 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. Answer: c d) none of the mentioned, https://www.youtube.com/watch?v=g754W6-_Zk0&list=PLelAq9xzEDXCZwXnq6z6f04dEhRqEWSmZ. A.To cool the vapour leaving the analyzer B.To separate ammonia and water C.To dissolve ammonia in water D.To add energy from external source E.None of the above, Your email address will not be published. b) to decrease the amount of water vapour in ammonia vapour 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. In a vapour absorption refrigeration system, the compressor of the vapour compression system is replaced by Absorber, generator and liquid pump Nusselt number (NN) is given by A. NN = … a cooling substance, as ice or solid carbon dioxide, used in a refrigerator, ), and Natural Refrigerants. Q7. 1 95 TOP MOST Refrigeration and Air Conditioning – Mechanical Engineering Multiple Choice Questions and Answers; 2 Refrigeration and Air Conditioning Interview Questions and Answers pdf. The weak solution containing very little ammonia is spread in absorber. in the area of centrifugal, rotary screw, scroll and reciprocating compresssors. Wet compression in vapour compression cycle means, 2. This strong solution from absorber is pumped into generator. a. weak solution of ammonia in water is heated, b. strong solution of ammonia in water is heated, c. only water is heated and heat is given to the ammonia to form its vapour, ANSWER: b. strong solution of ammonia in water is heated, Q5. In this system ammonia is used as refrigerant and solution is used is aqua ammonia. Many chemical reactions are exothermic but these must take place at temperatures below atmospheric temperature therefore absorption refrigeration system is required to remove the heat of reaction. With the help of 4BEngineers, students can avail online coaching through video lecture at an unimaginably affordable cost, access the coaching content from renowned teaching experts, and be one on one with their personal favorite coach. Strong solution of aqua ammonia contains as much as ammonia as it can and weak solution contains less ammonia. b) absorbent Next . Freons or halocarbons are synthetically produced. • Low working pressure. Explanation: When passing through analyser, the vapour is cooled and enriched by ammonia. 2. Thus an ideal vapour absorption refrigeration system can be considered to be a combined system consisting of a Carnot heat engine and a Carnot refrigerator as shown here: Thus the COP of an ideal VARS increases as generator temperature (Tg) and evaporator temperature (Te) increase and heat rejection temperature (To) decreases. Ammonia vapors coming out of evaporator are drawn in absorber. Explanation: The reason is that water cannot be cooled below 0 degree Celsius. Efficiency of a Carnot engine is given as 80%. 3. 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. Q1. Friday, May 27, 2016. a. throttling valve. a) to increase the amount of water vapour in ammonia vapour Exam Questions; Mathematical Problems Strength of Materials; IC Engine; Refrigeration; MCQ Q&A; Contact Us! Pick up the wrong statement. 8. Define refrigerants. 9. 2. or 3 fluid refrigeration? Ammonia-absorption refrigeration cycle requires (a) very little work input (b) maximum work input (c) nearly same work input as for vapour compression cycle (d) zero work input (e) none of the above. d) all of the mentioned Pick up the wrong statement. (b) Water. View Answer. Working of Simple Vapor absorption system: A Simple Vapor absorption system consists of evaporator, absorber, generator, condenser, expansion valve, pump & reducing valve. Q2. It causes refrigeration from heat. Water is used as a ____ in air conditioning units. c) to eliminate the water vapour from ammonia vapour Advantages of using Vapor – Absorption Refrigeration System • As there is no moving part in the entire system, the operation is essentially quite and subjected to a very little wear. c) both of the mentioned 1. b) refrigerant What is an advantage using analyser-rectifier in aqua-ammonia absorption system? Which type of energy is required to expend in vapour absorption refrigeration system? Refrigerants should have low freezing point than the normal operating conditions. What is the process carried out in generator of vapour absorption refrigeration cycle? ... With an Ozone Depleting Potential (ODP) of 0 and a Global Warming Potential (GWP) of 1, R744 (CO2) is a natural refrigerant. • Absorption system may be designed to use any readily available source of thermal energy such as process steam ,hot exhaust from furnaces and solar energy, therefore they can be used in places where electric power is hard to obtain or is very expensive. liquid pump generator absorber and generator absorber, generator and liquid pump ⇒ In vapour compression cycle using NH3 as refrigerant, initial charge is filled at suction of compressor delivery of compressor Q4. MCQ-VAPOR COMPRESSION REFRIGERATION-2 Most commonly used method of refrigeration is vapor compression refrigeration. a) true R744 (CO2) is refrigerant grade CO2, used as a replacement for R134a and R404A in ultra-low, low and medium temperature refrigeration applications. of reversed Carnot Cycle? The compressor in the vapour compression system id replaced by. It is safe for normal handling as it is non-toxic, non-flammable and non-corrosive. 2. ANSWER: c. either throttling valve or capillary tube. Vapor-compression refrigeration, 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. In absorber of aqua-ammonia absorption refrigeration system, a. strong solution is taken in and weak solution is given out, b. weak solution is taken in and strong solution is given out, c. the ammonia vapour from strong solution is taken out and made it a weak solution, ANSWER: b. weak solution is taken in and strong solution is given out. c) both condense at same temperature It is now being used as a replacement for R-12 CFC refrigerant in the area of centrifugal, rotary screw, scroll and reciprocating compresssors. agent, as a drug. In absorption refrigeration cycle, which of the following is used? Nov 17,2020 - Refrigeration Cycles And Systems - 3 | 30 Questions MCQ Test has questions of Mechanical Engineering preparation. The simple vapor compressor system is used where there is scarcity of Electricity and it is very useful at partial and full load. Q2. The classification also depends on their chemical elements chlorine (Cl), hydrogen (H), carbon (C), and Florine (F), that was completely banned from production by 1996 under the Montreal Protocol for depleting the ozone. a) ammonia vapour The compressor of vapor compressor system is replaced by an absorber, generator, reducing valve and pump. (even for above 1000 TR)  Can be operated at designed C.O.P’s or even at part loads by varying generator temperature. d) none of the mentioned are different. b. to remove water vapour out from ammonia after generator, c. to exchange heat between weak solution and strong solution, ANSWER: b. to remove water vapour out from ammonia after generator. Answer: a Correct Answer. A refrigerant should have (a) Tow specific heat of liquid (b) high boiling point (c) high latent heat of vaporization (d) higher critical temperature (e) low specific volume of vapour. What is the purpose of analyser-rectifire in aqua-ammonia absorption system? (d) … Ans: b. If the cycle direction be reversed, what will be the value of C.O.P. Refrigeration and air conditioning mcq questions converted ... vortex refrigeration cycle (Ans:c) In vapour absorption refrigeration system, heat is rejected in (a) condenser only (b) generator only (c) absorber only (d) condenser and absorber (Ans:d) An Electrolux refrigerator uses (a) one pump (b) two pump (c) no pump (d) three pump 19. In this system, the working substance is a refrigerant like NH 3, R-11, R-12.. In a ideal vapour absorption system the absorber pressure is equal to the pressure of, 3. Freon™ 124 (R-124) refrigerant is a hydrochlorofluorocarbon (HCFC) retrofit replacement for R-114 used in centrifugal chillers and high-ambient cooling applications, including overhead cranes. The schematic diagram of the arrangement is shown in Fig. Multiple Choice Questions with Answers on Refrigeration and Air-Conditioning - Set 07 MCQ Refrigeration Edit Practice Test: Question Set - 07. Explanation: In this, water is the refrigerant and solution of lithium bromide in water is the absorbent. View Answer. The heat flow in the system at generator, and work is supplied to pump. In addition to fluorine and carbon, Freons often contain hydrogen, chlorine, or bromine. Answer: b MCQ ~ Vapour Compression Refrigeration System 1. Answer: d Refrigeration is measured in tons of refrigeration. • The load variations does not effect the performance of a vapour absorption system. Which device is used for the expansion of refrigerant in vapour compression refrigeration cycle? Low Freezing Point. ... Because the cycle works at very low pressure, the volumetric cooling capacity of water vapor is very low. that was commonly used in centrifugal chillers and before the 1970's it was used as a propellant for aerosols. Answer: b TOP Refrigeration and Air Conditioning -Mechanical Engineering Multiple choice Questions and Answers ListBell-coleman (e) none of the above. 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