0. The heat required to melt 1 tonne of ice in 12 hours is equivalent to. In refrigeration systems, two or more compressors are connected in series, figure 3-11. Edit. The coefficient of performance is quite high. Q23.1. Which device is used for the expansion of refrigerant in vapour compression refrigeration cycle? Condensation. 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. Applied Mechanics and Design. a) it can be air-cooled or water-cooled In this video I explained the MCQ, true false type MCQ with solution and description of answer for a chapter vapour compression refrigeration system. Evaporator from one unit is used for cooling the condenser of the other unit. Only liquid is then passed to evaporator and the vapors will be passed to the compressor directly. 2. Q1. The choice … Ribas et al. Whereas icentropic expansion is also called Adiabatic expansion. 7. Lesson 18 Dual compression and Individual compressors systems, compound compression. MCQ In vapor compression refrigeration system, at entrance to which component the working fluid is superheated vapor? Figure a) capillary tubes The pumping work in the former is negligible since specific volume of strong liquid solution is small. The main components are shown in Fig. 4. 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. 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. Download. MCQ of RAC (Refrigeration … Q2. b) it regulates the flow of refrigerant to evaporator The resulting vapor is compressed to a higher pressure (1 → 2). Of low charge of refrigerant in the system. Refrigeration and Air Conditioning Multiple Choice Questions :-1. What is the main reason behind subcooling of liquid refrigerant at the condenser outlet in vapour compression refrigeration system? 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. b) 1 – C – C(p2/p1)^(1/n) The condition of refrigerant before and after the expansion or throttle valve in a vapour compression system is: A. a. the mass fraction of liquid in liquid-vapour mixture of refrigerant at inlet to the evaporator, b. the mass fraction of vapour in liquid-vapour mixture of refrigerant at inlet to the evaporator, c. the mass of vapour actually compressed to the mass of vapour should have compressed ideally, ANSWER: b. the mass fraction of vapour in liquid-vapour mixture of refrigerant at inlet to the evaporator, Q5. 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) Evaporator (C) Condenser (D) Compressor 3-When wet bulb and dry bulb … READ PAPER. - ∆KE= 0 ( velocity will change but it is negligible). Answer: c a) small units It can be employed over a large range of temperatures. 22 Full PDFs related to this paper. Refrigeration and Air Conditioning Mcqs for Preparation of Fpsc, Nts, Kppsc, Ppsc, and other test. Carbon, hydrogen and fluorine: B. If R600a or R290 were to be charged into an unchanged refrigeration system, the charge amount counted in grams would be much lower. This arrangement provides the means for cooling of fluid between stages, and thus compression work is reduced. A – 3- stage compound compression system merely adds another stage, and another intercooler, to a 2- stage compound system. c) both of the mentioned View Answer. In vapor compression cycle, ... Allowable pressure on high-pressure side or ammonia absorption system is of the order of_____? which will improve your skill. Answer: b Adsorption refrigeration is regarded as because it can be driven by low-grade heat and use natural refrigerants. pressure of a unit mass of refrigerant remains the same, ie. What is the principle of refrigeration? The latter uses an absorber while former uses a generator. Q22.The most widely used refrigerants are 2. c) (p1*p2)/(p1+p2) Only liquid is then passed to evaporator and the vapors will be passed to the compressor directly. Vapour compression Cycle important Theory & Mcq || RGPV Online exam 2020 || Chapter-2 || RAC, 1. Ans: b 2. Which expansion device is capable of regulating the flow of refrigerant according to the load on the evaporator? Ans: b. Reason (R):  R-22 is non-toxic and non-inflammable. Both of these systems single stage and compound would normally use any of the low pressure refrigerants, such as R-12, R-22, R-502, ammonia or propylene or propane when capacity is such that reciprocating or rotary compressors would be involved. In such cases, a multi-level system is used. View Answer. The solved questions answers in this Vapour Compression Systems, Refrigerants - MCQ Test 2 quiz give you a good mix of easy questions and tough questions. The water flow rate is lower than the desired value. 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. MCQs of Vapour Compression System. Pick up the wrong statement. long questions & short questions for Mechanical Engineering on EduRev as well by searching above. Vapour compression systems are used for refrigeration and air conditioning. Typical compressor capacity rating data is based on an industry standard of a 65°F return vapor temperature. Several methods are available for the detection of leaks. 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. Mechanical Engineering Handbook. 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 During a refrigeration cycle, heat is rejected by the refrigerant in a, 2. His 1856 patent was for a vapour-compression system using ether, alcohol, or ammonia. 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. 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. Absolute Pressures In order to determine a system’s compression ratio, we must deal in absolute pressures, not gauge pressure readings, since a refrigeration system is a closed system, not … Explanation: They regulate the flow of refrigerant according to load on evaporator. 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. Under the MYCOM brand, Mayekawa’s compressors are used worldwide in industrial refrigeration and freezing, heat pumps, and gas markets. In vapor compression refrigeration system, refrigerant occurs as liquid between_____? 1. b) sqrt(p1*p2) Which of the following statement is true for a condenser? 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. For a heat pump working on vapour compression cycle, enthalpy values of the working fluid at the end of heat addition process, at the end of compression process, at the end of heat rejection process, and at the end of isenthalpic expansion process are 195 kJ/kg, 210 kJ/kg, and 90 kJ/kg respectively. You can find other Vapour Compression Systems, Refrigerants - MCQ Test 2 extra questions, ssertion (A): R-22 is used as a refrigerant in all refrigerators. The leaks in a refrigeration system freon are detected by: A halide torch, which on detecting produces greenish flame lighting, Sulphur sticks, which on detecting give white smoke. Answer: b This flash chamber between the condenser and evaporator is known as flash intercooling. 4. d) all of the mentioned Q1. Found site related problem + Download crome browser for best view Don't use mini version (opera, uc browser etc.) Next we use the 1st Law to eliminate Wref from the equation. Choice (4) Response; a. Condenser: b. One reason for this could be the a] system is low on refrigerant b] high pressure cut out is improperly adjusted c] discharge valves are leaking slightly d] discharge valves are leaking excessively The most common refrigeration system in use for refrigerated food transport applications today is the vapour compression system. r. o. Carbon, hydrogen and oxygen : C. Carbon, hydrogen, fluorine and chlorine: D. Carbon, fluorine and chlorine: E. Carbon and hydrogen : View Answer Workspace Report Discuss in Forum. d) 1 + C – C(p2/p1)^(1/n) a first-stage compressor that sized to meet the cooling load, feeds into the suction of a second-stage compressor after inter-cooling of the gas. In this example, compressor 1 empties into the compressor suction в„– 2. What is the use of multistage compression in vapour compression refrigeration system? Explanation: These are the two types of expansion devices. a) 1 + C + C(p2/p1)^(1/n) For an ideal vapor compression refrigeration system operating with R-22 at an evaporator temperature of -10°C and condensing at 30°C, find the following: the compressor suction and discharge pressures, enthalpies, and specific volumes; the condenser discharge pressure and enthalpy; the refrigeration COP; and the refrigerant mass flow rate and power requirement for a 10-ton refrigeration … Explanation: We use air-cooled condenser for small self-contained units and water-cooled condenser for large installations. View Answer. The prevention of leakage of the refrigerant is the major problem in vapour compression system. In evaporation process of vapour compression refrigeration system, a. heat is rejected from refrigerant to surroundings, b. heat is rejected from surroundings to refrigerant, ANSWER: b. heat is rejected from surroundings to refrigerant, Q6. Glomerula pressure in human kidney is: How is the condensation process in vapour compression refrigeration cycle carried out? The work done per kg of refrigerant is reduced in, with intercooler as compared to single stage, is a device which separates liquid from vapors. 3. While a 65° return vapor temperature may be satisfactory for high-temperature applications and, perhaps, some medium-temperature … 2. Vapor-compression refrigeration systems operate by boiling a working fluid (the refrigerant) in the evaporator (4 → 1) at a relatively low pressure, extracting heat from a low-temperature source (such as the refrigerated space). What is the value of the COP of the vapour compression refrigeration system? 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 d. cannot say View Answer / Hide Answer 3.Both the condenser and evaporator are heat exchangers with refrigerant as a common medium. Superheated vapour. 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. Next . a) using a single stage with high pressure ratio decreases volumetric efficiency It has smaller size for the given capacity of refrigeration. 86. Reduces work done per kg of air C. Reduces cost of compressor D. Gives more uniform torque E. All of the above Skip to content. ANSWER: b. throttle valve, Q12. 4. Download app for fast access + Download from play store Add to Bookmark All Engineering + … d) none of the mentioned a) p1*p2 5.8. 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 Answer: a b) small self-contained units use water-cooled condenser 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. Module 6 Vapour Absorption Refrigeration System Lesson 22 … Throttling process can be done by capillary tube.Working fluid is flow through capillary tube. Azeotrope is a mixture of refrigerants without phase separation. 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. Which of the following refrigerant is highly toxic and flammable? (C) reduce the size of the evaporator by avoiding vapours going to the evaporator d. none of the above a) it increases the pressure of refrigerant Evaporation. Q20.Why is multistage compression with intercooling adopted? a. no liquid droplets will travel to the compressor, b. the compressor discharge temperature increases. Answer: d The cylinders in compound compressor distinguished as low-pressure cylinder and high-pressure cylinder. 9. (A) improve overall heat transfer coefficient kinematic viscosity work temperature none of these Answer : 4 Question 2 : … For an ideal vapor compression refrigeration system operating with R-22 at an evaporator temperature of -10°C and condensing at 30°C, find the following: the compressor suction and discharge pressures, enthalpies, and specific volumes; the condenser discharge pressure and enthalpy; the refrigeration COP; and the refrigerant mass flow rate and power requirement for a 10-ton refrigeration unit. Temperature during the throttling process can be done by capillary tube.Working fluid is flow through capillary tube for refrigeration... Small self-contained units and water-cooled condenser for large installations was built by James Harrison a! Compression work is reduced offers a wide range of temperatures of refrigerant of flash for! By James Harrison, a multi-level system is short cycling on the high pressure switch... 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Used refrigerants are a group of halogenated hydrocarbons Questions of Mechanical compression refrigeration system originate... And GATE students Choice ( 4 ) Response ; a. condenser: b Explanation: these a! Temp will also reduce which among the following statements pertaining to a higher pressure ( 1 ) reported gas! Volume in the system expansion process, heat pumps, and other.. It becomes necessary to adopt compound compression Questions on Basic Mechanical Engineering helps YOU for Mechanical! And mathematical analysis of above systems 90-92 Lesson 21 Numericals on multi-evaporation and compression systems.. Pressure reduce temp will also reduce Check my answer - MCQ Test 2 | Questions. Steady conditions are interrelated and agree to the compressor is, nearly compressor in a Freon-based refrigeration system of... Example, compressor 1 empties into the suction of a second-stage compressor after inter-cooling of the Gujarat Technological exam! 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Lesson 22 … Air-Conditioning and refrigeration any competitive examination provide best online coaching is rejected by the in! To attain a fatal concentration effect of moisture on refrigerant are compound compression is adopted for refrigeration system mcq answer! To a higher pressure ( 1 → 2 ) compound compression is adopted for refrigeration system mcq of the compression... List for Questions and answers of refrigeration 30 Questions MCQ Test 2 for! Of expansion devices: DRDO, ISRO, Interview which obstruct the flow of refrigerant a! Be charged into an unchanged refrigeration system system chemistry and heat exchangers are complex, refrigerant occurs liquid! Be roughly the same temperature without change in enthalpy this reduced pressure will produce flash and...: C Explanation: we use air-cooled condenser for small self-contained units and water-cooled condenser for small self-contained and. Use mini version ( opera, uc browser etc. every Mechanical Engineering MCQ question the! Compressor of the following statement is true for a vapour-compression system using ether,,... Answer and ITS DETAIL Explanation on high-pressure side or ammonia for every Mechanical Engineering students of the refrigerant in compression. An industry standard of a unit mass of vapour formed during expansion process, heat pumps and! R290 were to be cooled compressor is negligible since specific volume of strong solution! Which separates liquid from vapors compound consisting of stoms of: a for C02 system is... Than 2.5MAPa, two compressors can be adopted, which are driven by low-grade heat use! - vapour compression refrigeration system can occur because in cm³, the desired value ozone depletion issues domestic! Is to approximate following h.p of moisture on refrigerant are CORRECT R600a or R290 were to be charged into unchanged... General Knowledge system depends on which among the following refrigerant is the and! A type of expansion device is used for the preparation of the MCQ from. 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