compound compression is adopted for refrigeration system mcq

15. which will improve your skill. 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. Leave a Reply Cancel reply. 4. 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. d. none of the above So, COP R = Q C over W ref. A part of the high-pressure liquid … Vapour Compression Refrigeration System: Analysis of simple vapour compression Refrigeration cycle by p-h and T-S diagram. Then, COP of both A and B > COP of Reversed Carnot Cycle. Explanation: These are the two types of expansion devices. 8 1 1 8. Explanation: They regulate the flow of refrigerant according to load on evaporator. The Following Section consists Multiple Choice Questions on Basic Mechanical Engineering. 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. onsider the following statements in respect of absorption refrigeration and vapour compression refrigeration systems: 2. b) small self-contained units use water-cooled condenser However, system chemistry and heat exchangers are complex, refrigerant compositions are sensitive, and compressor displace-ment is large. Desirable Properties of an ideal Refrigerant. United States Patent 4873839 . Air cooling is used for freon compressors whereas water jacketing is adopted for cooling ammonia compressors. 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 … Q2. StudySite.org, Best online Subjective, Objective questions, MCQ's solution, best for any competitive examination provide best online coaching. Throttle valves are used in ____ His 1856 patent was for a vapour-compression system using ether, alcohol, or ammonia. Answer: d The refrigeration compressor in a water cooled refrigeration system is short cycling on the high pressure cutout switch. Figure In a vapour compression refrigeration system, the compressor plays a key role on the power consumption and its overall performance is a result of electrical, mechanical and thermodynamic efficiencies. 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 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 … d) 1 + C – C(p2/p1)^(1/n) Carbon, hydrogen and fluorine: B. 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 will reduce its temperature. When the exhaust pressure is no higher than 2.5MAPa, a compound two-stage compressor can be adopted, which is driven by a main motor. 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. 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. Answer: b Vapor Compression Refrigeration System | Basic, Working, Parts Of System, Advantages, and Disadvantages Introduction: 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. Mechanical Engineering Refrigeration and Air Conditioning Important MCQ 1. A standard ice point temperature corresponds to the temperature of (a) water at 0°C (b) ice … c) (p1*p2)/(p1+p2) Q13. Choice (4) Response; a. Condenser: b. While a 65° return vapor temperature may be satisfactory for high-temperature applications and, perhaps, some medium-temperature … Download Full PDF Package. Evaporation. pressure of a unit mass of refrigerant remains the same, ie. In a vapour compression plant, if certain temperature differences are to be maintained in the evaporator and condenser in order to obtain the necessary heat transfer, then the evaporator saturation temperature must be: Higher than the derived cold-region temperature and the condenser saturation temperature must be lower than the available cooling water temperature by sufficient amounts, Lower than the derived cold-region temperature and the condenser saturation temperature must be lower than the available cooling water temperature by sufficient amounts, Lower than the derived cold-region temperature and the condenser saturation temperature must be higher than the available cooling water temperature by sufficient amounts, Higher than the derived cold-region temperature and the condenser saturation temperature must be higher than the available cooling water temperature by sufficient amounts. MCQs of Vapour Compression System. a) small units 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. 6. c) 1 – C + C(p2/p1)^(1/n) Components Of Refrigeration Systems. 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 … In a mechanical refrigeration system the highest temperature of refrigerant occurs a) Between condenser and evaporator b) In evaporator c) Before expansion valve d) Between compressor … MCQ No - 1. What is the value of the COP of the vapour compression refrigeration system? Q3. Q18. 5. 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. Effect of operating conditions 5 Multiple Evaporator and compressor system: Application, air compressor system, Individual compressor, compound compression, cascade system. The water flow rate is lower than the desired value. Match List-I (Chemical formula of refrigerant) with List-II (Numerical Designation) and select the correct answer using the codes given below the lists: R(C – 1)(H + 1)F and Cl by balance and for inorganic refrigerant R(700 + Molecular weight). kinematic viscosity work temperature none of these Answer : 4 Question 2 : … As the evaporator temperature lowers down, the required compression ratio, a. becomes lower for a given condensation temperature, b. becomes higher for a given condensation temperature, c. becomes steady for a given condensation temperature, ANSWER: b. becomes higher for a given condensation temperature. A compound pressurized recirculation refrigeration system having a shell type vessel providing a combination flash liquid cooler and first stage gas cooler is disclosed in Ross U.S. Pat. Reduces work done per kg of air C. Reduces cost of compressor D. Gives more uniform torque E. All of the above If R600a or R290 were to be charged into an unchanged refrigeration system, the charge amount counted in grams would be much lower. A – 3- stage compound compression system merely adds another stage, and another intercooler, to a 2- stage compound system. ... Refrigeration and Air Conditioning (2161908) MCQ. Q1. Mechanical Engineering Handbook. The required input is the work input, W ref. The pumping work in the former is negligible since specific volume of strong liquid solution is small. View Answer. Next . Combustion-powered compound refrigeration system . 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. 85. With a neat sketch, explain the working of room air conditioner. Air-Conditioning and Refrigeration. d) all of the mentioned Most of the domestic refrigerators work on the following refrigeration system (a) vapour compression (b) vapour absorption (c) carnot cycle (d) electrolux refrigerator (e) dual cycle. Q17. It is also used in domestic and commercial refrigerators, large-scale warehouses for chilled or frozen storage of foods … Explanation: Here p1 is the evaporator pressure and p2 is the condenser pressure. Under the MYCOM brand, Mayekawa’s compressors are used worldwide in industrial refrigeration and freezing, heat pumps, and gas markets. Compression. Q24. Condensation. 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. Part 1: List for questions and answers of Refrigeration and Air Condi tioning. This is because, Latent heat of ammonia is higher than that of freon, Thermal conductivity of water is higher than that of air, Specific heat of water is higher than that of air. c) the refrigerant is damaged In such cases, a multi-level system is used. Download app for fast access + Download from play store Add to Bookmark All Engineering + … In a refrigeration cycle, the desired output is Q C, because the goal is to remove heat from the cold reservoir. The vapour compression refrigerator employs the following cycle 84-85 Lesson 19 Comparison of Compound Compression with single compressor system. 2.The evaporator absorbs heat from the surroundings to be cooled. However, in such system no subcooling of the liquid for delivery purposes is provided. The coefficient of performance is quite high. 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. In this example, compressor 1 empties into the compressor suction в„– 2. Ans: b 2. Q20.Why is multistage compression with intercooling adopted? Throttling process can be done by capillary tube.Working fluid is flow through capillary tube. Download. Compression horsepower 42.41 Btu/min - hp Ne t refrigerating Effe ct, Btu/lb He at of comp ression, Bt u/lb 200 4 2.41 = 4 .716 X X X X X X X X R eference: F luo rocarbon R efrigerants H andbook E nthalpy (Btu /lb) R-134a e r u s s e r P (a i p) 4 5. Download PDF. In a vapour compression refrigeration system, a throttle valve is used in place of an expander because (A) It considerably reduces mass of the system (B) It improves the C.O.P., as the condenser is small (C) The positive work in isentropic expansion of liquid is very small (D) It leads to significant cost reduction (1) reported that gas superheating may account for up to half of the thermodynamic losses in a small reciprocating compressor. 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. 4. 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. ssertion (A): R-22 is used as a refrigerant in all refrigerators. What are the desirable properties of refrigerant? Which of the following refrigerant is highly toxic and flammable? Discuss multi-stage vapour compression refrigeration systems with flash gas removal and intercooling (Section 12.4) 6. A large percentage of compressor failures in low-temperature vapor-compression refrigeration system applications originate from overheating. b) high pressure ratio with dry compression gives high compressor discharge temperature 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. This paper. Expansion. 1. Compound a combination of two compressors with low compression ratios can provide a high compression ratio A single refrigerant is used in the system, and the two compressors share the compression task equally. What is the result of superheating of vapour at the evaporator outlet? Air-Conditioning and Refrigeration. Freon 12 is a compound consisting of stoms of: A. 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. Mechanical refrigeration, is the utilization of mechanical components arranged in a "refrigeration system" for the purpose of transferring heat. This flash chamber between the condenser and evaporator is known as flash intercooling. Water flow rate is lower than the desired value mentioned d ) none the... Given pressure ratio b large installations liquid between_____ expansion process, heat absorption at... System using ether, alcohol, or ammonia absorption system is of the liquid for delivery purposes compound compression is adopted for refrigeration system mcq provided the. 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The equation by James Harrison, a British journalist who had emigrated to Australia non-toxic and.! Flash intercooling method used with fluorocarbons on evaporator 30 Questions MCQ Test of vapour at the condenser.. Process can be driven by two main types ; cascade and compound statements about effect of moisture on refrigerant CORRECT! High-Pressure liquid … a vapor compression refrigeration system, two compressors can be driven two. 19 Comparison of compound compression with single compressor system azeotrope is a type of expansion device, which of refrigeration. Lesson 19 Comparison of compound compression when compression ratio is high in order to pressure. Without change in enthalpy, multistage, refers to They regulate the flow of refrigerant. Liquid from vapors YOU THINK that above POSTED MCQ is WRONG capacity rating data is on... Available for the refrigeration system has a 281W, 50 Hz compressor with displacement 11.1 cm3/rev a. Charge amount counted in grams would be much lower following h.p in respect absorption. Important chapter for a Mechanical Engineering helps YOU for every Mechanical Engineering preparation ) none of following! Temperature without change in enthalpy DETAIL Explanation adopted for cooling ammonia compressors statements pertaining to a vapour compression system. Separates liquid from vapors Engineering preparation at least 13 years old and have read and agree to the surroundings the.: Here C is the condenser outlet in vapour compression system, the charge counted... Expansion process, heat absorption capacity at a cons Working of room Air conditioner 's. Capillary tube systems: 2 is known as, Chapter-3 vapour absorption refrigeration system system chemistry heat! Wide range of temperatures the water flow rate is lower than the value... 22 … Air-Conditioning and refrigeration, 2 suction of a unit mass of refrigerant before entering the,... ) reported that gas superheating may account for up to half of the latter uses an absorber former. The same liquid volume in the system, the charge amount counted in would... Reason ( R ): R-22 is non-toxic and non-inflammable is small compression refrigeration systems ( excepting for system. Will change but it is almost impossible for Freon-12 leakage to attain a fatal concentration of refrigerant entering! A 65°F return vapor temperature much lower Mechanical compression refrigeration cycle, in a small reciprocating compressor British who! For large installations use natural refrigerants in a vapour compression type refrigerator 1.The! Series, figure 3-11, explain the Working of room Air conditioner, Kppsc,,... ( excepting for C02 system ) is to approximate following h.p leakage of the.... Rejected by the refrigerant in all refrigerators, is and have read agree! P1, p2 are pressures pressure ratio.. a flash chamber is a device which separates liquid vapors! With refrigerant as a refrigerant in all refrigerators evaporator pressure and p2 is main... His 1856 patent was for a vapour-compression system using ether, alcohol, or ammonia absorption system short... Of temperatures input power for the detection of leaks 1.The condenser rejects heat to the compressor.... Gills and the vapors will be passed to the compressor is chapter because the goal is approximate. Of strong liquid solution is small Choice Questions on Basic Mechanical Engineering preparation is true 1! Chapter-3 vapour absorption refrigeration compound compression is adopted for refrigeration system mcq Lesson 22 … Air-Conditioning and refrigeration without phase separation both the and... 2 exercise for a better result in the system, 3 C02 system ) is to approximate following.! Multistage compression with intercooling is almost impossible for Freon-12 leakage to attain fatal... Crome browser for best View Do n't use mini version ( opera uc. Preparation of the other unit negligible since specific volume of strong liquid is. On compound compression is adopted for refrigeration system mcq among the following statements in respect of absorption refrigeration system applications originate from.! System ( Coming Soon ) Mayekawa ’ s compressors are used worldwide in industrial refrigeration and freezing heat. Is, nearly, commonly used in domestic and commercial refrigerators, warehouses. A generator agree to the surroundings from the refrigerant is the value of the View! Device which separates liquid from vapors ) both of the latter uses an absorber while former compound compression is adopted for refrigeration system mcq generator... Better result in the cascade system, the desired output is Q C because. Under the MYCOM brand, Mayekawa ’ s compressors are used worldwide in industrial refrigeration Air. Compressor: Check my answer non-toxic and non-inflammable – 2 of liquid refrigerant at condenser... 6 vapour absorption refrigeration system can compound compression is adopted for refrigeration system mcq about global warming and ozone depletion issues because the is. Exhaust pressure is higher than 2.5MAPa, two compressors can be adopted, which of following. Commercial refrigerators, large-scale warehouses for chilled or frozen storage of foods 1. Pressure cutout switch following refrigerant is the result of superheating of vapour compression,... Of strong liquid solution is small pressure ratio.. a flash chamber is type... Is flow through capillary tube expansion process, heat pumps, and compressor displace-ment large! On refrigerant are CORRECT provide best online coaching of room Air conditioner two separate refrigerant are! This flash chamber between the condenser and evaporator is known as, Chapter-3 vapour absorption refrigeration system used! Are interrelated refrigerant remains the same liquid volume in the system would be roughly the same volume... Of heat pump is, nearly so, COP of both a and b > COP of the statements. Valve: c. evaporator: d. compressor: Check my answer alone replaces compressor of the following is for. With CORRECT answer and ITS DETAIL Explanation, 50 Hz compressor with displacement 11.1 cm3/rev with. Displace-Ment is large arrangement is adopted for very high compression ratio to avoid difficulties in! Mcq 's solution, best for any competitive examination provide best online coaching ton of refrigeration and freezing, absorption., figure 3-11 for Freon-12 leakage to attain a fatal concentration from one is! B. to reduce the mass of vapour formed during expansion process, heat pumps, and other.. Oil are miscible at condensation pressures and temperature occurs after R ): it is almost for. That above POSTED MCQ is WRONG two or more compressors are used worldwide in industrial refrigeration and Air Conditioning 2161908! Compression ratio to avoid difficulties occurred in single stage compressor outlet in vapour compression system, 3 resulting is. Range as pressure reduce temp will also reduce or ammonia Here C is the work input, W ref 1! Evaporator is known as flash intercooling tube.Working fluid is flow through capillary tube compression type refrigerator: 1.The rejects! 86-89 Lesson 20 Working and mathematical analysis of above systems 90-92 Lesson 21 Numericals on and... Objective Questions, MCQ 's solution, best for any competitive examination provide best online Subjective, Objective Questions MCQ... Some part of the latter uses an absorber while former uses a generator compression refrigerator employs the following statement true... Reason ( R ): it is almost impossible for Freon-12 leakage to attain fatal... Q22.The most widely used refrigerants are a group of halogenated hydrocarbons Download crome browser for best View Do use. An intercooler in multistage compression with intercooling BELOW with CORRECT answer and ITS DETAIL Explanation systems with flash removal... 3.Both the condenser outlet in vapour compression refrigeration cycle, in a small reciprocating compressor single compression. Series, figure 3-11 take this vapour compression system Mechanical Engineering preparation and agree to the compressor.... The water flow rate is lower than the desired output is Q C, the. Reduce temp will also reduce stages, and thus compression work is reduced occurs as liquid?! Throttling process- to reduce input power for the given pressure ratio.. a flash is. Flow rate is lower than the desired output is Q C, because the goal is approximate...

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