COP of Reversed Carnot Cycle. a) it increases the pressure of refrigerant The latter uses an absorber while former uses a generator. 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. However, it is preferred in comfort air-conditioning. A part of the high-pressure liquid … Lesson 18 Dual compression and Individual compressors systems, compound compression. 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. How is the condensation process in vapour compression refrigeration cycle carried out? Mechanical Engineering Handbook. Throttling process can be done by capillary tube.Working fluid is flow through capillary tube. 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. The purpose of installing a flash chamber in the refrigeration circuit is to b) high pressure ratio with dry compression gives high compressor discharge temperature View Answer. The pumping work in the former is negligible since specific volume of strong liquid solution is small. Download. Distinguish between the vapor compression and vapor absorption refrigeration system. 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. (1) reported that gas superheating may account for up to half of the thermodynamic losses in a small reciprocating compressor. We also offer a full lineup of environmentally-friendly compressors that use natural refrigerants. 86. MCQ of RAC (Refrigeration … ANSWER: b. throttle valve, Q12. Choices. You can find other Vapour Compression Systems, Refrigerants - MCQ Test 2 extra questions, Desirable Properties of an ideal Refrigerant. The choice … Now, as per joule-thomson expansion for some specific temp range as pressure reduce temp will also reduce. A standard ice point temperature corresponds to the temperature of (a) water at 0°C (b) ice … Heating, ventilation, and air conditioning (HVAC) is the technology of indoor and vehicular environmental comfort. The first practical vapour-compression refrigeration system was built by James Harrison, a British journalist who had emigrated to Australia. First of all, please watch my important question videos of Rac, chapter wise after that you can visit here, where you show the answers to those questions and some MCQ regarding this chapter...... 2. 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. Mechanical Engineering Refrigeration and Air Conditioning Important MCQ 1. d) none of the mentioned 22 Full PDFs related to this paper. Wet compression is _____. Please read all the important question of that chapter because the MCQ comes from only this important topic. 4.The amount of heat exchanged in condenser and evaporator are equal under steady conditions. Only liquid is then passed to evaporator and the vapors will be passed to the compressor directly. During a refrigeration cycle, heat is rejected by the refrigerant in a, 2. Mechanical Engineering Handbook . Combustion-powered compound refrigeration system . The leakage in a Freon-based refrigeration system can be detected by using a/an, High condenser pressure in a refrigeration system can occur because. 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. 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. 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. Only liquid is then passed to evaporator and the vapors will be passed to the compressor directly. Adsorption refrigeration is regarded as because it can be driven by low-grade heat and use natural refrigerants. a) freon d) all of the mentioned The water flow rate is lower than the desired value. The resulting vapor is compressed to a higher pressure (1 → 2). Q23.1. c) (p1*p2)/(p1+p2) Explanation: They regulate the flow of refrigerant according to load on evaporator. If R600a or R290 were to be charged into an unchanged refrigeration system, the charge amount counted in grams would be much lower. Mechanical Engineering Under the MYCOM brand, Mayekawa’s compressors are used worldwide in industrial refrigeration and freezing, heat pumps, and gas markets. Improves volumetric efficiency for the given pressure ratio B. b) sqrt(p1*p2) His 1856 patent was for a vapour-compression system using ether, alcohol, or ammonia. Compound refrigeration system: Technical information Compressors Compound Refrigerating Systems. 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. Refrigeration and air conditioning alone forms about 25% of total energy usage in the United States during the summer months, and compressors are found in all refrigeration and AC devices. What is the result of superheating of vapour at the evaporator outlet? 2.The evaporator absorbs heat from the surroundings to be cooled. Download Full PDF Package. 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 . 4. 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. Ribas et al. The prevention of leakage of the refrigerant is the major problem in vapour compression system. 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. 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. d) all of the mentioned View Answer. Moisture should be removed from refrigerants to avoid. Q3. 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. Air cooling is used for freon compressors whereas water jacketing is adopted for cooling ammonia compressors. (D) all of the above, Q25.The process of undercooling is generally brought about by United States Patent 4873839 . 15. This paper. 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. 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 … Air-Conditioning and Refrigeration. Download app for fast access + Download from play store Add to Bookmark All Engineering + … b) genetron Of low charge of refrigerant in the system. This reduced pressure will produce flash evaporation and some part of refrigerant will evaporate by its own heat energy. All the statements about effect of moisture on refrigerant are correct. Q9. Q1. Explanation: Here C is the clearance and p1,p2 are pressures. Refrigeration and Air Conditioning Multiple Choice Questions :-1. Q10. Several methods are available for the detection of leaks. PLEASE COMMENT BELOW WITH CORRECT ANSWER AND ITS DETAIL EXPLANATION. However, in such system no subcooling of the liquid for delivery purposes is provided. 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. per ton of refrigeration Since for isentropic compression process. This arrangement provides the means for cooling of fluid between stages, and thus compression work is reduced. The main components are shown in Fig. hence it is preferred over icentropic expansion. 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. Abstract: Conventionally, food transport refrigeration is driven by the vehicle’s engine itself or by a diesel genset; the refrigeration cycle almost universally used is the vapour compression system (VCS), with … Name the essential parts of … Answer Title: Food Transport Refrigeration with Engine Exhaust and Metal Hydride Reactors. Question 49. Explanation: Because of these reasons we have to use multistage compression with intercooling. 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. c) arcton 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. b) 1 – C – C(p2/p1)^(1/n) 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. There are two main types; cascade and compound. Q2. 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) small units Mechanical refrigeration with the vapour compression cycle offers a wide range of options for compressor drive methods. The condition of refrigerant before and after the expansion or throttle valve in a vapour compression system is: A. Reduces work done per kg of air C. Reduces cost of compressor D. Gives more uniform torque E. All of the above View Answer. What are the desirable properties of refrigerant? Skip to content. c) both of the mentioned Which of the following refrigerants has the lowest boiling point? Answer: d Whereas icentropic expansion is also called Adiabatic expansion. Saturation pressure – temperature relationship. Selection of a refrigerant for a vapour – compression system depends on which among the following? Match List-I with List-II and select the correct answer using the codes given below the lists: Assertion (A): Freon-12 is odourless and its leakage cannot be easily detected. students definitely take this Vapour Compression Systems, Refrigerants - MCQ Test 2 exercise for a better result in the exam. Glomerula pressure in human kidney is: Then the heating capacity of heat pump is, nearly. Q19.The clearance volumetric efficiency is equal to 4. Found site related problem + Download crome browser for best view Don't use mini version (opera, uc browser etc.) Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. which will improve your skill. Pawan Gupta. Q13. 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). Reason (R):  R-22 is non-toxic and non-inflammable. This will reduce its temperature. (C) reduce the size of the evaporator by avoiding vapours going to the evaporator 85. Next we use the 1st Law to eliminate Wref from the equation. In such cases, a multi-level system is used. Prototypes have shown the ability to provide a 7°C of cold source at an ambient temperature of 30°C (COP equals to 3–7), comparable or higher than that of vapour compression heat pump systems. 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 … MCQs of Vapour Compression System. The highest temperature during the cycle, in a vapour compression system, occurs after, 4. Which expansion device is capable of regulating the flow of refrigerant according to the load on the evaporator? b) larger units Q24. 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. StudySite.org, Best online Subjective, Objective questions, MCQ's solution, best for any competitive examination provide best online coaching. Azeotrope is a mixture of refrigerants without phase separation. d) (p1+p2)/2 Our compressors leverage thermal technology developed through years of experience to consistently provide high quality. Answer: a Refrigeration and Air Conditioning Mcqs for Preparation of Fpsc, Nts, Kppsc, Ppsc, and other test. b) it regulates the flow of refrigerant to evaporator Components Of Refrigeration Systems. Answer: b Jan 15,2021 - Vapour Compression Systems, Refrigerants - MCQ Test 2 | 30 Questions MCQ Test has questions of Mechanical Engineering preparation. 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. Name, multistage, refers to any of the refrigeration system with more than one stage of compression. 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. This yields charges of approx. A – 3- stage compound compression system merely adds another stage, and another intercooler, to a 2- stage compound system. c) 1 – C + C(p2/p1)^(1/n) (D) any of the above 15. Vapour compression Cycle important Theory & Mcq || RGPV Online exam 2020 || Chapter-2 || RAC, 1. Q1. 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. The units of _____ and COP are the same. onsider the following statements in respect of absorption refrigeration and vapour compression refrigeration systems: 2. 3. Discuss multi-stage vapour compression refrigeration systems with flash gas removal and intercooling (Section 12.4) 6. View Answer. The most common is the soap-bubble method. It is also used in domestic and commercial refrigerators, large-scale warehouses for chilled or frozen storage of foods … * Metalfrio Solutions SA * MF Refrigeration Limited * Panasonic Corporation * Perlick Corporation * Powers Equipment Company, Inc. * QBD Modular Systems Inc. * Skope Industries Ltd. * … 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. 9. b. to reduce the mass of vapour formed during expansion process, c. to reduce vapour bubbles which obstruct the flow of liquid refrigerant. Both the gills and the lung are present in which of these. Leave a Reply Cancel reply. 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. By continuing, I agree that I am at least 13 years old and have read and agree to the. The refrigerant, commonly used in vapour absorption refrigeration system, is. Carbon, hydrogen and fluorine: B. 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. The work input, W ref b Explanation: Here p1 is the clearance p1. Reduce input power for the given pressure ratio.. a flash chamber between the condenser and evaporator is as... For a condenser displace-ment is large to eliminate Wref from the surroundings the! A knowledge-sharing community that depends on everyone being able to pitch in when They know.. During the cycles occurs after compressor drive methods ( Coming Soon ) by... Of vapour compression refrigerator employs the following refrigerant is the major problem in absorption. Www.Gtu-Mcq.Com is an online portal for the given pressure ratio.. a flash chamber a! Diploma Engineering students definitely take this vapour compression refrigeration system, the condition of refrigerant according to load on.! Gas superheating may account for up to half of the refrigerant is highly toxic and flammable resulting vapor is to... 'S solution, best online Subjective, Objective Questions, MCQ 's solution best... Exchangers are complex, refrigerant compositions are sensitive, and thus compression work is reduced is adopted very! Best online coaching room Air conditioner 1 tonne of ice in 12 hours is to! Former is negligible ) so, during the cycle, in such cases, British... Cylinder and high-pressure cylinder an online portal for the preparation of the for! Condensation process in vapour compression refrigeration cycle carried out 30 Questions MCQ Test of vapour compression systems refrigerants! Which expansion device this, between the condenser outlet in vapour absorption refrigeration is!, feeds into the suction of a refrigerant for a Mechanical Engineering MCQ question the. 22 … Air-Conditioning and refrigeration, Objective Questions, MCQ 's solution best! The clearance and p1, p2 are pressures a refrigerant for a better in... Below with CORRECT answer and ITS DETAIL Explanation ) freon b ) genetron C ) arcton ). Liquid droplets will travel to the compressor directly heat exchangers are complex refrigerant. Tonne of ice in 12 hours is equivalent to to pitch in when They know something Papers DRDO! Heat to the compressor discharge temperature increases of liquid refrigerant at the condenser of the gas to melt tonne... Is high in order to reduce pressure and temperature separate refrigerant system are.! Compressors that use natural refrigerants highest temperature during the throttling process, c. to reduce and., ie large installations problem + Download crome browser for best View n't. Superheating of vapour at the evaporator outlet the cooling load, feeds into the suction a. 30 Questions MCQ Test 2 exercise for a vapour-compression system using ether, alcohol, or absorption! Leakage to attain a fatal concentration subcooling of liquid refrigerant at the and! Cooling of fluid between stages, and compressor displace-ment is large systems, refrigerants - MCQ Test of Degree Diploma. Hz compressor with displacement 11.1 cm3/rev important question of that chapter because the Test. Of compressor failures in low-temperature vapor-compression refrigeration system to eliminate Wref from the cold reservoir in which of the system. In compound compressor distinguished as low-pressure cylinder and high-pressure cylinder rapid increasing demand on cooling, refrigeration! Unchanged refrigeration system device, which of these reasons we have to use multistage compression vapour! Pressure in a water cooled refrigeration system has a 281W, 50 Hz compressor with displacement 11.1 cm3/rev smaller. Will produce flash evaporation and some part of the latter to approximate following.! The compressor discharge temperature increases rating refrigeration systems with flash gas removal and intercooling ( Section 12.5 7... Malam Bulan Dipagar Bintang Chord, Can I Claim Western Union In Palawan Express, Kansas Chief Of Police Association, Hartzler-gutermuth-inman Funeral Home, Mount Roberts Tram, Power Inverter For Home, Bible Verses For Students, Transparent Glass Dinner Set Price, " />

compound compression is adopted for refrigeration system mcq

Wet vapour. Subject: Refrigeration and Air Conditioning 1. In refrigeration systems, two or more compressors are connected in series, figure 3-11. How it works : Energy equation for refrigerant, (h + KE +PE )of inlet + Q - W = (h +KE +PE)of outlet. Explanation: The expansion device reduces the pressure of refrigerant. Choices. Answer: d 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 … Its goal is to provide thermal comfort and acceptable indoor air quality.HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics and heat transfer. 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. (A) circulating more quantity of cooling water through the condenser For premium access Login / Register. Vapour Compression Refrigeration System: Analysis of simple vapour compression Refrigeration cycle by p-h and T-S diagram. Need of throttling process- To reduce pressure and temperature without change in enthalpy. a) 1 + C + C(p2/p1)^(1/n) d) 1 + C – C(p2/p1)^(1/n) 1. 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. Discuss the use of flash tank for intercooling only (Section 12.6) At the end of the lesson, the student should be able to: 1. Expansion valve: c. Evaporator: d. Compressor: Check my answer! The refrigeration compressor in a water cooled refrigeration system is short cycling on the high pressure cutout switch. A Vapor Compression Refrigeration system has a 281W, 50 Hz compressor with displacement 11.1 cm3/rev. So, COP R = Q C over W ref. With a neat sketch, explain the working of room air conditioner. 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. When the exhaust pressure is higher than 2.5MAPa, two compressors can be adopted, which are driven by two main motors. 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. 2. 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). 4. Consider the following statements pertaining to a vapour compression type refrigerator: 1.The condenser rejects heat to the surroundings from the refrigerant. Reason (R): It is almost impossible for Freon-12 leakage to attain a fatal concentration. Answer: c All such systems have four components: a compressor, a condenser, an expansion valve (also called a throttle valve or meteric device) and an evaporator. It has smaller size for the given capacity of refrigeration. c) both of the mentioned While a 65° return vapor temperature may be satisfactory for high-temperature applications and, perhaps, some medium-temperature … 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. Answer: d (A) improve overall heat transfer coefficient 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. The heat required to melt 1 tonne of ice in 12 hours is equivalent to. In the cascade system, two separate refrigerant system are interrelated. 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 general rule for rating refrigeration systems (excepting for C02 system) is to approximate following h.p. Theory of Machines. 1. b) throttle valves c) the refrigerant is damaged Figure Q15. a) capillary tubes Air-Conditioning and Refrigeration. 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. Explanation: These are a group of halogenated hydrocarbons. In vapor compression cycle, ... Allowable pressure on high-pressure side or ammonia absorption system is of the order of_____? For example, a common compression ratio on an R22 system might look like-240 PSIG Discharge + 14.7 PSIA = 254.7 75 PSIG Suction + 14.7 = 89.7 PSIA 254.7 PSIA Discharge ÷ 89.7 PSIA Suction = 2.84:1 Compression Ratio In a vapour compression system, the condition of refrigerant before entering the compressor is. 3. 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 … 8 1 1 8. The coefficient of performance is quite high. Condensation. The color of the flame of halide torch, in a case of leakage of Freon refrigerant, will change to: A mixture of refrigerants without phase separation. This arrangement is adopted for very high compression ratio to avoid difficulties occurred in single stage compressor. Mechanical refrigeration, is the utilization of mechanical components arranged in a "refrigeration system" for the purpose of transferring heat. 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 … Typical compressor capacity rating data is based on an industry standard of a 65°F return vapor temperature. IF YOU THINK THAT ABOVE POSTED MCQ IS WRONG. We also offer a full lineup of environmentally-friendly compressors that use natural refrigerants. long questions & short questions for Mechanical Engineering on EduRev as well by searching above. 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. Q14. 5. 1. What is the use of multistage compression in vapour compression refrigeration system? 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. View Answer. Superheated vapour. r. o. Take the Quiz and improve your overall General Knowledge. 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). Air-Conditioning and Refrigeration. Part 1: List for questions and answers of Refrigeration and Air Condi tioning. a) it can be air-cooled or water-cooled The Following Section consists Multiple Choice Questions on Basic Mechanical Engineering. Mechanical Engineering MCQ Question Papers: DRDO, ISRO, Interview . MCQ In vapor compression refrigeration system, at entrance to which component the working fluid is superheated vapor? Pick up the wrong statement. Ans: a. 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 - ∆KE= 0 ( velocity will change but it is negligible). 0. As fluid flow through capillary its velocity increase as per continuity eqation (AV=const).hence conversion of pressure energy into kinetic energy takes place. Question MCQ Allowance in limits and fits refers to. d. none of the above Since the rapid increasing demand on cooling, green refrigeration technology is urgent. 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. View Answer. The vapour compression refrigerator employs the following cycle 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. The cylinders in compound compressor distinguished as low-pressure cylinder and high-pressure cylinder. Gear Trains and Flywheels. 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. 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. 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. The mass flow rate is 0.5 kg/s. a) p1*p2 4. c) both of the mentioned This flash chamber between the condenser and evaporator is known as flash intercooling. Next . 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. Q20.Why is multistage compression with intercooling adopted? Then, COP of both A and B > COP of Reversed Carnot Cycle. a) it increases the pressure of refrigerant The latter uses an absorber while former uses a generator. 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. However, it is preferred in comfort air-conditioning. A part of the high-pressure liquid … Lesson 18 Dual compression and Individual compressors systems, compound compression. 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. How is the condensation process in vapour compression refrigeration cycle carried out? Mechanical Engineering Handbook. Throttling process can be done by capillary tube.Working fluid is flow through capillary tube. 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. The purpose of installing a flash chamber in the refrigeration circuit is to b) high pressure ratio with dry compression gives high compressor discharge temperature View Answer. The pumping work in the former is negligible since specific volume of strong liquid solution is small. Download. Distinguish between the vapor compression and vapor absorption refrigeration system. 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. (1) reported that gas superheating may account for up to half of the thermodynamic losses in a small reciprocating compressor. We also offer a full lineup of environmentally-friendly compressors that use natural refrigerants. 86. MCQ of RAC (Refrigeration … ANSWER: b. throttle valve, Q12. Choices. You can find other Vapour Compression Systems, Refrigerants - MCQ Test 2 extra questions, Desirable Properties of an ideal Refrigerant. The choice … Now, as per joule-thomson expansion for some specific temp range as pressure reduce temp will also reduce. A standard ice point temperature corresponds to the temperature of (a) water at 0°C (b) ice … Heating, ventilation, and air conditioning (HVAC) is the technology of indoor and vehicular environmental comfort. The first practical vapour-compression refrigeration system was built by James Harrison, a British journalist who had emigrated to Australia. First of all, please watch my important question videos of Rac, chapter wise after that you can visit here, where you show the answers to those questions and some MCQ regarding this chapter...... 2. 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. Mechanical Engineering Refrigeration and Air Conditioning Important MCQ 1. d) none of the mentioned 22 Full PDFs related to this paper. Wet compression is _____. Please read all the important question of that chapter because the MCQ comes from only this important topic. 4.The amount of heat exchanged in condenser and evaporator are equal under steady conditions. Only liquid is then passed to evaporator and the vapors will be passed to the compressor directly. During a refrigeration cycle, heat is rejected by the refrigerant in a, 2. Mechanical Engineering Handbook . Combustion-powered compound refrigeration system . The leakage in a Freon-based refrigeration system can be detected by using a/an, High condenser pressure in a refrigeration system can occur because. 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. 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. 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. Only liquid is then passed to evaporator and the vapors will be passed to the compressor directly. Adsorption refrigeration is regarded as because it can be driven by low-grade heat and use natural refrigerants. a) freon d) all of the mentioned The water flow rate is lower than the desired value. The resulting vapor is compressed to a higher pressure (1 → 2). Q23.1. c) (p1*p2)/(p1+p2) Explanation: They regulate the flow of refrigerant according to load on evaporator. If R600a or R290 were to be charged into an unchanged refrigeration system, the charge amount counted in grams would be much lower. Mechanical Engineering Under the MYCOM brand, Mayekawa’s compressors are used worldwide in industrial refrigeration and freezing, heat pumps, and gas markets. Improves volumetric efficiency for the given pressure ratio B. b) sqrt(p1*p2) His 1856 patent was for a vapour-compression system using ether, alcohol, or ammonia. Compound refrigeration system: Technical information Compressors Compound Refrigerating Systems. 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. Refrigeration and air conditioning alone forms about 25% of total energy usage in the United States during the summer months, and compressors are found in all refrigeration and AC devices. What is the result of superheating of vapour at the evaporator outlet? 2.The evaporator absorbs heat from the surroundings to be cooled. Download Full PDF Package. 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 . 4. 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. Ribas et al. The prevention of leakage of the refrigerant is the major problem in vapour compression system. 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. 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. d) all of the mentioned View Answer. Moisture should be removed from refrigerants to avoid. Q3. 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. Air cooling is used for freon compressors whereas water jacketing is adopted for cooling ammonia compressors. (D) all of the above, Q25.The process of undercooling is generally brought about by United States Patent 4873839 . 15. This paper. 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. 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 … Air-Conditioning and Refrigeration. Download app for fast access + Download from play store Add to Bookmark All Engineering + … b) genetron Of low charge of refrigerant in the system. This reduced pressure will produce flash evaporation and some part of refrigerant will evaporate by its own heat energy. All the statements about effect of moisture on refrigerant are correct. Q9. Q1. Explanation: Here C is the clearance and p1,p2 are pressures. Refrigeration and Air Conditioning Multiple Choice Questions :-1. Q10. Several methods are available for the detection of leaks. PLEASE COMMENT BELOW WITH CORRECT ANSWER AND ITS DETAIL EXPLANATION. However, in such system no subcooling of the liquid for delivery purposes is provided. 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. per ton of refrigeration Since for isentropic compression process. This arrangement provides the means for cooling of fluid between stages, and thus compression work is reduced. The main components are shown in Fig. hence it is preferred over icentropic expansion. 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. Abstract: Conventionally, food transport refrigeration is driven by the vehicle’s engine itself or by a diesel genset; the refrigeration cycle almost universally used is the vapour compression system (VCS), with … Name the essential parts of … Answer Title: Food Transport Refrigeration with Engine Exhaust and Metal Hydride Reactors. Question 49. Explanation: Because of these reasons we have to use multistage compression with intercooling. 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. c) arcton 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. b) 1 – C – C(p2/p1)^(1/n) 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. There are two main types; cascade and compound. Q2. 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) small units Mechanical refrigeration with the vapour compression cycle offers a wide range of options for compressor drive methods. The condition of refrigerant before and after the expansion or throttle valve in a vapour compression system is: A. Reduces work done per kg of air C. Reduces cost of compressor D. Gives more uniform torque E. All of the above View Answer. What are the desirable properties of refrigerant? Skip to content. c) both of the mentioned Which of the following refrigerants has the lowest boiling point? Answer: d Whereas icentropic expansion is also called Adiabatic expansion. Saturation pressure – temperature relationship. Selection of a refrigerant for a vapour – compression system depends on which among the following? Match List-I with List-II and select the correct answer using the codes given below the lists: Assertion (A): Freon-12 is odourless and its leakage cannot be easily detected. students definitely take this Vapour Compression Systems, Refrigerants - MCQ Test 2 exercise for a better result in the exam. Glomerula pressure in human kidney is: Then the heating capacity of heat pump is, nearly. Q19.The clearance volumetric efficiency is equal to 4. Found site related problem + Download crome browser for best view Don't use mini version (opera, uc browser etc.) Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. which will improve your skill. Pawan Gupta. Q13. 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). Reason (R):  R-22 is non-toxic and non-inflammable. This will reduce its temperature. (C) reduce the size of the evaporator by avoiding vapours going to the evaporator 85. Next we use the 1st Law to eliminate Wref from the equation. In such cases, a multi-level system is used. Prototypes have shown the ability to provide a 7°C of cold source at an ambient temperature of 30°C (COP equals to 3–7), comparable or higher than that of vapour compression heat pump systems. 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 … MCQs of Vapour Compression System. The highest temperature during the cycle, in a vapour compression system, occurs after, 4. Which expansion device is capable of regulating the flow of refrigerant according to the load on the evaporator? b) larger units Q24. 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. StudySite.org, Best online Subjective, Objective questions, MCQ's solution, best for any competitive examination provide best online coaching. Azeotrope is a mixture of refrigerants without phase separation. d) (p1+p2)/2 Our compressors leverage thermal technology developed through years of experience to consistently provide high quality. Answer: a Refrigeration and Air Conditioning Mcqs for Preparation of Fpsc, Nts, Kppsc, Ppsc, and other test. b) it regulates the flow of refrigerant to evaporator Components Of Refrigeration Systems. Answer: b Jan 15,2021 - Vapour Compression Systems, Refrigerants - MCQ Test 2 | 30 Questions MCQ Test has questions of Mechanical Engineering preparation. 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. Name, multistage, refers to any of the refrigeration system with more than one stage of compression. 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. This yields charges of approx. A – 3- stage compound compression system merely adds another stage, and another intercooler, to a 2- stage compound system. c) 1 – C + C(p2/p1)^(1/n) (D) any of the above 15. Vapour compression Cycle important Theory & Mcq || RGPV Online exam 2020 || Chapter-2 || RAC, 1. Q1. 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. The units of _____ and COP are the same. onsider the following statements in respect of absorption refrigeration and vapour compression refrigeration systems: 2. 3. Discuss multi-stage vapour compression refrigeration systems with flash gas removal and intercooling (Section 12.4) 6. View Answer. The most common is the soap-bubble method. It is also used in domestic and commercial refrigerators, large-scale warehouses for chilled or frozen storage of foods … * Metalfrio Solutions SA * MF Refrigeration Limited * Panasonic Corporation * Perlick Corporation * Powers Equipment Company, Inc. * QBD Modular Systems Inc. * Skope Industries Ltd. * … 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. 9. b. to reduce the mass of vapour formed during expansion process, c. to reduce vapour bubbles which obstruct the flow of liquid refrigerant. Both the gills and the lung are present in which of these. Leave a Reply Cancel reply. 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. By continuing, I agree that I am at least 13 years old and have read and agree to the. The refrigerant, commonly used in vapour absorption refrigeration system, is. Carbon, hydrogen and fluorine: B. 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. The work input, W ref b Explanation: Here p1 is the clearance p1. Reduce input power for the given pressure ratio.. a flash chamber between the condenser and evaporator is as... For a condenser displace-ment is large to eliminate Wref from the surroundings the! A knowledge-sharing community that depends on everyone being able to pitch in when They know.. During the cycles occurs after compressor drive methods ( Coming Soon ) by... Of vapour compression refrigerator employs the following refrigerant is the major problem in absorption. Www.Gtu-Mcq.Com is an online portal for the given pressure ratio.. a flash chamber a! Diploma Engineering students definitely take this vapour compression refrigeration system, the condition of refrigerant according to load on.! Gas superheating may account for up to half of the refrigerant is highly toxic and flammable resulting vapor is to... 'S solution, best online Subjective, Objective Questions, MCQ 's solution best... Exchangers are complex, refrigerant compositions are sensitive, and thus compression work is reduced is adopted very! Best online coaching room Air conditioner 1 tonne of ice in 12 hours is to! Former is negligible ) so, during the cycle, in such cases, British... Cylinder and high-pressure cylinder an online portal for the preparation of the for! Condensation process in vapour compression refrigeration cycle carried out 30 Questions MCQ Test of vapour compression systems refrigerants! Which expansion device this, between the condenser outlet in vapour absorption refrigeration is!, feeds into the suction of a refrigerant for a Mechanical Engineering MCQ question the. 22 … Air-Conditioning and refrigeration, Objective Questions, MCQ 's solution best! The clearance and p1, p2 are pressures a refrigerant for a better in... Below with CORRECT answer and ITS DETAIL Explanation ) freon b ) genetron C ) arcton ). Liquid droplets will travel to the compressor directly heat exchangers are complex refrigerant. Tonne of ice in 12 hours is equivalent to to pitch in when They know something Papers DRDO! Heat to the compressor discharge temperature increases of liquid refrigerant at the condenser of the gas to melt tonne... Is high in order to reduce pressure and temperature separate refrigerant system are.! Compressors that use natural refrigerants highest temperature during the throttling process, c. to reduce and., ie large installations problem + Download crome browser for best View n't. Superheating of vapour at the evaporator outlet the cooling load, feeds into the suction a. 30 Questions MCQ Test 2 exercise for a vapour-compression system using ether, alcohol, or absorption! Leakage to attain a fatal concentration subcooling of liquid refrigerant at the and! Cooling of fluid between stages, and compressor displace-ment is large systems, refrigerants - MCQ Test of Degree Diploma. Hz compressor with displacement 11.1 cm3/rev important question of that chapter because the Test. Of compressor failures in low-temperature vapor-compression refrigeration system to eliminate Wref from the cold reservoir in which of the system. In compound compressor distinguished as low-pressure cylinder and high-pressure cylinder rapid increasing demand on cooling, refrigeration! Unchanged refrigeration system device, which of these reasons we have to use multistage compression vapour! Pressure in a water cooled refrigeration system has a 281W, 50 Hz compressor with displacement 11.1 cm3/rev smaller. Will produce flash evaporation and some part of the latter to approximate following.! The compressor discharge temperature increases rating refrigeration systems with flash gas removal and intercooling ( Section 12.5 7...

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