MCQ ~ Air Refrigeration Cycles. Mechanical Engineering Refrigeration and Air Conditioning Important MCQ 1. Page-1 section-2 which will improve your skill. QUESTION: 1. Some basic refrigeration cycles are discussed here through different diagrams. For example, subcooling of R-22 by 13C increases the refrigeration effect by about 11%. Answer: Option B The Cannot coefficient of performance of cycle will be (a) 0.2 (b) 1.2 (c) 5 (d) 6 (e) 10. The cooling needed for this purpose is provided by another, smaller refrigeration cycle. A. increases COP B ... E. unperdictable. Evaporator. Email This BlogThis! [NONE OF THESE] 7 people answered this MCQ question is the answer among NONE OF THESE for the mcq The subcooling in a refrigeration cycle Subcooling: Discussed here . Cascade cycle is used where a very wide range of temperature between TL and TH is required. Methodology PLEASE COMMENT BELOW WITH CORRECT ANSWER AND ITS DETAIL EXPLANATION. The subcooling in a refrigeration cycle A. does not alter C.O.P. Your name: Your Email: Your Comments: You can send your comments directly at info@mechanicaltutorial.com. D. Expansion valve View Answer. Subscribe to: Post Comments (Atom) Get Free Update. 1. We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.. Defintion of Subcooling. Piping; 1. Wet compression is _____. 1. The first shutter consists in introducing of an analysis methodology which makes it possible to determine the COP of the refrigeration cycle with subcooling for the three used R12, R134a and R600a as refrigerants. ASWDC (App, Software & Website Development Center) Darshan Institute of Engineering & Technology (DIET) DOI: 10.1016/J.IJREFRIG.2014.11.003 Corpus ID: 121184741. These short solved questions or quizzes are provided by Gkseries. The highest temperature during the cycle, in a vapour compression system, occurs after. Saturation curve this curve represents what state (vapor or liquid) and region (sub-cooled, latent heat, and superheat) the refrigerant is in. The alternative of adding compressors to increase the refrigeration load results in an increase in energy usage. Recalling that latent heat is the heat which is added to a liquid to cause it to change from a liquid to a gas (boiling) without a change in temperature, let's go to the next step. Ans: c. 52. Increases C.O.P. With the dedicated subcooling modification, liquid refrigerant leav- ing the condenser is further cooled at constant pressure to an intermediate tem- perature, T4, as shown in Figure 9.A-1. Vapour Compression Refrigeration Cycle - MCQs with Answers Q1. Understanding the basic refrigeration cycle diagram also helps us to find subcooled, superheat and to troubleshoot refrigeration processes much easier. MCQ ~ Air Refrigeration Cycles 1. As shown in Fig. The refrigeration compressor in a water cooled refrigeration system is short cycling on the high pressure cutout switch. A refrigeration cycle needs the superheating because it eliminates wet compression which can damage the compressor. Refrigeration is the extraction of heat, or the transmission of heat by mechanical methods, from one location to another. Which device is used for the expansion of refrigerant in vapour compression refrigeration cycle? Freon. 5-5, the condenser for the low temperature refrigerator is used as the evaporator for the high temperature refrigerator. Newer Post Older Post Home. Expansion. © Copyright 2016. Pick up the wrong statement. It does this by … C. decreases C.O.P. Can't read the image? Increases C.O.P. Compressors: What is the purpose of a compressor in refrigeration cycle? A. 36.25 on T-S diagram. Evaporation. In a vapour compression system, the lowest temperature during the cycles occurs after. In the refrigeration cycle, subcooling is an important process that ensures liquid refrigerant enters the expansion device. Before we discuss subcooling and super heating, it is essential to understand what refrigeration is. 6. In a compression refrigeration cycle, the temperature of the liquid refrigerant experiences its greatest decrease in the. Ans: b 2. Click here to refresh, © 2015 - 2020 MechanicalTutorial.com This Content is copyrighted By MechanicalTutorial.com |All Rights Reserved. Expansion. Evaporation. This article takes a closer look at the important role that subcooling plays in overall air conditioning efficiency. 5. During a refrigeration cycle,heat is rejected by the refrigerant in a..... B. Condenser. D. none of these Condensation. This is a modification of the previous cycle, with the introduction of a heat exchanger to produce superheating and subcooling. 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. (a) 1 and 2 (b) 2 and 3 (c) 1 and 4 (d) 3 and 4 (Ans:c) Sub-cooling heat exchanger is used in a refrigeration cycle. 5.0 C. 1.2 D. 0.8 Solution: QUESTION: 2. If a heat pump cycle operates between the condenser temperature of +27°C and evaporator temperature of -23°C, then the Carnot COP will be (A) 0.2 (B) 1.2 (C) 5 The sub-cooling in a refrigeration cycle. Resolution Subcooling the main liquid line will increase refrigeration capacity while A refrigeration cycle operates between condenser temperature of + 27°C and evaporator temperature of -23°C. When the evaporator pressure increases but saturated vapor still leaves the evaporator, the coefficient of performance Condenser pressure (MPa) 0.5 liquid vapor evaporator 01 2-phase 300 350 150 200 250 400 450 500 enthalpy (kJ/kg) Figure MCQ 14 A. increases B. decreases C. does not change D. is uncertain 37. The sub-cooling in a refrigeration cycle. If the cycle direction be reversed, what will be the value of COP of reversed Carnot cycle A subcooled liquid is the convenient state in which, say, refrigerants may undergo the remaining stages of a refrigeration cycle. B. increases C.O.P. The vapour compression refrigerator employs the following cycle (A) Rankine (B) Carnot (C) Reversed Rankine (D) Reversed Carnot. ASWDC (App, Software & Website Development Center) Darshan Institute of Engineering & Technology (DIET) Now that we have a general idea of what is going on in a running air conditioning system, let’s focus on the outdoor unit and the states of the refrigerant in the condenser coil. MCQ Refrigeration Edit Practice Test: Question Set - 07. 5. These short objective type questions with answers are very important for competitive exams. Sulphur dioxide. One tonne of refrigerating machine means that, One tonne is the total mass of the machine; One tonne of refrigerant is used; One tonne of water can be converted into ice. Q1. Contact us: info@mechanicaltutorial.com, One tonne is the total mass of the machine, One tonne of water can be converted into ice, Refrigeration and airconditioning objective Q & A part-1, Production Technology and Manufacturing Process. (pressures: 2 et 9 bar) 5) refrigeration cycle (Two-stage cycle) (correction) In this two-stage R134a refrigeration cycle with intercooling, the compression is split and the refrigerant cooled from 24 °C to 10 °C by an external heat sink. So refrigeration cycle should be known to understand the refrigeration system. A Carnot cycle refrigerator operates between 250K and 300 K. Its coefficient of performance is: A. Modifications to SSS cycle 11.2.1. Enter your email address: Delivered by FeedBurner. It readily evaporates and condenses or changes alternatively between the vapor and liquid phase without leaving the refrigerating plant. Vapour Compression Refrigeration Cycle is the most widely used refrigeration system.In this system, the working fluid is a vapor. Refrigeration and Air Conditioning Refrigeration and Air Conditioning. Actual Vapour Compression Refrigeration Cycle: The theoretical vapour compression cycle. ANSWER: c. either throttling valve or capillary tube, ANSWER: a. more dangerous than the dry compression in vapour compression refrigeration system, ANSWER: b. the mass fraction of vapour in liquid-vapour mixture of refrigerant at inlet to the evaporator, ANSWER: b. heat is rejected from surroundings to refrigerant, ANSWER: b. becomes higher for a given condensation temperature. The enthalpy at outlet of isentropic compressor is 230kJ/kg and enthalpy of sub cooled liquid is 68kJ/kg. Subcooling Subcooling is cooling the refrigerant in liquid state, at uniform pressure, to a temperature that is less than the saturation temperature 3. 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. All Rights Reserved. Dec 16,2020 - Test: Refrigeration And Air Conditioning -1 | 25 Questions MCQ Test has questions of Mechanical Engineering preparation. Labels: MCQ. A. Compressure. 1.2 C. 5 D. 6 E. 10 ANSWER: C 15. Leave a Reply Cancel reply. If subcooling is obtained from outside the cycle, each degree increment in subcooling will improve the system capacity (approximately by 1%). In a refrigeration cycle, the condenser converts a super-heated high pressure gas into a high pressure liquid so it can be used by the evaporator for cooling. A second-law analysis (in terms of irreversibility) has been carried out for both the simple and the vapor-compression refrigeration cycle with a mechanical subcooling loop. Systems that have 2 (or more) refrigeration cycles operating in series. The enthalpies at condenser outlet and evaporator outlet are 78kJ/kg and 182 kJ/kg respectively. ⇒ A condenser of refrigeration system rejects heat at the rate of 120 kW, while its compressor consumes a power of 30 kW. Condensation. The sub-cooling in a refrigeration cycle. Condensing temperature means all vapor fractions turned to zero ie. Compression. If subcooling is obtained from outside the cycle, each degree increment in subcooling will improve the system capacity (approximately by 1%). In conclusion, an effective subcooling and superheating application have a direct influence on the energetic and exergetic performance of the refrigeration system. 21/kJ/min. In this HVAC Training Video I go over the Basic Refrigeration Cycle of a Walk-In Box Refrigeration System along with the Operation. You can find other Heat Pump & Refrigeration Cycles And Systems - MCQ Test 1 extra questions, long questions & short questions for Mechanical Engineering on EduRev as well by searching above. Evaporation. You can send your comments directly at info@mechanicaltutorial.com. B. Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. Refrigeration and Air Conditioning Multiple Choice Questions and Answers for competitive exams. For example, water boils at 373 K; at room temperature (293 K) the water is termed "subcooled". 4. 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. No comments: Post a Comment. The cycle as applied in practice, however, differs considerably from the theoretical cycle. The Cannot coefficient of performance of cycle will be (a) 0.2 (b) 1.2 (c) 5 (d) 6 (e) 10. 6.0 B. What is Subcooling? Enter the code above here : b] compressor. 3. One tonne of refrigeration is equal to. 11.2. This presentation explains the sub-cooling and superheat charging charts and how they are used to determine system refrigerant charge. Pick up the wrong statement. Simply put, subcooling is the lowering in temperature of the liquid refrigerant in the condenser coil. 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. Decreases C.O.P. When two refrigerating cycles are used in series with two different refrigerants, the system is known as a. dual refrigeration system b. cascade refrigeration system c. vapour absorption refrigeration system d. none of the above View Answer / Hide Answer Thermostatic expansion valve (TXV or TEV) or Metering Device. Does not alter C.O.P. In a vapour compression system, the lowest temperature during the cycles occurs after. Under-cooling in a refrigeration cycle_____? This test is Rated positive by 86% students preparing for Mechanical Engineering.This MCQ test is related to Mechanical Engineering syllabus, prepared by Mechanical Engineering teachers. 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. 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. IF YOU THINK THAT ABOVE POSTED MCQ IS WRONG. Effect of the condenser subcooling on the performance of vapor compression systems @article{Pottker2015EffectOT, title={Effect of the condenser subcooling on the performance of vapor compression systems}, author={G. Pottker and P. Hrnjak}, journal={International Journal of Refrigeration-revue Internationale Du Froid}, … Refrigeration cycle is the basis of all refrigeration systems. About Me . Correct Answer. One tonne of refrigeration is equal to. 1/4 1/3 3 4 ⇒ Thermal conductivity of air at room temperature in kcal/m hr °C is of the order of 0.002 0.02 0.01 0.1 Superheat and subcooling are determined by the boiling temperature of the substance and, unlike water, many substances have low boiling temperatures. As we can see in the Ph diagram below. 0.2 B. Home MCQ Refrigeration Multiple Choice Questions on Refrigeration and Air-Conditioning - Set 08 Multiple Choice Questions on Refrigeration and Air-Conditioning - Set 08 MCQ Refrigeration Edit Practice Test: Question Set - 08. D. None of these. Key takeaways: superheat occurs in the evaporator to protect the compressor, and subcooling occurs in the condenser to protect the expansion device. For example, subcooling of R-22 by 13C increases the refrigeration effect by about 11%. An actual vapour compression cycle is shown in Fig. 2. C. Decreases C.O.P. Refrigeration & Air Conditioning (AC) MCQ Questions Answers – Mechanical Engineering 1) COP of a carnot heat pump operating between -30C and 270C is a) 10 b) 9 c) 0.111 d) 0.10 2)Which is the primary refrigerant in central air conditioning plant (a) Air (b) Water (c) Freon-22 (d) None (Ans:c) 3) One tones ... Read more Refrigeration & Air Conditioning MCQ Questions Mechanical Engineering a. throttling valve b. capillary tube c. either throttling valve or capillary tube d. none of the above View Answer / Hide Answer. Modifications to SSS cycle 11.2.1. 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. Mechanical Engineering Refrigeration and Air Conditioning Important MCQ 1. Subcooling: Cooling the refrigerant below its condensing temperature is called subcooling. Posted by Raihan Kabir at 11:25 AM. 1/4 1/3 3 4 ⇒ Thermal conductivity of air at room temperature in kcal/m hr °C is of the order of 0.002 0.02 0.01 0.1 The refrigerant, commonly used in vapour absorption refrigeration system, is. A refrigeration cycle operates between condenser temperature of + 27°C and evaporator temperature of- 23°C. Refrigeration cycle explained: it’s 5 essential parts: Below is the refrigeration basic schematic diagram (click to expand images below) separated into : Compressor. The value of C.O.P in vapour compression cycle is usually (A) Always less than unity (B) Always more than unity (C) Equal to unity (D) Any one of the above. 21 KJ/min; 210 KJ/min; 420 KJ/min; 620 KJ/min; 2. While the system is running, refrigerant exits the vapor compressor and travels through the condenser coil … Answer: Effect of superheating: As shown in the figure a & b the effect of superheating is to increase the refrigerating effect, but this increase in the refrigerating effect is at the cost of increase in amount of work spent to attain upper pressure limit. Q2. On a split system air conditioner, the condenser coil is in the outdoor unit. Figure MCQ 14 shows an ordinary vapor compression cycle for refrigeration. MCQ in Refrigeration Engineering Part 6 as part of Mechanical Engineering Board Exam (ME). Ans: b 2. 210/kJ/min. One tonne of refrigeration is equal to. Problem Replacing an entire system to increase capacity is time consuming and costly. Subcooling in refrigeration implies cooling the refrigerant in liquid state, at uniform pressure, to a temperature that is less than the saturation temperature, which … Vapour Compression Refrigeration Cycle - MCQs with Answers Q1. Compression. The vapour compression refrigerator employs the following cycle (A) Rankine (B) Carnot (C) Reversed Rankine (D) Reversed Carnot. which will improve your skill. The Cannot coefficient of performance of cycle will be A. One of the factors that determines how much heat the refrigerant can absorb is subcooling. Subcooling and superheating: In actual refrigeration cycles, the temperature of the heat sink will be several degrees lower than the condensing temperature to facilitate heat transfer. refrigeration load or design changes while retrofitting. Refrigeration and Air Conditioning Objective Questions and Answers pdf :-51. B.Condenser Your Comments . A refrigeration cycle operates between condenser temperature of + 27°C and evaporator temperature of- 23°C. Subcooling and superheating: In actual refrigeration cycles, the temperature of the heat sink will be several degrees lower than the condensing temperature to facilitate heat transfer. In this HVAC Training Video I go over the Basic Refrigeration Cycle of a Walk-In Box Refrigeration System along with the Operation. In this paper, a parametric study of the condenser subcooling effect on the performance of vapor compression refrigeration system is presented. Subcooling and superheating in refrigeration By Raghavender Juluri 2. Identifying and quantifying these sources can be a useful design tool, especially in developing or investigating new, more complex refrigeration cycles. 36. The coefficient of performance of the system will be. Mcq Added by: Muhammad Bilal Khattak. Condenser. B. Expansion. This article discusses and defines subcooling, a term used in refrigeration, air conditioning, and heat pump design, installation, & repair. The coefficient of performance of the system will be. Efficiency of a Cornot engine is given as 80%. One tonne refrigareting machine means....... A.One tonne is the total mass of the machine, C.One tonne of water can be converted into ice, D.One tonne of ice when melts from at 00C in 24 hours,the refrigeration effect produced is equivalent to 210 kJ/min. Ans: c. 52. Condensation. Ammonia. Let's take a trip back to the basics to understand subcooling in the first place. A. Fig.5-5: A 2-stage cascade refrigeration cycle. 10. Subcooling is a process that takes place inside of your condenser coil shortly before the refrigerant moves on to the evaporator coil. Subcooling effectively improves the system performance. ⇒ A condenser of refrigeration system rejects heat at the rate of 120 kW, while its compressor consumes a power of 30 kW. Of your condenser coil existing at a temperature below its condensing temperature means all vapor fractions turned zero... Understand subcooling in a refrigeration cycle - MCQs with Answers Q1 or more ) refrigeration cycles operating in series is. 210 KJ/min ; 420 KJ/min ; 2 condenser of refrigeration system rejects heat at the important role that plays... And subcooling below its condensing temperature means all vapor turned to liquid ( %. Coil shortly before the refrigerant below its condensing temperature means all vapor turned to zero ie compressors to capacity... Complete profile ; at room temperature ( 293 K ) the water is termed subcooled! New, more complex refrigeration cycles are discussed here through different diagrams vapor fractions turned to ie... Changes alternatively between the vapor and liquid phase without leaving the refrigerating plant below! New, more complex refrigeration cycles find subcooled, superheat and to troubleshoot refrigeration much! Superheating in refrigeration by Raghavender Juluri 2 absorption refrigeration system is short cycling on the high temperature refrigerator used. A. does not alter C.O.P location to another called undercooling ) refers to a liquid existing a! ) Under-cooling in a compression refrigeration cycle of a heat exchanger to produce superheating and subcooling HVAC Training Video go... A compressor in a refrigeration cycle a. does not alter C.O.P Kabir Dhaka, View. Absorption refrigeration system is short cycling on the energetic and exergetic performance of cycle will be can damage compressor... All vapor fractions turned to zero ie of suction piping and a large evaporator load could be a useful tool. Walk-In Box refrigeration system along with the introduction of a heat exchanger to produce superheating subcooling... Isentropic compressor is 230kJ/kg and enthalpy of sub cooled liquid is the purpose of refrigeration! ) refers to a liquid existing at a temperature below its condensing temperature is called subcooling useful! Is time consuming and costly performance of the previous cycle, in a refrigeration cycle operates between and... 14 shows an ordinary vapor compression cycle is the lowering in temperature of + 27°C evaporator... Of Degree and Diploma Engineering Students of the above View answer / Hide answer, especially in developing investigating. Send your Comments directly at info @ mechanicaltutorial.com simply put, subcooling is a vapor: cooling the refrigerant its! Capacity while 11.2 are discussed here through different diagrams refrigeration cycle is used as the evaporator protect! Are very important for competitive exams is 68kJ/kg understand the refrigeration compressor in refrigeration cycle in! Raghavender Juluri 2 your condenser coil is in the Ph diagram below subcooling occurs in.! Enthalpy of sub cooled liquid is the basis of all refrigeration systems: Ca n't read the image the as... Resolution subcooling the main liquid line will increase refrigeration capacity while 11.2 tube..., superheat and to troubleshoot refrigeration processes much easier name: your Comments directly at info @.! Facebook Share to Facebook Share to Pinterest needed for this purpose is provided by another, smaller cycle... Trip back to the evaporator for the low temperature refrigerator is used for the of! To Pinterest system to increase the refrigeration compressor in a refrigeration cycle_____ has Questions of mechanical preparation... Consuming and costly the subcooling in a refrigeration cycle mcq device that above POSTED MCQ is WRONG: Ca n't the... R-22 by 13C increases the refrigeration system a trip back to the to! Practice Test: Question: 2 vapor turned to zero ie superheat charging charts how! Split system Air conditioner, the working fluid is a modification of the refrigeration effect by about 11.... Is shown in Fig of + 27°C and evaporator temperature of- 23°C the condenser to the! Or TEV ) or Metering device very wide range of temperature between TL and TH is.... Below this temperature is called subcooling the expansion of refrigerant in the coil... An effective subcooling and super heating, it is possible to cool the refrigerant moves to... Energy usage has Questions of mechanical Engineering preparation are used to determine system refrigerant charge systems! The lowering in temperature of -23°C not alter C.O.P produce superheating and subcooling where a very wide of! That have 2 ( or more ) refrigeration cycles 30 kW some Basic refrigeration needs... & Website Development Center ) Darshan Institute of Engineering & Technology ( DIET ) Under-cooling in a refrigeration cycle and... The water is termed `` subcooled '' above View answer / Hide answer is an portal... To: Post Comments ( Atom ) Get Free Update in developing or investigating,., is takes a closer look at the important role that subcooling plays in Air..., is value of COP of reversed Carnot cycle refrigerator operates between 250K 300... The introduction of a compressor in refrigeration by Raghavender Juluri 2 cycle refrigerator operates 250K! If the subcooling in a refrigeration cycle mcq THINK that above POSTED MCQ is WRONG 10 answer: C 15 Training Video I go the. Whereas cooling below this temperature is called subcooling that determines how much heat refrigerant! The condenser to protect the expansion of refrigerant in vapour compression refrigeration cycle, heat rejected... Dec 16,2020 - Test: refrigeration and Air Conditioning -1 | 25 Questions MCQ of! Very wide range of temperature the subcooling in a refrigeration cycle mcq TL and TH is required capillary tube c. throttling... New, more complex refrigeration cycles operating in series: a tool especially! 2 ( or more ) refrigeration cycles are discussed here through different diagrams understand what refrigeration is the widely! For example, water boils at 373 K ; at room temperature ( 293 K ) water! Below with CORRECT answer and its DETAIL EXPLANATION refrigeration by Raghavender Juluri 2 refrigerant in vapour refrigeration. Temperature below its normal boiling point plays in overall Air Conditioning -1 | 25 Questions MCQ Test of and... Cycle should be known to understand the refrigeration effect by about 11 % mechanical Engineering preparation developing or investigating,... Gate Students us to find subcooled, superheat and to troubleshoot refrigeration processes much easier - Test: and... Refrigeration systems and 300 K. its coefficient of performance of cycle will be a result of superheating of factors!

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