Q9. Q17. All refrigerators/heat pumps need energy input in some form, so as to not violate second law of thermodynamics. a) it can be air-cooled or water-cooled Pick up the wrong statement. Choose the letter of the best answer in each questions. (d) None Which of the following refrigerants has the lowest boiling point? b) it regulates the flow of refrigerant to evaporator Remote refrigeration: This is the cheapest system and it consists of a condensing unit and an evaporator unit. Which device is used for the expansion of refrigerant in vapour compression refrigeration cycle? Answer: a During a refrigeration cycle, heat is rejected by the refrigerant in a. Explanation: They regulate the flow of refrigerant according to load on evaporator. B. Vapour Compression Refrigeration Cycle - MCQs with Answers Q1. 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. On average you will not need a compressor larger than 1/4hp and anything 1/6hp or better is above average. F. condensing temperatures, net refrigeration effect is 49.06 Btu/lb. Answer (B) MCQs of Air Refrigeration. Factors that affect the performance of compressors are the speed of rotation, pressure at suction, pressure at discharge, and type of refrigerant being used. (c) >3.5 bars Posted: May 15, 2018 by Zander Buel. In this article, we’re going to be understanding the term refrigeration ton. (c) Pressure and volume What is the most common freon gas used in reciprocating compressors? compressors, known as “L” compressors, used refriger-ants 11 and 114 in two frame sizes for air-condi-tioning capacities between 90 and 600 tons. The function of the compressor is to compressor the gas in to liquid. C. F – 22. Q22.The most widely used refrigerants are C. High … The refrigerant, commonly used in vapour absorption refrigeration system, is. Basically, if someone had a 20 ton (non-packaged) unit with multiple air handling units (AHU’s), regardless of the piping, it would be assumed that the unit had somewhere between 60-80 pounds of refrigerant. A Compressor is a pump used to increase the low pressure of air to a greater pressure. One of the first things every HVAC/R student learns is that air conditioning units don’t create cool air. Occasionally, it is necessary to install the condensing unit several feet above the evaporator. C. F – 22. Wet vapour. The Frick® SGC, SGCH & SGCB bare screw compressors are designed to compress a variety of gases for quality solutions in refrigeration, water chilling, wellhead compression, gas gathering, and vapor recovery. Since some refrigeration equipment runs at temps significantly colder than 32°F sometimes, we’re going to need to add some heat because there simply isn’t enough heat in the refrigerated space to get the frost melted without causing significant damage to the product. The adjustable fan cycling control is set to cut in at the high end of your normal saturated condenser temperature (SCT). 1. For an introduction to the workings of a compression refrigeration system, go to Refrigeration 101. Home MCQ Refrigeration Multiple Choice Questions with Answers on Refrigeration and Air-Conditioning ... Set 07 Multiple Choice Questions with Answers on Refrigeration and Air-Conditioning - Set 07 MCQ Refrigeration Edit ... the pressure range of compressor should be (A) High (B) Low (C) Optimum (D) Any value. A thermostat controls the system. When it gets cold out the refrigerant pressures will drop too low … A. Dear all, I need to cool a water flow (4630 lbs/h) from 35 to about 8 degrees centigrade (antifreeze can be used) using a refrigeration cycle includes compressor, condenser and evaporator. (d) None ANSWER: b. throttle valve, Q12. Q23.1. b) 1 – C – C(p2/p1)^(1/n) A refrigeration system of a refrigerator consists of condensing unit and an evaporation coil. The effect of varying compressor efficiency on the COP of the three GSHP system configurations are presented in Fig. Page-1 section-2 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. This flash chamber between the condenser and evaporator is known as flash intercooling. High critical temperature. The condensing coil is often placed inside the walk-in refrigerator. Answer: b It can be employed over a large range of temperatures. (b) <1.5 bars (b) Pressure alone What is used as an intercooler in multistage compression of vapour compression refrigeration system? d) all of the mentioned 4. Proper division can obtain the relationship between refrigerating ability and volume of gas to be handled by the compressor. With the industry now in the midst of sweeping regulations, Emerson is leading the development of the next generation of refrigeration technology. b) throttle valves In all the household refrigerators, deep freezers, window air conditioners, split air conditioners, most of the packaged air conditioners, the hermetically sealed reciprocating compressor is used. If the suction riser in such an installation is over 30 ft, traps should be installed at 30-foot intervals or less, to catch the oil and refrigerant remaining in the suction line when the compressor stops. The air conditioner component of a building’s HVAC system essentially is a type of refrigerator that cools and dehumidifies the air in the building, ensuring thermal comfort for the occupants. Thermostatic expansion valve or TEV is one of the most commonly used throttling valve for the refrigerator and air conditioning systems. Our Copeland™ compressor line-up has continuously set the standard in performance and reliability. In a vapour compression system, the lowest temperature during the cycles occurs after, 5. (A) circulating more quantity of cooling water through the condenser B. F – 11. Compressor in a refrigeration system increases (a) Temperature and pressure (b) Temperature and volume (c) Pressure and volume (d) None (Ans:a) Reciprocating compressor is used in refrigeration when pressure difference between condenser and evaporator is (a) >1.5 bars (b) <1.5 bars (c) >3.5 bars (d) None (Ans:c) Reciprocating compressor is used in refrigeration when volume to be … One ton of the refrigeration is (a) the standard unit used in refrigeration problems (b) the cooling effect produced by melting 1 ton of ice (c) the refrigeration effect to freeze 1 ton of water at 0°C into ice at 0°C in 24 hours (d) the refrigeration effect to produce 1 ton of ice at NTP conditions Compressor. As gases are compressible, the compressor also reduces the volume of a gas. Scroll to the bottom to watch the YouTube tutorial on Centrifugal chillers The compressor is […] - ∆KE= 0 ( velocity will change but it is negligible). 2. Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. These units typically draw about 5A @ 12V DC when running, but with a properly insulated box, the average current draw can be as little as 2A. (Ans:a), Centrifugal compressor is used in refrigeration when pressure difference between condenser and evaporator pressures is (d) None (Ans:c), Reciprocating compressor is used in refrigeration when volume to be compressed The prevention of leakage of the refrigerant is the major problem in vapour compression system. 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. Evaporator: This is the part of the refrigeration system that is doing the actual cooling. Answer: c When do we need three compressors in a refrigeration unit? If … Why do we use this rather than just cycling the compressor off and on like a residential HVAC unit? b) larger units I do not think that you can get below 30 in merc. (d) None Refrigeration compressor units that are installed outdoors must have cold weather controls to operate properly and maintain proper temperature in the cooler or freezer during the cold winter season. Answer: b As fluid flow through capillary its velocity increase as per continuity eqation (AV=const).hence conversion of pressure energy into kinetic energy takes place. Q10. Slide the rotating unit onto the shaft with a turning motion up to the shoulder in the shaft. The coefficient of performance is quite high. The function of a compressor in a VCRS is to continuously draw the refrigerant vapour from the evaporator, so that a low pressure and low temperature can be maintained in the evaporator at which the refrigerant can boil extracting heat from the refrigerated space. 1. (a) Temperature alone 151. They’re more vulnerable against pulsation issues, valve problems, and other reciprocating compressor areas of concern. c) both of the mentioned Step 1. 01) full size refrigerator: compressor probably about 1/8 - 1/6hp 02) full size refrigerator freezer combo: compressor typically 1/6 - 1/3hp 03) chest freezer: compressor typically 1/4 - 1/2hp 04) full size freezer: compressor typically 1/5 - 1/3hp 05) mini fridge: compressor range 1/20 - 1/8hp 06) mini freezer: compressor range 1/10 - 1-6hp Service valves on Copeland® brand condensing units have a torque requirement of 22-25 ft lbs. View Answer. Q20.Why is multistage compression with intercooling adopted? The compressor is the heart of the cooling function of heating, ventilation and air conditioning (HVAC) systems. (a) >1.5 bars 1. d) (p1+p2)/2 Answer: b B. F – 11. This article is written by Jeremy Smith CM, experience refrigeration tech and all-around great dude. ... For the same compressor work, COP of the refrigerator as compared to COP of the heat pump is (A) low (B) high (C) same (D) unpredictable. Use the right tools! View Answer: Answer: Option … Defrost can be as simple as turning the compressor off for a period of time or as elaborate as reversing the flow of refrigerant for the whole system or … Refrigeration systems generally include five components: a compressor (essentially a pump), heat exchanger pipes outside the unit (the condenser), an expansion valve, heat exchanger pipes inside the box with your food (the evaporator), and a nontoxic fluorinated-ethane chemical (R-134a) called the refrigerant. Explanation: Here C is the clearance and p1,p2 are pressures. This reduced pressure will produce flash evaporation and some part of refrigerant will evaporate by its own heat energy. b) sqrt(p1*p2) Explanation: Here p1 is the evaporator pressure and p2 is the condenser pressure. d) all of the mentioned A: Whenever a condenser is located above the compressor, an inverted trap or check valve should be installed at the condenser inlet to prevent liquid refrigerant from flowing backwards into the compressor during off cycles. In fact, all major industries like foods, chemicals, and technology need refrigerating systems for maintaining cold storage. What is the result of superheating of vapour at the evaporator outlet? The highest temperature during the cycle, in a vapour compression system, occurs after, 4. Throttle valves are used in ____ Ans: b 2. In a vapour compression system, the condition of refrigerant before entering the compressor is, 3. From that point, you can go on to sizing your compressor, working fluid, operating pressure, condenser, evaporator, air flow rates, etc. View Answer. How does a compressor work? compressors, known as “L” compressors, used refriger-ants 11 and 114 in two frame sizes for air-condi-tioning capacities between 90 and 600 tons. Explanation: Because of these reasons we have to use multistage compression with intercooling. (a) When temperature to be achieved is around 5 0 C, (b) When temperature to be achieved is around –5 0 C, (c) When temperature to be achieved is around –50oC. Another example using a different split: A walk-in meat cooler at 35 ° F, load of 21,600 BTU/hr. Most of the Chemical Process Industries use compressors to achieve the desired Reaction pressure, Refrigeration effect … ASWDC (App, Software & Website Development Center) Darshan Institute of Engineering & Technology (DIET) 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. We’re getting closer to the day when all transport refrigeration units are 100% electric, but we’re not there yet. Q8. Home MCQ Refrigeration Refrigeration and Air-Conditioning Multiple Choice Questions with Answers - Set 03 Refrigeration and Air-Conditioning Multiple Choice Questions with Answers - Set 03 ... keeping the condenser temperature constant, the h.p. Q21.The intercooler pressure is given by (D) all of the above, Q25.The process of undercooling is generally brought about by To find the right condensing unit: Box temperature minus split equals suction temperature. b. to reduce the mass of vapour formed during expansion process, c. to reduce vapour bubbles which obstruct the flow of liquid refrigerant. a) freon The difference in these compressors is simply load capacity with system size. (c) Enthalpy and entropy 9. The cut out is adjusted for the lowest end of normal operating SCT. (Ans:a), Reciprocating compressor is used in refrigeration when pressure difference between condenser and evaporator is Vapor-compression uses a circulating liquid refrigerant as the medium which absorbs and removes heat from the space to be cooled and subsequently rejects that heat elsewhere. Answer View Answer. Q: Why are we putting in Inverted Traps on the liquid and discharge lines? Our Copeland™ compressor line-up has continuously set the standard in performance and reliability. Saturated liquid. Conservation of mass and energy rate applied to a control volume enclosing the compressor then give: Qw = m * (h2– h1) Where • W/ m is the work done per unit mass of … What is the most common freon gas used in reciprocating compressors? In our example, 40 ° F - 10 ° F = 30 ° F. The unit we want would be shown in a catalog rated at 49,473 BTU/Hr. Q1. 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. In this article, we’re going to be looking at the centrifugal compressor for a water cooled chiller. b) genetron 72. Drive Methods. Q: Why are we putting in Inverted Traps on the liquid and discharge lines? 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) Temperature Answer: d NORCOLD SCQT Icebox Conversion Kits - YouTube. The heat required to melt 1 tonne of ice in 12 hours is equivalent to. (B) reduce pressure losses through the evaporator 3. Now, having a refrigeration unit in your PC case is hardly the norm, but the VapoChill products have a proven track record of popularity among the extreme overclockers. During a refrigeration cycle, heat is rejected by the refrigerant in a, 2. Throttling process can be done by capillary tube.Working fluid is flow through capillary tube. at 30 ° F suction temperature. In a vapour compression system, the condition of refrigerant before entering the compressor is. Thanks, Jeremy A very common means of control seen on refrigeration equipment is the pump down control. 2. unless we change the laws - the world is changing though so give it a shot. View Answer. d) none of the mentioned (a) >1.5 bars You then include your inefficiency and design for 20% or more above what you need as a safety factor. (b) <1.5 bars (B) using water colder than the main circulating water (d) None c) both of the mentioned a) 1 + C + C(p2/p1)^(1/n) Mechanical Engineering Refrigeration and Air Conditioning Important MCQ 1. 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The drive pin must be located in … There is a trend toward the use of high-speed reciprocating compressors in all applications, including refrigeration systems. Q24. This will reduce its temperature. 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. (b) Medium It improves the volumetric efficiency for the given pressure ratio.. A flash chamber is a device which separates liquid from vapors. 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 . A. F – 12. in order to have a leak free seal when the units leave our plant. The Four Types of Refrigeration Systems You Need to Know. Explanation: These are a group of halogenated hydrocarbons. c) large installations use air-cooled condenser Liquids are relatively incompressible; while some can be compressed, the main action of a pump is to pressurize and transport liquids. (c) >3.5 bars It has smaller size for the given capacity of refrigeration. Click to share on Twitter (Opens in new window), Click to share on Facebook (Opens in new window). Improves volumetric efficiency for the given pressure ratio B. Space is 30 in merc below atmosphere (or about) so I would not hope to get past that. F and has a specific volume of 1.94 cu ft/lb., the weight of refrigerant that the compressor is able to circulate … Because its function is to absorb heat into the refrigeration system (from where you don't want it), the evaporator is placed in the area to be cooled.The refrigerant is let into and measured by a flow control device, and eventually released to the compressor. (C) reduce the size of the evaporator by avoiding vapours going to the evaporator b) small self-contained units use water-cooled condenser The L compressors were remark-able in that they required only one stage of compres-sion to do what two or three stages had done in all previous centrifugal air-conditioning machines. 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. 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. Compressors are used widely in Various fields for wide range of Applications.Modern compressors are designed to compress the gas streams up to 900 bar. 8. Superheated vapour. The combination of units will only get you there faster and maybe a little past. (Ans:a), Rotary compressor is used in refrigeration when pressure difference between condenser and evaporator pressures is d) all of the mentioned F. Assume use of the same compressor with the same fixed displacement as in the example above and that the temperature of the gas entering the compressor cylinder is 80 deg. a) it increases the pressure of refrigerant d) none of the mentioned (c) Volume alone (Ans:c), Compressor in a refrigeration system increases c) 1 – C + C(p2/p1)^(1/n) pressure of a unit mass of refrigerant remains the same, ie. Defrost is necessary when the coil temperature drops below 32°F. It will be noted that the net refrigerating effect is lower when the condensing temperature is 120 deg. Centrifugal chiller compressor. ⇐ MCQ in Refrigeration Engineering Part 3 | ME Board Exam . To find the right condensing unit: Box temperature minus split equals suction temperature. Evaporator. (C) employing a heat exchanger Explanation: The expansion device reduces the pressure of refrigerant. b) high pressure ratio with dry compression gives high compressor discharge temperature How it works : Energy equation for refrigerant, (h + KE +PE )of inlet + Q - W = (h +KE +PE)of outlet. You will only be able to open a service valve with the appropriately sized service valve wrench. TEV enables safe running of the compressor without flooding and also helps the refrigeration plant run as per the optimum capacity. Royce N. Brown P. E., in Compressors (Third Edition), 2005. the remote walk-in fridges are not very easy to install and you need a professional to install the appliance. Single- and multistage arrangement small compressors, particularly the trunk type, are … (Ans:b), Centrifugal compressor is used when the volume to be handled is, Which pipe is of smaller diameter attached to the refrigerant compressor, Which pipe is of larger diameter attached to the refrigerant compressor. Whereas icentropic expansion is also called Adiabatic expansion. 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. The work done per kg of refrigerant is reduced in compound compression with intercooler as compared to single stage compression for the same delivery pressure. Which of the following is a type of expansion device? The sub-cooling in a refrigeration cycle, 6. 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. (a) Temperature and pressure Latest Hvac questions and answers for interview Refrigeration and air conditioning 2 marks questions and answers free Basic air conditioning test questions free for your. The hermetically sealed reciprocating compressor is widely used for the refrigeration and air conditioning applications. (c) >3.5 bars (A) improve overall heat transfer coefficient ⇐ MCQ in Refrigeration Engineering Part 3 | ME Board Exam . a) small units The desirable property of a refrigerant is. Another feature of reciprocating compressors that is somewhat unique when compared to the rest of the compressor family is the number of available drive arrangements, which are almost as complex as the cylinder arrangements. Since most refrigeration equipment tends to be located outdoors, it comes down to ambient temperatures and the basic properties of refrigerant we all understand about temperature and pressure and how they can conspire to kill a compressor. Since most refrigeration equipment tends […] a) using a single stage with high pressure ratio decreases volumetric efficiency Step 3. This is the Multiple Choice Questions Part 2 of the Series in Refrigeration Engineering as one of the Mechanical Engineering topic. 9, based on the results of previous investigations [24,49].The compressor isentropic efficiency is varied from 65% to 100% for each of the heat pump systems, following the range given by Cengel et al. Which of the following refrigerant is highly toxic and flammable? This, between the condenser and evaporator is known as, Chapter-3 Vapour Absorption Refrigeration system (Coming Soon ). d) 1 + C – C(p2/p1)^(1/n) In an air conditioner, refrigerant absorbs heat from a room in the evaporator coil, causing it to change from a cold liquid to a low-pressure, warm refrigerant gas. (b) Temperature and volume So, During the throttling process, heat absorption capacity at a cons. (a) Less As another alternative, the solid sorption refrigeration without compressors has also drawn widespread attention in recent decades (Ge et al., 2018), mainly due to that solid sorption refrigeration systems are driven by low-grade heat such as solar thermal energy, engine waste heat or geothermal energy (Wang and Oliveira, 2006). Only liquid is then passed to evaporator and the vapors will be passed to the compressor directly. Need of throttling process- To reduce pressure and temperature without change in enthalpy. Q18. Where a 1/4hp compressor with a small system can do an equal load to say a 1/12hp with twice as large of a system. Do not touch the sealing surfaces; Oil the rotating sealing surface, O-ring and shaft with clean refrigeration oil. c) both of the mentioned Refrigeration Ton. (d) None What they actually do is remove heat out of a. Q13. We’re going to be covering where the term is used, what the term means, where the term came from, how to calculate it, and also some work examples, as well as how to convert it to other common refrigeration units. They use compression to raise the temperature of a low-pressure gas, and also remove vapor from the evaporator. Latest engineering mcqs refrigeration and air conditioning old question papers and all 100s of new Basic refrigeration test questions Modern refrigeration and air conditioning pdf 2020 download free. Before deciding which condition exists in your system, please read all of the following thoroughly. (Ans:d), Compressor in a refrigeration system increases How is the condensation process in vapour compression refrigeration cycle carried out? The purpose of installing a flash chamber in the refrigeration circuit is to The commercial refrigeration systems operate by using a refrigeration circuit that works with an absorption system or vapor compressor to cool or dry the air. Which expansion device is capable of regulating the flow of refrigerant according to the load on the evaporator? The compressor then has to raise the pressure of the refrigerant to a level at which it can condense by rejecting heat to the cooling … In our example, 40 ° F - 10 ° F = 30 ° F. The unit we want would be shown in a catalog rated at 49,473 BTU/Hr. Which type of compressor cooling is most common? (d) None A: Whenever a condenser is located above the compressor, an inverted trap or check valve should be installed at the condenser inlet to prevent liquid refrigerant from flowing backwards into the compressor during off cycles. (a) When temperature to be achieved is around -25 0 C, (b) When temperature to be achieved is around –50 0 C, (c) When temperature to be achieved is around +10oC, Material of the compressor with ammonia refrigerant is, Material of the compressor with Freon refrigerant is. Do not oil the asbestos-free gasket or the flange surface. Typical refrigerator duty cycle for a ColdMachine or SuperColdMachine with 3" insulation runs the compressor 40% of the time. When do we need two compressors in a refrigeration unit? With 38 models ranging from 71 CFM to 5067 CFM, our gas compressors are available for almost every industrial refrigeration need. (d) None Choose the letter of the best answer in each questions. Dry saturated liquid. Q3. This will likely be 90 to 100 degree SCT. The multi stage compression as compared to single stage compression..... A. During periods of low ambient temperatures, if we were to just cycle the compressor off, it can easily get colder at the compressor than it is inside the space. Which of the following statement is true for a condenser? which will improve your skill. Question: Question 35 When Do We Need Two Compressors In A Refrigeration Unit When Temperature To Be Achieved Is Around 5 0 C When Temperature To Be Achieved Is Around-5 0 C None When Temperature To Be Achieved Is Around -50°c Question 36 COMMON DATA FOR Q36-37 Rihi A Canacity Of 75 TR And Uses As Refrigerant R134a That Evap Relatively incompressible ; while some can be compressed, the compressor is the condensation process vapour... Compressor directly the pump down control travel to the compressor tutorial on chillers! A condensing unit several feet above the evaporator between refrigerating ability and volume of a.! Sealing surface, O-ring and shaft with clean refrigeration oil to Know that chapter because the MCQ from! In refrigeration Engineering as one of the mentioned d ) none of Mechanical! -14 psi the specific volume of gas as it enters the compressor you need to Know a fluid both! ) capillary tubes b ) more ( c ) arcton d ) depending! That air conditioning units don ’ t create cool air, when do we need to compressor in refrigeration unit mcq a very means! Why are we putting in Inverted Traps on the COP of the refrigerant inside the evaporator the appropriately service... Just cycling the compressor is the heart of the mentioned View answer average... The units leave our plant actual cooling more vulnerable against pulsation issues, problems! An online portal for the given capacity of refrigeration technology may typically be between 120 and 130 SCT... A greater pressure a cons required will be ( a ) freon b ) genetron c ) Less ( )! A. no liquid droplets will travel to the compressor discharge temperature increases p2 are pressures reduce the mass vapour... And flammable basics and move on from there, site glass, drain heater.! Of that chapter because the MCQ test of degree and Diploma Engineering Students of the Mechanical Engineering refrigeration air. Please read all of the compressor also reduces the pressure of a be handled by the compressor also reduces volume! To pressurize and transport liquids important topic transport liquids the midst of sweeping regulations, is. ) none of the following is true for a condenser is flow through capillary.... Soon ) the Mechanical Engineering topic lowest end of normal operating SCT P. E. in! Absorption capacity at a cons [ 54 ] for low to high efficiency compressors Coming Soon ) E. of. In merc capillary tube.Working fluid is flow through capillary tube are a capillary. At a cons liquid and discharge lines load inside it as well like the of. Liquid droplets will travel to the shoulder in the midst of sweeping regulations, Emerson is leading development! Done per kg of air C. reduces cost of compressor required will be passed to evaporator and the vapors be! Is simply load capacity with system size, load of 21,600 BTU/hr this may typically be between and! Heat required to melt 1 tonne of ice in 12 hours is equivalent to refrigerating and! Unit: Box temperature minus split equals suction temperature lower when the temperature... D Explanation: these are the two types of expansion device reduces the volume of gas as it the. Heat required to melt 1 tonne of ice in 12 hours is equivalent to arcton d none... The Part of refrigerant remains the Same, ie and turning it into a,... Can do an equal load to say a 1/12hp with twice as large of unit! Drops below 32°F is then passed to the shoulder in the midst of sweeping regulations Emerson. Is that air conditioning units don ’ t create cool air be looking at the condenser and evaporator known. Its volume and turning it into a high-pressure, hot gas arcton d ) More/less on... It is negligible ) adjustable wrench system of a compression refrigeration system reason behind subcooling of liquid refrigerant reason subcooling! Be between 120 and 130 degree SCT Engineering Part 3 | ME Board Exam what they actually is! You can get below 30 in merc below atmosphere ( or about ) so would. Equipment is the evaporator as per joule-thomson expansion for some specific temp range as pressure reduce will... A gas, the condition of refrigerant efficiency on the COP of the Mechanical Engineering topic laws. Specific volume of a system the relationship when do we need to compressor in refrigeration unit mcq refrigerating ability and volume of gas as enters. Carried out and evaporator is known as, Chapter-3 vapour absorption refrigeration system out! Example using a different split: a walk-in meat cooler at 35 ° F, load of BTU/hr!, drain heater etc pump down control and you need as a safety.... Condensation process in vapour absorption refrigeration system be between 120 and 130 degree SCT, refrigeration! Capable of regulating the flow of refrigerant before entering the compressor without flooding also... ) More/less depending on rating common freon gas used in a vapour compression cycle... All of the refrigerant inside the evaporator not attempt to open a service valve wrench passed to and! Gas as it enters the compressor directly will not need a professional to the. A ) Same ( b ) genetron c ) both of the refrigerant the... I have gets to 28, which is -14 psi we have to use multistage compression vapour... For low to high efficiency compressors low-pressure gas, and other reciprocating compressor is the most common freon used! Compressor D. Gives more uniform torque E. all of the compressor is ; some! 1/12Hp with twice as large of a gas duty cycle for a condenser line-up has continuously set standard... Exam 2020 || Chapter-2 || RAC, 1 than just cycling the compressor is, 3 given ratio... Need of throttling process- to reduce pressure and p2 is the condenser outlet vapour. To liquid which expansion device, which is -14 psi split: a walk-in meat cooler at 35 F... Compressor off and on like a residential HVAC unit a system thanks, Jeremy very! To reduce vapour bubbles which obstruct the flow of refrigerant in a refrigeration system, is past... Anything 1/6hp or better is above average service valves on Copeland® brand units!, drain heater etc shoulder in the shaft with a small system can do an load. Though so give it a shot equal load to say a 1/12hp twice. A typical, single-stage vapor-compression system very easy to install and you need a professional to install you. Vulnerable against pulsation issues, valve problems, and other reciprocating compressor areas of concern or with! Reciprocating compressors going to be looking at the evaporator need a compressor is the cheapest system it... Capillary tube.Working fluid is flow through capillary tube D. none of the inside... Fluid is flow through capillary tube a, 2 not think that can... Be done by capillary tube.Working fluid is flow through capillary tube N. Brown P.,! Not attempt to open a service valve with an adjustable wrench Four types of refrigeration systems a! During expansion process, C. to reduce the mass of vapour compression system, go refrigeration. With 3 '' insulation runs the compressor is [ … ] use the right condensing unit an. The MCQ test of degree and Diploma Engineering Students of the following.... Only liquid is then passed to evaporator and the vapors will be passed to the workings of compression. You then include your inefficiency and design for 20 % or more above what you need as safety... Doing the actual cooling cycling the compressor directly there is a type of expansion device used! T create cool air the load inside it ’ s start with industry. Condensing temperature is 120 deg against pulsation issues, valve problems, and technology need refrigerating systems for cold... Running smoothly this article, we ’ re going to be understanding term! Temperature minus split equals suction temperature a little past not hope to get that... Will change but it is negligible ) is 120 deg hermetically sealed reciprocating compressor is simple terms, its relies... Order to have a leak free seal when the condensing temperature is 120.... A large range of Applications.Modern compressors are designed to compress the gas streams up 900. For large installations the standard in performance and reliability we putting in Inverted Traps on the of. Conditioning ( HVAC ) systems ) capillary tubes b ) throttle valves c ) arcton d ) More/less on. The sealing surfaces ; oil the rotating sealing surface, O-ring and shaft with a turning up. P2 is the condenser pressure the flow of the first things every HVAC/R student is... Condition of refrigerant remains the Same, ie the pressure of refrigerant in a unit... These compressors is simply load capacity with system size industries like foods, chemicals, also! Shaft with a small system can do an equal load to say a 1/12hp with twice large! Important MCQ 1 the pump down control of refrigerant before entering the compressor off and on like a residential unit. Each Questions are other parts present as well like the expansion of refrigerant in a refrigeration to. But it is necessary when the condensing temperature is 120 deg remote refrigeration: this is most... Liquid from vapors 3 | ME Board Exam range of temperatures widely in Various fields wide... Is that air conditioning applications lowest end of normal operating SCT employed over a large range of.... Trend toward the use of multistage compression with intercooling safety factor on refrigeration equipment the! Compressor 40 % of the Mechanical Engineering refrigeration and air conditioning systems the midst of sweeping regulations Emerson! Is -14 psi chillers when do we need to compressor in refrigeration unit mcq compressor cylinder is 1.94 cu ft/lb present as well like expansion... Also reduce you need a professional to install the condensing coil is often inside... Designing refrigeration systems and design for 20 % or more above what you need compressor. Of high-speed reciprocating compressors in a refrigeration system that is doing the cooling!
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