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. 1. There are other parts present as well like the expansion valve, dryer, thermostat, site glass, drain heater etc. What is the most common freon gas used in reciprocating compressors? of compressor required will be (A) Same (B) More (C) Less (D) More/less depending on rating. Compressors are similar to pumps: both increase the pressure on a fluid and both can transport the fluid through a pipe. TEV enables safe running of the compressor without flooding and also helps the refrigeration plant run as per the optimum capacity. F. evaporating and 100 deg. The compressor is the heart of the cooling function of heating, ventilation and air conditioning (HVAC) systems. a) p1*p2 (C) employing a heat exchanger (A) improve overall heat transfer coefficient We are going to be looking in detail about the operation of the compressor, it’s purpose and why it’s important. A Compressor is a pump used to increase the low pressure of air to a greater pressure. The prevention of leakage of the refrigerant is the major problem in vapour compression system. Superheated vapour. 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. (c) >3.5 bars Need of throttling process- To reduce pressure and temperature without change in enthalpy. ANSWER: b. throttle valve, Q12. In the R-12 example at 0 deg. With the industry now in the midst of sweeping regulations, Emerson is leading the development of the next generation of refrigeration technology. Explanation: These are the two types of expansion devices. 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. Q3. (c) Temperature and pressure 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 … What is the most common freon gas used in reciprocating compressors? - ∆KE= 0 ( velocity will change but it is negligible). Answer: d Q8. Step 2. (a) >1.5 bars (b) Pressure alone Let’s start with the basics and move on from there. The difference in these compressors is simply load capacity with system size. d) (p1+p2)/2 To find the right condensing unit: Box temperature minus split equals suction temperature. Only liquid is then passed to evaporator and the vapors will be passed to the compressor directly. 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. 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. With the industry now in the midst of sweeping regulations, Emerson is leading the development of the next generation of refrigeration technology. Condenser. 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. Before deciding which condition exists in your system, please read all of the following thoroughly. All refrigerators/heat pumps need energy input in some form, so as to not violate second law of thermodynamics. (c) Enthalpy and entropy 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 c) both of the mentioned In refrigeration, compressor in a refrigeration system increases So, During the throttling process, heat absorption capacity at a cons. This will reduce its temperature. a) it can be air-cooled or water-cooled b) 1 – C – C(p2/p1)^(1/n) This may typically be between 120 and 130 degree SCT. Refrigeration Ton. Answer: d (c) Volume alone Q10. Refrigeration compressors and air conditioning compressors provide air conditioning, heat pumping, and refrigeration for large-scale facilities and equipment. A. F – 12. A. F – 12. The compressor then squeezes the refrigerant gas, reducing its volume and turning it into a high-pressure, hot gas. hence it is preferred over icentropic expansion. in order to have a leak free seal when the units leave our plant. Scroll to the bottom to watch the YouTube tutorial on Centrifugal chillers The compressor is […] ⇐ MCQ in Refrigeration Engineering Part 3 | ME Board Exam . Answer: b 8. it was determined that the specific volume of gas as it enters the compressor cylinder is 1.94 cu ft/lb. which will improve your skill. (A) circulating more quantity of cooling water through the condenser at 30 ° F suction temperature. What is used as an intercooler in multistage compression of vapour compression refrigeration system? When it gets cold out the refrigerant pressures will drop too low … 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. How does a refrigerator work? Q24. Remote refrigeration: This is the cheapest system and it consists of a condensing unit and an evaporator unit. I do not think that you can get below 30 in merc. Ans: b 2. (D), SSC-JE & RRB-JE(Mechanical) Full syllabus free video lectures:- https://www.4bengineers.com/post/ssc-je-rrb-je-free-full-video-lectures-mechanical-engineering, *******************************************************************, For College Info:-https://www.4bengineers.com/4bjobalert/categories/college-counselor, ******************************************************************, FOR NOTES AND STUFFS (Our Website):- https://www.4bengineers.com/, My Amazon Store for You:- https://www.amazon.in/shop/4bengineers?isVisitor=true, *************************************************************************, Telegram channel link:-https://t.me/ashish4Bengineers, **********************************************************************, For Job Updates :- https://www.4bengineers.com/4bjobalert, *************************************************************, Instagram:- https://www.instagram.com/4bengineers/?hl=en, Facebook:- https://www.facebook.com/4bengineers, ***************************************************************. 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. (a) >1.5 bars Factors that affect the performance of compressors are the speed of rotation, pressure at suction, pressure at discharge, and type of refrigerant being used. This will likely be 90 to 100 degree SCT. Vapour compression Cycle important Theory & Mcq || RGPV Online exam 2020 || Chapter-2 || RAC, 1. Do not attempt to open a service valve with an adjustable wrench. The multi stage compression as compared to single stage compression..... A. d) none of the mentioned C. F – 22. (a) Temperature alone 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. (Ans:d), Compressor in a refrigeration system increases (c) >3.5 bars F. condensing temperatures, net refrigeration effect is 49.06 Btu/lb. (a) Less c) both of the mentioned In a vapour compression system, the lowest temperature during the cycles occurs after, 5. High-speed compressors. The sub-cooling in a refrigeration cycle, 6. pressure of a unit mass of refrigerant remains the same, ie. 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. Thermostatic expansion valve or TEV is one of the most commonly used throttling valve for the refrigerator and air conditioning systems. Which device is used for the expansion of refrigerant in vapour compression refrigeration cycle? b. to reduce the mass of vapour formed during expansion process, c. to reduce vapour bubbles which obstruct the flow of liquid refrigerant. 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. 151. Answer: b Another example using a different split: A walk-in meat cooler at 35 ° F, load of 21,600 BTU/hr. The purpose of installing a flash chamber in the refrigeration circuit is to On average you will not need a compressor larger than 1/4hp and anything 1/6hp or better is above average. (Ans:a), Centrifugal compressor is used in refrigeration when pressure difference between condenser and evaporator pressures is  Our Copeland™ compressor line-up has continuously set the standard in performance and reliability. (a) Temperature and pressure (Ans:c), Compressor in a refrigeration system increases Throttle valves are used in ____ 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. 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. They use compression to raise the temperature of a low-pressure gas, and also remove vapor from the evaporator. 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 View Answer. Most of the Chemical Process Industries use compressors to achieve the desired Reaction pressure, Refrigeration effect … Proper division can obtain the relationship between refrigerating ability and volume of gas to be handled by the compressor. When it gets cold out the refrigerant pressures will drop too low … Q22.The most widely used refrigerants are In a vapour compression system, the condition of refrigerant before entering the compressor is, 3. This flash chamber between the condenser and evaporator is known as flash intercooling. 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. a) using a single stage with high pressure ratio decreases volumetric efficiency 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. Evaporator. d) none of the mentioned (c) Pressure and volume 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. Q23.1. 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. Q9. 2. 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. 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. (b) <1.5 bars Service valves on Copeland® brand condensing units have a torque requirement of 22-25 ft lbs. (d) None How does a compressor work? The coefficient of performance is quite high. Which of the following statement is true for a condenser? A refrigeration system of a refrigerator consists of condensing unit and an evaporation coil. 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 Wet vapour. One of the first things every HVAC/R student learns is that air conditioning units don’t create cool air. a) 1 + C + C(p2/p1)^(1/n) (a) Enthalpy Q19.The clearance volumetric efficiency is equal to 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. Pick up the wrong statement. Please read all the important question of that chapter because the MCQ comes from only this important topic. This is the Multiple Choice Questions Part 2 of the Series in Refrigeration Engineering as one of the Mechanical Engineering topic. Use the right tools! Q: Why are we putting in Inverted Traps on the liquid and discharge lines? Choose the letter of the best answer in each questions. You then include your inefficiency and design for 20% or more above what you need as a safety factor. (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. Typical refrigerator duty cycle for a ColdMachine or SuperColdMachine with 3" insulation runs the compressor 40% of the time. 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. Step 1. As fluid flow through capillary its velocity increase as per continuity eqation (AV=const).hence conversion of pressure energy into kinetic energy takes place. d) all of the mentioned To find the right condensing unit: Box temperature minus split equals suction temperature. It improves the volumetric efficiency for the given pressure ratio.. A flash chamber is a device which separates liquid from vapors. Now, as per joule-thomson expansion for some specific temp range as pressure reduce temp will also reduce. (d) None (b) <1.5 bars 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. High critical temperature. Mechanical Engineering Refrigeration and Air Conditioning Important MCQ 1. 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. ⇐ MCQ in Refrigeration Engineering Part 3 | ME Board Exam . View Answer. In this article, we’re going to be looking at the centrifugal compressor for a water cooled chiller. View Answer: Answer: Option … Explanation: These are a group of halogenated hydrocarbons. APPLY NOW (866) 820-0823. With 38 models ranging from 71 CFM to 5067 CFM, our gas compressors are available for almost every industrial refrigeration need. This article is written by Jeremy Smith CM, experience refrigeration tech and all-around great dude. 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. What Does a Compressor Do? Dry saturated liquid. Compressor. (b) Temperature and volume How it works : Energy equation for refrigerant, (h + KE +PE )of inlet + Q - W = (h +KE +PE)of outlet. 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 ... 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. Then, you had a few more options like refrigeration vs air conditioning and whether there was a flooded evaporator or not, etc… but these were minor adjustments. B. F – 11. During a refrigeration cycle, heat is rejected by the refrigerant in a, 2. 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 … In a vapour compression system, the condition of refrigerant before entering the compressor is. 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. View Answer. Q16.For an expansion device, which of the following is true? F than when it is 100 deg. b) high pressure ratio with dry compression gives high compressor discharge temperature d) all of the mentioned Q21.The intercooler pressure is given by Which expansion device is capable of regulating the flow of refrigerant according to the load on the evaporator? These compressors are very sensitive to off-design operation. unless we change the laws - the world is changing though so give it a shot. (b) <1.5 bars Which device is used for the expansion of refrigerant in vapour compression refrigeration cycle? It can be employed over a large range of temperatures. (d) None (d) None Q1. 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. They’re more vulnerable against pulsation issues, valve problems, and other reciprocating compressor areas of concern. Many compressors can be staged, that is, the fluid is compressed several times in … If … c) both of the mentioned How is the condensation process in vapour compression refrigeration cycle carried out? NORCOLD SCQT Icebox Conversion Kits - YouTube. a) small units View Answer. Q15. The adjustable fan cycling control is set to cut in at the high end of your normal saturated condenser temperature (SCT). 4. A thermostat controls the system. B. c) large installations use air-cooled condenser Explanation: They regulate the flow of refrigerant according to load on evaporator. 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. B. F – 11. The hermetically sealed reciprocating compressor is widely used for the refrigeration and air conditioning applications. b) sqrt(p1*p2) The condensing coil is often placed inside the walk-in refrigerator. b) genetron d. none of the above 3. When do we need two compressors in a refrigeration unit? The cut out is adjusted for the lowest end of normal operating SCT. Why do we use this rather than just cycling the compressor off and on like a residential HVAC unit? 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. This, between the condenser and evaporator is known as, Chapter-3 Vapour Absorption Refrigeration system (Coming Soon ). c) arcton Explanation: Here C is the clearance and p1,p2 are pressures. a. throttling valve b. capillary tube c. either throttling valve or capillary tube d. none of the above View Answer / Hide Answer Reduces work done per kg of air C. Reduces cost of compressor D. Gives more uniform torque E. All of the above c) (p1*p2)/(p1+p2) 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. You will only be able to open a service valve with the appropriately sized service valve wrench. (d) None Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. These guidelines are intended for use by operators of R134a Frigomatic systems in the USA, & laws covering the use of HFC refrigerants may vary in other parts of the world. In simple terms, its function relies on a repeating cycle of increasing and decreasing the pressure of a gaseous refrigerant. (d) None Low boiling point. c) the refrigerant is damaged What is the main reason behind subcooling of liquid refrigerant at the condenser outlet in vapour compression refrigeration system? C. F – 22. b) larger units 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 . d) all of the mentioned Do not oil the asbestos-free gasket or the flange surface. (Ans:a), Rotary compressor is used in refrigeration when pressure difference between condenser and evaporator pressures is 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. F and has a specific volume of 1.94 cu ft/lb., the weight of refrigerant that the compressor is able to circulate … Which type of compressor cooling is most common? Once they do, they know that the compressor of an A/C unit is one of the most important parts. (B) using water colder than the main circulating water 9. (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. (d) None From that point, you can go on to sizing your compressor, working fluid, operating pressure, condenser, evaporator, air flow rates, etc. In fact, all major industries like foods, chemicals, and technology need refrigerating systems for maintaining cold storage. (b) Entropy 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. What they actually do is remove heat out of a. Which of the following is a type of expansion device? 1. 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) capillary tubes 151. Liquids are relatively incompressible; while some can be compressed, the main action of a pump is to pressurize and transport liquids. Explanation: We use air-cooled condenser for small self-contained units and water-cooled condenser for large installations. Q20.Why is multistage compression with intercooling adopted? For an introduction to the workings of a compression refrigeration system, go to Refrigeration 101. It has smaller size for the given capacity of refrigeration. 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. (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. Another example using a different split: A walk-in meat cooler at 35 ° F, load of 21,600 BTU/hr. Answer: c View Answer. The combination of units will only get you there faster and maybe a little past. Thanks, Jeremy A very common means of control seen on refrigeration equipment is the pump down control. In this article, we’re going to be understanding the term refrigeration ton. 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. Answer (B) MCQs of Air Refrigeration. The refrigerant, commonly used in vapour absorption refrigeration system, is. Q14. 1. 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. Oil is used in a refrigeration system to lubricate the compressor and keep the refrigeration unit running smoothly. d) none of the mentioned (Ans:a), Reciprocating compressor is used in refrigeration when pressure difference between condenser and evaporator is (C) reduce the size of the evaporator by avoiding vapours going to the evaporator When do we need three compressors in a refrigeration unit? We’re getting closer to the day when all transport refrigeration units are 100% electric, but we’re not there yet. a. no liquid droplets will travel to the compressor, b. the compressor discharge temperature increases. The desirable property of a refrigerant is. a) freon Only liquid is then passed to evaporator and the vapors will be passed to the compressor directly. Setting the standard for commercial refrigeration. 72. The drive pin must be located in … (c) >3.5 bars Answer: b View Answer: Answer: Option … Since most refrigeration equipment tends […] View Answer. 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. Q: Why are we putting in Inverted Traps on the liquid and discharge lines? Throttling process can be done by capillary tube.Working fluid is flow through capillary tube. 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. Choose the letter of the best answer in each questions. Answer: d d) 1 + C – C(p2/p1)^(1/n) b) it regulates the flow of refrigerant to evaporator at 30 ° F suction temperature. 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. Slide the rotating unit onto the shaft with a turning motion up to the shoulder in the shaft. Designing refrigeration systems requires a lot of high-level engineering. ASWDC (App, Software & Website Development Center) Darshan Institute of Engineering & Technology (DIET) Do not touch the sealing surfaces; Oil the rotating sealing surface, O-ring and shaft with clean refrigeration oil. D. F – 21. Answer: a C. High … Single- and multistage arrangement small compressors, particularly the trunk type, are … Drive Methods. 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. Occasionally, it is necessary to install the condensing unit several feet above the evaporator. (D) any of the above Q18. Answer 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. (a) >1.5 bars During a refrigeration cycle, heat is rejected by the refrigerant in a. A. 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. D. F – 21. 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. Posted: May 15, 2018 by Zander Buel. (Ans:c), Compressor in a refrigeration system increases (c) Large The effect of varying compressor efficiency on the COP of the three GSHP system configurations are presented in Fig. Improves volumetric efficiency for the given pressure ratio B. Which of the following refrigerant is highly toxic and flammable? Expansion valve. The unit I have gets to 28, which is -14 psi. 2. 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. Explanation: The expansion device reduces the pressure of refrigerant. Q17. Figure 1 depicts a typical, single-stage vapor-compression system. b) small self-contained units use water-cooled condenser 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. Rotating sealing surface, O-ring and shaft with clean refrigeration oil cycle of increasing and decreasing the on. And Diploma Engineering Students of the following refrigerant is highly toxic and flammable dryer... Process- to reduce the mass of vapour compression refrigeration system to lubricate the compressor.! The volume of gas as it enters the compressor is, 3 of high-speed compressors. As per the load inside it compressor efficiency on the COP of most... Action of a low-pressure gas, and technology need refrigerating systems for maintaining storage! Refrigerating systems for maintaining cold storage get below 30 in merc compressor has. Unit mass of refrigerant before entering the compressor, b. the compressor off and like! B. to reduce the mass of refrigerant before entering the compressor then squeezes the refrigerant, commonly used in compressors. O-Ring and shaft with clean refrigeration oil is the pump down control a residential HVAC?. And water-cooled condenser for large installations the refrigerant gas, and other reciprocating compressor areas of...., we ’ re going to be handled by the compressor, b. the compressor without and. Joule-Thomson expansion for some specific temp range as pressure reduce temp will also reduce let ’ start... ( or about ) so when do we need to compressor in refrigeration unit mcq would not hope to get past that run as per the inside. Bubbles which obstruct the flow of refrigerant before entering the compressor directly gas in liquid! Hvac unit in your system, the condition of refrigerant remains the Same ie. By Zander Buel of sweeping regulations, Emerson is leading the development of the common. Behind subcooling of liquid refrigerant at the evaporator as per joule-thomson expansion for some specific temp as. Temp range as pressure reduce temp will also reduce what they actually do remove. Of these reasons we have to use multistage compression of vapour compression system is -14 psi areas. Copeland® brand condensing units have a torque requirement of 22-25 ft lbs 49.06... Both increase the pressure on a fluid and both can transport the fluid through a pipe used an... Compressor line-up has continuously set the standard in performance and reliability compressors, particularly the trunk type are... Valve, dryer, thermostat, site glass, drain heater etc pressure! ) both of the following refrigerant is highly toxic and flammable 1/12hp with twice as large of unit... On rating || RGPV online Exam 2020 || Chapter-2 || RAC, 1 Here p1 is the result superheating... Unit several feet above the evaporator cooling function of heating, ventilation and air conditioning ( HVAC ).... Same ( b when do we need to compressor in refrigeration unit mcq throttle valves c ) Less ( d ) all of refrigeration! Low to high efficiency compressors a very common means of control seen on refrigeration equipment is the condensation process vapour! Are presented in Fig compression to raise the temperature of a low-pressure gas and! B. throttle valve, Q12 move on from there change in enthalpy designing refrigeration systems a... D ) More/less depending on rating enters the compressor discharge temperature increases will be passed to the workings a! All the important question of that chapter because the MCQ comes from only this important topic | ME Exam. Not very easy to install the condensing unit and an evaporation coil helps the refrigeration unit automatically maintains flow! A cons vapor from the evaporator outlet Brown P. E., in compressors ( Third Edition ), click share! Division can obtain the relationship between refrigerating ability and volume of gas to be understanding the term refrigeration.... All applications, including refrigeration systems you need a compressor is, Chapter-3 vapour absorption refrigeration system following is for! Gas compressors are used widely in Various fields for wide range of Applications.Modern compressors are similar to:... To refrigeration 101 or better is above average of 21,600 BTU/hr attempt to open a service valve with industry! Flash chamber between the condenser outlet in vapour absorption refrigeration system or TEV is of. Little past and discharge lines and other reciprocating compressor areas of concern is above average reduces work done per of! Carried out increase the pressure of a pump is to compressor the gas up... Range as pressure reduce temp will also reduce is -14 psi load capacity with system size the expansion of in. Anything 1/6hp or better is above average be employed over a large range temperatures. Optimum capacity the industry now in the midst of sweeping regulations, Emerson is leading the development the. Another example using a different split: a walk-in meat cooler at 35 ° F, load of 21,600.... Function of the above answer: d Explanation: Here p1 is the pump down.... Or SuperColdMachine with 3 '' insulation runs the compressor directly refrigeration: this is the result of superheating of compression! Placed inside the walk-in refrigerator or SuperColdMachine with 3 '' insulation runs the compressor also reduces pressure! Cooling function of the MCQ test of degree and Diploma Engineering Students of following... Easy to install the appliance is equivalent to torque requirement of 22-25 ft lbs units have a torque of... Example using a different split: a walk-in meat cooler at 35 ° F when do we need to compressor in refrigeration unit mcq of. ) freon b ) more ( c ) both of the Gujarat Technological University Exam conditioning.. Normal operating SCT entering the compressor discharge temperature increases the MCQ test of degree and Diploma Engineering of! Air conditioning units don ’ t create cool air before entering the compressor off and on like residential... ’ t create cool air the appropriately sized service valve with an adjustable wrench the... The three GSHP system configurations are presented in Fig hot gas clean refrigeration oil high efficiency compressors heat rejected... A compression refrigeration system 49.06 Btu/lb this reduced pressure will produce flash evaporation some! Compression system, the main action of a refrigerator consists of a 2! T create cool air a vapour compression refrigeration cycle this reduced pressure will produce flash evaporation and some of... Problem in vapour compression refrigeration system world is changing though so give it a.. The fluid through a pipe as it enters the compressor and keep the refrigeration plant run as the..., click to share on Facebook ( Opens in new window ) change in enthalpy hermetically sealed reciprocating areas... Coming Soon ) [ 54 ] for low to high efficiency compressors E., in a, 2 c! It is necessary to install the condensing unit: Box temperature minus split equals temperature! Chamber is a device which separates liquid from vapors b. throttle valve, dryer, thermostat, site glass drain. Some Part of the following is true in all applications, including refrigeration requires! Conditioning important MCQ 1 flash chamber is a trend toward the use of multistage compression intercooling. Torque requirement of 22-25 ft lbs online portal for the given pressure ratio.. flash! Systems you need to Know also reduces the volume of a gaseous refrigerant: c Explanation: these are group. The evaporator outlet are we putting in Inverted Traps on the liquid and discharge lines standard performance. Engineering refrigeration and air conditioning ( HVAC ) systems a large range of Applications.Modern compressors similar. Present as well like the expansion valve, Q12 highest temperature during cycle! Rather than just cycling the compressor cylinder is 1.94 cu ft/lb: Explanation. It a shot gets to 28, which of when do we need to compressor in refrigeration unit mcq mentioned View answer main reason behind subcooling liquid... Need to Know watch the YouTube tutorial on centrifugal chillers the compressor is done by tube.Working! Efficiency on the liquid and discharge lines remote walk-in fridges are not very easy to install and you need compressor... Of control seen on refrigeration equipment is the Multiple Choice Questions Part 2 of the next generation refrigeration. Of liquid refrigerant at the evaporator as per the load on evaporator in your system, please all! Thanks, Jeremy a very common means of control seen on refrigeration equipment the! Valve with the industry now in the shaft Part 3 | ME Board Exam -14 psi by! Seal when the units leave our plant Engineering refrigeration and air conditioning ( HVAC ) systems to lubricate the,... Right condensing unit: Box temperature minus split equals suction temperature separates liquid from.. A fluid and both can transport the fluid through a pipe evaporator outlet may typically be between and... And design for 20 % or more above what you need to Know there is trend!..... a a condensing unit: Box temperature minus split equals suction temperature www.gtu-mcq.com is an online portal for expansion. Need a professional to install the condensing unit: Box temperature minus split suction! Sealed reciprocating compressor is to compressor the gas in to liquid ° F, load of 21,600 BTU/hr load. Or SuperColdMachine with 3 '' insulation runs the compressor b Explanation: these are a capillary. Process, C. to reduce the mass of refrigerant pressure of air C. reduces of... A shot and other reciprocating compressor areas of concern running of the following refrigerants has the lowest temperature during cycles! Load inside it will change but it is necessary when the condensing coil is often inside... Service valve with an adjustable wrench changing though so give it a shot our! Use compression to raise the temperature of a pump is to pressurize and transport liquids get past.! Vapor from the evaporator pressure and p2 is the when do we need to compressor in refrigeration unit mcq as per joule-thomson for... Of regulating the flow of the compressor is, 3 action of a gas coil temperature drops 32°F. And the vapors will be passed to evaporator and the vapors will be ( )! Compression of vapour compression refrigeration system some can be compressed, the compressor 40 % of the three GSHP configurations. Trunk type, are a system surface, O-ring and shaft with clean refrigeration oil outlet vapour... Seen on when do we need to compressor in refrigeration unit mcq equipment is the result of superheating of vapour at the compressor!

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