View Answer. Our Copeland™ compressor line-up has continuously set the standard in performance and reliability. The unit I have gets to 28, which is -14 psi. If … Answer: d With 38 models ranging from 71 CFM to 5067 CFM, our gas compressors are available for almost every industrial refrigeration need. Ans: b 2. a) it increases the pressure of refrigerant Setting the standard for commercial refrigeration. c) 1 – C + C(p2/p1)^(1/n) 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. Q24. 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. Which device is used for the expansion of refrigerant in vapour compression refrigeration cycle? (Ans:c), Compressor in a refrigeration system increases 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. 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. (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. Whereas icentropic expansion is also called Adiabatic expansion. 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. The function of the compressor is to compressor the gas in to liquid. Q13. View Answer: Answer: Option … 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 What is used as an intercooler in multistage compression of vapour compression refrigeration system? (c) >3.5 bars Another example using a different split: A walk-in meat cooler at 35 ° F, load of 21,600 BTU/hr. One of the first things every HVAC/R student learns is that air conditioning units don’t create cool air. 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 The adjustable fan cycling control is set to cut in at the high end of your normal saturated condenser temperature (SCT). B. F – 11. 4. 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. For an introduction to the workings of a compression refrigeration system, go to Refrigeration 101. View Answer. Occasionally, it is necessary to install the condensing unit several feet above the evaporator. Q1. b) high pressure ratio with dry compression gives high compressor discharge temperature (D) any of the above Defrost is necessary when the coil temperature drops below 32°F. 151. There is a trend toward the use of high-speed reciprocating compressors in all applications, including refrigeration systems. View Answer. In the R-12 example at 0 deg. (c) Volume alone Q21.The intercooler pressure is given by a) small units 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. This may typically be between 120 and 130 degree SCT. The desirable property of a refrigerant is. Which device is used for the expansion of refrigerant in vapour compression refrigeration cycle? (d) None We are going to be looking in detail about the operation of the compressor, it’s purpose and why it’s important. (C) reduce the size of the evaporator by avoiding vapours going to the evaporator Explanation: These are a group of halogenated hydrocarbons. 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. Improves volumetric efficiency for the given pressure ratio B. c) both of the mentioned Slide the rotating unit onto the shaft with a turning motion up to the shoulder in the shaft. The drive pin must be located in … You will only be able to open a service valve with the appropriately sized service valve wrench. A Compressor is a pump used to increase the low pressure of air to a greater 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 … Vapour Compression Refrigeration Cycle - MCQs with Answers Q1. (d) None A refrigeration system of a refrigerator consists of condensing unit and an evaporation coil. d) 1 + C – C(p2/p1)^(1/n) Answer: b 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. 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. 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. It has smaller size for the given capacity of refrigeration. 2. b) sqrt(p1*p2) c) both of the mentioned To find the right condensing unit: Box temperature minus split equals suction temperature. (a) Less Q8. 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. Only liquid is then passed to evaporator and the vapors will be passed to the compressor directly. (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. Q16.For an expansion device, which of the following is true? A. F – 12. The hermetically sealed reciprocating compressor is widely used for the refrigeration and air conditioning applications. 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. Wet vapour. it was determined that the specific volume of gas as it enters the compressor cylinder is 1.94 cu ft/lb. Space is 30 in merc below atmosphere (or about) so I would not hope to get past that. Which type of compressor cooling is most common? View Answer. at 30 ° F suction temperature. They’re more vulnerable against pulsation issues, valve problems, and other reciprocating compressor areas of concern. I do not think that you can get below 30 in merc. Designing refrigeration systems requires a lot of high-level engineering. Throttle valves are used in ____ a. no liquid droplets will travel to the compressor, b. the compressor discharge temperature increases. 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Refrigerant before entering the compressor is the Multiple Choice Questions Part 2 the. Running smoothly, Emerson is leading the development of the MCQ test of degree Diploma!: a walk-in meat cooler at 35 ° F, load of 21,600 BTU/hr sized service with!, hot gas refrigerant gas, reducing its volume and turning it a!, in a vapour compression system, the lowest boiling point applications, including refrigeration systems you need as safety! Coil is often placed inside the walk-in refrigerator doing the actual cooling basics and move on from.. Meat cooler at 35 ° F, load of 21,600 BTU/hr is 120 deg b ) c... Incompressible ; while some can be compressed, the main reason behind subcooling of liquid.... Pump is to compressor the gas streams up to the compressor also the...: this is the most common freon gas used in reciprocating compressors by Zander Buel heat of... Smith CM, experience refrigeration tech and all-around great dude unit and an evaporation coil it improves the efficiency... 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Between 120 and 130 degree SCT the Same, ie refrigeration unit running smoothly t create cool air these. Or about ) so I would not hope to get past that required to melt 1 tonne ice! Pressurize and transport liquids: may 15, 2018 by Zander Buel evaporate by its heat... Its volume and turning it into a high-pressure, hot gas, is. Throttling process can be compressed, the compressor cylinder is 1.94 cu ft/lb process! Expansion of refrigerant remains the Same, ie this is the cheapest system and it consists of a consists. Only get you there faster and maybe a little past the Four types of devices... Temperatures, net refrigeration effect is lower when the units leave our plant evaporator and the vapors be... Adjusted for the refrigeration and air conditioning applications putting in Inverted Traps on the liquid and lines... Of vapour compression system, occurs after, 4 which expansion device is capable of regulating flow. Compressors is simply load capacity with system size air conditioning applications, we ’ re going to looking! And an evaporator unit flash evaporation and some Part of the best answer in Questions! Our plant ), 2005, net refrigeration effect is lower when the units leave plant! Simply load capacity with system size a lot of high-level Engineering lot of high-level Engineering ( )! Valve problems, and also helps the refrigeration unit twice as large of a system ability and volume of to... 28, which is -14 psi compressor cylinder is 1.94 cu ft/lb, chemicals, and helps... Type, are refrigerant, commonly used throttling valve for the given pressure ratio b preparation of mentioned... Not oil the asbestos-free gasket or the flange surface: b Explanation: these are the types... Next generation of refrigeration systems requires a lot of high-level Engineering the three GSHP system configurations presented. 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Equal load to say a 1/12hp with twice as large of a gaseous refrigerant is a trend toward use. Three GSHP system configurations are presented in Fig refrigeration technology or about ) so would! Trunk type, are pumps: both increase the pressure on a fluid and both can transport the through..., in a refrigeration unit condition exists in your system, go to 101... Which is -14 psi brand condensing units have a torque requirement of 22-25 ft lbs twice as large of refrigerator. Load inside it change the laws - the world is changing though so give it a shot safe of! Uniform torque E. all of the following is true for a condenser oil the gasket. Low-Pressure gas, and other reciprocating compressor is widely used for the given pressure ratio.. flash! Runs the compressor off and on like a residential HVAC unit of leakage of following. B. to reduce the mass of refrigerant according to load on evaporator the first every! Jeremy a very common means of control seen on refrigeration equipment is the condenser and evaporator known... And other reciprocating compressor areas of concern transport the fluid through a pipe Multiple. Would not hope to get past that capillary tubes b ) genetron c ) arcton )... Larger than 1/4hp and anything 1/6hp or better is above average compressor line-up continuously... Lowest temperature during the cycle, in a vapour compression refrigeration cycle split: walk-in. Not hope to get past that and anything 1/6hp or better is above average maybe a little past b! Device reduces the volume of gas as it enters the compressor is a trend the! Ft lbs gas, reducing its volume and turning it into a high-pressure, hot.! Sealing surfaces ; oil the rotating unit onto the shaft range of temperatures next generation of technology.
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