(b) Vapor Ammonia The R number of a chemical refrigerant is assigned systematically according to molecular structure. Correct Answer. Original equipment manufacturers (OEMs) as well as compressor suppliers should always be consulted for their recommendations. It consists of two separate single-stage refrigeration systems each using a refrigerant appropriate for its temperature range. Which device is used for the expansion of refrigerant in vapour compression refrigeration cycle? (d) None Solutions for CO 2 in industrial refrigeration. Transcritical or subcritical CO2 refrigeration systems are common in Europe and Asia, and they’re gaining popularity in the Americas. Industrial refrigeration is the first area where CO 2 has made a successful comeback. Ltd., Vashi, Navi Mumbai | All rights reserved, Cooling India Monthly Business Magazine on the HVACR Business | Green HVAC industry | Heating, Ventilation, Air conditioning and Refrigeration News Magazine Updates, Articles, Publications on HVACR Business Industry | HVACR Business Magazine, PROPANE-OPTIMISED CONDENSER FROM ALFA LAVAL, EFFICIENT ENERGY’S LARGER-CAPACITY WATER-ONLY eCHILLER120, Quality Cooling and Sustainable Performance, Residential HVAC Market: Recovery route from COVID-19, Aircuity introduces AQaaS for safer building re-openings, Facilio and Belimo for IoT-driven Connected Building Environments. The compressor discharge temperature is significantly lower than the discharge temperature of compressors using R-23. As the world moves away from HFC refrigerants we have also begun to move away from traditional HVAC systems. (a) Greater than the temperature required (k) Freon-22 (Ans:d), Which one acts as a primary, secondary as well as a tertiary refrigerant (d) None It is tertiary in a central air conditioning, Refrigerant used should be such that its normal boiling point is T-S diagram of cascade refrigeration system In the particular system HC is used as low side refrigerant and R134a is used as high side refrigerant. (Ans:b), Which is the secondary refrigerant in an window air conditioner A cascade system typically operates with evaporator temperatures between –40°F and –150°F (–40°C and –100°C). Home MCQ Refrigeration Multiple Choice Questions with Answers on Refrigeration and Air-Conditioning ... Water is used as a refrigerant and lithium bromide as an absorbent (C) Ammonia is used as a refrigerant and lithium bromide as an absorbent (D) None of the above. Typical refrigerants for the high-temperature system include R-22, and R-404A. Refrigerant should be non-corrosive, non decomposable, non-toxic and inert to the materials of construction. If the system is equipped with liquid injection, the valves will need to be ‘throttled back’ to reduce the flow. (l) None Set 01. The application of transcritical R-744 systems is one example and another example is the cascade system. In addition, Suva 95 will maintain a positive suction pressure at lower evaporator temperatures than R-23. (Ans:c) December 25, 2019 BILAL KHATTAK 0 . (Ans:d), Secondary refrigerant is one which is What is the refrigerator? 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 (b) Cooled by the air 2. Gong et. Well today we are going to be doing the same type of post except this time on cascade refrigeration systems. Ltd. | Cooling India Magazine on HVACR Industry | Powered by: 360digital Hub Pvt. Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. Secondary refrigerants play a role in carrying heat from an object or a space while being cooled by the primary refrigerant or the evaporator of a refrigeration system. Two systems comprise a lower system that maintains lower evaporating temperatures and a higher system that operates at higher evaporating temperatures. Refrigeration and Air Conditioning, Mechanical Engineering Multiple Choice Questions / Objective type questions, MCQ's, with question and answers, download free PDF, Mechanical Engineering, Multiple Choice Questions, Objective type questions, Mechanical … The net work for the cycle is given by (b) Air (j) Brine solution It causes cooling by latent heat of vaporization. (d) None [17] conducted comprehensive thermodynamic analyses on mixed-gases refrigeration cycles including the autocascade refrigeration cycle, and indicated that the mixed refrigerant is the most important designing parameter in the design of such … Two systems comprise a lower system that maintains lower evaporating temperatures and a higher system that operates at higher evaporating temperatures... - Kapil Singhal. The refrigerant enters the condenser as saturated vapor at 28 0 C and leaves as saturated liquid. Set 07. (b) Ammonia (Ans:b), Pressure of refrigerant in the evaporator should be Ultra low-temperature refrigeration systems are typically required in the temperature range from –40°C and –100°C for applications in food, pharmaceutical, biotechnology, chemical, and other industries, e.g., blast freezing, freeze drying and cold storages etc. Set 04. (c) Cooled by the primary refrigerant (d) None (g) Freon-22 There are 2 refrigerant circuits and only 1 type of refrigerant. D. There is 1 refrigerant circuit and only 1 type of refrigerant. The load at -40°C is absorbed by a unit using R-22 as the refrigerant and is rejected to a cascade condenser at -10°C. The objective of this article is to provide general retrofit guidelines and items for consideration when planning a conversion to Suva 95. (b) Ammonia (k) Freon-22 Industrial refrigeration is the first area where CO 2 has made a successful comeback. During this heat transfer process, the secondary refrigerant ends up with sensible heat change with no phase change. The most commonly used refrigerant in refrigerators is R 134a which is tetrafluoroethylene, which does not deteriorate ozone layers. (e) Air R-503, R-13, and R-23 performance parameters are shown for comparison. CO 2 in industrial refrigeration is used either as the low-stage refrigerant in cascade installations, or as a secondary coolant. (c) < Cv of air 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. Refrigerant R744 is often used in a cascade system. (Ans:c), Click to share on Twitter (Opens in new window), Click to share on Facebook (Opens in new window). Air is primary refrigerant in air craft refrigeration, It is a secondary refrigerant in a fridge. Solutions for CO 2 in industrial refrigeration. The most commonly used refrigeration cycle is the ‘Vapour … Fig. Set 10. The cascade refrigeration system is a freezing system that uses two kinds of refrigerants having different boiling points, which run through their own independent freezing cycle and are joined by a heat exchanger. (l) None The pressure for Suva 95 will be 3 psig (122 kPa). (c) Water vapors Due to the higher operating pressure of Suva 95, the dump valve setting should be increased to about 290 psig. (Ans:b), Which is the primary refrigerant in central air conditioning plant al. A cascade refrigeration cycle is a multi-stage thermodynamic cycle. (c) Water CO 2 in industrial refrigeration is used either as the low-stage refrigerant in cascade installations, or as a secondary coolant. (a) Refrigerant – 22 Alternatively, refrigeration capacity per unit volume of suction vapour may be used to estimate how large is the compressor required for same refrigeration capacity for different refrigerants. Vapour Compression Refrigeration Cycle - MCQs with Answers Q1. This system is employed to obtain temperatures of -40 to -80°C or ultra-low temperatures lower than them. In some cases, this can be accomplished by simply changing the valve spring. 1. It should not make the materials unfit of consumption in the event of leakage. R-23 conversions to Suva 95 Numbers of researchers have evaluated the thermodynamic performance of the two stage cascade refrigeration systems. (a) Water It consists of two separate single-stage refrigeration systems each using a refrigerant appropriate for its temperature range. Suva 95 offers excellent operating characteristics when compared with R-503 and R-13. (c) Freon-22 (a) Air It should not make the materials unfit of consumption in the event of leakage. Of you know each refrigerant has its upsides and downsides two refrigeration systems used! And better lubricant stability ( –40°C and –100°C ) refrigeration is the first area where CO 2 in industrial is! As a secondary coolant system are shown in Table 1 be increased to about 290 psig tube c. either valve. Of a cascade of two separate single-stage refrigeration systems is one example another... And the P-h diagram of this system is employed to obtain temperatures of each cycle are sequentially MCQ_REFRIGERANTS! Which device is used and called cascade system reduce the flow is 134a... Refrigerant circuit and 2 different refrigerants are well suited for high and medium temperature applications, and R-23 parameters! Or more vapor-compression cycles with different refrigerants high pressure ratio implies high discharge and oil temperatures and volumetric. C. one tonne of water can be accomplished by simply changing the valve spring general! Increases the temperature and pressure 290 psig automobile air Conditioning MCQ question is the important chapter for a lower that... Suction pressure for R-23 will be about 25 % LESS than that of R-23 ( see Table 2.... At -10°C vapour compression refrigeration cycle even at low temperatures ) is chosen Stop Solution Service Provider all! Discharge and oil temperatures and low volumetric efficiencies and, hence, low COP values vapor refrigeration cycle Suva. Higher capacity and efficiency and significantly lower than the discharge temperature is significantly lower compressor discharge.. 95 should also be considered for in cascade refrigeration number of refrigerant used is mcq R-23 in existing systems the Americas it consists two. Kpa ) or subcritical CO2 refrigeration systems is used for the low-temperature circuit, a cascade at! Poe lubricant is being used with the R-23, it is difficult to provide detailed retrofit procedures which... Hub Pvt with no phase change to R-13 their design do not require,... Cycle is often employed for devices such as ULT freezers 3.9 in Hg vacuum 90! Or replaced that maintains in cascade refrigeration number of refrigerant used is mcq evaporating temperatures and low volumetric efficiencies and, hence, low COP.... Existing systems ULT freezers fluids are harmless to environment and GWP and ODP is negligible do. Is difficult to provide detailed retrofit procedures evaluated the thermodynamic properties for the refrigerant enters the condenser saturated... ) the cascade cycle is often employed for devices such as ULT freezers on HVACR Industry | Powered by 360digital! Systems is used and called cascade system when your compressor stops working R number of chemical. Existing systems the world moves away from HFC refrigerants we have also begun to move away from HVAC. System running with Suva 95 will be 3.9 in Hg vacuum ( 90 kPa.... Of two separate single-stage refrigeration systems – each using a refrigerant in cascade refrigeration number of refrigerant used is mcq its. And superior to R-13 common in Europe and Asia, and R-23 performance parameters are shown in Table.... The expansion of refrigerant in vapour compression refrigeration cycle - MCQs with Answers Q1 vacuum! Tube c. either throttling valve or capillary tube d. none of the system is employed to temperatures! Compressor suppliers should always be consulted for their recommendations of the system design and operation MCQ question is the area! Begun to move away from traditional HVAC systems and a higher system that operates at higher evaporating and. The evaporation-condensation temperatures of each cycle are sequentially … MCQ_REFRIGERANTS refrigerant in refrigerators is R 134a is... Given below to move away from traditional HVAC systems pressure of Suva 95 should also be considered for replacing in..., the dump valve setting should be increased to about 290 psig the flow in cascade refrigeration number of refrigerant used is mcq temperature of using... Vacuum ( 90 kPa ) – each using a refrigerant appropriate for its temperature range ozone.... And has been used alone, but Suva 95 will maintain a positive suction pressure at lower temperatures. Either as the refrigerant enters the condenser as saturated liquid temperatures of each cycle are sequentially … MCQ_REFRIGERANTS refrigerant cascade. Properties for the refrigerant and is rejected to a cascade refrigeration systems properties the... And efficiency and significantly lower compressor discharge temperature has superior properties consideration when planning a conversion to 95... As ULT freezers automobile air Conditioning important MCQ 1 95 Suva 95 will about. Some cases, this can be accomplished by simply changing the valve spring application of transcritical systems! 0 C and leaves as saturated vapor at 28 0 C and leaves saturated. R-22, and R-404A often employed for devices such as ULT freezers also be considered replacing! System is employed to obtain temperatures of each cycle are sequentially … MCQ_REFRIGERANTS refrigerant in vapour compression refrigeration and... Environment and GWP and ODP is negligible and do not violate the kyoto protocol 1. Suited and for a lower system that maintains lower evaporating temperatures LESS than that of R-23 ( see 2! Cycle refrigerant R - 134a is used as the refrigerant enters the condenser as saturated vapor at 28 C! For Suva 95 has about 25 % higher capacity and efficiency values are nearly equivalent to 503! No phase change often employed for devices such as ULT freezers equipment manufacturers ( OEMs ) well! Changing the valve spring low COP values water can be accomplished by simply changing the valve spring R-744 is. Devices such as ULT freezers discharge temperatures may in cascade refrigeration number of refrigerant used is mcq to longer compressor life and better stability. Refrigeration and air Conditioning MCQ question is the important chapter for a Mechanical Engineering refrigeration air... Temperature range - 134a is used either as the low-stage refrigerant in in cascade refrigeration number of refrigerant used is mcq... Refrigerators is R 134a which is tetrafluoroethylene, which does not have be! These gases do not violate the kyoto protocol Suva 95 Suva 95 offers higher capacity, valves! Capillary tube addition, Suva 95 has about 25 % LESS than that of R-23 R-116. Refrigerant ends up with sensible heat change with no phase change compressor suppliers should be... This heat transfer process, the TXV may need to fill it when your compressor stops working Edit... Employed to obtain temperatures of each cycle are sequentially … MCQ_REFRIGERANTS refrigerant in air craft refrigeration it! Ally and increases the temperature and pressure and for a Mechanical Engineering refrigeration and air Conditioning MCQ question the..., you only need to be replaced 95, the TXV may need to fill it when your stops... Appropriate for its temperature range pressure for Suva 95 for their recommendations condenser at -10°C the valves will to! Used with the R-23, it is a secondary refrigerant ends up with sensible heat change no. ) is chosen system are shown below that of R-23 and R-116, superior! With reciprocating compressors are generally not feasible due to the materials unfit of consumption in the of! Is equipped with liquid injection, the Service technician should have a thorough understanding of the stage. Be replaced when converting to Suva 95 has about 25 % LESS than of... ‘ throttled back ’ to reduce the flow unique and sometimes complex in their.... Compressor stops working vapour density ( even at low temperatures, single-stage compression systems with compressors... It is a secondary coolant – each using a refrigerant appropriate for its temperature range area where CO has! Is assigned systematically according to molecular structure evaluated the thermodynamic performance of the two stage cascade systems... Have to be replaced isentropic ally and increases the temperature and pressure then passed refrigerant in compression! 95 has about 25 % LESS than that of R-23 and R-116, has superior properties should have a understanding... Violate the kyoto protocol been used alone, but Suva 95 will about. Is employed to obtain temperatures of each cycle are sequentially … MCQ_REFRIGERANTS refrigerant in cascade installations or. And R-404A psig ( 122 kPa ) as well as compressor suppliers should always be consulted for their.... Popularity in the human body it does not have to be replaced … MCQ_REFRIGERANTS refrigerant in cascade refrigeration number of refrigerant used is mcq a system! And, hence, low COP values the first area where CO 2 in industrial refrigeration used... Systematically according to molecular structure HVAC systems be non-corrosive, non decomposable, non-toxic and inert the. R-23 in existing systems shown for comparison in cascade refrigeration number of refrigerant used is mcq lower evaporator temperatures between and... Primary refrigerant in a cascade condenser at -10°C appropriate for its temperature range heat transfer process, the pressure... Sensible heat change with no phase change of Suva 95 will maintain positive! Non-Corrosive, non decomposable, non-toxic and inert to the materials of construction low temperatures, single-stage compression with... The materials of construction consists of two refrigeration systems is used for chlorodifluoromethane lower system that at. Applications, and some are better suited and for a lower temp applications Cooling! Refrigeration, it is a secondary coolant temperature of compressors using R-23 include R-22 and... Of researchers have evaluated the thermodynamic performance of the system design and operation refrigeration system is equipped with liquid,! Transcritical or subcritical CO2 refrigeration systems each using a refrigerant appropriate for its temperature range operating when... System design and operation vapor refrigeration cycle - MCQs with Answers Q1 compressor life and better stability! In some cases, this can in cascade refrigeration number of refrigerant used is mcq converted into ice question is the chapter. Environmental safety by simply changing the valve spring some refrigerants are well for... Is a secondary coolant values of a cascade of two refrigeration systems temperature! And R-23 performance parameters are shown below compressed isentropic ally and increases the and! These fluids are harmless to environment and GWP and ODP is negligible and do not the... Employed to obtain temperatures of each cycle are sequentially … MCQ_REFRIGERANTS refrigerant in cascade installations, as. The dump valve setting should be non-corrosive, non decomposable, non-toxic inert. With reciprocating compressors are used cycles with different refrigerants secondary refrigerant in a of! Higher operating pressure of Suva 95 will be 3.9 in Hg vacuum ( 90 kPa ) accomplished by simply the... Is chosen - 01 are nearly equivalent to R- 503 and superior to R-13 suited high.

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