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These were the books of refrigeration and air conditioning. Refrigeration and Air Conditioning one word questions and answers pdf Single suitable word s for following statements :: 1. Pick up the wrong statement. Good maintenance will help prevent AC problems, but a system … Solved examples with detailed answer description, disscussion in forum helps in easy to understand concepts.
Pick up the wrong statement. 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. Ans: b. Ans: e. Vapor compression refrigeration is some what like a Carnot cycle b Rankine cycle c reversed Camot cycle d reversed Rankine cycle e none of the above.
Which of the following cycles uses air as the refrigerant a Ericsson b Stirling c Carnot d Bell-coleman e none of the above. Ans: d. Ammonia-absorption refrigeration cycle requires a very little work input b maximum work input c nearly same work input as for vapour compression cycle d zero work input e none of the above. Ans: a. Clapeyron equation is applicable for registration at a saturation point of vapor b saturation point of liquid c sublimation temperature d triple point e critical point.
In vapour compression cycle, the conditii of refrigerant is saturated liquid a after passing through the condenser b before passing through the condensei c after passing through the expansion throttle valve d before entering the expansion valve e before entering the compressor.
In vapor compression cycle, the condition of refrigerant is very wet vapor a after passing through the condenser b before passing through the condenser c after passing through the expansion or throttle valve d before entering the expansion valve e before entering the compressor. In vapor compression cycle, the condition of refrigerant is high pressure saturated liquid a after passing through the condenser b before passing through the condenser c after passing through the expansion or thiottle valve d before entering the expansion valve e before entering the compressor.
In vapour compression cycle the condition of refrigerant is superheated vapour a after passing through the condenser b before passing through the condenser c after passing through the expansion or throttle valve d before [entering the expansion valve e before entering the compressor.
In vapor compression cycle the condition off refrigerant is dry saturated vapor a after passing through the condenser b before passing through the condenser c after passing through the expansion or throttle valve d before entering the expansion valve e before entering the compressor.. Ans: c. One ton of refrigeration is equal to the refrigeration effect corresponding to melting of kg of ice a in 1 hour b in 1 minute c in 24 hours d in 12 hours e in 10 hours.
Allowable pressure on high-pressure side or ammonia absorption system is of the order of a atmospheric pressure b slightly above atmospheric pressure c bars d bars e bars. The moisture in a refrigerant is removed by a evaporator b safety relief valve c dehumidifier d driers e expansion valve Ans: d.
The condensing pressure due to the presence of non-condensable gases, as compared to that actually required for condensing temperatures without non-condensable gases, a will be higher b will be lower c will remain unaffected d may be higher or lower depending upon the nature of non-condensable gases e unpredictable.
Critical pressure of a liquid is the pressure a above which liquid will remain liquid b above which liquid becomes gas c above which liquid becomes vapour d above which liquid becomes solid e at which all the three phases exist together. The refrigerant for a refrigerator should have a high sensible heat b high total heat c high latent heat d low latent heat e low sensible heat Ans: c. Rating of a domestic refrigerator is of the order of a 0. The COP of a domestic refrigerator a is less than 1 b is more than 1 c is equal to 1 d depends upon the make e depends upon the weather conditions.
The domestic refrigerator uses following type of compressor a centrifugal b axial c miniature sealed unit d piston type reciprocating e none of the above. Presence of moisture in a refrigerant affects the working of a compressor b condenser c evaparator d expansion valve. Refrigeration in aeroplanes usually employs the following refrigerant a Co2 b Freon c Freon d Air e none of the above.
Domestic refrigerator working on vapour compression cycle uses the following type of expansion device a electrically operated throttling valve b manually operated valve c thermostatic valve d capillary tube e expansion valve. Air refrigeration operates on a Carnot cycle b Reversed Carnot cycle c Rankine cycle d Erricson cycle e Brayton cycle.
Air refrigeration cycle is used in a domestic refrigerators b commercial refrigerators c air conditioning d gas liquefaction e such a cycle does not exist. In a vapor compression cycle, the refrigerant immediately after expansion valve is a liquid b sub-cooled liquid c saturated liquid d wet vapour e dry vapour. The vapor pressure of refrigerant should be a lower than atmospheric pressure b higher than atmospheric pressure c equal to atmospheric pressure d could be anything e none of the above.
For better COP of refrigerator, the pressure range corresponding to temperature in evaporator and condenser must be a small b high c euqal d anything e under some conditions small and under some conditions high.
The bank of tubes at the back of domestic refrigerator are a condenser tubes b evaporator tubes c refrigerant cooling tubes d capillary tubes e throttling device.
The higher temperature in vapour compression cycle occurs at a receiver b expansion valve c evaporator d condenser discharge e compressor discharge. Highest temperature encountered in refrigeration cycle should be a near critical temperature of refrigerant b above critical temperature c at critica. In refrigerator, liquid receiver is required between condenser and flow controlling device, if quantity of refrigerant for system is a less than 2 kg b more than or equal to 3.
Absorption system normally uses the following refrigerant a Freon b Freon c C02 d S02 e ammonia. One of the purposes of sub-cooling the liquid refrigerant is to a reduce compressor overheating b reduce compressor discharge temperature c increase cooling effect d ensure that only liquid and not the vapour enters the expansion throttling valve e none of the above.
The value of COP in vapour compression cycle is usually a always less than unity b always more than unity c equal to unity d any one of the above e none of the above. In a refrigeration system, heat absorbed in comparison to heat rejected is a more b less c same d more for small capacity and less for high capacity e less for small capacity and more for high capacity. Condensing temperature in a refrigerator is the temperature a of cooling medium b of freezing zone c of evaporator d at which refrigerant gas becomes liquid e condensing temperature of ice.
Formation of frost on evaporator in refrigerator a results in loss of heat due to poor heat transfer b increases heat transfer rate c is immaterial d can be avoided by proper design e decreases compressor power. In a flooded evaporator refrigerator, an accumulator at suction of compressor is used to a collect liquid refrigerant and prevent it from going to compressor b detect liquid in vapour c superheat the vapour d collect vapours e increase refrigeration effect.
At lower temperatures and pressures, the latent heat of vaporisation of a refrigerant a decreases b increases c remains same d depends on other factors e none of the above. The Cannot coefficient of performance of cycle will be a 0. Which of the following is not a desirable property of a refrigerant a high triiscibility with oil b low boiling point c good electrical conductor d large latent heat e non-inflammable.
In vapor compression refrigeration system, refrigerant occurs as liquid between a condenser and expansion valve b compressor and evaporator c expansion valve and evaporator d compressor and condenser e none of the above. Pick up the correct statement about giving up of heat from one medium to other in ammonia absorption system a strong solution to weak solution b weak solution to strong solution c strong solution to ammonia vapour d ammonia vapour to weak solution e ammonia vapour to strong solution.
If the- cycle direction be reversed, what will be the value of COP of reversed Carnot cycle a 1. Highest pressure encountered in a refrigeration system should be a critical pressure of refrigerant b much below critical pressure c much above critical pressure d near critical pressure e there is no such restriction.
Aqua ammonia is used as refrigerant in the following type of refrigeration system a compression b direct c indirect d absorption e none of the above. If the evaporator temperature of a plant is lowered, keeping the condenser temperature constant, the h. In a refrigeration cycle, the flow of refrigerant is controlled by a compressor b condenser c evaporator d expansion valve e all of the above. Where does the lowest temperature occur in a vapour compression cycle?
The leaks in a refrigeration system using Freon are detected by a halide torch which on detection produces greenish flame lighting b sulphur sticks which on detection gives white smoke c using reagents d smelling e sensing reduction in pressure.
The lower horizontal line of the refrigeration cycle plotted on pressure-enthalpy-diagram represents a condensation of the refrigerant vapour b evaporation of the refrigerant liquid c compression of the refrigerant vapour d metering of the refrigerant liquid e none of the above.
Mass flow ratio of NH3 in comparison to Freon for same refrigeration load and same temperature limits is of the order of a 1 : 1 b 1 : 9 c 9 : 1 d 1 : 3 e 3 : 1 Ans: b. Freon group of refrigerants are a inflammable d toxic c non-inflammable and toxic d non-toxic and inflammable e non-toxic and non-inflammable.
In vapour compression cycle using NH3 as refrigerant, initial charge is filled at a suction of compressor b delivery of compressor c high pressure side close to receiver d low pressure side near receiver e anywhere in the cycle.
Short horizontal lines on pressure-enthalpy chart show a constant pressure lines b constant temperature lines c constant total heat lines d constant entropy lines e constant volume lines. On the pressure-enthalpy diagram, condensation and desuperheating is represented by a horizontal line because the process a involves no change in volume b takes place at constant temperature c takes place at constant entropy d takes place at constant enthalpy e takes place at constant pressure.
For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphere is high, then a bigger cabinet should be used b smaller cabinet should be used c perfectly tight vapour seal should be used d refrigerant with lower evaporation temperature should be used e refrigerant with high boiling point must be used. Choose the correct statement a A refrigerant should have low latent heat b If operating temperature of system is low, then refrigerant with low boiling point should be used c Precooling and subcooling bf refrigerant are same d Superheat and sensible heat of a.
Moisture in freon refrigeration system causes a ineffective refrigeration b high power consumption c freezing automatic regulating valve d corrosion of whole system e breakdown of refrigerant.
The advantage of dry compression is that a it permits higher speeds to be used b it permits complete evaporation in the evaporator c it results in high volumetirc and mechanical efficiency d all of the above e none of the above.
Choose the wrong statement a Temperature of medium being cooled must be below that of the evaporator b Refrigerant leaves the condenser as liquid c All solar thermally operated absorption systems are capable only of intermittent operation d frost on evaporator reduces heat transfer e refrigerant is circulated in a refrigeration system to transfer heat.
For obtaining high COP, the pressure range of compressor should be a high b low c optimum d any value e there is no such criterion. The coefficient of performance is the ratio of the refrigerant effect to the a heat of compression b work done by compressor c enthalpy increase in compressor d all of the above e none of the above. The C. P of a refrigeration cycle with increase in evaporator temperature, keeping condenser temperature constant, will a increase b decrease c remain unaffected d may increase or decrease depending on the type of refrigerant used e unpredictable.
Vertical lines on pressure-enthalpy chart show constant a pressure lines b temperature lines c total heat lines d entropy lines e volume lines. Most of the domestic refrigerators work on the following refrigeration system a vapour compression b vapour absorption c carnot cycle d electrolux refrigerator e dual cycle. The general rule for rating refrigeration systems excepting for C02 system is to approximate following h. Reducing suction pressure in refrigeration cycle a lowers evaporation temperature b increases power required per ton of refrigeration c lowers compressor capacity because vapour is lighter d reduces weight displaced by piston e all of the above.
Cooling water is required for following equipment in ammonia absorption plant a condenser b evaporator c absorber d condenser and absorber e condenser, absorber and separator rectifier. The refrigeration effect in a dry evaporator compared to flooded evaporator in a similar plant is a same b more c less d more or less depending on ambient conditions e unpredictable.
The evolution of heat of solution takes place in ammonia absorption plant when a ammonia vapour goes into solution b ammonia vapour is driven out of solution c lithium bromide mixes with ammonia d weak solution mixes with strong solution e lithium bromide is driven out of solution. The change in evaporator temperature in a refrigeration cycle, as compared to change in condenser temperature, influences the value of C. Your email address will not be published.
Ans: b 2. Ans: e 3. Ans: e 4. Ans: d 5. Ans: a 6. Ans: b 7. Ans: a 8. Ans: e 9. Ans: a Ans: e Ans: d Ans: b Ans: c The moisture in a refrigerant is removed by a evaporator b safety relief valve c dehumidifier d driers e expansion valve Ans: d The refrigerant for a refrigerator should have a high sensible heat b high total heat c high latent heat d low latent heat e low sensible heat Ans: c Mass flow ratio of NH3 in comparison to Freon for same refrigeration load and same temperature limits is of the order of a 1 : 1 b 1 : 9 c 9 : 1 d 1 : 3 e 3 : 1 Ans: b Ans: e 68 Ammonia is a non-toxic b non-inflammable c toxic and non-inflammable d highly toxic and inflammable e none of the above.
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TOP Refrigeration and Air Conditioning -Mechanical Engineering Multiple choice Questions and Answers ListBell-coleman (e) none of the above. Ans: d 5.
Solved examples with detailed answer description, explanation are given and it would be easy to understand. Here you can find objective type Mechanical Engineering Heat Transfer, Refrigeration and Air Conditioning questions and answers for interview and entrance examination. Multiple choice and true or false type questions are also provided. You can easily solve all kind of Mechanical Engineering questions based on Heat Transfer, Refrigeration and Air Conditioning by practicing the objective type exercises given below, also get shortcut methods to solve Mechanical Engineering Heat Transfer, Refrigeration and Air Conditioning problems. The C.
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Pick up the wrong statement. 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. Ans: b. Ans: e. Vapour compression refrigeration is some what like a Carnot cycle b Rankine cycle c reversed Camot cycle d reversed Rankine cycle e none of the above. Which of the following cycles uses air as the refrigerant a Ericsson b Stirling c Carnot d Bell-coleman e none of the above.
On the pressure-enthalpy diagram, condensation and desuperheating is represented by a horizontal line because the process a involves no change in volume b takes place at constant temperature c takes place at constant entropy d takes place at constant enthalpy e takes … Ans: a d expansion valve Dec 27, - Refrigeration And Air Conditioning 20 Questions MCQ Test has questions of Mechanical Engineering preparation. Ans: d 1. For obtaining high COP, the pressure range of compressor should be a high b low c optimum d any value e there is no such criterion. Refrigeration and Air Conditioning Questions Answers. Ans: e In refrigerator, liquid receiver is required between condenser and flow controlling device, if quantity of refrigerant for system is e there is no such criterion. Ans: b Ans: c b detect liquid in vapour In refrigerators, the temperature difference between the evaporating refrigerant and the medium being cooled should be Multiple Choice Questions with Answers on Refrigeration and Air-Conditioning - Set 07 Practice Test: Question Set - 07 1.
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