Description : Most of the domestic refrigerators work on the following refrigeration system (a) vapour compression (b) vapour absorption (c) carnot cycle (d) electrolux refrigerator
Last Answer : Ans: a
Description : Which of the following has the minimum value of COP for a given refrigeration effect? (A) Reverse Carnot cycle (B) Ordinary vapour-compression cycle (C) Vapour-compression process with a reversible expansion engine (D) Air refrigeration cycle
Last Answer : (D) Air refrigeration cycle
Description : Out of the following refrigeration cycles, which one has the minimum COP (Co-efficient of performance)? (A) Air cycle (B) Carnot cycle (C) Ordinary vapour compression cycle (D) Vapour compression with a reversible expansion engine
Last Answer : A) Air cycle
Description : A refrigerator is working on reversed carnot cycle between temperature of 30°C to –10°C with capacity of 10 tonnes. Calculate. (i) The COP (ii) Define ton of refrigeration (iii) Give the industrial application of refrigeration
Last Answer : (ii) Ton of refrigeration: It is defined as the quantity of heat required to be removed from 1Ton water at 0oC to get ice at 0oC in one day. (iii) Industrial applications of refrigeration ... food stuff such as meat, fruit, fruit juice, vegetables etc. 5. Ice cooling of concrete for dam.
Description : Vapour compression refrigeration is some what like (a) Carnot cycle (b) Rankine cycle (c) reversedCamot cycle (d) reversed Rankine cycle
Last Answer : Ans: C
Description : The vapour compression refrigerator employs the following cycle (a) Rankine (b) Carnot (c) Reversed Carnot. (d) Brayton
Last Answer : Ans: c
Description : Pick out the wrong statement. (A) A refrigeration cycle violates the second law of thermodynamics (B) Refrigeration cycle is normally represented by a temperature vs. entropy plot (C) In a refrigerator, ... (D) One ton of refrigeration is equivalent to the rate of heat absorption equal to 3.53 kW
Last Answer : (A) A refrigeration cycle violates the second law of thermodynamics
Description : The Carnot co-efficient of performance (COP) of a domestic air conditioner compared to a household refrigerator is (A) Less (B) More (C) Same (D) Dependent on climatic conditions
Last Answer : (A) Less
Description : In vapour compression refrigeration system, if the evaporator temperature and the condenser temperatures are -13°C and 37°C respectively, the Carnot COP will be (A) 5.2 (B) 6.2 (C) 0.168 (D) Data insufficient, can't be found out
Last Answer : A) 5.2
Description : 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
Description : Out of the following refrigeration cycles, which one has maximum COP? (A) Air cycle (B) Carnot cycle (C) Ordinary vapor compression cycle (D) Vapor compression with a reversible expansion engin
Last Answer : (B) Carnot cycle
Description : 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
Last Answer : Ans: d
Description : Air refrigeration operates on (a) Carnot cycle (b) Reversed Carnot cycle (c) Rankine cycle (d) Brayton cycle.
Description : The following cycle is used for air craft refrigeration (a) Brayton cycle (b) Joule cycle (c) Carnot cycle (d) Bell-Coleman cycle (e) Reversed-Brayton cycle.
Last Answer : Answer : e
Description : The main feature of Carnot refrigeration cycle is that, it (A) Does not need the addition of external work for its functioning (B) Transfers heat from high temperature to low temperature (C) Accomplishes the reverse effect of the heat engine (D) None of these
Last Answer : (C) Accomplishes the reverse effect of the heat engine
Description : Ideal refrigeration cycle is (A) Same as Carnot cycle (B) Same as reverse Carnot cycle (C) Dependent on the refrigerant's properties (D) The least efficient of all refrigeration processes
Last Answer : (B) Same as reverse Carnot cycle
Description : Which of the following units is not present in both the vapor compression refrigeration system and absorption refrigeration system? (A) Expansion valve (B) Condenser (C) Refrigerator (D) Compressor
Last Answer : (D) Compressor
Description : 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) increase refrigeration effect
Description : In thermodynamics, a throttling process, also called a _________, is a type of isenthalpic process where a liquid or gas is cooled as it passes from a higher pressure state to a lower pressure state. a. Rankine Process b. Carnot Cycle c. Joule-Thomson process d. Refrigeration process
Last Answer : Joule-Thomson process
Description : Air refrigeration cycle is used in (a) domestic refrigerators (b) gas liquefaction (c)commercial refrigerators (d) Chillers
Last Answer : Ans: b
Description : Air refrigeration cycle is used in (a) domestic refrigerators (b) commercial refrigerators (c) air conditioning (d) gas liquefaction
Description : Co-efficient of performance of a Carnot cycle refrigerator operating between - 23°C and + 27°C is (A) 3 (B) 5 (C) 0.5 (D) 1.5
Last Answer : Option A
Description : During which of following process does heat rejection take place in Carnot vapour cycle? [IES-1992] (a) Constant volume (b) constant pressure (c) Constant temperature (d) constant entropy
Last Answer : (c) Constant temperature
Description : 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) all of the above.
Description : 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
Description : What is the use of flash chamber in a vapour compression refrigeration cycle to improve the COP of refrigeration cycle ?
Last Answer : When liquid refrigerant as obtained from condenser is throttled, there are some vapours. These vapours if carried through the evaporator will not contribute to refrigerating effect. Using a flash ... out in stages. Similarly compression process is also done in two separate compressor stages.
Description : Describe with a neat diagram the working of a simple vapour compression refrigeration system. Represent the cycle on P–V and T–S diagram.
Last Answer : Vapour compression refrigeration cycle: The 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. Figure shows ... the compressor. P-V Diagram T-S diagram:
Description : Heat pump (A) Accomplishes only space heating in winter (B) Accomplishes only space cooling in summer (C) Accomplishes both (A) and (B) (D) Works on Carnot cycle
Last Answer : (C) Accomplishes both (A) and (B)
Description : Refrigeration capacity of a household refrigerator may be round about __________ tons. (A) 0.15 (B) 1.5 (C) 4.5 (D) 6.5
Last Answer : (A) 0.15
Description : A domestic refrigerator has a/an __________ cooled condenser. (A) Water (B) Air (C) Evaporative (D) Gas
Last Answer : (B) Air
Description : Thermal power plant works on (a) Carnot cycle (b) Joule cycle (d) Rankine cycle (d) Otto cycle (e) Brayton cycle.
Last Answer : Answer : c
Description : A refrigerator may be termed as a (A) Heat pump (B) Heat engine (C) Carnot engine (D) None of these
Last Answer : (A) Heat pump
Description : Thermodynamic cycle involved in the working of a thermal power plant is the __________ cycle. (A) Joule (B) Carnot (C) Rankine (D) Brayton
Last Answer : (C) Rankine
Description : Carnot cycle is also termed as the constant __________ cycle in thermodynamics. (A) Entropy (B) Pressure (C) Volume (D) Heat
Last Answer : Option D
Description : COP of a refrigerator drawing 1 kW of power per ton of refrigeration is about (A) 0.5 (B) 3.5 (C) 4.5 (D) 8.5
Last Answer : (B) 3.5
Description : Co-efficient of Performance (COP) of a refrigerator is the ratio of the (A) Work required to refrigeration obtained (B) Refrigeration obtained to the work required (C) Lower to higher temperature (D) Higher to lower temperature
Last Answer : (B) Refrigeration obtained to the work required
Description : Lowering of condenser temperature (keeping the evaporator temperature constant) in case of vapour compression refrigeration system results in (A) Increased COP (B) Same COP (C) Decreased COP (D) Increased or decreased COP; depending upon the type of refrigerant
Last Answer : (A) Increased COP
Description : Which of the following is a widely used refrigerant in vapour compression refrigeration system (using large centrifugal compressor)? (A) Freon (B) Liquid sulphur dioxide (C) Methyl chloride (D) Ammonia
Last Answer : (A) Freon
Description : The effect of changing the evaporator temperature on COP as compared to that of changing the condenser temperature (in vapour compression refrigeration system) is (A) Less pronounced (B) More pronounced (C) Equal (D) Data insufficient, can't be predicted
Last Answer : (B) More pronounced
Description : Pick up the incorrect statement (a) lithium bromide used in vapour absorption cycle is nonvolatile (b) lithium bromide plant can't operate below 0°C (c) a separator is used in lithium ... of solution coming out of lithium bromide generator is more in comparison to that entering the generator
Description : A refrigeration cycle is the same as a __________ cycle, (A) Turbine (B) Heat engine (C) Reversed heat engine (D) None of these
Last Answer : C) Reversed heat engine
Description : Air-refrigeration cycle (A) Is the most efficient of all refrigeration cycles (B) Has very low efficiency (C) Requires relatively large quantities of air to achieve a significant amount of refrigeration (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : The efficiency of Stirling cycle is __________ Carnot cycle. A. greater than B. less than C. equal to
Last Answer : Answer: C
Description : How Vapour Compression Cycle Works ?
Last Answer : The Vapor-Compression Refrigeration Cycle is comprised of four steps. ... The condenser is in contact with the hot reservoir of the refrigeration system. (The gas releases heat into the hot reservoir because of the external work added to the gas.) The refrigerant leaves as a high pressure liquid.
Description : What is the value of maximum COP in case of absorption refrigeration, if refrigeration provided is at temperature, TR (where, T1 and T2 are source & surrounding temperatures respectively.)? (A) TR/(T2 - TR) (T1 - T2 )/T1 (B) TR ... T1 /(T1 - T2 ) (C) TR/(T1 - TR) (T1 - T2 )/T1 (D) None of these
Last Answer : (A) TR/(T2 - TR) × (T1 - T2 )/T1
Description : The C.O.P. of a domestic refrigerator in comparison to domestic air conditioner will be (a) same (b) more (c) less (d) dependent on weather conditions
Description : For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphereis high, then (a) bigger cabinet should be used (b) smaller cabinet should ... tight vapour seal should be used (d) refrigerant with lower evaporation temperature should be used
Description : In vapour 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
Description : The benchmarking parameter for a vapour compression refrigeration system is a) kW / kg of refrigerant used b) kcal / m3 of chilled water c) BTU / Ton of Refrigeration d) kW / Ton of Refrigeration
Last Answer : d) kW / Ton of Refrigeration
Description : In otto cycle compression ratio is 8. Calculate air standard efficiency. Will it be grater than Carnot Cycle ? Justify your answer.
Last Answer : No, the Otto cycle efficiency 56.47% will always be lower than Carnot cycle efficiency. Justification: Carnot theorem states that keeping operating conditions same, Carnot engine is more efficient than any other engine. So, Otto cycle efficiency is lower than Carnot cycle efficiency.