Description : 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
Last Answer : Ans: b
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
Last Answer : Ans: c
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
Last Answer : Ans: a
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 : Most of the domestic refrigerators work on the following refrigeration system (a) vapour compression (b) vapour absorption (c) carnot cycle (d) electrolux refrigerator
Description : The suction pipe diameter of refrigerating unit compressor in comparison to delivery side is (a) bigger (b) smaller (c) equal (d) smaller/bigger depending on capacity
Description : The size of inlet valve of an engine in comparison to exhaust valve is A. more B. less C. same D. varies from design to design
Last Answer : ANSWER : B
Description : 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
Description : The thermal efficiency of a diesel cycle having fixed compression ratio with increase in cut-off ratio will a. increase b. decrease c. independent d. increase or decrease depending upon other factors
Last Answer : ANSWER b. decrease
Description : 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
Description : If the evaporator temperature of a plant is lowered, keeping the condenser temperature constant, the h.p. of compressorrequired will be (a) same (b) more (c) less (d) more/less depending on rating
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 : The condition of refrigerant before entering the expansion or throttle valve, in a vapour compression system (a) dry vapour (b) wet vapour (c)liquid-vapour mixture (d) high pressure saturated liquid
Last Answer : Ans: d
Description : 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
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 : Where does the lowest temperature occur in a vapour compression cycle ? (a) condenser (b) evaporator (c) compressor (d) expansion valve
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 higher temperature in vapour compression cycle occurs at (a) compressor discharge. (b) expansion valve (c) evaporator (d) condenser discharge
Description : In a vapour compression cycle, the refrigerant immediately after expansion valve is (a) liquid (b) sub-cooled liquid (c) saturated liquid (d) wet vapour
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
Description : The vapour compression refrigerator employs the following cycle (a) Rankine (b) Carnot (c) Reversed Carnot. (d) Brayton
Description : In vapour compression cycle the condition off refrigerant is dry saturated vapour (a) after passing through the condenser (b) before passing through the condenser (c)before entering the expansion valve (d) before entering the compressor
Last Answer : Ans: D
Description : 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) beforeentering the expansion valve
Description : In vapour 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 throttle valve (d) before entering the expansion valve
Description : In vapour compression cycle, the condition of refrigerant is very wet 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
Description : In vapour compression cycle, the condition of refrigerant is saturated liquid (a) after passing through the condenser (b) before passing through the condenser (c) after passing through the expansion throttle valve (d) before entering the expansion valve
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 : 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 strong solution.
Description : 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 weather conditions.
Description : The air requirement of a petrol engine during starting compared to theoretical air required for complete combustion is a. more b. less c. same d. may be more or less depending on engine capacity
Last Answer : ANSWER b. less
Description : Aqua ammonia is used as refrigerant in the following type of refrigeration system (a) compression (b) direct (c) indirect (d) absorption
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 : 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 : 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 : 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 : In diesel engine, the compression ratio as compared with the expansion ratio is a. same b. less c. more d. variable
Last Answer : ANSWER c. more
Description : In a refrigeration system, heat absorbed in comparison to heat rejected is (a) more (b) less (c) less for small capacity and more for high capacity. (d) more for small capacity and less for high capacity
Description : For obtaining high COP, the pressure range of compressor should be (a) high (b) low (c) optimum (d) any value
Description : Under-cooling in a refrigeration cycle (a) increases COP (b) decreases COF (c) COP remains unaltered (d) other factors decide COP
Description : Superheating in a refrigeration cycle (a) increases COP (b) decreases COP (c) COP remains unaltered (d) other factors decide COP
Description : If a heat pump cycle operates between the condenser temperature of +27°C and evaporator temperature of - 23°C,then the Carnot COP will be (a) 0.2 (b) 1.2 (c) 5 (d) 6
Description : Efficiency of a Carnot engine is given as 80%. If the- cycle direction be reversed, what will be the value of COP ofreversed Carnot cycle (a) 1.25 (b) 0.8 (c) 0.5 (d) 0.25
Description : For better COP of refrigerator, the pressure range corresponding to temperature in evaporator and condenser must be (a) small (b) high (c) equal (d) anything
Description : The relative coefficient of performance is (a) actual COP/theoretical COP (b) theoretical COP/actual COP (c) actual COP x theoretical COP (d) 1-actual COP x theoretical COP
Description : Mass flow ratio of NH3 in comparison to Freon-12 for same refrigeration load and same temperature limits is of the orderof (a) 1 : 1 (b) 1 : 9 (c) 9 : 1 (d) 1 : 3
Description : The ratio of partial pressure of water vapour in a mixture to the saturation pressure of water at the same temperature of the mixture is called as A. humidity B. partial humidity C. specific humidity D. relative humidity
Last Answer : ANSWER : D
Description : When dry bulb temperature (DBT) and wet bulb temperature (WBT) are measured, greater the difference between DBT and WBT, A. greater the amount of water vapour held in the mixture B. smaller the amount of ... the mixture C. same the amount of water vapour held in the mixture D. none of the above
Description : For same compression ratio and heat input a. Otto cycle is more efficient b. Diesel cycle is more efficient c. Both are equally efficient d. None of the above
Last Answer : ANSWER a. Otto cycle is more efficient
Description : The C.O.P. of a refrigeration cycle with lowering of condenser temperature, keeping the evaporator temperatureconstant, will (a) increase (b) decrease (c) may increase or decrease depending on the type of refrigerant used (d) remain unaffected