Description : The bank of tubes at the back of domestic refrigerator are (a) condenser tubes (b) evaporator tubes (c) refrigerant cooling tubes (d) capillary tubes
Last Answer : Ans: a
Description : 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
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
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 : The change in evaporator temperature in a refrigeration cycle, as compared to change in condenser temperature, influences the value of C.O.P. (a) more (b) less (c) equally. (d) unpredictable
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
Description : The C.O.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
Description : Where does the lowest temperature occur in a vapour compression cycle ? (a) condenser (b) evaporator (c) compressor (d) expansion valve
Description : In a refrigeration cycle, the flow of refrigerant is controlled by (a) compressor (b) condenser (c) evaporator (d) expansion valve
Last Answer : Ans: d
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 : 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 : A refrigeration cycle operates between condenser temperature of + 27°C and evaporator temperature of- 23°C. TheCarnot coefficient of performance of cycle will be (a) 0.2 (b) 1.2 (c) 5 (d) 6
Description : The higher temperature in vapour compression cycle occurs at (a) compressor discharge. (b) expansion valve (c) evaporator (d) condenser discharge
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 : For ammonia refrigerating systems, the tubes of a shell and tube condenser are made of (a) copper (b) aluminium (c) steel (d) brass
Description : Describe any two sources of air leak in surface condenser. Also describe effect of air leak on latent heat of steam and cooling water requirements.
Last Answer : ✓ The main sources of air leakage found in condenser are given below: 1) There is leakage of air from atmosphere at the joint of the parts which are internally under a pressure less ... hence evaporation enthalpy of steam increases therefore more amount of cooling water required in the condenser.
Description : 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
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 : Aqua ammonia is used as refrigerant in the following type of refrigeration system (a) compression (b) direct (c) indirect (d) absorption
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 : Absorption system normally uses the following refrigerant (a) Freon-11 (b) Freon-22 (c) C02 (d) ammonia.
Last Answer : Ans: e
Description : Allowable pressure on high-pressure side or ammonia absorption system is of the order of (a) atmospheric pressure (b) slightly above atmospheric pressure (c) 2-4 bars (d) 5-6 bars
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 : 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 3.65 kg (c) more than 10 kg (d) there is no such consideration
Description : The bank of tubes located at the back of the domestic refrigerators are the __________ tubes. (A) Refrigerant cooling (B) Evaporator (C) Condenser (D) Throttling
Last Answer : C) Condenser
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 : Air can be cooled and dehumidified by A. circulating chilled water in tube across air flow B. placing evaporator coil across air flow C. spraying chilled water to air D. all of the mentioned
Last Answer : ANSWER : D
Description : 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
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 : Formation of frost on evaporator in refrigerator (a) results in loss of heat due to poor heat transfer (b) increases heat transfer rate (c) decreases compressor power. (d) can be avoided by proper design
Description : The moisture in a refrigerant is removed by (a) evaporator (b) safety relief valve (c) dehumidifier (d) driers
Description : Presence of moisture in a refrigerant affects the working of (a) compressor (b) condenser (c) evaparator (d) expansion valve.
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 : Identify modes of heat transfer involved applications with brief explanation. (1) Radiator of automobile (2) Condenser of domestic refrigerator.
Last Answer : Modes of heat transfer Automobile radiator-A radiator is a type of heat exchanger. It is designed to transfer heat from the hot coolant that flows through it to the air blown through ... of heat transfer plays very important deciding factor transferring heat from condenser tube to atmosphere.
Description : In milk chilling plant, the usual secondary refrigerant is (a)ammonia (b)sodium silicate (c) glycol (d) brine
Description : The COP of a vapour compression plant in comparison to vapour absorption plant is (a) more (b) less (c) same (d) more/less depending on size of plant
Description : For steam power plant having capacity 600 MW capacity a cooling tower is required to set up with condenser. Suggest the type of condenser and cooling tower with justification.
Last Answer : For Steam power plant having Capacity 600 MW the requirement of condenser and cooling tower is as follow. 1) Condenser:- Given Capacity is medium to low capacity for this we can use Jet Condenser ... and efficiency of tower is high -Temperature of water coming out from tower can be controlled.
Description : In the manufacture of sulphuric acid from elemental sulphur, the following sequence of major operations is followed: (A) Furnace → converter → absorber (B) Furnace → evaporator → absorber (C) Furnace → converter → evaporator (D) Converter → furnace → absorber
Last Answer : (A) Furnace → converter → absorber
Description : Ammonia is (a) non-toxic (b) non-inflammable (c) toxic and non-inflammable (d) highly toxic and inflammable
Description : A certain refrigerating system has a normal operating suction pressure of 10 kg/cm gauge and condensing pressure ofabout 67 kg/cm. The refrigerant used is (a) Ammonia (b) Carbon dioxide (c) Freon (d) Brine
Description : The boiling point of ammonia is (a) -100°C (b) -50°C (c) - 33.3°C (d) 33.3°C.
Description : 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 ... ice at 0°C in 24 hours (d) the refrigeration effect to produce 1 ton of ice at NTP conditions
Description : The cooling tower uses the phenomenon of evaporative cooling to cool warm water above the dbt of air. A. true B. false
Last Answer : ANSWER : B
Description : In SI engines knocking can be reduced by (a) Increasing the compression ratio (b) Increasing the cooling water temperature (c) Retarding the spark advance (d) Increasing the inlet air temperature
Last Answer : Ans :c
Description : The formation of frost on cooling coils in a refrigerator (a) increases heat transfer (b) improves C.O.P. of the system (c) increases power consumption (d) reduces power consumption
Description : Under-cooling in a refrigeration cycle (a) increases COP (b) decreases COF (c) COP remains unaltered (d) other factors decide COP