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
Last Answer : Ans: a
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
Last Answer : Ans: d
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 : 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
Last Answer : Ans: c
Description : 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) Pre-cooling and sub-cooling bf refrigerant are same (d) Superheat and sensible heat of a. refrigerant are same
Last Answer : Ans: b
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 refrigerant for a refrigerator should have (a) high sensible heat (b) high total heat (c) high latent heat (d) low latent heat
Description : Which of the following is not a desirable property of a refrigerant (a) highmisibility with oil (b) low boiling point (c) good electrical conductor (d) large latent heat
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 : 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
Description : Highest temperature encountered in refrigeration cycle should be (a) near critical temperature of refrigerant (b) above critical temperature (c) atcritica. temperature (d) much below critical temperature
Description : What is the perfect condition for dehumidification of air? A. air is heated above its dew point temperature B. air is cooled up to its dew point temperature C. air is heated below its dew point temperature D. air is cooled below its dew point temperature
Last Answer : ANSWER : D
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
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 : Air refrigeration cycle is used in (a) domestic refrigerators (b) gas liquefaction (c)commercial refrigerators (d) Chillers
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 : Air refrigeration cycle is used in (a) domestic refrigerators (b) commercial refrigerators (c) air conditioning (d) gas liquefaction
Description : Consider the following statements 1. Large cold storage plants use ammonia as refrigerant while domestic refrigerators use chlorofluorocarbons. 2. Ammonia can be liquefied at ambient temperatures and at low pressures. 3. Chlorofluorocarbons are ... 3 only (b) 2 and 3 only (c) 1, 2 and 3 (d) 3 only
Last Answer : Ans:(a)
Description : In milk chilling plant, the usual secondary refrigerant is (a)ammonia (b)sodium silicate (c) glycol (d) brine
Description : 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
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 : In a refrigeration cycle, the flow of refrigerant is controlled by (a) compressor (b) condenser (c) evaporator (d) expansion valve
Description : Aqua ammonia is used as refrigerant in the following type of refrigeration system (a) compression (b) direct (c) indirect (d) absorption
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 : 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
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 : At lower temperatures and pressures, the latent heat of vaporization of a refrigerant (a) decreases (b) increases (c) remains same (d) depends on other factors
Description : Accumulators should have adequate volume to store refrigerant charge at least (a) 10% (b) 25% (c) 50% (d) 75%
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 : Absorption system normally uses the following refrigerant (a) Freon-11 (b) Freon-22 (c) C02 (d) ammonia.
Last Answer : Ans: e
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 at the back of domestic refrigerator are (a) condenser tubes (b) evaporator tubes (c) refrigerant cooling tubes (d) capillary tubes
Description : The vapour pressure of refrigerant should be (a) lower than atmospheric pressure (b) higher than atmospheric pressure (c) equal to atmospheric pressure (d) could be anything
Description : Refrigeration in aeroplanes usually employs the following refrigerant (a) Co2 (b) Freon-11 (c) Freon-22 (d) Air
Description : Presence of moisture in a refrigerant affects the working of (a) compressor (b) condenser (c) evaparator (d) expansion valve.
Description : The moisture in a refrigerant is removed by (a) evaporator (b) safety relief valve (c) dehumidifier (d) driers
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 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 : Which of the following cycles uses air as the refrigerant? (a) Ericsson (b) Stirling (c) Carnot (d) Bell-coleman
Description : When the humidity ratio of air increases the air is said to be A. dehumidified B. humidified C. heated D. cooled
Last Answer : ANSWER : B
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
Description : The power required to drive a turbo compressor for a given pressure ratio decreases when A. Air is heated at entry B. Air is cooled at entry C. Air is cooled at exit D. Air is heated at exit
Description : Which of the following situations can be approximated to a steady state heat transfer system? (A) A red hot steel slab (having outside surface temperature as 1300°C) exposed to the atmospheric air at ... flowing at the rate of 6 Kg/minute through a copper pipe exposed to atmospheric air at 35°C
Last Answer : (B) 10 kg of dry saturated steam at 8 kgf/cm2 flowing through a short length of stainless steel pipe exposed to atmospheric air at 35°C
Description : In adiabatic evaporative cooling, heat transfer between chamber and surroundings is ____ A. zero B. high C. low D. none of the mentioned
Last Answer : ANSWER : A
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 : Onion seeds can germinate at a temperature of : a. 0-1°C b. 1-5°C c. 5-11°C d. 15-20°C
Last Answer : 1-5°C
Description : For obtaining high COP, the pressure range of compressor should be (a) high (b) low (c) optimum (d) any value