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 : 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
Last Answer : Ans: c
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
Last Answer : Ans: b
Description : Absorption system normally uses the following refrigerant (a) Freon-11 (b) Freon-22 (c) C02 (d) ammonia.
Last Answer : Ans: e
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 : 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 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 : 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 : 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 a refrigeration cycle, the flow of refrigerant is controlled by (a) compressor (b) condenser (c) evaporator (d) expansion valve
Last Answer : Ans: d
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 : 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 : Refrigeration in aeroplanes usually employs the following refrigerant (a) Co2 (b) Freon-11 (c) Freon-22 (d) Air
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 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 milk chilling plant, the usual secondary refrigerant is (a)ammonia (b)sodium silicate (c) glycol (d) brine
Description : An important characteristic of absorption system of refrigeration is (a) noisy operation (b) quiet operation (c) very little power consumption (d) its input only in the form of heating.
Last Answer : Ans: D
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 : 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 : 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 : 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
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 : 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 : 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 : 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 : 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 : 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 : 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 : 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 : Cooling water is required for following equipment in ammonia absorption plant (a) condenser (b) evaporator (c) condenser and absorber (d) condenser, absorber and separator (rectifier).
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 : 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
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 general rule for rating refrigeration systems (excepting for CO2 system) is to approximate following h.p. per ton of Refrigeration (a) 0.1 to 0.5 h.p. per ton of refrigeration (b) 0.5 to 0.8 h.p. per ... (c) 1 to 2 h.p. per ton of refrigeration (d) 2 to 5 h.p. per ton of refrigeration
Description : Moisture in freon refrigeration system causes (a) ineffective refrigeration (b) high power consumption (c) freezing automatic regulating valve (d) corrosion of whole system
Description : 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) sensing reduction in pressure.
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 : 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 : 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 : 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 refrigerators, the temperature difference between the evaporating refrigerant and the medium being cooled should be (a) high, of the order of 25° (b) as low as possible (3 to 11°C) (c) zero (d) any value
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 : 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 : 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