Railways NTPC (Technical Ability) Refrigeration and Air-Conditioning Question Bank

done Refrigeration and Air-Conditioning Total Questions - 120

• question_answer1)
  In a domestic refrigerator, a capillary tube controls the flow of refrigerant form the:
  A)
  Expansion valve to the evaporator done clear
  B)
  Evaporator to the thermostat done clear
  C)
  Condenser to the expansion valve done clear
  D)
  Condenser to the evaporator done clear
  View Solution play_arrow

• question_answer2)
  The coefficient of performance (COP) of a refrigerator working as a heat pump is given by:
  A)
  \[{{(COP)}_{\text{heat}\,\,\text{pump}}}\,=\,\,{{(COP)}_{\text{refrigerator}}}+2\] done clear
  B)
  \[{{(COP)}_{\text{heat}\,\,\text{pump}}}\,=\,\,{{(COP)}_{\text{refrigerator}}}+1\] done clear
  C)
  \[{{(COP)}_{\text{heat}\,\,\text{pump}}}\,=\,\,{{(COP)}_{\text{refrigerator}}}-1\] done clear
  D)
  \[{{(COP)}_{\text{heat}\,\,\text{pump}}}\,=\,\,{{(COP)}_{\text{refrigerator}}}\] done clear
  View Solution play_arrow

• question_answer3)
  Consider the following steps:

  1. Starting of compressor.

  2. Starting of cooling tower pump

  3. Starting of chiller water pump

  4. Starting of blower motor of cooling coil

  The correct sequence of these steps in the starting of a central air conditioning plant using chilled water cooling coil, is:
  A)
  3, 1, 4, 2 done clear
  B)
  1, 3, 2, 4 done clear
  C)
  3, 2, 1, 4                       done clear
  D)
  1, 3, 4, 2 done clear
  View Solution play_arrow

• question_answer4)
  Match List-I with List-II and select the correct answer using the codes given below the Lists:

  List-I		List-II
  A.	Freon 12	1.	Centrifugal systems
  B.	Freon 22	2.	Low temperature cold storage
  C.	Feron 11	3.	Window type units
  D	Ammonia	4.	Ice plants

  Codes:
  A)
  A\[\to \]3, B\[\to \]2, C\[\to \]1, D\[\to \]4 done clear
  B)
  A\[\to \]3, B\[\to \]1, C\[\to \]2, D\[\to \]4 done clear
  C)
  A\[\to \]1, B\[\to \]2, C\[\to \]4, D\[\to \]3 done clear
  D)
  A\[\to \]1, B\[\to \]3, C\[\to \]4, D\[\to \]2 done clear
  View Solution play_arrow

• question_answer5)
  The equivalent diameter D of a circular duct corresponding to a rectangular duct having longer side ?a? and shorter side ?b? the same velocity and pressure drop is given by:
  A)
  \[D=\frac{a+b}{ab}\]                done clear
  B)
  \[D=\frac{ab}{a+b}\] done clear
  C)
  \[D=\frac{(a+b)}{2ab}\]            done clear
  D)
  \[D=\frac{2ab}{a+b}\] done clear
  View Solution play_arrow

• question_answer6)
  Consider the following statements: During sensible heating

  1. moisture content increases

  2. dry bulb temperature and wet bulb temperature increase.

  3. dew point remains constant.

  4. relative humidity increases.

  Of these statements
  A)
  1, 2 and 3 are correct done clear
  B)
  2, 3 and 4 are correct done clear
  C)
  2 and 3 are correct done clear
  D)
  1 and 2 are correct done clear
  View Solution play_arrow

• question_answer7)
  Which of the following statements are correct?

  1. The human body can lose heat even if temperature is less than the atmospheric temperature.

  2. Relative humidity can be increased by cooling dehumidification.

  3. Warm air increases the rate of radiation of heat from the human body.

  4. Increase in air movement increases the evaporation from the human body.

  Select the correct answer using the codes given below:
  A)
  1 and 4             done clear
  B)
  2 and 4 done clear
  C)
  1 and 3             done clear
  D)
  2 and 3 done clear
  View Solution play_arrow

• question_answer8)
  When the air is passed through an insulated chamber having sprays of water maintained at a temperature higher than the dew point temperature of entering air but lower than its dry bulb temperature, then the air is said to be:
  A)
  Cooled and humidified done clear
  B)
  Cooled and dehumidified done clear
  C)
  Heated and humidified done clear
  D)
  Heated and dehumidified done clear
  View Solution play_arrow

• question_answer9)
  The atmosphere air at dry bulb temperature of \[15{}^\circ C\]enters a heating coil maintained at \[40{}^\circ C.\]The air leaves the heating coil at \[25{}^\circ C.\]The bypass factor of the heating coil is:
  A)
  0.376                done clear
  B)
  0.476 done clear
  C)
  0.6                                done clear
  D)
  0.67 done clear
  View Solution play_arrow

• question_answer10)
  If the specific heats of dry air and water vapour are \[1.00\,\,kJ/kg\,-K\] and \[1.88\,\,kJ/kg\,-K\]respectively and the humidity ratio is 0.011, then the specific heat of moist air at \[25{}^\circ C\] and 50% relative humidity will be
  A)
  \[1.0207\,\,kJ/kg-K\]        done clear
  B)
  \[1.869\,\,kJ/kg-K\] done clear
  C)
  \[1.891\,\,kJ/kg-K\]          done clear
  D)
  \[0.9793\,\,kJ/kg-K\] done clear
  View Solution play_arrow

• question_answer11)
  If a sample of moist air of 50% relative humidity at atmospheric pressure is isothermally compressed to a pressure of two atmospheres, then:
  A)
  Its relative humidity will reduce to 25% done clear
  B)
  Its relative humidity will remain unchanged done clear
  C)
  The sample of air will become saturated done clear
  D)
  Saturation pressure will increase to twice the value done clear
  View Solution play_arrow

• question_answer12)
  Evaporative regulation of body temperature fails when the body temperature is:
  A)
  More than wet bulb temperature but less than dry bulb temperature done clear
  B)
  More than dew point but less than wet bulb Temperature done clear
  C)
  More than dew point but less than dry bulb Temperature done clear
  D)
  Less than dew point done clear
  View Solution play_arrow

• question_answer13)
  Consider the following statements:

  Effective temperature is not a true comfort index because

  1. Discomfort may be experienced at extremely high or low humidity.

  2. The radiation effect of surrounding surfaces has not been taken into account.

  3. It presumes the absence of drafts.

  Of these statements:
  A)
  1, 2 and 3 are correct      done clear
  B)
  1 and 2 are correct done clear
  C)
  1 and 3 are correct          done clear
  D)
  2 and 3 are correct done clear
  View Solution play_arrow

• question_answer14)
  If wet bulb depression is equal to the sum of range and approach of a cooling tower, then the water:
  A)
  Inlet temperature is equal to the wet bulb temperature of ambient air done clear
  B)
  Outlet temperature is equal to the wet bulb temperature of ambient air done clear
  C)
  Inlet temperature is equal to dry bulb temperature of ambient air done clear
  D)
  Outlet temperature is equal to dry bulb temperature of ambient air done clear
  View Solution play_arrow

• question_answer15)
  Which of the following are the special features of a hermetically sealed compressor of a refrigerator?

  1. The compressor may be reciprocating to rotary type.

  2. No shaft seal is necessary.

  3. More silent in operation.

  4. COP is more than that of open compressor.

  Select the correct answer using the codes given below:
  A)
  2 and 4             done clear
  B)
  1, 2 and 3 done clear
  C)
  1, 3 and 4                      done clear
  D)
  2, 3 and 4 done clear
  View Solution play_arrow

• question_answer16)
  Consider the following statements.

  The pressure in a capillary tube of a refrigerator decreases because:

  1. Tube wall offers frictional resistance.

  2. Refrigerant accelerates in the tube.

  3. Tube transfer the heat.

  4. Potential energy decreases

  Of these statements:
  A)
  1 and 2 are correct          done clear
  B)
  1, 2 and 3 are correct done clear
  C)
  2 and 4 are correct   done clear
  D)
  3 and 4 are correct done clear
  View Solution play_arrow

• question_answer17)
  Consider the following statements:

  High condenser pressure in a refrigeration system can occur because:

  1. The water flow rate is lower than the desired value.

  2. Non-condensible gases are present in the system.

  3. of accumulation of lubricating oil in condenser

  4. of low charge of refrigerant in the system

  Of these statements:
  A)
  1, 3 and 4 are correct done clear
  B)
  1, 2 and 3 are correct done clear
  C)
  1, 2 and 4 are correct done clear
  D)
  2, 3 and 4 are correct done clear
  View Solution play_arrow

• question_answer18)
  Consider the following statements:

  Dry compression in reciprocating compressor is preferred because it:

  1. Prevents valve damage.

  2. Enables use of thermostatic exansion valve

  3. Minimizes irreversibilites in the compressor.

  4. Prevents washing out of the lubricating oil from cylinder walls.

  Of these statements:
  A)
  1 and 2 are correct          done clear
  B)
  2 and 3 are correct done clear
  C)
  1 and 4 are correct          done clear
  D)
  3 and 4 are correct done clear
  View Solution play_arrow

• question_answer19)
  Match List-I with List-II and select the correct answer using the codes given below the lists:

  List-I (Refrigerant)		List-II (Designation)
  A.	Dichlorodifluoromenthane	1.	R 718
  B.	Water	2.	R 22
  C.	Methyl chloride	3.	R 40
  D.	Monochlorodifluoromethane	4.	R 12

  Codes
  A)
  A\[\to \]1, B\[\to \]4, C\[\to \]2, D\[\to \]3 done clear
  B)
  A\[\to \]1, B\[\to \]4, C\[\to \]3, D\[\to \]2 done clear
  C)
  A\[\to \]4, B\[\to \]1, C\[\to \]3, D\[\to \]2 done clear
  D)
  A\[\to \]4, B\[\to \]1, C\[\to \]2, D\[\to \]3 done clear
  View Solution play_arrow

• question_answer20)
  Consider the following statements:

  1. In Freon 22 system, moisture choking generally does not occur

  2. Freon 11 is mainly used in large capacity air- conditioning plants with centrifugal compressors.

  3. Presence of lubricating oil in evaporator will increase the heat transfer coefficient.

  4. Refrigerants that are completely miscible with oil, do not cause oil choking.

  Of these statements:
  A)
  1, 2 and 3 are correct done clear
  B)
  1, 2 and 4 are correct done clear
  C)
  2, 3 and 4 are correct done clear
  D)
  1, 3 and 4 are correct done clear
  View Solution play_arrow

• question_answer21)
  A Carnot refrigerator works between the temperatures of 200 K and 300 K. If the refrigerator receives 1 k W of heat, the work requirement will be:
  A)
  0.5 k W             done clear
  B)
  0.67 k W done clear
  C)
  1.5 k W             done clear
  D)
  3 k W done clear
  View Solution play_arrow

• question_answer22)
  The refrigerant-12 (R-12) used in vapour compression refrigeration system is:
  A)
  \[CHCl{{F}_{2}}\]                     done clear
  B)
  \[CC{{l}_{2}}{{F}_{2}}\] done clear
  C)
  \[CHC{{l}_{2}}F\]                     done clear
  D)
  \[CCl{{F}_{2}}\] done clear
  View Solution play_arrow

• question_answer23)
  An expansion valve is not used for reducing pressure in the:
  A)
  vapour compression refrigeration cycle done clear
  B)
  vapour absorption refrigeration cycle done clear
  C)
  steam-jet refrigeration cycle done clear
  D)
  Gas refrigeration cycle done clear
  View Solution play_arrow

• question_answer24)
  The function of a compressor in a vapour absorption system is performed by the:
  A)
  Absorber done clear
  B)
  Absorber and pump done clear
  C)
  Pump and generator done clear
  D)
  Absorber, pump and generator done clear
  View Solution play_arrow

• question_answer25)
  Consider the following statements:

  In a reciprocating compressor, clearance volume is provided:

  1. so that position does not hit and damage the valves

  2. To account for differential thermal expansion of piston and cylinder

  3. To account for machining tolerances

  4. To achieve isentropic compression

  Which of these statements are correct?
  A)
  1, 2 and 3                      done clear
  B)
  1, 2 and 4 done clear
  C)
  1, 3 and 4                      done clear
  D)
  2, 3 and 4 done clear
  View Solution play_arrow

• question_answer26)
  Replacing a water cooled condenser with an air-cooled one in a vapour compression refrigeration system with constant evaporator pressure result in:
  A)
  Increase in condensation pressure done clear
  B)
  Decrease in pressure ratio done clear
  C)
  Increase in pressure ratio done clear
  D)
  Increase in condensation temperature done clear
  View Solution play_arrow

• question_answer27)
  If the measured wet-bulb temperature and the thermodynamic wet-bulb temperature are equal, than the non-dimensional number with a value of unity is the:
  A)
  Lewis number     done clear
  B)
  Prandtl number done clear
  C)
  Schmidt number done clear
  D)
  Sherwood number done clear
  View Solution play_arrow

• question_answer28)
  The ratio of weight of water vapour associated with unit weight of dry air to the weight of water vapour associated with unit weight of dry air saturated at the same dry-bulb temperature and pressure is known as:
  A)
  Specific humidity            done clear
  B)
  relative humidity done clear
  C)
  Absolute humidity           done clear
  D)
  degree of saturation done clear
  View Solution play_arrow

• question_answer29)
  Consider the following statements:

  1. If air heated in a closed chamber, its dew point will increase

  2. As relative humidity decreases the difference between the wet-bulb temperature and dew point will increase

  3. In spray humidification process, the enthalpy of air will decrease

  4. The dew-point temperature is always an indication of moisture content of the air

  A)
  1 and 2             done clear
  B)
  2 and 4 done clear
  C)
  1 and 3             done clear
  D)
  3 and 4 done clear
  View Solution play_arrow

• question_answer30)
  When moist air comes into contact with a waited surface whose temperature is less than the dry-bulb temperature but more than the wet-bulb temperature:
  A)
  Sensible, latent and net heat transfers are from air to surface done clear
  B)
  Both sensible and net heat transfers arc from air to surface but latent neat transfer is from surface to air done clear
  C)
  Sensible heat transfer is from air to surface but both latent and net heat transfer are from surface to air done clear
  D)
  Sensible heat transfer is from surface to air but both latent and net heat transfers arc from air to surface done clear
  View Solution play_arrow

• question_answer31)
  In a certain ideal refrigeration cycle, the COP of heat pump is 5. The cycle under identical conditions running as heat engine will efficiency as:
  A)
  Zero                              done clear
  B)
  0.20 done clear
  C)
  1.00                              done clear
  D)
  6.00 done clear
  View Solution play_arrow

• question_answer32)
  The power (kW) required per ton of refrigeration is \[\frac{N}{COP,}\] where COP is the coefficient of performance then N is equal to:
  A)
  2.75                              done clear
  B)
  3.50 done clear
  C)
  4.75                              done clear
  D)
  5.25 done clear
  View Solution play_arrow

• question_answer33)
  Match List-I with List-II and select the correct answer using the codes given below the lists:

  List-I		List-II
  A.	Refrigerant 11	1.	\[CC{{l}_{2}}{{F}_{2}}\]
  B.	Refrigerant 12	2.	\[{{C}_{2}}C{{l}_{2}}{{F}_{4}}\]
  C.	Refrigerant 22	3.	\[CC{{l}_{3}}F\]
  D.	Refrigerant 114	4	\[CHCl{{F}_{2}}\]
  		5.	\[C{{H}_{2}}ClF\]

   Codes:
  A)
  A\[\to \]2, B\[\to \]1, C\[\to \]5, D\[\to \]3 done clear
  B)
  A\[\to \]3, B\[\to \]4, C\[\to \]5, D\[\to \]2 done clear
  C)
  A\[\to \]3, B\[\to \]1, C\[\to \]4, D\[\to \]2 done clear
  D)
  A\[\to \]5, B\[\to \]1, C\[\to \]4, D\[\to \]3 done clear
  View Solution play_arrow

• question_answer34)
  The expression, where \[\frac{0.622{{p}_{v}}}{{{p}_{b-}}{{p}_{v}}}\] where \[{{p}_{v}}\,=\] partial pressure of water vapour: \[{{p}_{b}}\,=\] atmospheric barometric pressure, is used for calculating:
  A)
  Relative humidity            done clear
  B)
  degree of saturation done clear
  C)
  Humidity ratio    done clear
  D)
  pressure of air done clear
  View Solution play_arrow

• question_answer35)
  A cooling coil with a by-pass factor of 0.1 and apparatus dew point (adp) of \[12{}^\circ C\] comes in contact with air having a dry-bulb temperature of \[38{}^\circ C\] and dew point of \[9{}^\circ C.\] Over the cooling coil, the air would undergo:
  A)
  Sensible cooling done clear
  B)
  Cooling and humidification done clear
  C)
  Cooling and dehumidification done clear
  D)
  Adiabatic saturation done clear
  View Solution play_arrow

• question_answer36)
  The main process which takes place in a desert cooler is:
  A)
  Sensible cooling done clear
  B)
  Dehumidification done clear
  C)
  Adiabatic saturation done clear
  D)
  Cooling and dehumidification done clear
  View Solution play_arrow

• question_answer37)
  In a vapour compression cycle, the refrigerant, immediately after expansion valve is:
  A)
  Saturated liquid  done clear
  B)
  sub-cooled liquid done clear
  C)
  dry-vapour                     done clear
  D)
  wet vapour done clear
  View Solution play_arrow

• question_answer38)
  Consider the following statements pertaining to a vapour compression type refrigerator:

  1. The condenser rejects heat to the surroundings from the refrigerant.

  2. The evaporator absorbs heat from the surroundings to be cooled.

  3. Both the condenser and evaporator are heat exchangers with refrigerant as a common medium.

  4. The amount of heat exchanged in condenser and evaporator are equal under steady conditions.

  Which of the above statements are correct?
  A)
  1 and 2             done clear
  B)
  1, 2 and 3 done clear
  C)
  1, 2 and 4                      done clear
  D)
  2, 3 and 4 done clear
  View Solution play_arrow

• question_answer39)
  The throttling device used in the domestic refrigerator is:
  A)
  Internally equalized thermostatic expansion valve done clear
  B)
  Externally equalized thermostatic expansion valve done clear
  C)
  Automatic expansion valve done clear
  D)
  Capillary tube done clear
  View Solution play_arrow

• question_answer40)
  In system A vapours are superheated by \[10{}^\circ C\] in the evaporator while in system B vapours are superheated by \[10{}^\circ C\] in a liquid vapour regenerative heat exchanger, other conditions being the same. Then:
  A)
  C.O.P of A = COP of B done clear
  B)
  C.O.P. of both A and B > C.O.P. of Reversed Carnot Cycle done clear
  C)
  C.O.P. of A > C.O.P. of B done clear
  D)
  C.O.P. of A < C.O.P. of B done clear
  View Solution play_arrow

• question_answer41)
  Match List-I (chemical formula of refrigerant) with List-II (Numerical Designation) and select the correct answer using the codes gives below the lists:

  List-I (Chemical formula of Refrigerant)		List-II (Numerical Designation)
  A.	\[N{{H}_{3}}\]	1.	12
  B.	\[CC{{l}_{2}}{{F}_{2}}\]	2.	22
  C.	\[CHCl{{F}_{2}}\]	3.	40
  D.	\[CC{{l}_{2}}FCCl{{F}_{2}}\]	4.	113
  		5.	717

  Codes:
  A)
  A\[\to \]4, B\[\to \]1, C\[\to \]5, D\[\to \]2 done clear
  B)
  A\[\to \]5, B\[\to \]3, C\[\to \]2, D\[\to \]4 done clear
  C)
  A\[\to \]4, B\[\to \]3, C\[\to \]5, D\[\to \]2 done clear
  D)
  A\[\to \]5, B\[\to \]1, C\[\to \]2, D\[\to \]4 done clear
  View Solution play_arrow

• question_answer42)
  The efficiency of a carnot engine is given as 0.75. If the cycle directions is reversed, what will be the valve of C.O.P. for the carnot refrigerator?
  A)
  0.27                              done clear
  B)
  0.33 done clear
  C)
  1.27                              done clear
  D)
  2.33 done clear
  View Solution play_arrow

• question_answer43)
  In a regenerative cycle, steam with enthalpy of 3514 kJ/kg is expanded in h.p. turbine to a state corresponding to saturated enthalpy of water equal to 613 kJ/kg. If the pump work requirements in high pressure and low pressure zones are respectively 3 and 1 kJ/kg, amount of heat transferred in boiler is:
  A)
  2897 kJ/kg                     done clear
  B)
  2898 kJ/kg done clear
  C)
  2904 kJ/kg                     done clear
  D)
  2905 kJ/kg done clear
  View Solution play_arrow

• question_answer44)
  A refrigerator storage is supplied with 3600 kg of fish at a temperature of\[27{}^\circ C\]. The fish has to be cooled to \[23{}^\circ C\] for preserving it for a long period without deterioration. The cooling takes place in 10 hours. The specific heat of fish is 2.0 kJ/kg K above freezing point of fish and 0.5 kJ/kg K below freezing point of fish, which is\[-\,3{}^\circ C\]. The latent heal of freezing is 230 kJ/kg. What is the power to drive the plant if the actual COP is half that of the ideal COP?
  A)
  30 kW               done clear
  B)
  15 kW done clear
  C)
  12 kW               done clear
  D)
  6 kW. done clear
  View Solution play_arrow

• question_answer45)
  Which one of the following is the most important function of thermostatic expansion valve?
  A)
  To control the degree of superheat done clear
  B)
  To control the evaporator temperature done clear
  C)
  To control the pressure drop done clear
  D)
  To control the evaporator pressure done clear
  View Solution play_arrow

• question_answer46)
  Which one of the following statements is correct?
  A)
  Dehumidifier coil surface temperature is above the dew point temperature but below the freezing point temperature done clear
  B)
  Dehumidifier coil surface temperature is below the dew point temperature but above the freezing point temperature done clear
  C)
  Dehumidifier coil surface temperature is below the dew point temperature and the freezing point temperature done clear
  D)
  Dehumidifier coil surface temperature is above both the dew point temperature and the freezing point temperature done clear
  View Solution play_arrow

• question_answer47)
  Consider the following statements:

  If moist air is adiabatically saturated in an air washer then:

  1. Wet bulb temperature remains constant.

  2. Relative humidity increases.

  3. Dry bulb temperature decreases.

  4. Humidity ratio decreases.

  Which of these statements are correct?
  A)
  1, 2 and 3                      done clear
  B)
  1, 2 and 4 done clear
  C)
  2, 3 and 4                      done clear
  D)
  1, 3 and 4 done clear
  View Solution play_arrow

• question_answer48)
  Which one of the following statements is true for effective temperature, ET?
  A)
  ET increases with increase in level of activity and it decreases with increase in air velocity done clear
  B)
  ET decreases with increase in level of activity and it increases with increase in air velocity done clear
  C)
  ET increases with increase in level of activity and it increases with increase in air velocity done clear
  D)
  ET decreases with increase in level of activity and decreases with increase in air velocity done clear
  View Solution play_arrow

• question_answer49)
  In on-off control refrigeration system, which one of the following expansion devices is used?
  A)
  Capillary tube                 done clear
  B)
  Thermostat done clear
  C)
  Automatic expansion valve          done clear
  D)
  Float valve done clear
  View Solution play_arrow

• question_answer50)
  When does L.P. cut-off occur in a refrigeration system?
  A)
  If the ambient temperature is low done clear
  B)
  If non-condensable gases are present in the condenser done clear
  C)
  If refrigerant charge is low done clear
  D)
  If lubricating oil gets accumulated-in the condenser done clear
  View Solution play_arrow

• question_answer51)
  Moist air exists at a pressure of 1.01 bar. The partial pressure and saturation pressure of water vapour are 0.01 bar and 0.02 bar, respectively. What are the relative humidity and humidity ratio of the moist air, respectively?
  A)
  50% and 0.00622           done clear
  B)
  100% and 0.0126 done clear
  C)
  50% and 0.0126 done clear
  D)
  100% and 0.00622 done clear
  View Solution play_arrow

• question_answer52)
  In order to cool and dehumidify a stream of moist air, it must be passed over a coil at a temperature:
  A)
  Which to lies between the dry bulb and wet bulb temperatures of the incoming stream done clear
  B)
  Which lies between the wet bulb and dew point temperatures of the incoming stream done clear
  C)
  Which is lower than the dew point temperature of the incoming stream done clear
  D)
  Of adiabatic saturation of incoming stream done clear
  View Solution play_arrow

• question_answer53)
  Which of the features of expansion valves in the following lists are correctly matched?

  Expansion Device		Feature
  1.	Capillary tube	:	Chocking
  2.	Thermostatic Expansion valve	:	Constant temperature
  3.	Automatic Expansion valve	:	Constant degree of superheat
  4.	Float valve	:	Mass flow rate of refrigerant is proportional to load

  Select the correct answer using the codes given below. Codes:
  A)
  1 and 2            done clear
  B)
  1 and 3 done clear
  C)
  1 and 4             done clear
  D)
  3 and 4 done clear
  View Solution play_arrow

• question_answer54)
  If moist air sensibly cooled above its dew point, which of the following statements are correct?

  1. Relative humidity decreases

  2. Wet bulb temperature decreases,

  3. Wet bulb temperature increases

  4. Humidity ratio remains constant.

  Select the correct answer using the codes given below: Codes:
  A)
  1 and 2             done clear
  B)
  1 and 3 done clear
  C)
  3 and 4             done clear
  D)
  2 and 4 done clear
  View Solution play_arrow

• question_answer55)
  Water in an insulated evaporative cooler evaporates at the rate of 0.003 kg/s. Air flow rate is 1 kg/s. What is the air temperature decrease if the specific heat of humid air is 1 kJ/kg. K and latent heat of water is 2500 kJ/kg?
  A)
  \[2.5{}^\circ C\]                        done clear
  B)
  \[3.0{}^\circ C\] done clear
  C)
  \[7.5{}^\circ C\]                        done clear
  D)
  \[10{}^\circ C\] done clear
  View Solution play_arrow

• question_answer56)
  Match List-I with List-II and select the correct answer using the codes given below the lists:

  List-I		List-II
  A.	Sulphur candle test	1.	Propane
  B.	Halide torch test	2.	Ammonia
  C.	Soap and water test	3.	Halocarbon refrigerants
  D.	Ammonia swab test	4.	Sulphur  dioxide

  Codes:
  A)
  A\[\to \]2, B\[\to \]3, C\[\to \]1, D\[\to \]4 done clear
  B)
  A\[\to \]4, B\[\to \]1, C\[\to \]3, D\[\to \]2 done clear
  C)
  A\[\to \]2, B\[\to \]1, C\[\to \]3, D\[\to \]4 done clear
  D)
  A\[\to \]4, B\[\to \]3, C\[\to \]1, D\[\to \]2 done clear
  View Solution play_arrow

• question_answer57)
  When a refrigeration plant is started, the evaporator temperature of the required value. During this period, how does the compressor power requirement vary?
  A)
  It increases continuously. done clear
  B)
  It decreases and then becomes constant done clear
  C)
  It reaches a peak and then decreases. done clear
  D)
  It remains constant done clear
  View Solution play_arrow

• question_answer58)
  A Bell-Coleman air refrigeration system operates on which one of the following cycles?
  A)
  Reverse Diesel cycle done clear
  B)
  Reverse cannot cycle done clear
  C)
  Reverse Brayton cycle done clear
  D)
  Reverse Otto cycle done clear
  View Solution play_arrow

• question_answer59)
  When the lower temperature is fixed, how can the C.O.P. of a refrigerating machine be improver:
  A)
  By raising the higher temperature done clear
  B)
  By lowering the higher temperature done clear
  C)
  By operating the machine at higher speeds done clear
  D)
  By operating the machine at lower speeds done clear
  View Solution play_arrow

• question_answer60)
  An Electrolux system of refrigeration has:
  A)
  No liquid pump   done clear
  B)
  One liquid pump done clear
  C)
  Liquid pumps     done clear
  D)
  three liquid pumps done clear
  View Solution play_arrow

• question_answer61)
  In a vapour compression refrigeration cycle, following data are obtained:

  Ethalpy at suction to the compressor	:	\[180\,\,kJ/kg\]
  Ethalpy at discharge from the compressor	:	\[210\,\,kJ/kg\]
  Enthalpy at exit from	:	\[80\,\,kJ/kg\]

  What is the C.O.P. of the cycle?
  A)
  5.33                              done clear
  B)
  4.33 done clear
  C)
  3.33                              done clear
  D)
  2.33 done clear
  View Solution play_arrow

• question_answer62)
  Consider the following statements pertaining to Room Sensible Heat Ratio (RSHR) line:

  1. It is the line drawn on psychrometric chart through the room conditions.

  2. Its slope is the ratio of sensible cooling load to room latent heat load.

  3. The supply air condition must lie on this line for satisfactory performance.

  Which of the statements given above are correct?
  A)
  1, 2 and 3                      done clear
  B)
  1 and 2 done clear
  C)
  1 and 3             done clear
  D)
  2 and 3 done clear
  View Solution play_arrow

• question_answer63)
  When \[40{}^\circ C\] and \[25{}^\circ C\] are the dry bulb temperatures of air entering and leaving a cooling coil, then the cooling coil temperature is \[20{}^\circ C.\]What is the bypass factor for the case of sensible cooling?
  A)
  0.20                              done clear
  B)
  0.25 done clear
  C)
  0.50                              done clear
  D)
  0.60 done clear
  View Solution play_arrow

• question_answer64)
  A water chiller with a capacity of 30 tons of refrigeration cools \[20\,{{m}^{3}}/hr\] of water entering at \[12{}^\circ C.\] what is the temperature of water leaving the chiller?
  A)
  \[5{}^\circ C\]                           done clear
  B)
  \[6{}^\circ C\] done clear
  C)
  \[7{}^\circ C\]                           done clear
  D)
  \[7.5{}^\circ C\] done clear
  View Solution play_arrow

• question_answer65)
  Consider the following refrigerants:

  1. Ammonia

  2. Carbon dioxide

  3. Dichlorodifluoro methane

  4. Tetrafluoromethane

  Which one of the following is the correct order of their boiling points in the descending order?
  A)
  1 - 2 - 3 - 4                    done clear
  B)
  4 - 3 - 1 - 2 done clear
  C)
  3 - 1 - 2 - 4                    done clear
  D)
  2 - 4 - 1 - 3 done clear
  View Solution play_arrow

• question_answer66)
  Evaporator is used sometimes to dehumidify the air for conditioning purpose. Which is one of the following is the correct statement? In this situation the evaporator temperature should he kept:
  A)
  Lower than the cooling fluid temperature done clear
  B)
  More than the apparatus dew point temperature done clear
  C)
  Lower than the apparatus dew point temperature done clear
  D)
  Lower than the boiling temperature of fluid done clear
  View Solution play_arrow

• question_answer67)
  In a Bell Coleman cycle refrigeration plant compression and expansion of air are isentropic if the temperatures of air entering and leaving the expander are 300 K and 180 K respectively, what is the coefficient of performance of the plant?
  A)
  1.5                                done clear
  B)
  2.0 done clear
  C)
  2.5                                done clear
  D)
  3.0 done clear
  View Solution play_arrow

• question_answer68)
  Match List-I with List-II and select the correct answer using the code given below the lists:

  List-I		List-II
  A.	Bell Coleman refrigeration	1.	Expansion
  B.	Reversed Carnot cycle	2.	Heat Pump
  C.	Milk chilling plant	3.	Decreases COP
  D.	Superheating in refrigeration cycle	4.	Compressor
  		5.	Brine
  		6.	Vortex refrigerator
  		7.	Increases COP

  Codes:
  A)
  A\[\to \]1, B\[\to \]6, C\[\to \]5, D\[\to \]3 done clear
  B)
  A\[\to \]4, B\[\to \]2, C\[\to \]3, D\[\to \]7 done clear
  C)
  A\[\to \]1, B\[\to \]2, C\[\to \]5, D\[\to \]3 done clear
  D)
  A\[\to \]4, B\[\to \]6, C\[\to \]3, D\[\to \]7 done clear
  View Solution play_arrow

• question_answer69)
  Which one of the following is the correct statement? When moist air passes through a cooling tower, the process is:
  A)
  Evaporative cooling done clear
  B)
  Adiabatic saturation done clear
  C)
  Cooling and dehumidification done clear
  D)
  Heating and humidification done clear
  View Solution play_arrow

• question_answer70)
  Which one of the following is the correct statement? During sensible cooling process for a moist air:
  A)
  Specific humidity will decrease done clear
  B)
  Relative humidity will increase done clear
  C)
  Relative humidity will decrease done clear
  D)
  Specific humidity will increase done clear
  View Solution play_arrow

• question_answer71)
  During a comfort air conditioning process, the moisture content of the air may start decreasing. Which one of the following is the correct statement? In order to maintain the same level of comfort:
  A)
  WBT should be decreased done clear
  B)
  DBT should be increased done clear
  C)
  Air velocity should be increased done clear
  D)
  Moisture content should be increased done clear
  View Solution play_arrow

• question_answer72)
  The comfort air-conditioning can be obtained by innumerable combinations of DBT and relative humidity. Which one of the following combinations within the comfort zoom recommended to save the energy?
  A)
  Higher DBT and lower relative humidity done clear
  B)
  Lower DBT and lower relative humidity done clear
  C)
  Lower DBT and higher relative humidity done clear
  D)
  Higher DBT and relative humidity done clear
  View Solution play_arrow

• question_answer73)
  A refrigerating machine in heat pump mode has a C.O.P. of 4. If it is worked in refrigerating mode with a power input of 3 kW, what is the heat extracted from the food kept in a refrigerator?
  A)
  180 kJ/min                     done clear
  B)
  360 kJ/min done clear
  C)
  540 kJ/min                     done clear
  D)
  720 kJ/min done clear
  View Solution play_arrow

• question_answer74)
  To maintain comfort in an air conditioned space, how can a small increase in temperature be compensated?
  A)
  By humidification done clear
  B)
  By ventilation done clear
  C)
  By increasing air velocity done clear
  D)
  By decreasing air velocity done clear
  View Solution play_arrow

• question_answer75)
  Where is an oil separator in vapour compression refrigeration system installed?
  A)
  Between compressor and condenser done clear
  B)
  Between expansion valve and receiver tank done clear
  C)
  Inside compressor machinery done clear
  D)
  Outside compressor machinery done clear
  View Solution play_arrow

• question_answer76)
  Which one eco-friendly refrigerant out of the following is used in many domestical and a air- conditioners now-a-days?
  A)
  \[R-22\]              done clear
  B)
  \[R-113\] done clear
  C)
  \[R-123\]                        done clear
  D)
  \[R-134\] done clear
  View Solution play_arrow

• question_answer77)
  Which one of the following is the correct statement? Adiabatic saturation process is moist air involves:
  A)
  Cooling and humidification. done clear
  B)
  Cooling and dehumidification done clear
  C)
  Change in dew point temperature. done clear
  D)
  Constant relative humidity. done clear
  View Solution play_arrow

• question_answer78)
  Which one of the following is the correct statement? In domestic air conditioners air undergoes the process of:
  A)
  Sensible cooling done clear
  B)
  Cooling and humidification. done clear
  C)
  Cooling and dehumidification done clear
  D)
  Dehumidification done clear
  View Solution play_arrow

• question_answer79)
  Which one of the following is the correct statement? Sensible heating of moist air will not affect the:
  A)
  Relative humidity            done clear
  B)
  Absolute humidity done clear
  C)
  Specific humidity            done clear
  D)
  Wet bulb temperature done clear
  View Solution play_arrow

• question_answer80)
  In an ideal refrigeration (reversed Carnot) cycle, the condenser and evaporator temperatures are \[27{}^\circ C\] and \[-13{}^\circ C\] respectively. The COP of this cycle would be'
  A)
  6.5                                done clear
  B)
  7.5 done clear
  C)
  10.5                              done clear
  D)
  15.0 done clear
  View Solution play_arrow

• question_answer81)
  What is the process represented by the line\[0-1\] shown on the psychrometric chart (0 to 1)?
  A)
  Humidification and heating done clear
  B)
  Humidification and cooling done clear
  C)
  Dehumidification and cooling done clear
  D)
  Dehumidification and heating done clear
  View Solution play_arrow

• question_answer82)
  When are the wet bulb temperature and the temperature of adiabatic saturation equal?
  A)
  If Lewis number is equal to 1 done clear
  B)
  If Praridtl number is equal to 1 done clear
  C)
  If Schmidt number is equal to 1 done clear
  D)
  If Sherwood number is equal to 1 done clear
  View Solution play_arrow

• question_answer83)
  The cooling loads for a building are:

  RSH = 100 kW (Room sensible heat)

  RLH = 25 kW (Room latent heat)

  OASH = 10 kW (Outside air sensible heat)

  OALH = 10 kW (Outside air latent heat)

  The bypass factor of the cooling coil is 0.15. What are the values of the room sensible heat factor and external sensible heat factor respectively?
  A)
  0.72 and 0.8                  done clear
  B)
  0.8 and 0.79 done clear
  C)
  0.79 and 0.8                  done clear
  D)
  0.79 and 0.72 done clear
  View Solution play_arrow

• question_answer84)
  Which one of the following statements is correct? Dew point temperature of a moist air sample remains constant during:
  A)
  A sensible heating or cooling process done clear
  B)
  An adiabatic saturation process done clear
  C)
  A dehumidification process done clear
  D)
  A humidification process done clear
  View Solution play_arrow

• question_answer85)
  Which one of the following statements is correct? For a cooling and dehumidification process, the moist air has to be passed through a coil whose temperature is below the:
  A)
  dry-bulb temperature of the air done clear
  B)
  wet-bulb temperature of the air done clear
  C)
  dew-point temperature of the air done clear
  D)
  Critical temperature of the air done clear
  View Solution play_arrow

• question_answer86)
  Which one of the following is the correct statement? For a specified condenser temperature, the coefficient of performance of a refrigerator,
  A)
  Increases with the increase in the evaporator temperature done clear
  B)
  Decreases with the increase in evaporator temperature done clear
  C)
  is independent of the evaporator temperature done clear
  D)
  is proportional to the square of the evaporator temperature done clear
  View Solution play_arrow

• question_answer87)
  Match List-1 with List-11 and select the correct answer using the code given below the lists:

  List-I (Commercial name of Refrigerant)		List-II (Chemical formula of Refrigerant)
  A.	R 11	1.	\[CHCl{{F}_{2}}\]
  B.	R 12	2.	\[CC{{l}_{2}}{{F}_{2}}\]
  C.	R 13	3.	\[CC{{l}_{3}}{{F}_{{}}}\]
  D.	R 22	4.	\[Cl{{F}_{3}}\]

  Codes:
  A)
  A\[\to \]3, B\[\to \]1, C\[\to \]4, D\[\to \]3 done clear
  B)
  A\[\to \]4, B\[\to \]2, C\[\to \]3, D\[\to \]1 done clear
  C)
  A\[\to \]3, B\[\to \]2, C\[\to \]4, D\[\to \]1 done clear
  D)
  A\[\to \]4, B\[\to \]1, C\[\to \]3, D\[\to \]2 done clear
  View Solution play_arrow

• question_answer88)
  In a centralized air conditioning system, what is the power of a fan directly proportional to?
  A)
  Fan speed                      done clear
  B)
  \[{{\left( Fan\,\,speed \right)}^{2}}\] done clear
  C)
  \[{{\left( Fan\,\,speed \right)}^{3}}\]       done clear
  D)
  \[{{\left( Fan\,\,speed \right)}^{4}}\] done clear
  View Solution play_arrow

• question_answer89)
  Which one of the following types of expansion valves is suitable for a refrigeration plant operating at constant load?
  A)
  Thermostatic expansion valve done clear
  B)
  Automatic expansion valve done clear
  C)
  Capillary tube done clear
  D)
  None of the above done clear
  View Solution play_arrow

• question_answer90)
  What is the cause of burn out of hermetically sealed refrigerant compressors?
  A)
  Phase to phase short because of worn insulation done clear
  B)
  By prolonged overload operation done clear
  C)
  By some mechanical failure done clear
  D)
  All the above done clear
  View Solution play_arrow

• question_answer91)
  Consider the following statements: When a GSHF line is extended, it may strike the saturation curve at a point. This point is called:
  A)
  Effective surface temperature. done clear
  B)
  Air saturation temperature. done clear
  C)
  Water boiling temperature. done clear
  D)
  Apparatus dew point. done clear
  View Solution play_arrow

• question_answer92)
  Flash chamber is used in refrigeration for which one of the following?
  A)
  Decreasing the pressure during multistage compression done clear
  B)
  Increasing the compressor pressure ratio done clear
  C)
  Effective inter cooling medium for purpose of increasing COP done clear
  D)
  Maintaining the same pressure and temperature done clear
  View Solution play_arrow

• question_answer93)
  In order to substantially reduce of heat from atmosphere into cold refrigerant flowing in small diameter copper lindrically wrapped around the tubes, must be:
  A)
  Higher than critical radius of insulation done clear
  B)
  Slightly lower than critical radius of insulation done clear
  C)
  Equal to the critical radius of insulation done clear
  D)
  Considerably higher than critical radius of insulation done clear
  View Solution play_arrow

• question_answer94)
  A building in a cold climate is to be heated by a Carnot heat pump. The minimum outside temperature is \[-\,23{}^\circ C.\] If the building is to he kept at \[27{}^\circ C\] and heat requirement is at the rate of 30 kW, what is the minimum power required for heat pump?
  A)
  180 k W            done clear
  B)
  30 k W done clear
  C)
  6 k W                done clear
  D)
  5 k W done clear
  View Solution play_arrow

• question_answer95)
  The deposition of frost on evaporator tubes of an air conditioner will result in:
  A)
  Decrease in heat transfer done clear
  B)
  Increase in heat transfer done clear
  C)
  No change in heat transfer done clear
  D)
  Increase in capacity of evaporator done clear
  View Solution play_arrow

• question_answer96)
  A single-stage vapour compression refrigeration system cannot be used to produce ultralow temperatures because:
  A)
  Refrigerants for ultra-low temperatures are not available done clear
  B)
  lunbricants for ultra-low temperatures are not available done clear
  C)
  Volumetric efficiency will decrease consider- ably done clear
  D)
  Heat leakage into the system will be excessive done clear
  View Solution play_arrow

• question_answer97)
  Fans used for mechanical draft (induced) cooling towers are:
  A)
  Axial flow type   done clear
  B)
  Radial flow type done clear
  C)
  Centrifugal type  done clear
  D)
  Propeller type done clear
  View Solution play_arrow

• question_answer98)
  When the lower temperature is fixed COP of a refrigerating machine can be improved by:
  A)
  Operating the machine at higher speeds done clear
  B)
  Operating the machine at lower speeds done clear
  C)
  Raising the higher temperature done clear
  D)
  Lowering the higher temperature done clear
  View Solution play_arrow

• question_answer99)
  The coefficient of performance of heat pump \[[{{(COP)}_{HP}}]\] and that refrigerator \[[{{(COP)}_{R}}]\]
  A)
  \[{{(COP)}_{HP\,}}\,\,=\,\,{{(COP)}_{R}}\,+1\] done clear
  B)
  \[{{(COP)}_{HP\,}}/{{(COP)}_{R}}\,1\] done clear
  C)
  \[{{(COP)}_{HP\,}}\,\,=\,\,{{(COP)}_{R}}\,-\,1\] done clear
  D)
  \[{{(COP)}_{HP\,}}\,\,<\,\,{{(COP)}_{R}}\] done clear
  View Solution play_arrow

• question_answer100)
  A good refrigerant should have:
  A)
  High latent heat of vaporization and low freezing point done clear
  B)
  High operating pressure and low freezing point done clear
  C)
  High specific volume and high latent heat of vaporization. done clear
  D)
  Low COP and low freezing point. done clear
  View Solution play_arrow

• question_answer101)
  Which of the following statements are true for Ammonia as a refrigerant?

  1. It has higher compressor discharge temperature compared to fluororarbons.

  2. It is toxic to mucous membranes.

  3. It requires larger displacement per TR compared to fluorocarbons.

  4. It reacts with copper and its alloys.

  Select the correct answer using the codes given below:
  A)
  1 and 2             done clear
  B)
  1, 2 and 3 done clear
  C)
  1, 2 and 4                      done clear
  D)
  2, 3 and 4 done clear
  View Solution play_arrow

• question_answer102)
  Vapour absorption refrigeration system works using the:
  A)
  Ability of a substances to get easily condensed or evaporated done clear
  B)
  Ability of a vapour to get compressed or expanded done clear
  C)
  Affinity of a substance for another substance done clear
  D)
  Absorptivity of a substance. done clear
  View Solution play_arrow

• question_answer103)
  Moist air is a mixture of dry air and water vapour. Hence, three independent intrinsic thermodynamic three independent intrinsic thermodynamic properties are required to fix its thermodynamic state. While using psychrometric chart, however, only two thermodynamic properties are needed since, psychrometric chart:
  A)
  Is an approximation to actual properties done clear
  B)
  Assumes that both water vapour and dry air behave like perfect gases done clear
  C)
  Is drawn for actual properties of water vapour and dry air done clear
  D)
  Is drawn for a fixed pressure done clear
  View Solution play_arrow

• question_answer104)
  In a saturated air-water vapour mixture, the
  A)
  Dry bulb temperature is higher than the wet bulb temperature: done clear
  B)
  Dew point temperature is lower than the wet bulb temperature done clear
  C)
  Dry bulb, wet bulb and dew point temperatures are the same done clear
  D)
  Dry bulb temperature is higher than the dew point temperature done clear
  View Solution play_arrow

• question_answer105)
  Effective temperature is that temperature of saturated air which gives the same degree of comfort as the air at given:
  A)
  DBT, WBT and incidental solar radiation done clear
  B)
  WBT, incidental solar radiation and air flow rate done clear
  C)
  DBT, sol-air temperature and air flow rate done clear
  D)
  DBT, WBT and air flow rate done clear
  View Solution play_arrow

• question_answer106)
  A human body feels comfortable when the heat produced by the metabolism of human body is equal to the:
  A)
  Heat dissipated to the surroundings done clear
  B)
  Heat stored in the human body done clear
  C)
  Sum of A and B done clear
  D)
  Difference of A and B done clear
  View Solution play_arrow

• question_answer107)
  In the case of sensible cooling of air, the coil efficiency is given by:           (BPF = Bypass factor)
  A)
  \[BPF-1\]                       done clear
  B)
  \[1-BPF\] done clear
  C)
  \[\frac{1}{BPF}\]                       done clear
  D)
  \[1+BPF\] done clear
  View Solution play_arrow

• question_answer108)
  In a spray washing system if the temperature of water is higher than the dry temperature of entering air, than the air is:
  A)
  Heated and dehumidified done clear
  B)
  Heated and humidified done clear
  C)
  Cooled and humidified done clear
  D)
  Cooled and dehumidified done clear
  View Solution play_arrow

• question_answer109)
  In a psychrometric process, the sensible heat added is 30 kJ/sec and the latent heat added is 20 kJ/sec. The sensible heat factor for the process will be:
  A)
  0.3                                done clear
  B)
  0.5 done clear
  C)
  0.67                              done clear
  D)
  1.5 done clear
  View Solution play_arrow

• question_answer110)
  The operating temperature of a cold storage is \[-2{}^\circ C,\] Heat leakage form the surrounding is 30 kW for the ambient temperature of \[40{}^\circ C.\] the actual COP of the refrigeration plant used is one fourth that of an ideal plant working between the same temperatures. The power required to drive the plant is:
  A)
  1.86 kW            done clear
  B)
  3.72 kW done clear
  C)
  7.44 kW            done clear
  D)
  18.60 kW done clear
  View Solution play_arrow

• question_answer111)
  Which of the following refrigerant has the maximum ozone depletion in the stratosphere?
  A)
  Ammonia                      done clear
  B)
  Carbon dioxide done clear
  C)
  Sulphur dioxide  done clear
  D)
  Fluorine done clear
  View Solution play_arrow

• question_answer112)
  If air is passed through a solid chemical absorbent, the psychrometic process followed is:
  A)
  Heating and dehumidification with the bulb temperature remaining fairly constant done clear
  B)
  Cooling and dehumidification done clear
  C)
  Dehumidification with sharp rise in wet bulb temperature done clear
  D)
  Dehumidification at constant dry bulb temperature. done clear
  View Solution play_arrow

• question_answer113)
  A thermostatic expansion valve in a refrigeration system:
  A)
  Ensures the evaporator completely filled with refrigerant of the load done clear
  B)
  is suitable only for constant load system done clear
  C)
  Maintains different temperatures in evaporator done clear
  D)
  None of the above. done clear
  View Solution play_arrow

• question_answer114)
  By pass factor for a cooling coil:
  A)
  Increases with increase in velocity of air passing through it done clear
  B)
  Decrease with increase in velocity of air passing through it done clear
  C)
  Remains unchanged with increase in velocity of air passing through it done clear
  D)
  May increase or decrease with increase in velocity of air passing through it depending upon the condition of air entering done clear
  View Solution play_arrow

• question_answer115)
  During sensible cooling:
  A)
  Relative humidity remains constant done clear
  B)
  Wet bulb temperature increases done clear
  C)
  Specific humidity increases done clear
  D)
  Partial pressure of vapour remains constant done clear
  View Solution play_arrow

• question_answer116)
  A heat pump working on a reversed carnot cycle has a COP of 5. If it works as a refrigerator taking 1 kW work input, the refrigerating effect will be:
  A)
  1 kW                 done clear
  B)
  2 kW done clear
  C)
  3 kW                 done clear
  D)
  4 kW done clear
  View Solution play_arrow

• question_answer117)
  A refrigerating system operating on reverse Brayton refrigeration cycle is used for maintaining 250 K. If the temperature at the exit of constant pressure cooling is 300 K and rise in the temperature of air in the refrigerator is so K, then the network of compression will be (assume air as the working substance with \[{{c}_{p}}=\,\,1\,\,KJ\,per\,kg\,per{}^\circ C)\]
  A)
  250 kJ/kg                       done clear
  B)
  200 kJ/kg done clear
  C)
  50 kJ/kg             done clear
  D)
  25 kJ/kg done clear
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• question_answer118)
  In a vapour compression refrigeration plant, the refrigerant leaves the evaporator at 195 kJ/kg and the condenser at 65 kJ/kg. For every kg of refrigerant the plant can supply per second a cooling load of:
  A)
  70 kW               done clear
  B)
  100 kW done clear
  C)
  130 kW             done clear
  D)
  160 kW done clear
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• question_answer119)
  While designing the refrigeration system of an aircraft prime consideration is that the:
  A)
  System has high COP done clear
  B)
  H.P. / ton is low done clear
  C)
  Weight of refrigerant circulated in the system is the low done clear
  D)
  Weight of the refrigeration equipment is low done clear
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• question_answer120)
  A valve which maintains a constant degree of superheat at the end of the evaporator coil, is called:
  A)
  Automatic expansion valve done clear
  B)
  High side float valve done clear
  C)
  Thermostatic expansion valve done clear
  D)
  Low side float valve done clear
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