71501. In a shell and coil condenser, water flows in the shell and the refrigerant in the coil.
71502. In a saturated air-water vapour mixture, the
71503. Dew point temperature corresponds to the saturation temperature of vapour at its partial pressure.
71504. The capillary tube is not used in large capacity refrigeration systems because
71505. The ratio of emissive power of a body to the emissive power of a perfectly black body is called emissivity.
71506. The thermostatic expansion valve operates on the changes in the
71507. In a vapour compression system, the condition of refrigerant before entering the expansion or throttle valve is
71508. The freezing point of R-12 is
71509. The refrigerant supplied to a compressor must be
71510. The unit of thermal diffusivity is
71511. The comfort conditions in air conditioning are at (where DBT = Dry bulb temperature, and RH = Relative humidity)
71512. The dry bulb temperature lines, on the psychrometric chart are
71513. The pressure at the outlet of a refrigerant compressor is called
71514. A simple air cooling system is good for __________ flight speeds.
71515. The highest temperature during the cycle in a vapour compression system occurs after evaporation.
71516. In a psychrometric chart, dew point temperature lines are horizontal and non-uniformly spaced.
71517. If the evaporator temperature is kept constant, the coefficient of performance of a refrigeration cycle __________ with the increase in condenser temperature.
71518. Which of the following is known as ‘Sport of Wealth’?
71519. The evaporator used in house-hold refrigerators is
71520. The drier in a refrigeration system removes moisture in the system.
71521. The __________ point of ammonia is -77.7°C.
71522. Sulphur dioxide has the lowest boiling point.
71523. For a given dry bulb temperature, as the relative humidity __________ the wet bulb temperature will increase.
71524. The lowest thermal diffusivity is of
71525. A low wet bulb temperature indicates very __________ humidity.
71526. The operating temperature of a cold storage is - 2° C. The heat leakage from the surrounding is 30 kW for the ambient temperature of 40° C. The actual C.O.P. of refrigeration plant used is one fourth that of ideal plant working between the same temperatures. The power required to drive the plant is
71527. In chemical dehumidification process,
71528. A one tonne refrigerating machine means that
71529. The air cooling system mostly used in transport type aircrafts is
71530. The critical thickness of insulation is the ratio of thermal conductivity of the insulating material (k) to the heat transfer coefficient at the outer surface of the insulation (h0).
71531. In counter-current flow heat exchanger, the logarithmic temperature difference between the fluids is __________ as compared to parallel flow heat exchanger.
71532. Environmental protection agencies advice against the use of chloro-fluoro-carbon refrigerants since
71533. When the lower temperature of a refrigerating machine is fixed, then the coefficient of performance can be improved by
71534. The refrigerant carbon dioxide is not widely used because of its __________ power require ments per tonne of refrigeration and high operating pressures.
71535. The by-pass factor of a cooling coil decreases with
71536. Dehydration is the process of removing water vapour from the surrounding air.
71537. The cooling of air, without any change in its specific humidity, is known as sensible cooling.
71538. The capacity of the cooling tower and spray ponds __________ as the wet bulb temperature of air decreases.
71539. A mixture of dry air and water vapour, when the air has diffused the maximum amount of water vapour into it, is called
71540. The total pressure exerted by the mixture of air and water vapour is equal to the sum of pressures which each constituent would exert, if it occupied the same space by itself. This statement is called
71541. The expansion valve in a refrigerator controls the flow of refrigerant.
71542. Upto the critical radius of insulation,
71543. The relative humidity lines on a psychrometric chart are
71544. The creature in which the external fertilization take place?
71545. A vapour absorption refrigeration system
71546. The rato of energy transferred by convection to that by conduction is called
71547. A refrigerating system operating on reversed Brayton refrigeration cycle is used for maintaining 250 K. If the temperature at the end of constant pressure cooling is 300 K and rise in the temperature of air in the refrigerator is 50 K, then the net work of compression will be (assume air as working substance with cp = 1 kJ/kg)
71548. Wet bulb temperature indicates the moisture content in air.
71549. A designer chooses the values of fluid flow rates and specific heats in such a manner that the heat capacities of the two fluids are equal. A hot fluid enters the counter flow heat exchanger at 100° C and leaves at 60° C. A cold fluid enters the heat exchanger at 40° C. The mean temperature difference between the two fluids is
71550. The inclined and non-uniformly spaced straight lines on a psychrometric chart indicates wet bulb temperature.