Heat Transfer, Refrigeration and Air Conditioning Questions

• The pressure at the outlet of a refrigerant compressor is called
• For unsaturated air, the dew point temperature is __________ wet bulb temperature.
• A thermostatic expansion valve in a refrigeration system
• The inclined and non-uniformly spaced straight lines on a psychrometric chart indicates wet bulb temperature.
• The C.O.P. of a heat pump working on a reversed Carnot cycle is
• 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
• The dry bulb temperature lines, on the psychrometric chart are
• The temperature rise, between the condenser outlet and expansion valve in ammonia vapour compression system, should be as low as possible.
• The refrigerant carbon dioxide is not widely used because of its __________ power require ments per tonne of refrigeration and high operating pressures.
• 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
• The comfort conditions in air conditioning are at (where DBT = Dry bulb temperature, and RH = Relative humidity)
• A low wet bulb temperature indicates very __________ humidity.
• 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)
• In chemical dehumidification process,
• The highest temperature during the cycle in a vapour compression system occurs after evaporation.
• During dehumidification process, __________ remains constant.
• In a psychrometric chart, dew point temperature lines are horizontal and non-uniformly spaced.
• A simple air cooling system is good for __________ flight speeds.
• Sulphur dioxide has the lowest boiling point.
• The lowest thermal diffusivity is of