Heat Transfer, Refrigeration and Air Conditioning Questions

• The heat transfer by conduction through a thick sphere is given by
• The wet bulb temperature during sensible heating of air
• During sensible cooling of air __________ decreases.
• The relative humidity decreases as air gets wet.
• An electrolux refrigerator is called a __________ absorption system.
• The heat transfer by radiation __________ a medium.
• The C.O.P. of an absorption type refrigerator is given by (where T1 = Temperature at which the working substance receives heat, T2 = Temperature of cooling water, and T3 = Evaporator temperature)
• The highest thermal diffusivity is of
• The thickness of thermal and hydrodynamic boundary layer is equal if Prandtl number is
• Thermal diffusivity is a
• Reynolds number (RN) is given by (where h = Film coefficient, l = Linear dimension, V = Velocity of fluid, k = Thermal conductivity, t = Temperature, ρ = Density of fluid, cp = Specific heat at constant pressure, and μ = Coefficient of absolute viscosity)
• Thermal conductivity of water __________ with rise in temperature.
• A refrigeration system
• A perfect black body is one which
• While designing the refrigeration system of an aircraft, the prime consideration is that the
• The difference between dry bulb temperature and wet bulb temperature, is called
• The wet bulb temperature lines, on the psychrometric chart, are curved lines.
• Nusselt number (NN) is given by
• The relative humidity is defined as
• In a refrigerating machine, heat rejected is __________ heat absorbed.