Heat Transfer, Refrigeration and Air Conditioning Questions

• The process of removing moisture from the air, without change in its dry bulb temperature, is called dehumidification.
• Thermal diffusivity of a substance is
• Fouling factor is used
• Which of the following refrigerant has the lowest freezing point?
• The critical pressure of a liquid is the pressure
• Free convection flow depends on
• Air conditioning means
• The specific humidity during dehumidification process
• During cooling and dehumidification, dry bulb temperature
• The curved lines on a psychrometric chart indicates
• The material of pipe lines for a system using ammonia as a refrigerant should be copper.
• A vapour absorption refrigerator uses __________ as a refrigerant.
• The wave length corresponding to the maximum energy is inversely proportional to the absolute temperature. This statement is called Planck's law.
• The automobile radiator is a heat exchanger of
• For evaporators and condensers, for the given conditions, the logarithmic mean temperature difference (tm) for parallel flow is __________ that for counter flow.
• For a white body, absorptivity (α ) = 0, reflectivity (ρ) = 1 and transmittivity (τ) = 0.
• The use of heat exchangers is made in
• The ratio of the thickness of thermal boundary layer to the thickness of hydrodynamic boundary layer is equal to (Prandtl number)n, where n is equal to
• The sensible heat factor during the heating and humidification process is given by (where h1 = Enthalpy of air entering the heating coil, h2 = Enthalpy of air leaving the heating coil, and hA = Enthalpy of air at the end of humidification process)
• The horizontal and uniformly spaced lines on a psychrometric chart indicates relative humidity.