The total radiation from a black body per second per unit area is __________ fourth power of the absolute temperature. This statement is known as Stefan-Boltzmann law.
For ammonia refrigerating systems, the tubes of a shell and tube condenser are made of
The optimum effective temperature for human comfort is
The highest thermal diffusivity is of
The heat transfer by conduction through a thick sphere is same as through a thick cylinder.
The optimum effective temperature for human comfort is
The heat transfer by conduction through a thick sphere is same as through a thick cylinder.
The wet bulb temperature during sensible heating of air
Which of the following statement is wrong?
Which of the following statement is wrong?
In free convection heat transfer transition from laminar to turbulent flow is governed by the critical value of the
In a refrigerating machine, heat rejected is __________ heat absorbed.
Which of the following refrigerant has the highest freezing point.
The sensible heat gain is due to the __________ difference between the fresh air and the air in space.
Air conditioning means
During cooling and dehumidification, dry bulb temperature
The emissivity for a black body is
The conditioned air supplied to the room must have the capacity to take up
Fouling factor is used
The coefficient of performance of electrolux refrigerator is the ratio of
The wet bulb temperature atrelative humidity is __________ dew point temperature.
For evaporators and condensers, for the given conditions, the logarithmic mean temperature difference (tm) for parallel flow is __________ that for counter flow.
Sulphur dioxide is extremely toxic and non-flammable.
Which of the following would lead to a reduction in thermal resistance?
Free convection flow depends on
The process of removing moisture from the air, without change in its dry bulb temperature, is called dehumidification.
The natural convection air cooled condensers are used in
The sulphur sticks, in case of leakage of ammonia refrigerant, gives white smoke.
The use of heat exchangers is made in
A vapour absorption refrigerator uses __________ as a refrigerant.