What is the instantaneous sol-air temperature for a wall with the following conditoins?
Total of direct and diffuse solar radiation: 250 W/m2
Absorptivity of surface : 0.8
Outside surface heat-transfer coefficient:
Outside air temperature : 35°C
Which of the following is considered as hypothetical temperature to calculate the heat received by the outside surface of a building wall by the combined effect of convection and radiation?
The sol-air temperature is equal to the
The sol-air temperature depends on
1. outside air temperature
2. intensity of solar radiation
3. absorptivity of wall
4. convective heat transfer coefficient at outer surface of wall
5. indoor design temperature
Q. Select the correct answer from the codes given below:
te: Sol-air temperature
I : Intensity of solar radiation
h: Out-side film coefficient of heat transfer
t0-. Outside air temperature
The temperature te is called the solair temperature and can be considered as an equivalent outside air temperature such that the total heat transferred is the same as due to the combined effect of the incident solar radiation and outside air and the wall temperature difference.
When the outside air is introduced for ventilation purposes, there is a
Sensible heat gain due to ΔTbetween fresh air and air in space. Latent heat gain due to humidity.
All of the following sources of heat transfer is responsible for sensible heat gain except
The latent heat gain may occur due to any one or all of the following sources:
1. The heat gain due to condensation of moisture from occupants.
2. The heat gain due to moisture in the outside air entering by infiltration.
3. The heat flowing into the building by conduction through exterior walls, floors, ceilings, doors and windows due to the temperature difference on their sides.
4. The heat gain due to moisture passing directly into the conditioned space through permeable walls or partitions from the outside or from adjoining regions where the water vapour pressure is higher.
Q. Which of the above statements are valid?
The most suitable pair of refrigerant and absorbant combination for solar refrigeration is