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3.4.9. Building facade Roof: ”
Windows facing the south sun to allow maximum heat gain from south sun and to maintain comfort level of the user. Also, the north side can be insulated to prevent the heat loss. Living areas which are used actively should be located on the south or southwest side whereas the service areas or the store can be located on the other side or back side. Air-lock lobbies at entry of the building reduce heat loss and maintain the comfort level. The heat generated in kitchen can be used to heat up the room during winter season or chimneys could be provided.
Low on a south-facing slope to increase solar radiation; low enough to give wind protection but high enough to avoid cold air collection at the bottom of the valley. Valley winds blows uphill during the day. At night the wind blows down the valley. Surface perpendicular to the sun rays receives most radiations per unit surface area. Steeper slope generally receives more sun than flat surfaces.
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3.4.9. Building facade
Roof:
”False ceilings are a regular roof feature of houses in cold climates. One can also use internal insulation such as polyurethane foam (PUF), thermocol, wood wool, etc. An aluminium foil is generally used between the insulation layer and the roof to reduce heat loss to the exterior. A sufficiently sloping roof enables quick drainage of rain water and snow. A solar air collector can be incorporated on the south facing slope of the roof and hot air from it can be used for space heating purposes. Skylights on the roofs admit heat as well as light in winters. The skylights can be provided with shutters to avoid over heating in summers.”
Walls:
”Walls should be of low U-value to resist heat loss. The south-facing walls (exposed to solar radiation) could be of high thermal capacity (such as Trombe wall) to store day time heat for later use. The walls should also be insulated. The insulation should have sufficient vapor barrier (such as two coats of bitumen, 300 to 600gauge polyethylene sheet or aluminium foil) on the warm side to avoid condensation. Hollow and lightweight concrete blocks are also quite suitable. On the windward or north side, a cavity wall type of construction may be adopted.
