SUSTAINANLE TECHNOLOGY SUN
Shading devices Shading device can be provided by natural landscaping, such as trees and hills. Also, it can be provided by building elements, such as overhangs, awings, fins and trellises. It can be identified as two main types: horizontal and vertical shading devices. The advantages of using shading devices are that if can reduce the building peak cooling load and corresponding energy consumption and enhance daylight utilization in buildings, and avoid glare by reducing contrast ratios of building interior. However, for the vertical shading device, it may restrict the views of the building. Low-e reflective glazing Low emissivity glass has a special metal coating on one side - either Pyro-lytic (hard coat) or sputtered (soft coat). The microscopically thin and almost invisible coating acts as a filter that it blocks the long wave radiation (such as infrared heat) and passes the short wave radiation (such as UV and visible light) through the exterior to the interior. The pros of using low-e reflective glazing are that it can reduce the thermal gain and loss of interior, thus. It can reduce the demand of air-conditioning, so reduce the emission of carbon dioxide. Also, it can reduce the demand of artificial lighting since the natural sunlight can pass through the glazing. However, the low-e reflective glass is more expensive than the normal glass. Moreover, the reflective glazing may produce glare to the next building. Insulated glazing Insulated glass consists of 2 or more panes of glass which are bonded together with plastic material (e.g. PVB). The space between the panes acts as a thermal buffer and can be filled with dehydrated air, inert gas or in vacuum. Since heat transport through a laminated glass unit by convection, radiation, conduction, filled with gas between the panes would be insulation layer which can reduce the heat gain and heat loss from exterior to interior of the building. The advantages of using insulated glazing are that is can reduce the heat gain and loss of the building, and it can also enhance the noise insulation. However, it is more expansive than the normal glazing and the maintenance cost of insulating glass is high.
WIND
Openable windows There are two main methods which are cross ventilation and stack effect to apply for openable windows to provide natural ventilation for buildings. For cross ventilation, it relies on wind to force cool exterior air into the building through an inlet and to force warm interior air out of the building through an outlet. Adding hedges can maximise the wind flow into the room. Windcatcher Windcatcher often used in combination with courtyards and domes as overall ventilation. It is usually a tall, capped tower with one face open at the top (facing prevailing wind). Opening faces the wind that can bring air flow into the tower and then maintain ventilation to cool the interior of the building. However, it can only apply for low-rise building. Louvers Louver is a framed opening, as in a wall, door, or window, fitted with fixed or movable horizontal slats. It admits natural ventilation and also lighting into the interior and sheds the rain. The louver windows can open and shut. Therefore, sunshine control and privacy protection are possible so to improve the energy saving effect. The advantages of using louvers are that natural ventilation can be provided so that it is good for human health and reduces the demand of using air-conditioning.