SOLAR CONTROL AND DAYLIGHTING
The primary means of meeting thermal performance is the frame and glass selection. In addition to the proper selection of frame and glass, the integration of sun control devices into a project could add significant benefits. Sun control devices can consist of exterior attachments (i.e. sunshades and shutters), interior attachments (i.e. light shelves and blinds), integrated devices (blinds) and photovoltaic devices.
Proper use of these devices can save money, make money and/or improve occupant satisfaction and productivity.
Exterior Shade Devices
Exterior components are typically sunshades or shutters. Whereas shutters are operable components, sunshades are usually fixed products that project out from the building. Popular in Southern and Western regions, sunshades will reduce direct sunlight entering the building, which in turn reduces the cooling load required. At the same time, it does allow some sunlight into the buildings. The use of sunshades also allows for less expensive glass types since expensive glass tints may not be necessary.
Besides glass types, the main means of solar protection is the use of sunshades. They are intended to provide shading from direct sunlight through louvers (to diffuse sunlight) or solid covers (to provide complete shading). Likewise, sunshades are usually placed in a horizontal orientation but can also be placed vertically.
Unless the use of the sunshade is purely aesthetic, in order to optimize the effectiveness of sunshade devices, it is important to know the orientation of the building to the path of the sun. This will enable consultants to properly select the placement of sunshades on a building.
Generally used in residential projects, shutters can be used in commercial applications for punched openings. By the nature of their design, they are not very effective sun control devices. Therefore, they are used almost exclusively as protective devices for hurricanes, tornadoes and blast protection.
Interior Shading Devices
Interior shading devices are on the interior side of the glass or frame. These include light shelves and blinds or shades. These can be used to reflect light within the building or diffuse direct sunlight. These could in turn reduce heating and cooling loads, as well as electricity usage. Blinds can be manually or automatically controlled. In the case of light shelves, proper usage or incorporation should be considered when designing the lighting within the building.
Photo above is an artist’s rendering of interior light shelf.
These are customized configurations that are actually blinds located between two panes of glass. These can be either situated in the air void in insulated glazing units that are glazed within the framing system or two monolithic glass panes that are glazed on each side of a blind. The blinds are controlled exterior of the glazing unit(s).
In the photo above, notice the partial shading of the glass. These blinds are integrated into glazed wall.
Solar Power Generated Devices
Solar power generation can be accomplished through panels incorporated into sunshades, spandrel panels and frame covers. These are becoming more varied and price competitive, but all aspects of their use – aesthetics, job-specific effectiveness, cost effectiveness and availability – should be considered before committing to their use. Inclusion of certain types of power-generating components into a project may limit bidders or manufacturers from which to select.
Notice in the photo above, solar panels circle the upper portion of building envelope.