chapter  2
Multiple and Added Solar Value
Pages 34

This chapter deals with alternative approaches to maximizing opportunities for stimulating solar architecture. Windows intrinsically imply multiple and added solar value, but they can simultaneously present problems. They provide daylight, which can and should displace electrical lighting. However, realizing this benefit is not nearly as easy as it sounds. They can provide the means to capture useful solar heat, although orientation is naturally significant and they can lose more heat than they gain. They can also provide the means to limit solar overheating and glare. This aspect may be dealt with passively 2.1(1) by the tilt and orientation of the glass relative to solar geometry, bearing in mind that transmission of solar radiation falls off rapidly once the angle of incidence 2.1(2) exceeds fifty degrees. It can also be tackled by the physics of the glass itself, or by a discrete screening or shading device – blinds, awnings, louvres etc. Glazing technology to tackle these conflicting characteristics became increasingly sophisticated during the 20th century, and the quest to improve on current technology and to bring it further into the marketplace continues apace.