INTEGRATED SOLAR PHOTOVOLTAICS FOR BUILDINGS

Abstract

INTRODUCTION Photovoltaic (solar) cells (Corkish, 2004) are semiconductor devices that directly create electric current and voltage from the collection of photons (quanta of light). They convert sunlight to electricity silently and without moving parts, require little maintenance, are reliable, being sold with warranties of up to twenty-five years, generate no greenhouse gases in operation and are modular, rapidly deployable and particularly suited to urban rooftops, façades and similar applications. Hence, they are easily located close to where electricity is consumed. Solar cells of 15% efficiency covering an area equivalent to just 0.25% of the global area under crops and permanent pasture could meet all the world's primary energy requirements today (Archer and Hill, 2001), yet most or all of that area could be otherwise alienated land, such as on buildings, for example. "On any given day, the solar energy falling on a typical oilfield in the Middle East is far greater than the energy contained in the oil extracted from it." (CarbonFree, 2006). However, solar cells remain an expensive option for most power generation requirements relative to fossil and nuclear sources, especially if the natural environment is attributed little or no value, and to some other sustainable options such as the enhancement energy efficiency, solar thermal (eg. solar water heating) or wind energy. Photovoltaics are synergistic with efficiency enhancement and solar thermal use and are usually more easily applied in urban situations than are wind turbines. Here, we aim to acquaint practising architects, builders and engineers with the fundamentals of solar photovoltaic energy production and devices and building-related applications (Green, 1995, Wenham et al., 2006, Prasad & Snow, 2005, Strong et al., 2005, Sick, 1996).