<P> A solar chimney (or thermal chimney, in this context) is a passive solar ventilation system composed of a vertical shaft connecting the interior and exterior of a building . As the chimney warms, the air inside is heated causing an updraft that pulls air through the building . Performance can be improved by using glazing and thermal mass materials in a way that mimics greenhouses . </P> <P> Deciduous trees and plants have been promoted as a means of controlling solar heating and cooling . When planted on the southern side of a building in the northern hemisphere or the northern side in the southern hemisphere, their leaves provide shade during the summer, while the bare limbs allow light to pass during the winter . Since bare, leafless trees shade 1 / 3 to 1 / 2 of incident solar radiation, there is a balance between the benefits of summer shading and the corresponding loss of winter heating . In climates with significant heating loads, deciduous trees should not be planted on the Equator - facing side of a building because they will interfere with winter solar availability . They can, however, be used on the east and west sides to provide a degree of summer shading without appreciably affecting winter solar gain . </P> <P> Solar cookers use sunlight for cooking, drying and pasteurization . They can be grouped into three broad categories: box cookers, panel cookers and reflector cookers . The simplest solar cooker is the box cooker first built by Horace de Saussure in 1767 . A basic box cooker consists of an insulated container with a transparent lid . It can be used effectively with partially overcast skies and will typically reach temperatures of 90--150 ° C (194--302 ° F). Panel cookers use a reflective panel to direct sunlight onto an insulated container and reach temperatures comparable to box cookers . Reflector cookers use various concentrating geometries (dish, trough, Fresnel mirrors) to focus light on a cooking container . These cookers reach temperatures of 315 ° C (599 ° F) and above but require direct light to function properly and must be repositioned to track the Sun . </P> <P> Solar concentrating technologies such as parabolic dish, trough and Scheffler reflectors can provide process heat for commercial and industrial applications . The first commercial system was the Solar Total Energy Project (STEP) in Shenandoah, Georgia, USA where a field of 114 parabolic dishes provided 50% of the process heating, air conditioning and electrical requirements for a clothing factory . This grid - connected cogeneration system provided 400 kW of electricity plus thermal energy in the form of 401 kW steam and 468 kW chilled water, and had a one - hour peak load thermal storage . Evaporation ponds are shallow pools that concentrate dissolved solids through evaporation . The use of evaporation ponds to obtain salt from seawater is one of the oldest applications of solar energy . Modern uses include concentrating brine solutions used in leach mining and removing dissolved solids from waste streams . Clothes lines, clotheshorses, and clothes racks dry clothes through evaporation by wind and sunlight without consuming electricity or gas . In some states of the United States legislation protects the "right to dry" clothes . Unglazed transpired collectors (UTC) are perforated sun - facing walls used for preheating ventilation air . UTCs can raise the incoming air temperature up to 22 ° C (40 ° F) and deliver outlet temperatures of 45--60 ° C (113--140 ° F). The short payback period of transpired collectors (3 to 12 years) makes them a more cost - effective alternative than glazed collection systems . As of 2003, over 80 systems with a combined collector area of 35,000 square metres (380,000 sq ft) had been installed worldwide, including an 860 m (9,300 sq ft) collector in Costa Rica used for drying coffee beans and a 1,300 m (14,000 sq ft) collector in Coimbatore, India, used for drying marigolds . </P>

Solar and wind energy can be classified as