This involves the use of heat obtained from light conversion for:

• heating water (for domestic and industrial use), swimming pools,
• space heating of buildings, and
• Meeting other heat needs as listed in the list of applications.

(i) Solar Water Heating

Solar heating systems for heating water, heating swimming pools and for similar uses can be active or passive systems. Active Solar Water Heaters require pumps to pump the water through the solar water system, whereas, in passive heaters water flows under its own pressure.

Both systems require collectors to collect sun rays. Cold water is either pumped (active) or flow under pressure (passive) from the heat exchanger through a piping system to a panel with outer surface equipped with a collector facing the sun. As the water passes through the panel, it is heated up and returned into the heat exchanger. In the heat exchanger, hot water rise to the top because it is hot and is released to serve the end users.

Collectors are either non-concentrating (i.e. collector area is same as absorber area) or concentrating (i.e. collector area is greater than the absorber area).

The solar heating systems can be adapted to achieve all the other heating needs such cooking, distillation, disinfection, drying etc, listed above.

(ii) Solar Space Heating / Cooling

Space heating involves he use of solar energy to provide wholly or partially the heat needs for warming up a house in winter times. The system can also be adapted with fans to provide cooling during the summer months.

Space Heating can be either "Active" or "Passive". Active Systems use collector (s) to collect sunlight and convert the light to heat needed in the house. Passive systems make use of direct light from Sun to provide energy, without recourse to any mechanical or electrical medium. The passive systems can easily be adapted to provide heat (Passive Solar Heating (PSH)) to provide heat during winter or cool down the house (Passive Solar Cooling (PSC)) in summer months. PSH design collects and stores thermal energy from direct sunlight. PSC minimizes the effects of solar radiation through shading or generating air flows with convection ventilation. Passive systems are design based, involving the use of the building components to collect, store and redistribute solar heat gains. This is achieved through proper materials' selection, sizing and orientation of windows, doors and other building components.

Related information on EB:

Photovoltaic Cells

Solar Energy

Solar Electricity

Daylighting

Other Sources of Information:

• Solar Energy - Energy from the Sun
• EIA Energy Kids - Solar