S U S T A I N A B L E     T E C H N O L O G Y     E D U C A T I O N     P R O J E C T
home  |  about Practical Action  |  contact us  |  site map  | 
The materials on this site are no longer being updated. For Practical Action's main school site go to www.practicalaction.org/schools

Heating houses by sunlight

The technology of photovoltaic cells

Dr Roaf's solar house uses two key methods of harnessing the sun's energy:
Photovoltaic cells were discovered in 1839, when a French scientist noticed that shining light onto one side of a simple battery cell increased the amount of current generated.

Today, PV cells are made from silicon and are used to produce electricity directly from the sun's energy. A typical cell is about 12.5cm across and will produce about 1 watt of electricity in bright sunlight. About 30 of these cells are usually linked together into a module that produces 12 volts of direct current electricity. Any number of modules can be connected to produce the voltage required. The power can also be transformed to change it into an alternating current.

The electricity produced by PV cells can either be: Although PV cells are an expensive way to produce electricity, costs are coming down all the time and cells last for at least 20 years.

Facts about PV cells

When is it appropriate to use PV cells?

next page »



print this page back to top
Practical Action - Technology challenging povertyEuropean Commission - Department for International Development

S U S T A I N A B L E     T E C H N O L O G Y     E D U C A T I O N     P R O J E C T