The word ‘solar’ comes from the word ‘sun’ that has been a great powerhouse for us since time immemorial. However, it is only quite recently that we have learnt a little bit of how to accumulate and harness that power to our benefit. And with this knowledge, we are just beginning to use solar power for our many benefits. However its usage is still much restricted. Till now, solar power is being utilized for (a) Generating thermal or heat energy and (b) Generating electricity. Perhaps a day will come soon when solar power will be used for most of our daily functions.
Thermal or heat energy is utilized for keeping home and work places warm as also for heating swimming pools. The conventional way of gaining this facility comprises laying tubes that are painted black (for greater absorption of heat) on rooftops or any other convenient place that receives sunlight most of the day. Pumping water at the lower end of the tube allows the water to reach the upper levels through convection and the process continues all the while as the tube gets heated up by sunrays. When taken round homes or offices in the form of ‘radiators’, the adjoining areas are automatically heated to the desired temperature. Swimming pools are also warmed up in the same fashion.
Solar power is utilized for generating electricity in two primary ways, namely, through Photovoltaic (PV devices) popularly called ‘Solar Cells’ and Solar Power Plants that generate electricity by ‘indirect’ means. Photovoltaic or PV devices are generally used in remote village areas or isolated pockets of population that are not connected to power grids as also in smaller forms for powering pocket calculators, wrist watches and illuminated emergency road signs.
Since solar cells play a prominent role in most cases, some preliminary discussion on the topic may be helpful for the reader. To be precise, photovoltaic power or energy, whatever it may be called, tantamount conversion of sunlight straightaway to electricity. And the photovoltaic cell or solar cell is the non-mechanical device made from silicon alloys that does it. When the photons derived from the sunlight strike a solar cell, some of it go away reflected by its surface but some also get absorbed within it. These absorbed protons provide the needed energy to generate electricity. When sufficient sunlight is absorbed by the semiconductor, i.e. the silicone material, electrons from the material’s atoms get dislodged. As the especially designed frontal surface of the material is more receptive to the free electrons, they migrate to the surface en masse.
When too many electrons, each carrying a negative charge starts traveling towards the frontal surface, the resultant imbalance of charge between the silicone’s front and rear creates a voltage potential that is similar to the negative and positive terminals of a battery. If at that point that these two are connected through an external load, and the electricity flows through them. The PV or Photovoltaic cell therefore, is the basic building block of a PV system. Though individual cell varies in dimension from 1 cm or .5” to around 10 cm or 4”, they can at best produce only a watt or 2 of electricity which is much too less for any application. In order to get more power output, several electrically connected cells are made into packaged weather-proof modules. When several such modules are connected to form an array, the desired power output can be obtained.
Solar thermal power plants on the
other hand generate electricity ‘indirectly’ through a
‘heat transfer system”. Here the sunrays are made to
heat a fluid which in turn produces steam. Not unlike
coal fired steam turbines, this solar heat powered steam
also runs turbines that are coupled to conventional
generators that produce electricity. However, solar
thermal power plants customarily use concentrator
systems for the high degree of temperature needed to
heat the fluid. Currently three principal types of
solar-thermal power systems are in use in most Solar
Thermal Power Plants that include (i) The parabolic
trough; (ii) The solar dish and (iii) Solar Power Tower.
Save power and cut your electricity bill with solar power. You can also earn some extra money by selling your surplus power and of course this is an eco-friendly alternative as well. So are you ready to install a system in your home? Get a guide that shows you where to install it, how to set up the solar power system, where to get the parts and batteries from cheaply, how to wire the system and also the safety precautions. With this information you can do it quite easily and of course safely.