This is an effort to give maximum information on SOLAR HOT WATER SYSTEM :

Applications : Used for bathing or some cases Industrial purposes too. Useful for household e.g. Bungalow, Row houses, Terrace Flats, Housing Societies, Restaurants, Hotels, Hostels, Health clubs, Hospitals, laundries etc.

Useful information for a new Buyer : A solar water heater heats water by tapping the solar energy into a flat plate collector. The heated water is stored in an insulated tank made of a special grade stainless steel with a sacrificial anode ensuring corrosion resistance and longer life. To meet hot water requirements on days when there is no sunshine, electrical heating element with thermostat control, is provided inside the tank.

There are basically two types of solar water heaters:

THERMOSYPHON TYPE (natural flow) : Most suitable for domestic applications, this type of solar water heater operates on the principle that the hot water has a lower density than the cold water and thus has a tendency to rise. Due to this natural phenomenon the water circulates from solar collector to storage tank by natural convection.

FORCED-CIRCULATION TYPE: In this type of solar water heater, water is pumped from the collectors to the tank. This system has greater control on temperature output and is thus ideal for commercial and industrial establishments where hot water requirements are high.

How do Photovoltaics Work?

Photovoltaics is the direct conversion of light into electricity at the atomic level. Some materials exhibit a property known as the photoelectric effect that causes them to absorb photons of light and release electrons. When these free electrons are captured, an electric current results that can be used as electricity.

During the energy crisis in the 1970s, photovoltaic technology gained recognition as a source of power for non-space applications.

The diagram above illustrates the operation of a basic photovoltaic cell, also called a solar cell. Solar cells are made of the same kinds of semiconductor materials, such as silicon, used in the microelectronics industry. For solar cells, a thin semiconductor wafer is specially treated to form an electric field, positive on one side and negative on the other. When light energy strikes the solar cell, electrons are knocked loose from the atoms in the semiconductor material. If electrical conductors are attached to the positive and negative sides, forming an electrical circuit, the electrons can be captured in the form of an electric current -- that is, electricity. This electricity can then be used to power a load, such as a light or a tool.

A number of solar cells electrically connected to each other and mounted in a support structure or frame is called a photovoltaic module. Modules are designed to supply electricity at a certain voltage, such as a common 12 volts system. The current produced is directly dependent on how much light strikes the module.

Multiple modules can be wired together to form an array. In general, the larger the area of a module or array, the more electricity that will be produced. Photovoltaic modules and arrays produce direct-current (dc) electricity. They can be connected in both series and parallel electrical arrangements to produce any required voltage and current combination.