Friday, August 2, 2013

Photovoltaic Systems and Solar Water Heating

Solar energy is basically the energy which is extracted from sun. Solar energy or sun’s energy can be used for heating, lighting, electricity, cooling, businesses and industries. Day by day energy needs are growing as the human development goes on! Solar energy is not unknown to anyone now. There are different ways to extract and use the sun’s energy. As sun is free source of energy so it will be more beneficial for mankind. Here we will discuss about Photovoltaic systems (Solar Cells) and solar water heating.

1. Photovoltaic Systems (Solar Cells)

Photovoltaic systems or solar cells coverts the sunlight into electricity, these are made of semi conducting materials. They absorb the sunlight, and solar energy lets the electrons loose from their atoms. This process allow the electrons to flow through the photovoltaic cell, in result electricity is produced.

This process of converting sunlight into electricity is called photovoltaic effect (PV).

2. Solar Hot Water

If we check any lake where sun shine perfectly we will judge that shallow water of the lake will be warm, while the depth water temperature will be less. That’s nature’s way of heating water. This tells us that we can use solar energy to heat the water also.

The sun can be used to heat the buildings and swimming pools. The most common water heating systems for buildings have two main parts:

  • Solar Collector
  • Storage tank

Solar Collector

Flat plate collector is most common solar collector. Flat plate collector is mounted on roofs. Flat plate collector is a thin, flat, rectangular box with transparent cover.  The transparent cover faces the sun which collects the solar heat directly.

There are small tubes which run through the box carrying water or fluid to get it heated. There is an absorber attached with the tubes painted black. The absorber heats up and makes the water heat up in the tubes. 

Storage Tank

After that the liquid is passed to storage tank which hold the liquid. The storage tank is perfectly insulated to keep liquid hot.

Solar water heaters can be active or passive. But most common are the active systems. In active systems usually pumps are used to move the water between tank and collector. On other side the passive heating systems rely on gravity and tendency of water to move as it heat up.

Solar Water Heating for Swimming Pools

Solar water heating systems for swimming pools are simple. Filter pump of the pool pumps water from the solar collector. Solar collector is made of black plastic or rubber. The water from solar collector is pumped into the pool.