Solar Pond is one of the most promising technologies in the use of solar energy for various purposes. It is a large-scale energy collector with internal thermal energy in different ways, such as heating, cooling and drying.
The air becomes lighter or rises above when it is heated Similarly, when the water is heated by the sun’s ray, the hot water from the bottom of the pond rises and reaches the surface, and loses the heat it has acquired from the atmosphere. The result is that the pool water remains at a temperature close to atmospheric temperature. To prevent this heat loss by convection in a solar pool, the salt is dissolved in the bottom layer of the water. This makes the water too heavy to rise (even when hot) to the surface. Thus, solar energy remains trapped in the pond.
A solar pool is made up of three zones. The upper zone or the surface zone remains at atmospheric temperature and has a low salt content. The lower area is very hot (110 degrees C) and salty with a density of around 1.20. It is this area that collects and stores solar energy in the form of heat and is therefore called the storage area. The separation of these two areas is the gradient area which acts as a transparent insulator, allowing sunlight to reach the lower area and its thermal energy to remain trapped there. The useful energy is then withdrawn from the solar pool in the form of heat.
Solar ponds have three major advantages over other solar technologies.
1. They have a low cost per unit area.
2. They can be built on large surfaces to concentrate the solar radiation scattered on a large scale.
3. They can provide energy even during the monsoon season.
India is the first Asian country to have a solar pond in Bhuj (Gujrat). The Bhuj Solar Pond was designed to provide approximately 220 million kilowatts of thermal energy per year, approximately 1.25,000 kilowatts of electricity per year and approximately 80,000 liters of potable water per day.
Source by Jay Rawat