18-06-2013, 02:53 PM
SOLAR BOILERS
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Abstract
We are using fossil fuels for many decades as a result of which it starts depleting and it will not be available after two or more decades. On the same time it is more polluting and causes various diseases to human beings and leads to global warming. So it is become necessary to use non polluting and renewable energy source to fulfill our needs and to replace the depleting fossil fuels.
Solar energy from sun is available for many hundreds of years. It is non polluting and non depleting. It have high power which can be properly harnessed to replace every harmful energy sources. Our ancestors are using solar energy from ancient time for drying of clothes and for preserving grains etc.
This document explain the usage of renewable energy i.e., solar energy for the purpose of boiling of water in boilers. This will replace the use of fossil fuels which is depleting and cause pollution.
INTRODUCTION
Solar water boilers use solar energy for boiling of water. Boilers are used in almost every industry from small scale textile industry to large scale nuclear power plants. It uses fossil fuels for production of heat which cause depletion of fossil fuel and also cause large pollution.
So the replace of fossil fuels by solar energy will less the pollution to a great extent because the solar energy is pollution less. It also increases the availability of fossil fuels to some years.
PRINCIPLE
Solar water boiler has the principle as solar furnace. It’s principle is similar to the using of concave lens to focus sun rays to concentrate on a single point so as to increase its temperature and we use it to burn dry leaves in our childhood days.
In solar water boiler, the heliostats reflects to sun rays to fall on the concentrator collector which is at the bottom of the boiler. The concentrator collector focuses the sun rays to the single point on the boiler. Thus the temperature on the focusing point of the boiler increases tremendously that can be used to boil the water to convert the water into steam, which is used for industrial applications.
BOILERS
Boiler is a device where the water is converted into wet steam and then is further converted into superheated steam. Its size varies according the type of industry where it is used. In case of small industry a low pressure boilers are used and for large purposes like power plant very high pressure boilers are used.
In case of solar water boilers, the boiler should be made up of metals having high melting point and high thermal conductivity. The metal should have high melting point because the temperature of sun rays are not constant and it varies from low temperature to maximum temperature. So the boiler has to withstand the sudden temperature rise. The metal should have high thermal conductivity because in the concentrator collector focuses the sun light to a small volume in the boiler. The metal should be able to transfer the heat from that small volume to the whole area so the water will be boiled.
The main factor is the metal should be very less in cost. The setup of the mirrors for heliostats and concentrator collector will cause huge investment. So the boiler should be inexpensive .
WORKING
The solar rays from the sun falls on the heliostats. The heliostats focuses the sun rays to fall on the concentrator collector. The concentrator collector focuses the sun rays to fall on the single point of the boiler.
Thus the sun rays intensity increases as well as the temperature of the rays also increases. This temperature is used to heat or boil the water present in the boiler.
CONCLUSION
The solar boilers will not replace the use of fossil fuels completely but they can extend the availability of fossil fuels. So we the engineers should take necessary measures to replace the use of fossil fuels by solar energy.