Solar Water Heating System
Energy from the Sun :
Is the world’s largest energy resource and solar energy is a form of renewable energy which is abundant in our environment. More importantly, the use of solar energy can reduce the use of fossil fuels as well as reduce harmful environmental emissions resulting from the burning of fossil fuels.
Solar energy can be utilized in many ways. The most common method is to convert sunlight into heat energy to produce hot water. This technology has been using for a long period of time and sufficient products are available commercially. This leaflet explains the concept of a solar thermal systems for hot water production and provides an overview of the basic components, types of systems, and installation issues.
Using a Solar water heating system will help you help to reduce harmful emissions from fossil fuels. You can also enjoy the Sun which could save your energy cost in heating water.
Basic components :
The basic form of a Solar water heating system comprises solar collectors, a Storage tank, and interconnecting pipework. the solar collector is usually mounted on the roof of a building to capture solar radiation. Small tubes Run through the Solar collectors and carry fluid either water or heat transfer liquid with a low boiling point. the fluid absorbs heat from the solar collectors and transfers heat to incoming water.
Common types of Solar water heating systems :
Solar water heaters are characterized as either direct (also called an open loop) or indirect ( also called closed loop) depending on whether the incoming water is heated directly in the collectors or is indirectly heated via heat exchanger. Both types of systems can be other active or passive. An active system uses an electric pump to circulate water or a heat transfer fluid storage tank through the collectors.
where is a passive system relies on gravity and the tendency for water to Naturally circulating as it is heated, allowing water or heat transfer fluid to move through the system without the use of a circulating pump? The main factors that will govern the choice of types of to be installed include the climatic conditions, hot water demand size of the system and availability for placing extra components etc. For example, low maintenance passive direct system can be used in smaller facilities with low hot water demand whereas active indirect system is usually installed in larger facilities with high effort water demand.
Two types of solar collectors :
Flat plate collector :
A flat plate collector is a rectangular box with a metal absorber plate inside the box. the box is painted in dark color to maximize absorption of solar energy. the collector is glazed and insulated to limit the amount of heat escaping from the box such that the fluid inside the collector can be maintained at warm temperatures.
Evacuated tube collectors :
Evacuated to Collector is made up of parallel rows of transparent glass tubes, similar to fluorescent tubes. each tube contains an inner glass tube and an Outer glass tube covered with a special coating that absorbs solar energy well. As the tube is round in shape the sun’s rays are always striking the tube surface at right angles ( that is perpendicular to the surface of the tube in all directions), thus maximizing the total amount of solar radiation absorbed in addition the tube works in the same way vacuum flask with air is withdrawn from the between the inner and Outer tubes forming a vacuum, which can minimize the heat loss from the collector and reduce temperature drop of the heated water or heat transfer fluid inside the tube. The evacuated tubes employing heat transfer fluid inside the inner glass tube is known as the evacuated heat pipe collector. evacuated tube collectors can heat water to fairly high temperatures.
Storage tank :
Solar water heating system generally a well insulated Storage tank to hold the solar heated water. The storage tank may sometimes be housed with a backup electric or gas heater to boost the solar heated water to a desired temperature when the temperature of the solar water heater is lower than the desired temperature. this may happen fan solar energy is not available, for example at night or on a cloudy day.
Packaged type solar water heaters :
Packaged type solar water heaters, with solar collectors and an insulated Storage tank in one package, are also available in the market. Since the installation of this type of system is less complicated it is suitable for smaller facilities for household use. The package type solar water heaters are available in different sizes. A smaller one is sufficient for a family of 2 and a larger one can provide hot water for 8 people. This type of system is suitable for low-density Housing Development villas low rise houses and village houses as they tend to have more roof for installation.