Concrete slab solar water heating system

Abstract

Renewable energy is the energy which comes from natural resources such as sun light, wind, rain, tides, and geothermal heat which are renewable(naturally replenished) Main types of renewable energies are wind power, solar energy, biomass, bio-fuel and geothermal energy. Solar energy is the energy derived from the sun through the form of solar radiation. Solar technologies are broadly characterized as either passive solar or active solar depending on the way they capture, convert and distribute solar energy. Active solar techniques include the use of photovoltaic panels and solar thermal collectors to harness the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air Water heating by using conventional solar water heating system is known to everyone. It has many advantages like it can save electricity, fuel, increase utilization of solar energy and it is eco-friendly device. Still its use is very limited in India because of its high cost, high maintenance and low efficiency. In India about 70% of people are living in rural area and many of them cannot afford this costly conventional system. Understanding the requirement of these people, it is necessary to lower the cost of solar water heating system. Our main objective is to reduce the cost of solar water heating system, which could be affordable to common people. The main and most expensive part of the conventional solar water heating system is the solar panel, which consist of delicate evacuated tubes and glass packing. Instead of conventional panel, the present experiment uses a concrete slab imbibing a network of copper tubing as the solar heat collecting device. Metallic scrap and metal powder are also used while making the concrete slab to increase the heat conducting properties of the slab. The copper tubing network is so arranged that the heat collected by the slab is transferred to it in an efficient manner. A low cost tank for storage of hot water has been developed with a tank in tank model incorporating PUF insulation. Trials on the above equipment showed promising results. The temperature of water could be increased from 30°C to 60°C on the day of average sunshine with outdoor temperature at 33°C Replacing the solar panel with concrete slab resulted in a reduction in the cost of the solar water heating system by about 75% in comparison with the conventional solar water heating system. Concrete slab water heaters need not be a separate device. Any tilted surface to south direction of a building could be modified so that it could act as a solar collector.