A solar water heater is the most competitive alternative to conventional water heating methods such as electric geysers and fuel-fed boilers. It makes an attractive and sustainable option, with its global distribution, pollution free nature, virtually inexhaustible supply and near-zero operational cost. Solar water heaters run on a free fuel (i.e. sunshine), thus saving on energy costs that help recover its initial cost in just 2-4 years. Hot water throughout the year: the system works all year round, though you'll need to heat the water further with a boiler or immersion heater during the winter months. Cut your bills: sunlight is free, so once you've paid for the initial installation your hot water costs will be reduced. Cut your carbon footprint: solar hot water is a green, renewable heating system and can reduce your carbon dioxide emissions. Solar water heating systems use solar panels, called collectors, fitted to your roof. These collect heat from the sun and use it to heat up water which is stored in a hot water cylinder. A boiler or immersion heater can be used as a back up to heat the water further to reach the temperature you want. There are two types of solar water heating panels:
evacuated tubes (as in the picture above)
flat plate collectors, which can be fixed on the roof tiles or integrated into the roof. Larger solar panels can also be arranged to provide some contribution to heating your home as well. However, the amount of heat provided is generally very small and it is not normally considered worth while. Maintenance costs for solar water heating systems are generally very low. Most solar water heating systems come with a five-year or ten-year warranty and require little maintenance. Once fitted your installer should leave written details of any maintenance checks that you can carry out from time to time, ensuring everything is working properly. Perhaps the most important thing you can check for yourself from time to time is whether there are any leaks. If there are any leaks of anti-freeze (even if you can’t see any liquid) this will have a strong smell. If you notice this you should contact your installer. In general you should keep an eye on your system to check that it is doing what it has been designed to do. If you are not getting hot water or the solar pipework is cold (when the pump is running) on warm, sunny days then again you should contact your installer. For peace of mind some installation companies offer an annual service check. You should have your system checked more thoroughly by an accredited installer every 3-7 years, or as specified by your installer. It is likely that after this period of time the anti-freeze that is used to protect your system in the winter months will need to topped up or be replaced as it breaks down over time reducing the performance of your system. Anti-freeze lasts better if the solar water system is used throughout the year and not left unused during the warmest weeks of the year. This cost of replacing the anti-freezer is usually around £100. The other thing that your installer should check is the pump. In a well maintained system, pumps can last for ten years plus and usually cost around £90 to replace.
Solar water heating systems can achieve savings on your energy bills. Based on the results of our recent field trial, typical savings from a well-installed and properly used system are £60 per year when replacing gas heating and £85 per year when replacing electric immersion heating; however, savings will vary from user to user. Typical carbon savings are around 230kgCO2/year when replacing gas and 500kgCO2/year when replacing electric immersion heating.
Spherical reflector type cooker
Spherical mirrors are the simplest type of concentrator and are easy to build and use. It is easy to focus sun rays, and if one opts for a moving vessel to meet the focus, cooking can also be done very easily. Such a design was suggested for the first time in the...
Please join StudyMode to read the full document