Home Solar Energy - The Basics
by Phil Nichol There is a common myth that solar heating is the primary use for solar energy in the home but in actual fact it’s not always useful for this. In the winter, when you use your heating, the sun is lower in the sky and there are less hours of daylight. At other times of the year when solar energy would be more effective you’re less likely to need it. Solar heating can supplement the other heating in your home but not take over totally from it. The Technology behind Solar Energy A number of technologies have been developed to make use of solar radiation. Some of these make direct use of solar energy for lighting and heating etc., while others produce electricity. They are: 1. A solar thermal energy collection system generates electricity a system of tubes containing a fluid and mirrors. 2. Solar thermal collectors which are used to make heat. 3. Photovoltaic panels which generate electricity directly from sunlight. However, they generate D.C. current, which has to be converted to A.C. if you want to use it in the home. This would requires a large surface areas to provide enough energy for a single home. This is why solar panels are rarely used for residential heating. 4. Solar

hot water panels which are often employed in residential situations to heat water. How Efficient are Solar Panels? Solar panels are only efficient when they receive direct sunshine producing very little power in cloudy conditions or shade. However, it is the sunlight that generates electricity. Solar panels used in very hot climates are less efficient than those used in sunny but cold climates because heat actually interferes with electricity production. Efficiency decreases when the temperature of the panel is more than 50 degrees centigrade. Most energy is generated when solar panels are directly pointed towards the sun. So just how much power is produced also depends upon the time of day since the sun’s angle differs. Usually the best choice is to incline the panel although on shady days, horizontal mounted panels are better. Although the popularity of home solar energy has been decreasing since the 1970s, billions of dollars have been spent on developing Photovoltaic systems in America and Japan. Lately, Germany has also joined in the research so costs are falling. Also, in some countries you can recoup some of your expenses by selling excess energy back to the electricity companies.