SAVOIA Renewable equipment

Solar Power Basics

by Gary Letterman

Solar power works well for most items except large electric appliances that use an electric heat element such as a water heater, clothes dryer and electric stove - for example - or total electric home heating systems. It is not cost effective to use solar power for these items. Conversion to natural gas, propane or other alternatives is usually recommended. Solar power can be used to operate a gas clothes dryer (Maytag, etc) because the electrical requirement is limited to the drum-motor and/or ignito- lighter, but not a HEAT element for drying the clothes,for example.

Sunlight "solar energy" can be used to generate electricity, provide hot water, and to heat, cool, and light buildings.  A power plant can also use a concentrating solar power system, which uses the sun's heat to generate electricity.  The sunlight is collected and focused with mirrors to create a high-intensity heat source. This heat source produces steam or mechanical
power to run a generator that creates electricity.

Solar water heating systems for buildings have two main parts: a solar collector and a storage tank. Typically, a flat-plate collector (a thin, flat, rectangular box with a transparent cover) is mounted on the roof, facing the sun.

The sun heats an absorber plate in the collector, which, in turn, heats the fluid running through tubes within the collector. To move the heated fluid between the collector and the storage tank, a system either uses a pump or gravity, as water has a tendency to naturally circulate as it is heated. Systems that use fluids other than water in the collector's tubes usually heat the water by passing it through a coil of tubing in the tank.    Many large commercial buildings can use solar collectors to provide more than just hot water. Solar process heating systems can be used to heat these buildings. A solar ventilation system can be used in cold climates to preheat air as it enters a building. And the heat from a solar collector can even be used to provide energy for cooling a building.

With the increasing cost and hazards of burning fossil fuels, the concept of using solar power for heating and electricity production has become ever more popular. Alternative solar energy solutions, depending on whether you want to heat water, air, or both, or produce electricity; are found in three basic types. Solar panels to consider are photovoltaic, flat
plate hydronic panels, and Forced Convection Hot air solar Heating Systems.

A rectangular designed and insulated enclosure with a glass or plastic cover is lined with metal and painted black. Small tubes carrying water or glycol solution run through the box. As heat builds up in the collector, the liquid passing through the tubes is heated.

*This article is courtesy of the SOLAR POWER Newsletter