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 technologies include the use of photovoltaic panels and other types of thermal collectors to harness the sun’s energy to produce electricity or heat water and other fluids. These systems are by far the most familiar to the general public and are currently being actively marketed. In active solar systems external energy is utilized, often in the form of pumps or fans. A closed loop solar hot water heater, where an anti-freeze type liquid is pumped through a heat exchanger is an example of an active solar system. Photovoltaic solar systems are a method of generating electricity by converting solar radiation directly to electricity by means of photovoltaic semi-conductors.
Passive Solar design incorporates the building itself as the system for collecting and storing the sun’s heat during the winter and dissipating unwanted heat during the summer. The building itself is the system. Passive solar techniques include orienting the building to the sun and selecting materials with favorable thermal mass. Passive solar technologies rely on the inherent thermo-dynamic properties of the design to function. No external energy is added to the system. The building itself, via the creative use of standard materials and methods, becomes the core of the heating and cooling the system.
Earth Sheltered structures add a significant additional element of energy efficiency. When a passive solar building is sheltered from the elements via the use of earth berms or the natural topography, the structure becomes an earth sheltered pasive solar building. Click here for more information on earth sheltering...