How Solar Energy Works

By Robert Berge

It probably is no surprise that sunlight can be harnessed and used for energy – calculators have had solar cells for quite some time now – but did you ever wonder how solar energy works?  Well, the actual technical details are a bit complicated, but here is a general overview of the types of solar energy uses and how solar energy works:

Solar Heat Collectors:  simple designs for buildings to collect and store solar energy. This is the most basic method describing how solar energy works.  Solar collectors, for example, sit on the rooftops of buildings to collect solar energy for space heating, water heating, and space cooling. Most are big, flat boxes painted dark on the inside and enclosed with glass. The typical design includes pipes in the box that carry liquids transferring heat from the box to the building. This heated liquid— frequently a water-alcohol mixture to avoid freezing—is used to heat water in a tank or is sent through radiators that heat the air.

Solar Thermal Concentrating Systems:  using mirrors and lenses to concentrate solar rays, these systems can create exceptionally high temperatures— up to 3,000 degrees Celsius.  This powerful heat can be used in industrial applications or used to generate electricity.

Photovoltaics:
In 1839, French scientist Edmund Becquerel discovered that specific materials would create a spark of electricity when hit with solar rays.  This photoelectric effect was used in early solar cells made in the late 1800s. Then, in the 1950s, scientists revisited the technology and, with silicon, fashioned solar cells that could convert 4% of the solar energy directly to electricity. After a few years, these photovoltaic (PV) cells were powering satellites and spaceships.

Solar technologies are ready for considerable growth in the 21st century. A growing number of designers and contractors are realizing the value of solar energy and learning how solar energy works to effectively incorporate it into building designs.  Solar hot water systems can compete economically with conventional systems in some areas. And as we learn more about how solar energy works, the cost of solar PV continues to decline, and these systems will break through increasingly larger markets. In fact, the solar PV industry aspires to supply half of all new U.S. electricity generation by 2025.  So join the movement and help better our environment by learning how solar energy works, and once we all have the knowledge, we can make a difference.