The summer months provide a great use case for renewable solar energy solutions. Solar energy use has surged at about 20 percent each year over the past 15 years thanks to rapidly falling prices and gains in efficiency. Japan, Germany, and the U.S. are major markets for solar.
With tax incentives, solar electricity can pay for itself in 5-10 years.
Solar energy capture is broken down into four types:
- Daylighting: daylight and sunlight used to provide illumination within a building, especially to supplement or replace electric lighting.
- Active: photovoltaics or PV (solar panels) used to directly convert sunlight to electricity.
- Passive: large windows placed on the south side of a building to allow sunlight to heat materials on the floor and walls.
- Thermal: collectors on a roof heat liquid in tubes that supply hot water.
Daylighting
Lighting is the largest energy load in commercial buildings today, with electric demands that occur predominantly during the day when daylight is available. Because the energy demand is so high, and daylight is so widely available, this is among the largest impact areas for integrating renewable energy.
Effective daylighting involves a variety of techniques and technologies, including efficient window placement; the use of special window coatings that minimize reflection or can alter the window’s transmittance depending on the weather; and the use of daylight collectors and fiber optics to transmit sunlight into a building.
In the last decade, there has been active research on hybrid solar lighting, combining daylight with electric lighting. Through this approach, consistent illumination can be provided at a lower cost than with conventional electric lighting.
Active Solar Energy
PV-based solar energy has become one of the most successful energy technologies in history by greatly minimizing energy costs. A flat-plate PV can be mounted at a fixed angle facing south on the roof, or it can be mounted on a tracking device that follows the sun, allowing it to capture the most sunlight over the course of a day. The sun produces a lot of energy in a wide light spectrum, but PV’s have only captured portions of that spectrum to convert into electricity. With more research, this concept with continue to grow and save a building or home owner’s electricity costs.
Passive Solar Energy
Passive solar design takes advantage of a building’s site, climate, and materials to minimize energy use. Well-designed passive solar applications first reduce heating and cooling loads through energy-efficiency strategies, then meet those reduced loads in whole or part with solar energy. Using the sun’s energy to offset heating demands in a building’s shared spaces is an important renewable energy source.
Thermal Solar Energy
The final renewable energy type is thermal, which is the use of solar energy to produce hot fluids. Heat builds up in a vehicle if it is parked in the sun on a hot summer day. Solar thermal energy works in the same way, except that the heat generated is put to practical use to heat spaces or water. In addition, solar thermal systems contribute to preserving energy reserves and protecting the environment by reducing CO2 emissions.
If you were to combine all of these solar energy systems, your building efficiency would drive costs down significantly.
This article is adapted from BOMI International’s course High-Performance Sustainable Building Practices, part of the BOMI-HP® designation program. More information regarding this course is available by calling 1.800.235.2664. Visit BOMI International’s website, www.bomi.org.