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Builders, architects and engineers have a unique opportunity to bring renewable energy to Colorado consumers. Residential and small commercial buildings can be designed with passive solar in mind, taking advantage of solar energy for heating but preventing overheating in summer by strategic use of overhangs and landscaping. Active solar collectors can be installed to heat water for residential buildings or for commercial buildings with large hot water needs. Commercial buildings can be designed for daylighting - the use of natural sunlight instead of electric lights. Commercial buildings can also utilize transpired solar collectors for preheating ventilation air. Solar or wind energy can be specified to provide electricity to commercial and residential buildings.This web site is designed to give you a brief summary of the opportunities for incorporating solar and wind energy into buildings in Colorado. It also contains a guide to the most current resource information and products available for designing and building with renewable energy.
As our most natural and renewable energy source, the sun's heating energy can be utilized in many different areas of design. Some solar strategies must be incorporated at the earliest stages of design, others can be added later. However, cost effectiveness and aesthetics are greatly enhanced if these decisions are made early in the design process.
Buildings under 10,000 square feet are ideal candidates for passive solar heating in the winter, and shading in the summer. Buildings more than 10,000 square feet can also utilize passive solar systems, but energy efficiency can be further enhanced by incorporating additional renewable energy design strategies such as daylighting.
Some passive solar strategies include:
· Building Orientation - Orient the building with its long orientation going east-west for high solar gains in winter, but good solar control in summer.
· Windows - Orient most of the windows to the south and minimize window area on the east, west, and north to maximize solar gain in winter but avoid overheating in summer. Utilize special glazing that reduces solar gains when good summer shading is not possible.
· Overhangs - Shade south windows with a properly sized overhang.
· Thermal Mass - Incorporate thermal mass, like concrete, brick, or other masonry into the building interior to store solar heat during the day for use during the cold night.
NOTE: The ENERGY-10 software tool (available through the Passive Solar Industries Council at www.psic.org) is specifically designed to analyze passive solar and daylighting strategies in buildings under 10,000 square feet.
Effective daylighting strategies result in reduced electric lighting and allow cooling systems to be down-sized since using fewer lights produces less heat. According to recent studies, incorporating daylighting strategies into architectural designs is not only good for saving energy, but it's good for the soul, as improved natural light affects the psychological and physiological comfort of the building's occupants.
Incorporating an ample amount of daylight, while avoiding overheating can be accomplished through several design strategies, such as proper shading, use of north light and reflected light, and specification of glazing that minimizes heat gain but maximizes visible light transmission.
Additional daylighting strategies include:
· Windows - Incorporate clerestories, light shelves (on east, west and south windows), atria and cupola structures into the design. Select glazing that maximizes light transmission but minimizes heat gain.
· Colors - Make sure interior wall and floor colors are light, so daylight can be reflected deep into the building.
· Lighting Controls - Automatic lighting controls maximize electric light energy savings and peak load reduction from daylighting. These controls dim or turn off the electric lights when the natural light level is adequate for the task.
Solar hot water systems have come a long way over the last fifteen years in increased efficiency and improved quality. It is most aesthetically pleasing to consumers if solar collectors are flush mounted on the roof. For maximum output, the roof should be facing south and sloped at 40 degrees from horizontal. However, even collectors mounted on a 6/12 roof slope (27 degrees) can be successfully used for domestic hot water.
Forty square feet of flat plate solar collector provides about 50% of the hot water needs for a typical Colorado residence. The Colorado Solar Energy Industries Association (COSEIA) publishes a membership directory, which includes a current list of certified solar hot water system installers. Additionally, the Solar Rating and Certification Corporation (SRCC) rates and certifies solar collectors and whole solar hot water systems to ensure high quality.
These renewable heat systems are typically used to provide hot water for industrial, government and commercial applications. They can be flat plate collectors or parabolic trough collectors. Examples of buildings suitable for this type of system include universities, recreation centers, prisons, or other buildings with large laundry or shower facilities.
Industrial processes that require significant amounts of steam and/or hot water can also utilize solar thermal systems cost effectively.
Solar hot water can be used effectively for heating residences or small commercial buildings through radiant floors or a fan coil unit. These systems use low temperature water (90ºF to 120ºF), which is optimal for collector efficiency. For commercial buildings, transpired solar collectors can be used to warm the outside air as it flows through tiny holes in a dark colored, south facing, unglazed sheet metal solar collector. Air that comes through the holes into the collector is warmed and then drawn into the building's ventilation air duct system. Commercial buildings that might benefit from this type of heating system include major manufacturing plants, chemical storage buildings, laboratory facilities, animal care facilities and school gymnasiums.
Photovoltaic (PV) systems convert sunlight directly into electricity. PV systems can utilize batteries for storage or be connected directly to the electrical grid in many Colorado locations. Building-integrated PVs include special roof shingles, exterior cladding, or skylights that generate electricity and replace typical building materials.
The cost of PV systems continues to fall as manufacturing innovations increase and quantity production of panels and associated equipment rise. Special programs and rebates can make them more affordable for many applications. For example, Public Service Company of Colorado (PSCo) and the Colorado Governor's Office of Energy Conservation are helping more than 25 public schools install 3kW systems for generating power and educating students.
Wind turbines can be connected to batteries for off-grid applications or connected to the electricity grid. Grid-tied systems are typically large wind turbines that are owned or contracted by utility companies. Public Service Company of Colorado installed seventeen wind turbines in early 1999, and plans to install another fourteen by late spring 1999. These turbines are connected to the utility grid, just as a coal-fired power plant would be connected. Building owners or individual residents can purchase the power from these wind turbines by simply signing a year-long contract with PSCo. Colorado Springs Utilities, Fort Collins Light & Power, Holy Cross Electric Association, and Yampa Valley Electric offer similar wind power opportunities.
Individual wind turbines are a good consideration for remote applications with a 10 mph average wind speed and electricity costs of .10¢ per kWh, or where the utility grid does not exist.
