Going Solar in the Mountains
By Scott Schmitz, Green Power Designs

Colorado sunshine creates a perfect environment for solar photovoltaic and solar thermal energy systems. With lots of experienced professionals in Colorado, "Going Solar" in the mountains is easier than you think. Two main types of solar energy systems have successfully been installed throughout Colorado. Solar Photovoltaic Systems produce electricity, and Solar Thermal Systems produce domestic hot water heat, assist in space heating, and pool/hot tub heating.



Whether you are retro fitting your current home or considering a solar energy system for new construction, there are many factors to consider. When retro fitting, it is best to have a professional evaluate your existing home. They can help lower your current energy use and make recommendations on how to best integrate a solar system. If you are planning new construction, you can really reap the benefits, as you can start from the ground up. A properly designed home can greatly reduce the energy requirements from the start. Then any solar energy system installed can be sized for the lower energy requirements on the system, and in some cases eliminate your utility bills altogether. When planning new construction, consider the home's orientation and roof plan so the solar panels have a place to go. Look at utilizing passive solar characteristics with the type of windows and window layout so the sun can heat the mass of the home through the windows. Consider roof overhangs to reduce the heating effect in the summer. Use high quality insulation and proper ventilation to eliminate ice dams and increase the air quality. The use of a high-efficiency boiler and radiant floor heating is essential. You can achieve a very comfortable 70-degree temperature in the middle of the winter using 90 to 100 degree fluid circulating through the floor. The home remains at a constant temperature and the boiler operates more efficiently. A forced hot air system on the other hand requires the boiler to ramp up to 180 degrees or full throttle to blow air across a heated surface. It's comparable to driving a car at slower speeds. You still arrive at the same destination; you just do it using much less fuel.

If you are considering a solar renewable energy system, follow these guidelines, as the design will greatly increase the performance.

1. You must have unobstructed access to the sun for at least 5.5 hours on the shortest day of the year, December 21st, and it must be during the peak period from 8:30 a.m. to 4:30 p.m.. Shade from trees, dormers on the roof, roof vents, neighboring homes and hillsides can greatly affect the system's performance. Even a shadow from a power line that covers 1% of the array can reduce the output by 80%.
2. The correct orientation is also essential. Due south is best, and 15 degrees in either direction has a minimal effect on output; more than 15 degrees will begin to reduce the output, and 45 degrees or more can reduce the output by 50%. Living in the mountains since 1991, I have learned that mornings tend to be crystal clear, while afternoons can become cloudy, so a little to the east tends to be better than a little to the west.
3. Roof pitch can also play a large role. If you are using conventional solar photovoltaic panels a 12/12 pitch (45 degrees) is best for year-round performance. The panels will perform well in the summer, and when the sun is low in the sky during the winter months, it is more direct than a roof pitch of a lesser degree. This pitch aids the ability to shed snow and increases the rate at which the snow will melt. If your roof pitch is less, a tilt to the panels should be considered. For an off-grid home where power production is essential, a pole-mounted array that can be adjusted from summer to winter will greatly increase your energy production. In the summer the array can be tilted back to 20 degrees when the sun is directly overhead. In the winter the array can be tilted up to 65 degrees, greatly increasing the ability to shed the snow, and keeping the sun as direct as possible. A properly adjusted pole-mounted array will increase the annual output by 20–25% over a roof-mounted array.
4. Another option is to consider a standing seam metal roof integrating Uni-solar laminate solar panels similar to the home pictured on the cover. Uni-solar panels adhere to the standing seam metal roof using a linoleum roller. Since the panels produce less energy per square foot, more roof space will be required; however, due to the panels' viscous characteristics, they will be the first place to shed the winter snow even at a 7/12 pitch. Just be sure the snow will shed to an area that does not cause any safety hazards. Snow rails to prevent snow shedding to the ground should never be used.
5. When installing a Solar Thermal System for domestic hot water (DHW) and space heating, a greater pitch should be considered. Since the demand for energy is much greater in the winter months, the 65 - 70 degree pitch will maximize the system's performance when it is needed most, and also keep the panels clear of snow, allowing them to begin producing hot water as soon as the sun is in direct contact. Solar Thermal Systems work by heating water stored in tanks located in the mechanical room. That water is then used for your DHW, or can be injected into the radiant floor, pool, or hot tub via a heat exchanger. On a clear sunny day in February 2009, a four panel system installed near the airport in Steamboat had a return temperature of 184 degrees Fahrenheit heating two 105 gallon Schuco storage tanks. That's a really hot shower, so be sure to install thermal mixing valves to prevent scalding injuries if you are doing it yourself.

Designing and installing solar systems can be quite complicated, and performance is everything. If you are building new, be sure to use an architect and builder familiar with renewable energy systems. They will be able to point you in the right direction, and design the home with the solar energy systems in mind rather than trying to implement them as an afterthought. Contact your solar energy system provider as soon as possible in the design process so they can make suggestions that will increase the overall performance. As a provider in the mountains there is nothing worse than being handed a full set of blueprints ready for construction and telling the customer to go back to the drawing board. When selecting your solar energy professional, be sure to ask about their experience in your area, as installing systems in the Front Range can be much different from installing them high in the mountains. Ask for references and to see a portfolio so you can get a feel for what the system will look like and how it will operate. They can also provide you with rebate and tax credit information (see “Tax Credits for Home Efficiencies,” this issue) as well as estimate the savings you can expect on your utility bills and the increased value that will be added to your home.

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