Sights on the Sun

When it comes to building a zero-net energy building or a near-zero net energy building, there is no greater resource available to facilitate this than the big ball of fire in the sky that lights up planet earth.

According to the University of Tennessee, by the time the sun’s energy travels 93,000,000 miles to our planet’s upper atmosphere, the energy density of that light and radiation is 1,368 watts per square meter. By the time it reaches Earth’s surface, the energy density is 1,000 W/m2 for a surface that the sun beams down on at sea level on a clear day.

The UTIA goes onto explain that if all the sunlight energy striking the Earth’s surface in Texas could be converted to electricity, it would be up to 300 times the total power output of all the power plants in the world!

With so much potential for solar, it wasn’t hard for my wife and I to decide that we definitely wanted solar panels to be an integral part of our project. I plan on harnessing as much of the sun’s power as I can for my new eco-friendly home.

On the southwest-facing rear of our home, I have been planning from the beginning to install 42 solar panels onto the roof - 42 is about the number we can fit onto the roof without sacrificing other features of the home or altering the framing/insulation plans. With these solar panels, we should be able to offset a great deal of our energy usage and save some money on our electricity bills.

Before we really begin the framing and wall construction processes, I want to make sure I know how to maximize our use of the sun as it relates to our home's positioning. So for this episode, I brought in one of the most knowledgeable professionals who I know of on this subject. George Keithan of Consulting Engineering Services has a great deal of experience working on projects that involve renewable energy, and his advice on how best to proceed will be a essential addition to my project.

I’m looking forward to working with George as the project moves forward — his knowledge and expertise is definitely a key part of my homebuilding journey.

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  • Dave Sweet
    Hi Kevin, thanks for the tips. I wanted to add a few more solar panels than we actually need at this point to plan for eventualities like a swimming pool or like you said, an electric vehicle.

    I do plan on putting a radiant underfloor heating system throughout the home… stay tuned for the progress!
  • Kevin Wyman
    Looks great! 42 panels will be a lot of panels for two people in the house unless you are thinking about geothermal for heating & cooling and/or that future electric vehicle that will get you back and forth to Rhode Island. I have 30 panels (18 facing South and 12 West) and that takes care of 100% of our home for electric but not heating. You could even consider a few more panels at the bottom in the horizontal direction if you want to get more electricity generation. It could help heat the pool year round. Or again go towards a heat pump system for heating. Congratulations on the progress. One of the things you might find is that traditional boiler systems will be way over sized for a super-insulated house so if you are planning on radiant system, make sure to have a large buffer tank or if going with solar thermal a combination of tanks. Looking forward to your progress.