Sunday, November 30, 2014
High performance solar collectors can readily displace fossil fuels. Though there are none today that are easy to use, perform well in winter, and are inexpensive. We need some that:
1. Intensify sunlight 1,000 times to power tiny receivers that deliver both heat and power;
2. Harvest more than 80% of available sunlight;
3. Are made with home shop tools without welding or expensive equipment;
4. Can be installed using hand tools and then operate without expert attention;
5. Replace in less than six months the energy invested in making it;
6. Operate for 30 years: all parts easily cleaned or replaced;
7. Utilize only materials that can easily be reused or recycled;
8. Power both themselves and connected energy systems so they work after storms;
9. Provide year-round hot water, air conditioning and space heating; and
10. Pay for themselves in fewer than ten years, without subsidies.
We may be 80% there but will take more work to realize these goals. I’ve been building two-axis tracking solar collectors since the mid 1970’s and some even won national awards. None, though, were homeowner ready. Each generation improved on its predecessor, and we built experimental plants that steam-cleaned aircraft parts, cured concrete blocks, made fresh water from the Red Sea or generated enough electricity for 40 homes. When support for high performance solar evaporated in 1988, I continued building table-top solar collector models to solve problems that earlier equipment seemed all too happy to point out.
In future posts I’ll cover structures, tracking drives, mounting solar electric panels and making mirror panels that are becoming mature. Other posts will define heat transfer packages and tracking controllers that we’ll need help with so homeowners won’t have to worry about operating these high performance solar collectors. They'll be in charge of the thermostat. Solar equipment should use sunlight for power and operate all by itself, report how well it's doing and how much more it would be able to do if given more tasks, like providing light, drying clothes, cooking, dehumidifying basements and preserving food.
Creating a friendly solar tracking controller is ongoing. I developed models that have the sensors, motors and structural assemblies required for tracking high performance solar collectors and quantifying local solar resources. We showed them at MakerCon at the New York Hall of Science two months ago. Though hundreds of folks stopped by our booth, no one there seemed interested in models tracking the sun’s daily and seasonal motions or stowing upside down for hail protection and keeping mirrors and PV panels free of frost, freezing rain and snow.
We’re looking for help, especially with controls. It will take mechanical me years to write and test code that enables solar collectors to initialize themselves once installed and track automatically, let alone report performance. Developing, spinning and populating the circuit boards will probably take me another year. We offer working models and even larger equipment in exchange for electronics and code help.