Thursday, January 16, 2014

Sustainability: Past and Future

Because our food, our homes, our businesses and our transportation system primarily depend on burning fossil fuels, the way we live today is not sustainable. During the past 200 years probably around one billion people helped burn the first half of these valuable energy resources that can be economically procured. Seven billion folk now appreciate how wonderful life can be in every season, with food and inexpensive goods available from around the globe, in comfortable homes with running hot and cold water, and in vehicles that go where and whenever we want (and much farther than horses that need pastures, grain and hay, not to mention, rest). The other soon to be nine billion folk want the lives we live and will compete for the second half of available raw materials.
In early 20th century people worried about managing food and manure for horses in cities as populations grew. But those problems disappeared when it took only a few minutes to refuel vehicles with exhausts that “disappear”.

We live at a time with both tremendous opportunities and impending peril. Each of us in the US is responsible for consuming 17 tons of resources each year, or 1,343 metric tons in a lifetime.

In the UK, the Office for National Statistics (ONS) estimates the national total raw materials consumption at close to 2 billion tons per year. This is equivalent to 30 tons per person, per year, and it does not even take into account the consumption of raw materials hidden in imported finished products. OPENING PANDORA’S BOX: The New Wave of Land Grabbing by the Extractive Industries and the Devastating Impact on Earth (2012) by Philippe Sibaud, presents these alarming statistics in:

As we draw down these resources we have an opportunity to not only create the tools that harness renewable resources but also develop the culture and facilities to reuse and recycle materials instead of exploiting new resources. For more than thirty years it has been evident that we have been using resources at an ever increasing rate that will, in one generation, deplete most of what is worth acquiring. Soon the only raw materials left will be too expensive to mine, pump or frack. It seems to be in the best interest of those who profit from selling raw materials, including all fossil fuels, to discourage competition and challenge serious discussions of climate change or responsibility for conserving resources for our children, others who follow, or even consider other organisms on this planet. Therefore: individuals and communities have to develop both the tools and orientation we’ll need for a sustainable future.

That’s why I develop solar collectors that use sunlight to deliver the same high temperatures developed in the hottest coal, oil and gas fired furnaces and boilers. These harvesting tools working together with storage and equipment that burns biomass should soon be able to completely service buildings, farms and other stationary facilities.

Friday, January 10, 2014

Gimbal-mounted Solar Collectors

I design, build and test powerful solar collectors that:

1.  Can be made with home shop tools and erected by hand with no welding or other expensive equipment required;
2.   Harvest high quality energy ( >500oC, 932oF, if appropriate) delivering power and heating space/ water for 30 years;

3.  Replace the energy invested in materials within 5 months (cold, northern US);

4.    Primarily use aluminum, glass mirrors and fasteners that are readily recycled or reused with a defective sensor or motor replaced in a few minutes;

5.    Follow the sun all day and turn upside down at night or during storms (hurricanes, hail, snow and freezing rain) so mirrors are clean and frost free when the sun comes out; and

6.    Without subsidies pay for themselves in fewer than five years if owners assemble them and use the energy they harvest, longer if a company installs them with a warranty or if energy during long summer days with good weather is not harvested because there are no appliances that can use it.

The approach my brother and I now work on is based on many years of experience with these point focus solar collectors that track the sun on two axes. The early solar collectors followed the direction of the sun around a vertical axis and moved the mirrors around horizontal axes to accommodate elevation changes. In these, both drives must accommodate changes every minute all day long to follow the sun as it rises until noon and falls until it sets. The current design rotates around an axis that is perpendicular to the axis of the earth and the primary drive must simply power the collector so it makes one revolution a day, or 15 degrees an hour, or a degree every four minutes like the hour hand of a 24 hour clock. The other axis has to accommodate the tilt of the earth, 23.5 degrees, over a year so on many days it doesn’t have to move at all. 

A Computer Model of a 25 Square Meter Gimbal Mounted Solar Collector

Building and operating four generations of this equipment have shown what works well and what needs to be improved. In future posts I’ll describe what aspects are pretty mature and which still need refining. A technical description of the advantages of our approach using a gimbal that rotates around a polar axis (right ascension) with the concentrator/receiver rotating around the declination axis for the seasons is in the patent document: