“Design is not just what it looks like and feels like. Design is how it works.” –Steve Jobs


How Sunreps solar space heating collectors work:


A black porous geotextile fabric is secured to a metal superstructure and placed on a commercial building rooftop and faced south toward the sun close to the rooftop package unit (RTU). The sun heats the black fabric and that heat is then pulled through the collector's tiny holes and into the fresh air intake of the RTU.


This very simple and elegant technology has been recognized and memorialized as one of the most important inventions in the past 200 years by the American Society of Mechanical Engineers (ASME), through their publication, ENGINEERING THE EVERYDAY AND THE EXTRAORDINARY Milestones in Innovation. Under chapter 5, "Energy/Power "one can see the the extraordinary company Solarwall (the first transpired solar collector) shares in the view of the country's mechanical braintrust.  The incandescent light bulb, internal combustion engine, and other very recognizable inventions also share this category of nine innovations.


Many commercial building's heating and cooling systems use Rooftop Package Units (RTUs, the green boxes on flat roofs) The RTUs are required to continuously pull some fresh air into commercial buildings for the health of the occupants. The 1980's showed how important this fresh air flow is. ASHRAE , the HVAC standards organization, lowered the minimum fresh air levels required in commercial buildings in order to lower energy costs during the second energy crisis. The results were immediate and unpleasant. Lowering fresh air requirements gave way to a new health problem called  the "sick building syndrome". In 1989 ASHRAE reversed course and reset the fresh air standards back to pre-1980 levels. The sick building syndrome quickly faded from the news and is no longer considered a major health problem.  


With the installation of Sunreps' collectors, all of a building’s required fresh air can be  pre-heated by the sun before it is blended with the building's recirculated air. The results of incorporating solar pre-heating is a reduction in the need to burn fossil fuel to attain a building's desired indoor air temperature. In Seattle, during the heating season a small Sunreps collector system can reduce heating costs from 20-30% on each RTU.

When a commercial building is calling for cooling the collectors are by-passed and so only non-heated outdoor air is pulled into the RTU.

Sunreps collectors represent the continuing evolution of the “transpired solar collector” laws of physics. The simplicity of the science behind our collectors cannot be overstated but that is also their beauty and their financial advantage. There is not solar collections device that is more efficient or lower in cost.


The link below shows real-time temperatures of outside air and the temperatures inside the three 420 sf,  307 collectors. The first chart is the current outside air  temperature and the other three charts the collector's temps.  The collectors are located outside of Chehalis, WA (two hours south of Seattle) There is over a year's worth of temperature history that is observable.


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