Solargon Research

 Carrick Eggleston PhD has compiled the following data from research conducted on his Solargon 30. "The results are impressive considering the building is not completely sealed and there is no internal heat source or heating system installed."




 View from Carrick's Sand Creek Solargon


Compiled by Carrick Eggleston
As university professors with expertise in solar and other forms of renewable energy,  behavioral and cultural change, and educational strategies, we offer our clients and partners a wide-ranging background in essential fields. Our goal is to help improve understandings of new energy technologies within the wider population of people who are interested in alternatives to a fossil fuel based lifestyle, yet are unsure of how to proceed in a way that will not force them to change their day-to-day life completely.


"The mission of Cultural Energy is to promote the transformation to new cultures of energy and environmental resource use through education, experience and innovation."


 "The Solargon has captured our attention as an outstanding "demonstrator"- a base to which we would want to add an array of renewable/alternative energy options. With a Solargon, our fledgling company would demonstrate the practicalities of photovoltaic, solar thermal, and wind energy sources in a highly efficient high solar gain Solargon with LED lighting, a small wood stove, composting toilet, and conservative water management."

  By: Sarah Strauss and Carrick Eggleston



 "While we're not entirely "do-it-yourselfers", we have been doing quite a bit of this project ourselves and hiring help with things that would take us too long.  Thanks to the Solargon design, as you can see on the blog, the main structure went up very quickly so that we were able to get windows in and a roof on right away, followed by tar paper and siding.  We got the shed built before the recent series of snow storms made access difficult. One thing that has impressed us lately is that true to its design, the Solargon is quite warm inside simply on the basis of solar gain, even on frigid days! Also, the last time I was up there the wind was as fierce as I've seen it.  The Solargon is solid!"


 Carrick Eggleston, PhD


Solargon Research:


    Just so you know, I have a set of data loggers from Onset going in and outside the Sand Creek Solargon.  They are recording temperatures in various locations (main solargon, in sun, in shade, vestibule, outside) along with light intensities and other data. I also wanted to get your reaction to the following.  I know that some of you were against not insulating the slab - but here's the reasoning:

(a) A friend with a nearby "Earth Ship" swears by an uninsulated slab for keepingthe place cool in summer despite solar gain, and giving up heat to the structure in winter.
(b) My investigation of shallow frost-protected foundations got me to thinking about the formation of a mild "heat island" under the Solargon, aided by the ICFs for the foundation wall.
  I calculate that with a 15F temperature difference between the sub-slab and the air in the Solargon, the floor will give up about 6000 BTUh (about half of the heat needed to keep the interior at 40F if outside is -30F).  The other half - and more - is provided by solar gain on sunny days. The point is that, yes, heat is lost to the Earth in all this - but only when the interior temperature of the Solargon exceeds that of the sub slab.  When it really tries to get cold, the enormous thermal mass of not only the slab but also the rock/gravel underneath it gives up heat to the Solargon.  Incidentally, I have 500' of PEX installed at a depth of over 3 feet below the slab as a heat dump for the solar panels.  This simply helps ensure that (a) the solar thermal system does not overheat, and (b) that the temperature gradient into the subsurface is steep enough to provide more than 6000 btuh during cold snaps.




  I was able to get to the cabin (through outstanding mud!) yesterday and downloaded the data from the data loggers.  I'll send plots of the data shortly, when I figure out how to get it off of the ancient computer that still talks to the data loggers (through RS-232) and onto something else, but I can report that:


1) Indeed, despite outside temperatures that went to -23C, -10F, the BACK or north side of the Solargon never got down to freezing.


2) The data logger right under the front window, out of sunlight, did reach slightly below freezing, as did another logger in the vestibule.


  I have relative humidity and light intensity as well, but for now my theory on the temperature outcome is that when it gets cold outside at night, the cold air drops down the windows on the inside and cools those temperature probes such that they record a bit below freezing on really cold nights.  As the air then moves northward across the floor in a slow convection cycle, it warms with heat from the slab such that the back or north side of the Solargon never gets down to freezing.


  Keep in mind that we have not finished the interior yet, so that the insulation will actually get a bit better with interior siding and window trim and sealing up places that are not all that well sealed at present.  Also, with night-time window coverings, the heat loss at the windows will be reduced considerably.



  In both cases, the blue trace is the outside temperature. The red trace is an inside temperature in each case; in one plot, the temperature of a probe in sunlight is given (its temperature

soars to over 100°F in full sun) and you'll notice that the temperature of that probes, near the front window but only about 10 inches above the floor, dipped below freezing on the coldest night. In the other plot, the inside temperature from the north side of the Solargon, in the shade of some wood, is given. Notice that it does not go below freezing.


  This is, of course, with no active heating and in the absence of interior finish work - no interior siding and some seams still needing to be sealed.  That is, the insulation of the structure will get a bit better over the summer.  It's remarkable given the temperatures and WIND outside the structure.

Carrick Eggleston:
Sarrah Strauss: