Thermosyphon Solar Air Space Heater (with 1 year payback)


These articles describe the simple and inexpensive passive solar collector that I use to heat my shop/barn.  The total cost for the 150 sqft collector is about $350, and all the materials are available at your local hardware/lumber store.  No fans or electronics -- its driven by natural thermosyphoning.  The design can be adapted to suit a wide variety of spaces, including a living space.  At our current propane prices ($2.00 per gallon), this project has a one year payback.


I would suggest reading both the Mother Earth and Home Power articles (below), as they each have some unique material that will be helpful if you are building the collector.  Also review the 2012 updates section for some potential refinements.



NEW -- A video by Peter Brown on our thermosphon collector...


solar collector video



NEW -- 2012 Updates...


Mother Earth News article on the collector.




A full description and all the details on how to build your own are available in these two articles:

+ The December/January 2006 issue of Mother Earth News --

Read the online version of the Mother Earth News article


+ The October/November 2005 issue of HomePower Magazine

Download the HomePower Article (500K pdf)  -- Thanks to HomePower for providing this!


2012 Updates and Changes

The collector was built in the winter of 2003-2004 and has been faithfully pumping out heat ever since.  This is an update on how things have gone with it, some recent performance testing, and a new "commercial" version of the collector:


+ Maintenance


+ Potential changes and refinements


+ Recent Testing:

+ Effect of reducing vent size on performance

+ Effect of dust filters on performance

+ Efficiency testing

+ Flow rate testing
+ Back of collector as large radiant heating panel


+ Commercial version



Home Power article on the collector



Note: I noticed that the design guidelines for thermosyphon collectors did not make it into the document above, so here they are:


Design Guidelines for Thermosyphon Collectors

The buoyancy forces that drive the air flow through a Thermosyphon collector are weak.
The collector must be designed to minimize flow resistance. High flow resistance will
result in higher collector temperatures, higher losses, and lower efficiency. For low flow
resistance, flow passages must be large, and the absorber must transfer heat to the air
efficiently and with little flow resistance.


Front view of collector with main parts labeled  (picture from Home Power Article)



blog comments powered by Disqus




Gary 5/12/2006, 11/19/06, Nov 18, 2007