Heat Transfer Fluids for Solar Heating Systems : Exchanger

 Would love to hear experiences with different fluids and type of heat
exchanger .  Are there different types of Fluids for radiant heat ? Are
there alternatives materials to using a cement slab ?








  the coefficient of expansion, viscosity, thermal capacity, freezing
point,

boiling point, and flash point. For example, in a cold climate, solar
systems

require fluids with low freezing points

  Drew Cutter wrote:

We use the RV version of Propylene glycol. Good freeze protection to
-50F (35%pg, 65% water), and prevents corrosion in our metal piping.
It's food grade, but we use double wall heat exchangers anyway. For 2nd
floor radiant heating we use PEX tubing fastened to the bottom of the
floor boards. First floor is concrete slab, same tubing embedded. Water
is heated with combination solar and wood boiler.


--
Steve Spence
Dir., Green Trust, http://www.green-trust.org
Contributing Editor, http://www.off-grid.net
http://www.rebelwolf.com/essn.html

 Steve ;

    No way to get around concrete on the first floor for embedded the
Pex tubing ? I'm guessing that you would recommend ripping the floor out
to lay the concrete and tubing ?


Steve Spence wrote:

 Drew Cutter wrote:

you could build a wooden sub floor on top and put the piping in that.


--
Steve Spence
Dir., Green Trust, http://www.green-trust.org
Contributing Editor, http://www.off-grid.net
http://www.rebelwolf.com/essn.html

 

Just be sure to put plenty of insulation *under* the tubing.  In Steve's
second story case, downward heat transfer isn't a problem since there is a
living space below it.  But unless you want to heat a basement under the
first floor, you'll want to insulate under the tubing there.

daestrom