Sometime, I'll get around to posting some pictures of this project we're working on...
We totally gutted our '69 Ambassador, reinsulated the trailer with the aluminum foil bubble insulation. (Which is really wonderful stuff. Sooo much better than fiberglass). We actually used two layers of it. One layer pressed against the skin of the trailer and ribs. Then as we attached our wall panels we used another layer by laying it on top of the ribs to provide a barrier between the walls and the ribs. We were a little worried about the insulation being too poofy and the rivits sinking in to cause a quilted look, but that really wasn't much of a concern once we tried it out.
We also installed radiant pex tubing on top of a foil/vinyl/foil sheet from the same company that makes the bubble wrap (we special ordered it from a local hardware store). We actually used 3/8" tubing and ripped 1/2" strips of wood to screw to the subfloor to use as channels for the tubing.
I have to interject and say that this came about because my dad suggested we put in a radiant floor. As a plumber/heating man he was convinced this would work, and we agreed. We're currently living with him, and he is helping us get it going.
So now we have our RV500 hooked up. We're using a closed loop system with antifreeze in it because I imagine we will be in some pretty cold places and we want the tubing in our floor to be protected. We could have a used and open system and just circulated our fresh water through it, but this just seemed like a better solution for us.
It did complicate things more because we needed a heat exchanger (stainless steel plate type-a small one) and another pump. We went with a couple of the smallest el sid pumps purchased from The Solar Biz (http://www.thesolar.biz/Our%20Comple...0Inventory.htm
nice people. best price. they have a lot of cool things in stock esp. solar panels & batteries. We sent up our plumbing for the loops according to a diagram from the radiantcompany.com site. They have a diagram for a Takagi - another instantaneous heater so we figured it would work well for our system too. One nice thing about this method is that you can use domestic hot water while the radiant floor heat is on. Before we found this diagram we thought we would have to switch it back and forth.
We are having some problems at the moment because the RV500 is short cycling due to the hot water coming back to it. Dad just recently talked to Pricision Temp (The company that makes the RV 500) and he is in the process of obtaining info about how to modify the system to prevent this from happenning. One thing we will need to do is install a small storage tank for the hot water. I'll write back more when we've figured out a little more.
This has gotten pretty complicated and we are spending a lot of time & money tinkering with it. But if it works as well as we are hoping, it will have been worth it because my partner Andy & I plan on living in this Airstream for several years.
If anyone has any advice for this type of system, I'd love to hear it.