Heat storage in van

[karl]

<font size="3">My son and I created a heat storage system under the bed in Lurch since much of my travels are in cooler weather.<br>After a couple false starts we settled on a recycled air compressor tank that holds 30 gallons, a heater core salvaged from a step van, a manual heater shutoff valve, some 1/2'' copper tubing and heater hose, a drain for the tank, and some pvc plumbing fittings to fill it.<br>We first cut a hole in the top of the tank large enough for the heater core to slide in, cleaned the tank some, and using copper tubing and couplings- soldered extensions onto the heater and through a steel plate we cut and formed to overlap the tank cutout by a couple inches, used high temp silicone gasket goop (NAPA, Auto Zone...) and self drilling screws to cap the hole, added a drain valve at the bottom, then ran heater hoses/pipe to where we could tee into the existing heater hoses, with our new valve in one of the lines where we could run a push/pull cable to the dash. <br>Sorry, no pics of the build...maybe if I take it apart to paint the inside....<br>&nbsp;On a month long shakedown trip it worked even better than we anticipated- the van was still warm hours after stopping, even in 5 degree weather. My mattress is nice and warm when I crawl in too. <br>The down side is that you have to drive every day or two in freezing weather or drain the tank (could add nontoxic antifreeze ) I had anticipated using hot water from the tank for bathing, dish washing, etc. but so far have not. Another negative is hauling an additional 250 lbs constantly, but I think it is a minimal sacrifice for the comfort.<br>A couple of things we learned do not work- plastic tanks deform from the heat and weight, breaking seals and leaking. Butyl tape for sealing stinks something awful and looses its seal with heat. In a perfect world I would prefer a rectangular stainless steel tank for better fit and water quality. <br>I would NEVER consider the water from these tanks for consumption in case of a heater leak and contamination.<br>We have considered a simpler system that would simply circulate engine coolant through a tank without the heater core as an exchanger, but it would always be full and this way we can dump the excess weight.<br><br></font>

 

[akrvbob]

Karl, that is a brilliant idea and outstanding execution! I am so sorry you don't have pictures because I would love to have you write an article for the site! So how much water do you think is in the tank, 25 gallons? Any idea how hot it gets? Were you concerned about building up pressure and blowing gaskets?<br><br>Thanks so much for posting this, very creative! Bob<br>&nbsp;<br>

 

[karl]

Thanks Bob,&nbsp; I think there is about 29 gallons after installing the heater core. Water temp gets to about 185-190- pretty much engine operating temp. I drilled a 1/16" vent hole in the 2" pvc plug&nbsp; where we fill the tank, it is 3 or 4 inches above the tank so no slopping of water.<br>I have since had some thoughts on simpler methods of installing the heater without soldering.<br><br><br>

 

[Seraphim]

<P><FONT size=3>Is it a radiant heat system, or does it use a blower to circulate warm air?</FONT></P>

 

[karl]

It just radiates and has been adequate. We did consider a loop through a toespace heater from a home hydronic system or another heater core but think it is unnecessary. <br>

 

[Mobilesport]

How do you keep it from blowing gaskets? 
Also how do you seal the hoses that go through the metal plate?
Here's  how I picture it.
Thanks 

 

[Mobilesport]

Oh I see now , there's only pressure in the lines and heater core ,  no pressure coming from the water in the tank .
 sealing where the lines come through wouldn't be a problem , about anything could seal those holes.
Awesome project. 
Thanks again

 

[Mobilesport]

You got me thinking , my van came with a rear heater core , it probably wouldn't be too hard for me to just submerge my existing heater core in a water tank and be done with it , my van even has a valve already installed under van on the heater line , no push pull cable though.

 

[karl]

Oh I see now , there's only pressure in the lines and heater core ,  no pressure coming from the water in the tank .
 sealing where the lines come through wouldn't be a problem , about anything could seal those holes.
Awesome project. 
Thanks again

Late, but you figured it out....made a coupe since and find I prefer rectangular tanks  for better use of space.
I only valve the input side so that there is no buildup of pressure in the core or lines.
Have also reduced the size of tank to ten gallons- doesnt over heat van as much.

 

[akrvbob]

Wow, this must be a world record for a dormant thread coming back to life!

You started this thread almost 5 years ago--very impressive!
Bob