Lets talk about hydronic radiant heat in a van

[robin.bankx]

Anyone thought of this? I have an idea in my head about it could really be beneficial esp having a diesel. Thoughts?

 

[jimindenver]

I know of a person that tapped into his hot water heater on a RV to create a system. He added the hoses, valves radiator/fan and pump to an existing hot water system.

I don't know if there are kits that would burn diesel but I do know the systems exist on big motor homes. My thought is by the time you burn enough fuel to heat the water for the system, you will be cooked out of the van before you can use it. When I lift the cover to my hot water heater it produces a fair amount of heat in use.

 

[robin.bankx]

My plan was to use a 6 gal lp rv water heater i have laying around and plumb it into my coolant lines in addition to running lines in the entire floor and i have a small heater core and fan to install in the rear. I figure this could solve a few issues. One- being able to full time in very cold climates with out worrying about condensation or CO, and also not worry about sleeping with the Heat on, or leaving the vehicle with heat going for a pet. TWO- this would also keep my engine block and posibly WVO tank heated through the night in very cold temps to help with starting. I could run the front blower fan from my battery bank and have heat that way too. Ive been brainstorming about this for about a year but im getting more serious because im about to rebuild my interior

 

[grummy]

Well, there is no reason whatsoever that this wouldn't work, but I'm not convinced on it being an efficient way to get heat unless you can insulate adequately the water lines from the exterior cold zone. The weaker the R-Factor between the tubing and the exterior floor will mean a lot of heat is going to be wasted in the wrong cavity.... the outside !

If you take in-floor hydronic heat in your average home, your not usually dealing with a lack of space under the tubing, space that is either basement, or at minimum, an area with enough room for adequate insulation.

A Van simply is not going to give a person much room to pull this off properly. Off the top of my head, I'd think I would want about 4" of insulation UNDER the tubing so that the heat is maintained inside the vehicle. I have a step van with much higher side walls than a van, and I would shutter to think about giving up 4" for insulation, 1/2" for tube and 1/2"-3/4" for a floor on top of that.

Now there IS closed cell expanding foam specifically for the EXTERIOR... like under coaches and large Rv's. I dont think it is a DIY project though, you have to go to someone who does it. I would love that under my step van, and a step van is a lot more "organized" underneath to actually accomplish this than your average van. Unlike a step van which often has "C" Channel that runs across the top of the frame rails making a perfect GAP for such a foam spray, the traditional van has a whole lot of "attachments" to the floor itself making it rather "hit or miss" on both placement and thickness.

It can be done, but, I think it will be inefficient without adequate insulation.

 

[Donedirtcheap]

RV water heaters suck propane and lose heat. Worst than an RV furnace, but an RV furnace is not all bad when it is weighed against the alternatives. Worse part of an rv furnace is the 5.5 amp draw but that is overcome with 4 gc2's and good charging equipment. (not practical in a van). Until you move up to the Cat, all the other portable type heaters dump moisture and some amount of fumes into the living area. If one is to be comfortable it needs to be thermostatically controlled, efficient, safe (vented).

The airtronic 2 seems to have a great potential. It can be exterior mounted, quiet, safe, fuel efficient, lightweight, easy service access, relatively low current draw. It would be easier to under mount about a 5 gallon diesel fuel tank than to carry at least 40 pounds of propane. Diesel is on every corner. Propane is pricey and only at select places.

http://www.ebay.com/itm/Heater-Espa...08?pt=Other_Vehicle_Parts&hash=item4d257fe06c


http://www.espar.com/fileadmin/data/countrysites/EB_Kanada/pdf/RV_Brochure_WEB_READY_060514.pdf

http://ventedcatheater.com/2.html

 

[robin.bankx]

I think even with out the floor tubing having the water heater operate a heater coil in the rear could be pretty beneficial. If you also add engine assist and vice versa to that i think its even better. I think i could solve the insulation in the floor issue. I have a few ideas in my head but in a van this is all still an experiment. I read somewhere else that someone had a similar setup and used a liquid to liquid heat exchanger to then hAve on demand potable hot water from either the engine heat or water heater heat. Im familiar with those as i already have one to preheat my fuel. I think this type of system is worth trying because i need to be back full timing and as i have a dog and a job (he stays in the van while i work) and often spend time in the cold id like to have a safe way for us both to stay warm

 

[Optimistic Paranoid]

To some extent, you are trying to reinvent the wheel here. There are already diesel fired furnaces, and some models of them can be plumbed into the engine's cooling system to keep the engine warm overnight in sub-zero temperatures.

Espar or Espach or maybe Esbach (sp?) Is one such company you could do some research on.

The big question in my mind is " How many btu's per hour can the water heater produce, and will that be enough, given your amount of insulation and what the outside temperatures are?"

There is a huge difference in output between a water heater and a furnace.

A secondary question is " How long will the water heater last if it is run on a continuous or near continuous duty cycle, which I'm sure the designers never intended?"

Regards
John

 

[LeeRevell]

I also keep thinking about Mr. Murphy showing up. All that neat plumbing hidden under the floor, all those fragile joints, all that water waiting to leak out....... could get beyond simply messy real quick.

 

[ccbreder]

I would not use to heat the engine. Too much loss. I would use the engine to heat the floor. You don't need more than 1/2 or 3/4 foam, foil backed, insulation under the tubes. The tubes used for hydrophobic heating are very robust and have been used successfully for many years in construction. But don't expect more than a warm floor in a van.

 

[sparky1]

ok, here you go---3/8" pex pipe serpentine around the Van floor above some good insulation board--" black board" insulation cut out to fit the 3/8 pex in it-maybe add 1/2" plywood Max over that.
when the engine is operating. the cooling system would have the van very warm. could add a manual valve to throttle the heat.
JUST DON"T close off water that MUST circulate to keep the engine from overheating.

as another mentioned a RV water heater into that system maintaining & a small 12 volt water pumpless than $100 cycling "that water". circuit.
I see no reason HW heating system would Not work---great in a RV ---you might LOOSE 1.5" at the most.
my 2 cents.

 

[akrvbob]

To me, a simpler solution is to use a regular heater of your choice and then devise a system to bring the heat down from the ceiling to the floor.

One I've seen used is a large piece of PVC in the corners of he van with 90 degree bends at the top and bottom. You put a computer van at either end to push or pull the heat down from the roof and shoot it out onto the floor.

It's a simple, low draw heat circulation system. I think that would be much easier than any hydronic system.
Bob

 

[grummy]

Even I often think of a hydronic system too, but not with tubes in the floor. I know how cold a truck or van interior is inside when it is 0 degrees out.... Even the best possibly insulated traditional van will require at least 6000 btu if we are talking the winter weather I am familiar with, and that's not enjoying 72+ degrees at all times like you can in your home.

The thought of just having 1/2" or 3/4" of insulation under the tubes already makes me see $$$$ and Btu wasted as heat is sapped out by the cold outside rather than heating the vehicle. Will it heat ? Sure, but not all of your fuel will be heating the inside of the truck !

My desire for hydronic falls short of using it in freezing weather, but useable for that 35-55 degree need. It just includes a properly sized automotive heater core fed by a DIY small exterior solid fuel water heater not much unlike having an outdoor wood burner.... OR better yet, a small stainless steel coil of tubing placed directly in the fire or lingering coals. I mostly want this as a cheap method to heat my sink and shower water when the engine is not running (it will be heated by the coolant via exchanger when the engine is running).

The above other than the parts and labor would come as close to free heat as I could dream up, but frankly, I dont think you can beat the espar for something forced air that uses a small amount of current, or a Dickenson which I believe can be set up to use no electricity. The espar literally sips fuel, and I am sure it sips a lot less than their hydronic units do. Power useage is very manageable if you have an extra battery system.

And as an aside, I hate practically everything about propane when it comes to anything but off the shelf 1lb tanks. I hate having to get propane, I hate having to store propane, I hate how the tanks freeze up, I hate how when they get cold you really can not get all the gas you pay for out of them. A large frame mount tank could make me feel better perhaps....... take that back.... I'd hate that too !

 

[highdesertranger]

just want to remind everyone, the laws of physics tell us every time we convert energy from one form to another there are losses, the more conversion the more losses. the most efficient system is the most direct. highdesertranger

 

[ccbreder]

Yes. But a warm floor? what luxury!

 

[Almost There]

Yes. But a warm floor? what luxury!

Is it a warm floor or warm feet that are the primary concern?

Me, I only care that my feet stay warm!

 

[highdesertranger]

yeah not saying it's bad just inefficient. my buddy lives at 7,000 feet in New Mexico, it gets quite cold in the winter. his house is heated this way, it is nice but he says it takes 10-12 hours to heat up if it's cold and the heat system hasn't been run in a few days. highdesertranger

 

[robin.bankx]

Espars and wabascos are so expensive. And i already have the parts needed for this. That was my thinking.

 

[karl]

Have some experience with Espar (D2 airtronic)- convenient, noisier than I like, a bit fussy about power, damned expensive to fix.

Hydronic radiant works best with steady, moderate heat input and mass. It can be done in a van, but for the way I travel, and wanting heat long after parking, I'm going a different route.

Have used engine coolant through an exchanger to heat a tank (40 gal in a stepvan) - the tank radiates heat long after the vehicle stops, sometimes too much heat. In the interest of reducing weight and more control of temps I have reduced the tank size to 10 gal. and am installing a tiny wood stove(my design, shielded, power vented, safe).

Everyone's needs are unique, I encourage you to try it since you have the materials, and keep in mind that time may find you making adjustments.

 

[GrantRobertson]

...am installing a tiny wood stove(my design, shielded, power vented, safe).

I would very much like to discuss your wood stove design ... in a separate thread, of course.

 

[highdesertranger]

x2 on your wood stove karl. highdesertranger