Alde hydronic furnace/heater-------- Has the future arrived?

I came up with the same Idea, but some folks say that the BTU's of the atwood may not be enough, then found the Alde system. They cost $3K but I found a dented one on ebay for less than $200. Just got it. I'm gonna play with it a bit before I install it. I may keep the stock water heater since it is (now) in the bathroom and this one will go under the stove where the current blast furnace lives. It will feed the kitchen sink.

RoyB wrote:
I tolled with this concept alittle bit. I know of a couple that has done this with there smaller trailers and was amazed how well it worked.

Several on here have some things already working along this line...


My IDEA here...


Here is one install that worked great...


I know of a couple of designs using wall mounted heat registers in a couple of zones around the trailer - bath room being one...


I know of another HYDRONIC Install using tubing coils around the underbelly tanks to keep from freezing that works fine with circulating hot water.

Many of the big Diesel MOTORHOMES already use this concept with multi-heat zones...

I could setup my HOT WATER heater to do this for my OFF-ROAD POPUP for around $300 and completely do away with the propane fired furnace and very loud furnace 12VDC blower

Roy Ken

opnspaces wrote:
I've always found this intriguing and want to build one some day. I'm curious though if it could be made without the water pump. I seem to remember that back in the late 70's or early 80's when the water cooled motocross bikes came out that the Kawasaki KX bikes did not use a pump. I don't know what it's called, convection, thermal dynamics, whatever, but the concept was that hot water would rise to the radiator and the cold water would sink back to the motor.

I don't know how well this system worked for a high revving motocross bike, but for what we're talking it might be perfect.

I believe a pump is necessary for this application. Of course, it all depends on room size, ambient temp, and insulation values. Using a smallish exchanger and assuming typical RV construction, one would like the hottest temperature possible at the exchanger. That would mean a pump is necessary.

IIRC, Forum member smkettner uses an non-impeller pump (magnetic drive) for recirculating water through his system to abate plumbing freeze-up. Maybe he'll chime in with the name of the pump.

Besides the lack of noise while using hot water heat, it's also very efficient because you have the mass of the water working for you.

FWIW, I have a fanless furnace in my rig, an older Sportsman propane fired heater. The 20K BTU Sportsman will cook me out of the rig if left on High for any extended time. Even at Winter deer hunting camp, we turn it down to just idle through the night. It isn't as efficient as a hydronic system but probably burns less propane than a forced air unit.

For those wishing to use hydronic as an adjunct to a forced air system (eliminate some of the run time), I would bet recirculating water from the water heater would be all that is needed. Unfortunately the water heater has some noise involved, also.

Open, that's called 'thermosiphon' effect... same as a chimney, except for being a closed loop.

For me, it's always been about the sudden blast of noise that wakes me up, and the rather high battery drain. I don't mind sleeping cold, but I resent the very devil out of having to crawl out of that warm bed to turn the furnace on in the AM. I finally moved the thermostat to within easy reach of the head of the overcab bunk. I think my problem's solved, but I await next winter to find out.

If that doesn't work out for some reason, I've toyed with the idea of a hydronic system based on the existing water heater in my 19' Tiger CX. Just a thought experiment for now, but you can buy individual components made for water-cooling desktop computer CPU's (used by gamers & such). Small 12V pumps and fans and heat exchangers in various sizes aren't that expensive.

I want to find out what temperature drop I can expect to see over the various sizes of exchangers before I go much further. I might build a small unit for 'background' heat, just for the heck of it.

Jim, "Some days the best thing about my job is that the chair spins."

The ironic thing is that Truma has been selling these these for years in Europe and elsewhere, but refuses to sell them (well refuses to sell -anything- except their propane level meter) in the US. They have a model (Combi 6E) that is both propane and electric powered (can use either/or), and is a furnace/water heater. If the temperature gets below 35, it will turn on just enough to keep from freezing, and if that doesn't work, will passively dump the tank outside so it won't rupture.

I've always found this intriguing and want to build one some day. I'm curious though if it could be made without the water pump. I seem to remember that back in the late 70's or early 80's when the water cooled motocross bikes came out that the Kawasaki KX bikes did not use a pump. I don't know what it's called, convection, thermal dynamics, whatever, but the concept was that hot water would rise to the radiator and the cold water would sink back to the motor.

I don't know how well this system worked for a high revving motocross bike, but for what we're talking it might be perfect.

duplicate post

beemerphile1 wrote:
This thing looks good. I think many boondockers have been waiting for this.

Very interesting indeed! Thanks for sharing.
For those of you in the market for an alternative air/water heating source Truma was showing their new hydronic heaters at Overland Expo this year which can operate on propane or diesel (not both).
Cheers
-Mark
PS. I picked up one of Truma's LevelCheck ultrasonic LPG measurement doohicky's… also very cool.

beemerphile1 - you are probably correct there as well... Another good point to consider...

Precision Temp has had one for a bit now- not cheap, but 55k btu/hr LP input, plus dual 1500 watt elements. A bit expensive though.