Converting rear heat to hot water heat exchanger

[Tripsouth]

Has anyone converted their rear heat to be used to heat water for a shower/cooking/cleaning? I have no use for it as a heater and it seems like it'd be easier to tap off than under the hood.

[Astrofarian]

Not sure what you want to "tap into" ? Are you into showering with DexCool?

The heat source is the engine coolant. Eliminate the coolant and all that's left is a fan.
-M!ke-

[gavio]

I get the impression that what you're thinking is to use the coolant line as a source for a heat exchange coil in a hot water tank? If so, then yes, I've seen it (and similar) done before.... I think best would be to replace the heater core with a copper coil, then enclose that in a dedicated hot water tank, add a thermostat and solenoid to control the heating to it doesn't become overly hot (or at least add a temperature gauge so you can turn it off in time and there ya go.... SImple, yes?

You could try using the heater core as it exists, just dropping that into a tank, but that design, while very good as a water-to-air heat exchanger is sub-optimal as a water-to-water exchanger...

As with most things, the devil's i the details so a good investment of time would be to google up the ways other folks have done it...

[Leeann_93]

I get the impression that what you're thinking is to use the coolant line as a source for a heat exchange coil in a hot water tank? If so, then yes, I've seen it (and similar) done before.... I think best would be to replace the heater core with a copper coil, then enclose that in a dedicated hot water tank, add a thermostat and solenoid to control the heating to it doesn't become overly hot (or at least add a temperature gauge so you can turn it off in time and there ya go.... Simple, yes?

You could try using the heater core as it exists, just dropping that into a tank, but that design, while very good as a water-to-air heat exchanger is sub-optimal as a water-to-water exchanger...

As with most things, the devil's in the details so a good investment of time would be to google up the ways other folks have done it...

^ that. There are RV systems you can buy that do this, but why not build your own?

[Tripsouth]

Thanks for the replies. Yes, I've found a few examples of these using the coolant lines directly under the hood. I just wanted to see if anyone had any Astro specific examples using the rear heat.

[Tripsouth]

I've disassembled the rear heat and removed the blower. Now I'm left with the heater core attached to the coolant lines. If I remove the heater core is it going to leak coolant everywhere? Do I need to drain the system or can I quickly cap it somehow?

[97cargocrawler]

Sure it's doable. I made a heat exchanger using coolant. It's not a very good use of the gasoline if you're just heating water, but if you plan it right (morning warmup to recharge battery...etc.) then sure go for it. It took me 10-15 minutes of the engine running to get 18 gallons of water up to 105 degrees. The intended purpose was a shower.

[Tripsouth]

Quick update:
I bought a 14 plate heat exchanger: http://www.ebay.com/itm/322190015825
Cut a few holes in the bottom of the rubber heater line below the rear heat (under the van) that is attached to the metal pipes coming from the engine. Drained what I hoped was most of the coolant.
Removed the rear heater core through lots of prying and cutting and drilling.
Scrapped/cut off the rear heater hose.
Swapped in fresh hoses and connected to the heat exchanger using fittings and hose clamps from O'Reilly's.
I'm trying to work out the rest of my plumbing system but initial tests are promising. Need to get a thermocouple/RTD now...

[gavio]

I'm very interested to see how this turns out..... I hadn't thought of doing it that way.... Good luck.