Flat plate heat exchanger for shower?

[glenn bell]

I searched but didn't come up with anyone who has tried this.

A flat plate heat exchanger like this

FG3X8-14 - FlatPlate FG3X8-14 - 14 plate, 3/4" Thread, 8 GPM Heat Exchanger (3" x 8")

Was thinking of removing rear underseat heater and pluming this in and then running domestic water into it for showers. Has anyone done this with good results.

[joeblack5]

I think that would work well. A similar size is used as domestic water heater that are combined in natural gas hydronic boilers.
The catch is that your engine coolant is pretty hot. You need at least an ant scalding device and a thermostatic mixing valve on the shower side.
Later j

[jazty]

You also want to be absolutely sure that the engine antifreeze will not make it's way into any drinking water.

I've heard of systems that use glycol to heat water that will utilize two flat plate heat exchanges to provide lots of distance between the two. One heat exchange takes hot antifreeze and heats water. The next heat exchange takes that hot water and heats the house water. A bit of worthwhile redundancy to make sure nobody gets poisoned in the case of a heat exchange leak due to corrosion, impact or whatever.

With scheduled inspection any problem should be identified before both heat exchanges are leaking.

[somewhereinusa]

I have one a bit bigger between my engine and heating system. There is also one in my marine hot water heater that picks up heat from heating system. Heating water uses non poisonous antifreeze. If you do it you need a pressure relief valve in the domestic water since it's a closed system.

[glenn bell]

Thank you for the replys....gives me a little extra to think about.

[Jolly Roger]

For that system a relief valve is a must. You can pipe it back into the radiator overflow reservoir that way when not if it does pop off then the glycol/antifreeze is not wasted.
The glycol to water exchanger piped to the water to water exchanger is the safest route but on the water to water side I would reccomend a storage tank and pump for the water to water exchanger to maintain and with a few check valve and/or dedicated shutoff valves a solar system,propane system or any other heat source could be added easily for when the bus is sitting idle.
I would add a pump to the bus radiator system because your engines pump was only designed to move so much water? If you are changing a 1-row coil to a 4- row coil that could me you are starving your engine of 3-gal. A minute of cooling .
Just more food for thought?