Well this is very nice, and has inspired me to look into this type of a project.
But I have a couple questions:
1. Are you concerned about the engine compartment being too hot for the water hoses you use (clear PVC with nylon braid reinforcement)?
2. You mention your engine runs at 210 degrees; what is the best way to find this out? Is it related to thermostat opening temperature? For my rig (2000 nissan xterra), the thermostat opens at 180*; does that correlate with the operating temperature somehow, to you knowledge?
3. I've found 16 plate heat exchanger, which seems a good compromise between 10 and 20 plate; what do you think?
4. How cold of a temperature does your thermostatic mixing valve permit? Assuming it's cold enough, can't you just forgo the cold water outlet and turn the mixing valve to it's coldest setting for those extra hot days?
Please, anyone else with knowledge, do chime in. And once again, theksmith, thanks for the awesome project and writeup!
1 - yes, but i didn't bother to look it up till just now - i am in fact exceeding the service rating of clear PVC which appears to be 120-140* depending on where you look! however the melting point is extremely high, so i don't think it'll burst, maybe just not be drinkable-safe. PEX was recommended to me by the hardware store, but it would be impossible to route in the engine bay. perhaps i should have just used car heater hose. time will tell, obviously i'm no plumber!
2 - my temp gauge reads 210 once the jeep is warmed up, if you don't have an actual gauge, harbor freight sells those no-contact laser thermometers for cheap
3 - on my rig, the 10 plate turned out to be plenty hot, hotter than you could put your hand under. if your rig runs considerably cooler than mine, then maybe you do need a 15/16 plate, but i bet a 10 plate would be ok (though some people want boiling hot water as an option for cooking/cleaning)
4 - if i remember correctly, my mix valve would do a min output of 80*, depending on the difference between the inputs (if the "cold" water is actually pretty warm from sitting on the roof all day, then the min would actually not be that low). 80* is obviously cool to the touch, but because i'm crazy, i wanted the option of having a really cold shower on a hot day (like ice-chest water cold!). that, and the mixing valve is ussually set and left alone in it's native use, so i didn't know if constant adjustment would wear it prematurely in any way... again, i'm no plumber! my plan is it will get adjusted some as the seasons change, but overall not be moved alot.
and as Xterabl said, anyone with knowledge please chime in!
