DIY; On-Board unlimited hot-water shower for the trail!

[BURNINGAIR]

Ok, over the next week or so I'll be adding to this post. This is a hot shower set-up than can be installed on any rig. I just got the most critical two peices; The heat exchanger and the pump, all the hoses and fittings will be installed and noted as I go.
The basic idea is to use the trucks cooling system run into a heat exchanger to heat water from a lake, stream, river, container etc. any water supply available.
The heat exchanger. This is the heart of the system. I'm using a "Flat plate heat exchanger" from Dudadiesel. its a 10 plate 7.5"x2.9" unit with chevron rifted plates in the middle (because I think it will disrupt the flow a little and cause better heat transfer then a non-chevron exchanger). There are several diff. kinds of heat exchangers available but for price and effective heat transfer this is what I settled on. I got it on ebay for $40 after shipping.
Flat plate heat exchangers are offered in many diff. configs.. I saw 8 plate to 30 plate (the plates work like a waffle cookie, it gives you a layer of hot to layer of cold. hence the transfer of heat as it flows through the unit and both coolant and water never come in contact with eachother) the 10 plate is cheaper and from what companies say, the surface area is MUCH more important than how many plates they have. so longer/wider is better. this one seems more than capable for the temps one would want to shower in.

 

[BURNINGAIR]

The next part is the pump. I also got this on e-bay and for just over $50 after shipping. I'm using a Flowjet 2.9 gpm RV pump.
What you want is any pump the is "self priming" and is "auto pressure regulating" self priming meansyou can stick your cold water intake into any water source and it will pull the water without you doing anything, like sucking on a straw. auto pressure regulating means if you turn the shower head off, it will stop pumping. AND you want it with the "run dry" ability, meaning it can run dry without destroying itself.. but thats normal with any pupmp thats self priming. This unit covered all those points and is at a price that kept me happy!.. (it also got good reviews) As well it's said to be able to draw water from 9' below the pump.. this is important because you want to be able to toss your intake tube in below where you are. I'm betting its a good bit more than that depending on how flexible you intake tube is.. (you don't want it to be like a cheap straw that collapses while its sucking the water up)
This pump isn't filtered but dose need one.. I plan on using a intake filter thats on the end of the intake line I toss into the stream/lake, and maybe another inline before the pump. I'm not sure yet.. but I'll certainly let you guys know all the details as I go.. and all the "damn! don't do that! and this is why!"... but we'll see where this goes..
So far I think I'm on the right path to make my wife SOOO much happier while on extended middle of nowhere trips! I hope to keep the whole thing under $250 while keeping all the parts high quality. And temp controll is a big issue as well.. we'll see, and I'll let you know!

 

[BURNINGAIR]

Heres a pic that should give a idea of the side of the parts

 

[BURNINGAIR]

And this.

 

[jdkilroy]

Great project !

This could be handy to have after a day on the ocean (kayaking).

 

[BURNINGAIR]

Salt water isnt something I have taken in consideration... But I'm sure with a few added filters, and sone consideration to how saltwater would be corrosive.. Hmm.. I'm sure it can be done! I'm always on fresh water as a norm. If people are interested to have the same system with saltwater I'll be happy to give that a try too.. But fresh water is the current build.

 

[hrt4me]

nice!

 

[SigSense]

Very interesting, keep us updated.

 

[KidVermicious]

Did you consider pump efficiency? How much will that be drawing your battery down?

 

[BURNINGAIR]

I'm going to run a 10amp inline fuse. At just under 1k rpm it should actually draw near 1amp per cycle... Depending on the how many ft I'm running to, and up from the water source.. Thats just a educated guess at best tho.. But any way you look at it the only draw needed will be the pump(aside from any normal draw) I'm planning on regulating the idle if need be. But after seeing allot of real world results, it seems to be allot less of a burden than the numbers would suggest! Yet to be seen! Lol.. Keeping this mod open as there are so many variables its stupid!.. But thats part of the fun! This is actually the first mod I've seen fit to do a write up on! Probably because its just a "neat" one.. And it actually wont surprise me at all if I FAIL on all the "shoulda known better" spots! Lol! Gonna wing it!

 

[fish0281]

HA! I like your thinking! I have been pondering this exact same idea, but for a different end-use. I was looking into a propane shower heater, but then use the hot water as a means to keep warm during winter truck-camping. Think heated flooring meets sleeping platform... great minds think alike!

Salt water will destroy that HEX as will mineral deposits (but at a slower rate). I'd keep it to fresh water and run some sort of cleaner through it after every use or so. I have a decent amount of experience with those things and they can be finicky. Also, keep in mind that your rate of heat transfer is dependent on your flow rates and incoming water temp - if it's too slow, there's a chance you'll have scalding hot water (pretty much anything over 110F will scald, coolant is at 180F). I don't know the specs of that particular HEX, but I'm sure there's a spec sheet for it that outlines some basic parameters. Source: I've developed a few HEX's in my time.

Let me know if you have any questions on that side of things.

 

[phillyd2]

Nice. But I would find a better place to mount the Flowjet than the tire :bounce:

 

[Tresvn]

you might want to consider a cold water supply too, then either use a mixing valve set to a certain temp or even a small shower valve. If the temp of the water is dependant on flow through the HEX, a little debris on the filter and your liable to end your shower a lttle faster than you had expected.
Cool Idea by the way. I cant wait to see the outcome.

 

[Kurtis]

Subscribed... I've been wanting to do this for a long time now. I just haven't had the time. I'm glad someone else can show me the "don't do that's" first.

 

[BlackWorksInc]

HA! I like your thinking! I have been pondering this exact same idea, but for a different end-use. I was looking into a propane shower heater, but then use the hot water as a means to keep warm during winter truck-camping. Think heated flooring meets sleeping platform... great minds think alike!

Salt water will destroy that HEX as will mineral deposits (but at a slower rate). I'd keep it to fresh water and run some sort of cleaner through it after every use or so. I have a decent amount of experience with those things and they can be finicky. Also, keep in mind that your rate of heat transfer is dependent on your flow rates and incoming water temp - if it's too slow, there's a chance you'll have scalding hot water (pretty much anything over 110F will scald, coolant is at 180F). I don't know the specs of that particular HEX, but I'm sure there's a spec sheet for it that outlines some basic parameters. Source: I've developed a few HEX's in my time.

Let me know if you have any questions on that side of things.

Would CLR be a good idea? I was thinking the same thing about the salt water... Also, what kind of filter would you be running? I wonder if you could use a very fine filter to use say distilled water to make Ramen!

I am digging the idea and its such a small compact unit that it makes sense. The person who mentioned hooking up a cold water source for the shower had a good point.

 

[Kurtis]

Would CLR be a good idea? I was thinking the same thing about the salt water... Also, what kind of filter would you be running? I wonder if you could use a very fine filter to use say distilled water to make Ramen!

I am digging the idea and its such a small compact unit that it makes sense. The person who mentioned hooking up a cold water source for the shower had a good point.

Just make a Y-gate after the pump. One side is the hot side and goes thru the heat exchanger while the other is the cold side and goes directly to the vold side of the faucet. Temperature is control by the knobs just like your kitchen or bathroom.

 

[BURNINGAIR]

Ok, the shower is finished! With a water source at 35 deg I'm getting to about 120 deg at its hottest! I can set the temp by just turning my heater setting to hot or cold.. I set the flow rate at 2gpm which I can change on the nossel.. It is working AMAZINGLY well.. And soooo simple! The total cost came in at $230.
All I have to do is attach the 2 hoses to my cold in and hot out lines that I put in the wheel well, flip a switch on the dash and set the temp!
I'll do the complete write up this weekend, as its late and dark here so its pointless to get any pics of it in action.. But here are a few of the completed unit with as much as you can see under the hood!

 

[BURNINGAIR]

Heatexchanger

 

[BURNINGAIR]

Whole thing minus the inlet and outlet ofcourse

 

[BURNINGAIR]

.and this one