On Board Hot Water Shower System

[cruiseroutfit]

I am not sure who is using the 10 plates...

Many, including some in this thread, which you participated and shared on TW fwiw

10, 20, 30... it's not a linear relationship. You're not going to see twice the fresh water Δ despite having twice the surface area going from a 10 to a 20, there is a point of diminishing returns particularly when dealing with limited space under the hood. Helton and other shower manufactures have tested many options over the years and all have seemed to settle on approx .075 - .15m², and they work for the needs of many.

 

[damienperu]

Go and tell any "normal" person that you're going to run to your car real quick and take a hot shower and they're going to look at you like you have 5 heads.

well i don't care how many heads people think i have , but in an attempt to not have to fire up the motor at camp for many other reasons, I'm about to set up my helton to be fed directly by a Hydronic 5... its not at all the reason i got the hydronic in the first place, but i figure it will be an extra bonus to run that for the shower early in the morning instead of disturbing the wildlife.

 

[PlethoraOfGuns]

Children, calm down. There are many ways to get hot water for a shower. Different systems work for different people who do different things in different scenarios. What matters most is that you have that hot water coming out of the shower head. The OP has a great setup! Have you figured out a way? Post some pics, let's see how everyone gets hot water to their shower heads!

 

[kalieaire]

Dang guys, I was not expecting my observations and theories to elicit such a reaction. But it's nice to see the discussion is still lively.

My needs are absolutely different from everybody's it seems. I do care about being able to pull water from a nearly frozen lake to have a piping hot shower. It seems only natural after a day of fishing in the cold. 2GPM is roughly the minimum amount I would need to cover my entire body with enough hot water to not have to worry about the outside temperature.

Something around the level of a Commando 450 sounds good.

As far as hydronics go, I'd need something in the 24kw realm, if my previous calculations were right, to heat 2gpm with a 80F Δ.

I've also considered wrapping a band of copper tubing around the exhaust section post cat to recover some heat, kinda like the concept of a muffpot but to bring the water up that last 30F.

I figure with a Helton at +50 then to the exhaust, I might be able to get the results I want assuming that the cat is running hot enough at idle.

 

[Chris Boyd]

Commando 450 ******!

 

[rayra]

And your numbers are where? ...etc

As long as you are going to play scientist on the internet, you better quantify the heat exchange effects of the velocity / flow. Too fast a flow hinders heat exchange as much as a limited flow. We already have 'empirical evidence' that plate exchangers work well and in a more compact and sturdy manner.

 

[cruiseroutfit]

As long as you are going to play scientist on the internet, you better quantify the heat exchange effects of the velocity / flow. Too fast a flow hinders heat exchange as much as a limited flow...

Which is exactly what I covered here

Helton's will not be very efficient with 2+ gpm flows, absolutely true. A 20-30 plate exchanger is going to fit the bill there. Helton's are designed with a 1 gpm flow rate (similar to that of a camper/rv shower), any more than that and your &#916; drops significantly (not linear). For the needs of many (such as me), the low volume flow is preferred. When showering out of water cans in arid places, a <1 gpm shower isn't going to eat up your water supply in minutes. Helton designed these for use in the deserts of Australia.

Oh, and I'm not a scientist so much as a Mechanical Engineer.

We already have 'empirical evidence' that plate exchangers work well and in a more compact and sturdy manner...

More compact and sturdier than a tube in shell? Sorry, that isn't empirical but rather opinion evidence. Let's go back to the 10-plate brand commonly used in home-brew shower systems as discussed earlier. Choosing a unit with a similar exchange surface area (.136 vs. .140), the volume of the two is near identical, 8.5" (with fittings) x 3" diameter for the Helton and 7.8" x 3.5" x 1.25 (+ the fittings themselves which are 1.5" min). And, I'll counter it's far easier imo (again let's be clear on opinion here) that having all the fittings on one 3" diameter surface makes plumbing extremely easy and clean.

And again I'll state my opinion evidence, Plate style exchangers work great for some, tube work great for others, there isn't a singe one-size fits all answer to every install. There are far more tube-in-shell auto showers in the field (remember Helton, Twine, R&M, Glind, Piranha, etc have all been selling these in Aus, Africa and the US for 20+ years now), than there are plate exchangers. To make any "sturdiness" claims with non-existent failure rate on behalf of the tube-in-shell is just posturing at best. With time we may find that plate style exchangers hold up to the vibrations, heat cycles, freezing water, etc... and for the price perhaps they'll make more sense than some of the overseas production units. I've got a couple different plate exchangers here that we intend to tinker and test with, I've made no claims that the tube-in-shell is the only viable option.

 

[PlethoraOfGuns]

So what you guys are saying is that if we go for the Commando 450, we're going to be better off with a plate exchanger? Say, 180 plate? And a low flow head would work good with a Helton type?

 

[toyotech]

My buddy has been running this set up for some time now. I got to test it out in moab and that sucker was nice! Perfect temp shower.
The picture shows the stuff I got recently and plan to do the same but with a tank. Goal is to Cycle the water and have hot/warm water when I'm at camp so I don't have to run the engine to shower.


Sent from my iPhone using Tapatalk

 

[cruiseroutfit]

So what you guys are saying is that if we go for the Commando 450, we're going to be better off with a plate exchanger? Say, 180 plate? And a low flow head would work good with a Helton type?

Sounds about right


But I think there is already a mobile solution

 

[fiddypal]

How much propane does the Eccotemp unit burn up during a typical shower? Can i get away with using the smaller green tanks or do i pretty much need a big grill size one?

 

[VanIsle_Greg]

How much propane does the Eccotemp unit burn up during a typical shower? Can i get away with using the smaller green tanks or do i pretty much need a big grill size one?

It doesn't use much, but a small tank likely doesn't have enough pressure (though I have not tried one yet)? I have smallish 10# LPG tanks, and they work awesome, a 5# would also work. I can get many days use out of one while doing dishes, having a quick rinse shower and or cooking. Camping showers are fast, enough to wash my hair and face and have a rinse. So you don't burn much doing that, and being on demand they only burn while water is flowing.

 

[dbreid]

I love this thread. Josh, your build was excellent!

 

[fiddypal]

Yeah i will be copying this for my build, this is how it should be done! Looks like it was part of the truck, which is the best part. I need to drop my spare and see how much room (if any) i have to work with to place a water tank. Otherwise i have to eat up precious storage room in the truck bed.

 

[macjack]

eccotemp and propane

The Eccotemp L5 does in fact work with a small 1 lb propane bottle. It needs a small adapter ~$10 but everything hooks up nicely. We have had many showers on it so far, and it is really nice. Not sure how many showers per 1lb bottle, but I heard about 2 hrs of water flow. (I have a larger stock propane tank that will go under the van and hook to the system at some point, but until then, the little 1lb bottle is still going strong, and we keep a spare in the van for when it runs out. I do look forward to not having to recycle/throw out those little bottles, eventually.
The whole thing is quite compact, so long as you can deal with the ventilation of the eccotemp unit, it will fit in a small cabinet, including the propane bottle, pump, hoses, etc. (in the second pic, looking in the cabinet door, the eccotemp on the right and small propane bottle in the back just to the left of the eccotemp). We have ours in the back cabinet of our Vanagon Westfalia, and there is room for several other things in there, and it is not a large cabinet.
Because I have a tire swing away in the back that holds two 5 gallon jerry cans of water, we just pull out the supply line (on the left in first picture), which has about 4 feet of hose (most of the braided hose in the third and last pics is the supply hose, pushed back through the cabinet hole when not using it), and put it in the jerry can. Then pull the marine knob and it turns on two AV fans (in the black housing in the pics)- one fan in one fan out- and powers the pump to pressurize the system to 35psi. The showerhead (tucked above the cabinet for storage in the first picture) has an on/off switch built into it and the pump has a built in power switch based on pressure, so once pressurized, the pump only runs when you have the showerhead switch on, and water flows. The pump has a (very) small pressure tank built in, so there is no pulsing. When water flows, the propane unit turns on and heats it, like immediately. The two knobs on the eccotemp control flow rate and temp. we got it set how we like it and just leave it there, that way, we don't have to open the cabinet. Just pull the knob, the fans turn on, the system pressurizes itself, and you are ready to turn on the showerhead.

I actually like leaving the showerhead unattached to the vehicle, so one handed showering makes you more likely to shut off the water for full lathering, etc. The showerhead will hook onto the tire swing away while lathering. Can get two showers from one 5gallon jerry can easily that way. Pulled very cold water from a high altitude mountain river outside Telluride, into the jerry can, and still the heater got it up to temp no problem. Of course, a particle filter on the end of the supply line helps, plus an inline filter before the pump keeps everything running smoothly.
Power draw is minimal, and no starting the van. A different option from the heat exchanger approach.
-macjack