On Board Hot Water Shower System

[Wainiha]

My friend just bought the same heater for a home outside shower. He paid $200

I thought the pressure a the shower head was quite low. Maybe because it was hooked up to the garden house for temporary test setup.

What is the pressure like on your setup compared to your home shower, TheJosh?

 

[Dazed]

Bit of an old thread revival. Did you ever get around to a parts list? thanks Dazed

 

[TheJosh]

Sorry I never did get around to it, got distracted building a tiny house

 

[mp_tx]

Very cool systems. Thanks for the ideas.

 

[PlethoraOfGuns]

What a great thread. Got lots of ideas and came out my own system.


Started with the core of the system, a 30 plate heat exchanger. Mounted it inline before coolant goes into heater core. Could have gotten a 20 plate as the 30 plate makes more than enough heat. We're talking 165+ degrees in the winter with a single pass.



Also used a 18 gallon Valterra tank. These things are so simple and a great bargain. I had to weld up an aluminum cradle to hold it up under the truck bed.


Few options with this pump setup. I can pump water into and out of the onboard storage tank or 5 gallon water cans, run the 25' hose with coarse filter out to a lake or river and pump it right from there, or hook up a water hose from someone's house or something and not even use the pump. Before any water goes through pump, it runs through small particle screen filter.


And on the business end I had to incorporate a mixing valve to get the temperature down to showering temperature. Also have a valve before shower head to conserve water. If needed, a hose can attach after mixing valve to was the dogs or someones car or whatever.


Of course, had to make the ladies happy with a shower curtain. Just bent some 1/2" EMT and got a 9" curtain.


Curtain rod gets stored up on roof around spare tire.


Ahhh, perfect shower temperature everytime!


Here is a recent setup taking water out of water cans. Full bore flow, 5 gallons last about 4 minutes.


Nothing beats a nice warm shower after a few days out and about...

 

[damienperu]

View attachment 276841
Nothing beats a nice warm shower after a few days out and about...

interesting light setup, do you offer free showers to fellow female campers? :drool:

 

[PlethoraOfGuns]

interesting light setup, do you offer free showers to fellow female campers? :drool:

Free showers to female campers? I'm the only one in camp with a shower, they come running up in a line to use it. How do you think the female in the photo got to use it?

 

[PlethoraOfGuns]

Hey now, watch that hidden cam in there!

Shhhh, don't go public with the location of the hidden camera, that will ruin our "star gazing"... :Astrologist:

 

[kalieaire]

I've been looking at this system and similar systems but it looks like nobody is able to bring 32F water to 115F for a hot water shower in one pass. I'm assuming that for a standard 4L engine at idle, the coolant heats to ~170f depending on the thermostat inside the engine. At one pass, you're peeling off no better than a 50F Δ with a single HW1 Helton.

Assumptions from what I've read, if it takes multiple passes to bring it up water temp to 165 then I can assume one of two things:

A) The helton heat exchanger isn't very efficient since the flow rate for most of these shower systems are <2g/m.
B) There's not that much latent heat within the radiator coolant and that a single pass depletes the stored energy inside the coolant thus causing a max temp increase of 50F.

B concerns me since it makes me think that it wouldn't be feasible to simply run two helton heat exchangers.

Has anyone done any testing of ECT after it passes through the Helton or similar heat exchangers? I'm really curious what the &#916; is between in/out.



** I just ran some calculations

the specific gravity of water is .977 at 160f
the specific gravity of egwm (ethlyene gylcol mix) is .85 at 160f

Calculating the heat capacity of a Tacoma and 9.6 gallons of fluid, there's about 110,000 joules vs 148,000 joules. roughly 25.6 % less heat capacity in coolant than the water we're transferring heat to. I'm starting to think it's a heat capacity issue of the coolant and output of the engine.

Considering the inefficiency of the setup, I think I'm just going to look at a hydronic heater setup or just go with a eccotemp propane setup.

 

[PlethoraOfGuns]

I've been looking at this system and similar systems but it looks like nobody is able to bring 32F water to 115F for a hot water shower in one pass. I'm assuming that for a standard 4L engine at idle, the coolant heats to ~170f depending on the thermostat inside the engine. At one pass, you're peeling off no better than a 50F &#916; with a single HW1 Helton.

Assumptions from what I've read, if it takes multiple passes to bring it up water temp to 165 then I can assume one of two things:

A) The helton heat exchanger isn't very efficient since the flow rate for most of these shower systems are <2g/m.
B) There's not that much latent heat within the radiator coolant and that a single pass depletes the stored energy inside the coolant thus causing a max temp increase of 50F.

B concerns me since it makes me think that it wouldn't be feasible to simply run two helton heat exchangers.

Has anyone done any testing of ECT after it passes through the Helton or similar heat exchangers? I'm really curious what the &#916; is between in/out.



** I just ran some calculations

the specific gravity of water is .977 at 160f
the specific gravity of egwm (ethlyene gylcol mix) is .85 at 160f

Calculating the heat capacity of a Tacoma and 9.6 gallons of fluid, there's about 110,000 joules vs 148,000 joules. roughly 25.6 % less heat capacity in coolant than the water we're transferring heat to. I'm starting to think it's a heat capacity issue of the coolant and output of the engine.

Considering the inefficiency of the setup, I think I'm just going to look at a hydronic heater setup or just go with a eccotemp propane setup.

Too much math for me, haha. I took to some guesstimations and trial/error. I can't have an opinion on the Helton exchangers, except that they may not be as efficient as plate exchangers, as the plate units most likely have more surface area than tube units. My system runs less than 1gpm and increases the temperature around 100 degrees fahrenheit in one pass with a 30 plate exchanger when vehicle is at idling temperature. Personally, that's way overkill. I enjoy using an engine coolant heat exchanger setup because it doesn't steal any storage space.

 

[cruiseroutfit]

There is WAY more surface area in a Plate heat exchanger then any Helton.

And your numbers are where? A Helton HW1 has just under 15' of tube within the tube. Plate exchangers come in a variety of sizes, many of which have less surface area. You're absolutely right they can come with much more surface area, but they also have increased head pressure at similar surface area specs and ths you reduce coolant flow through the exchanger and therefor reduce heat exchange. This is where tube-in shells are favored, less resistance at similar surface area numbers. Less talk, lets get quantitative.

Take the commonly used 10-plate exchanger

Advertised as a 0.120 m² surface area.

Helton HW1, 0.136 m² surface area (4.5m x (2*π*(0.0048m)))

Numbers

Simplistic and less that could go wrong with it.

Tube-in-shell exchangers are extremely simple & very stalwart. We've had a single internal failure out of the thousands sold and we are pretty sure fresh water froze within, which will kill any style exchanger. Under what experience are you saying the "Helton style" has more that could go wrong? All the user experiences around the globe show quite the opposite, keep in mind every major vehicle shower system manufacture (Helton, Twine, R&M, Glind, Piranha, etc) use a tube in shell, robust, simple and clean mounting. Look, I don't care if you want a Helton, but you can't use completely qualitative comments to compare. Plate style exchangers work great for some, tube work great for others, both can be plenty "simplistic" for users

 

[cruiseroutfit]

I've been looking at this system and similar systems but it looks like nobody is able to bring 32F water to 115F for a hot water shower in one pass. I'm assuming that for a standard 4L engine at idle, the coolant heats to ~170f depending on the thermostat inside the engine. At one pass, you're peeling off no better than a 50F &#916; with a single HW1 Helton.

Assumptions from what I've read, if it takes multiple passes to bring it up water temp to 165 then I can assume one of two things:

A) The helton heat exchanger isn't very efficient since the flow rate for most of these shower systems are <2g/m.
B) There's not that much latent heat within the radiator coolant and that a single pass depletes the stored energy inside the coolant thus causing a max temp increase of 50F.

B concerns me since it makes me think that it wouldn't be feasible to simply run two helton heat exchangers.

Has anyone done any testing of ECT after it passes through the Helton or similar heat exchangers? I'm really curious what the &#916; is between in/out.



** I just ran some calculations

the specific gravity of water is .977 at 160f
the specific gravity of egwm (ethlyene gylcol mix) is .85 at 160f

Calculating the heat capacity of a Tacoma and 9.6 gallons of fluid, there's about 110,000 joules vs 148,000 joules. roughly 25.6 % less heat capacity in coolant than the water we're transferring heat to. I'm starting to think it's a heat capacity issue of the coolant and output of the engine.

Considering the inefficiency of the setup, I think I'm just going to look at a hydronic heater setup or just go with a eccotemp propane setup.

Great questions and comments. I feel like I'm back thermodynamics class, it's been 10 years

I'll answer where I can.

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.

I've not done any ECT measurements before/after a Helton or any other heat exchanger (we've installed plate style systems too) but it would be interested to know. Your also going to have to dig into the coolant flow rate through the heat exchanger. Helton's are designed to have very low head loss. Automobile cooling systems have multiple paths and they will choose the path of least resistance. The tighter the passages in the heat exchanger, the less amount of coolant you'll get. Ever seen a heater core so clogged up that coolant doesn't make the loop and the cooling system is otherwise functioning just perfectly, no overheat, etc. You see where I'm going.

I absolutely think the fresh water &#916; is a heat capacity issue of the engine coolant and more specifically a flow issue, too much coolant flow. If there were a way to slow down the coolant without allowing it to bypass the heater/exchanger circuit all together, we would be able to capture far more of the heat exchange but without some complex plumbing... not happening. Hope that helps!

Next time we do an install here in the shop I'll see if we can't do some measurements before/after the heat exchanger at the same.

 

[damienperu]

My helton works for me, my first criteria was for durability due to lack of joints, I can only imagine the plate exchangers have many more (than 6) soldered joints, and thinner more fragile one's at that. but the temperature it generates works perfect with my low volume pump. You'd have to have an endless water supply or just be doing overnighters to use a high volume shower pump in an expedition vehicle, unless you master the 30 second shower!

 

[WMDunkin]

A little off topic has anyone tried this?

http://www.mrheater.com/sporting/aquacube-companion-instant-hot-water-portable-shower.html

 

[PlethoraOfGuns]

Yes, at overland east last year. Not bad. Still lots of components involved. Power, propane, water.

I think any shower system is going to have lots of componants. Let's face it, you have a vehicle, and want to take a shower with it. The logistics of that is a little more complicated than putting ice in a cooler to keep your food/drinks cold. 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.