Solar shower gravity hot water project

After an un start last year i am determined to get it done this year , namely an out door shower on the cheap !
I have been using the 25mm black irrigation hose during the summer and it gets real hot , but i only get about a few gallons as i have no storage tank for gravity feed or thermo syphon . I,m now set on an idea of a small frame or wooden tower or a roof for the hot storage tank with the shower underneath however i lack some basic knowledge on how  to get started.
If i use coils in a black box will it still thermo syphon ?? or should i use vertical tubes array in the black box . I,m thinking of a 100lt black plastic garbage bin for the hot water storage above the shower and feeding the cold to mix from our house cold feed pipe ?. At the moment the system albeit very crude makes steam during high summer so any improvement will be even better. I do have more questions but one step at a time . Maybe someone could give me a few pointers or diagrams / photos please.

Many thanks

Malcolm Thomas wrote:After an un start last year i am determined to get it done this year , namely an out door shower on the cheap !
I have been using the 25mm black irrigation hose during the summer and it gets real hot , but i only get about a few gallons as i have no storage tank for gravity feed or thermo syphon . I,m now set on an idea of a small frame or wooden tower or a roof for the hot storage tank with the shower underneath however i lack some basic knowledge on how  to get started.
If i use coils in a black box will it still thermo syphon ?? or should i use vertical tubes array in the black box . I,m thinking of a 100lt black plastic garbage bin for the hot water storage above the shower and feeding the cold to mix from our house cold feed pipe ?. At the moment the system albeit very crude makes steam during high summer so any improvement will be even better. I do have more questions but one step at a time . Maybe someone could give me a few pointers or diagrams / photos please.

Many thanks

If you use coils it will not thermosyphon. You can have vertical tubes (risers) or horizontal with a tilt. If your tubes are straight, there will be no traps. Manifolds should connect all risers, like a sideways ladder as an image.

A trash can will make an oil slick in your storage water. Recycled plastic trash cans are a dirty mess even brand new. A 50 gallon food drum will be thicker and better to drill plumbing entrances into. At 150 deg.f a trashcan will be like a trash bag!

A lool heating collector for 100-200$ and 20' x 4' is an awesome shower heater! Ready to go and with threead fittings on the manifold already.

I use a shurflo diaphram pump to push water up to the collector from the bottom corner and out the raised opposite corner and gravity feed back down. A snap disc adjustable worth the 25 bucks or a differential thermostat is the rest of it. 3 wraps of doibble bubble a fill valve, garden wand for shower head and a float indicator for when the tank is full os all there is.

Our float was a glass geralsteiner water bottle with a car antenna screwed to the lid. 1/8" hole in drum lid and weather box lid allowed me to see fill level while choring around the yard.

With a heater like this our temp bathroom served 5 people and was at 150 deg f by noonish most days! I might have photos.

Thanks for the reply.
So i will have to make a tube set up , copper tubes or black irrigation pipe for the collector ??. It will be drained during winter so copper should be no problem. The garbage bin was a cheap option brand new never used but i take your point about the temp as it will get very hot and fold up. Planning on putting the tubes into a vented wooden box with a glass cover. Whats the max distance between the collector and the water storage tank ?.

Plastics fine for a plastic heater..... use either real small diameter or real large depending on gallons per minute. You only need 1-2 gpm any more will just not raise temp on a pass.

Didtance only matters if it loses too much heat between the tank and roof or if circulation pumps are on the edge of capability to get it up there. Within 75 feet i wouldnt worry. 1/2"-3/4" feed and return lines will be fine. Risers could be 3/4" down to 1/4" many 1/4" risers over 20 feet of collector or possibly fewer 1/2" risers if longer.

You will be sooooo much happier with one of these. I commend the diy, but you will get reliable showers with this and it will last 20 to 30 years...... no box needed until october in the north. It straps on with basically shipping strap.

It will stay straight and can be run vertical or horizontal and it will stay straight with just a few screws........ and it will stay straight.

Did i mention, it will stay straight? That is important!


https://www.walmart.com/ip/4-x20-Above-Ground-In-Ground-Swimming-Pool-Solar-Heating-Add-On-Panels/399992768?wmlspartner=wlpa&selectedSellerId=575&adid=22222222228069214908&wmlspartner=wmtlabs&wl0=&wl1=g&wl2=m&wl3=176590210216&wl4=aud-566049426705:pla-282330622953&wl5=9058203&wl6=&wl7=&wl8=&wl9=pla&wl10=113515664&wl11=online&wl12=399992768&wl13=&veh=sem&gclid=EAIaIQobChMI2rjInaaR4QIVgYJpCh1kKg8ZEAQYAiABEgI6XPD_BwE

That collector will be less expensive than a bunch of fittings and tube, even if the tube is free. Riser spacing would be 3-5 inches with diy tubing and a quarter inch with a molded collector. Way more capacity per square or lineal foot.

Ok thanks for the info , not sure if i can get the collector here where i am so maybe a DIY job .

Malcom, a little context would help us help you. You said you want an outdoor shower on the cheap...
What's cheap - do you have a budget in mind?
Are you doing it cheap for the fun of it or because you have a hard $ limit?
Which is more important - getting it done cheap or getting it done this season (or faster)?
Any information about the deadline, the budget, project motivation, how many people it must serve and how often?
Do you have any scrap materials available to recycle - pipe or tubing, metal roofing that might be used as an absorber plate, tanks, large glass windows or sliding doors, etc? How are your tool collection and skills?
More context helps us to give better answers.

That said, I think you're getting excellent answers already.

There are many other directions we could take the discussion depending on your priorities... here's a few threads if you want to pull on them...

You asked a question about a thermosyphon. Do you understand how a thermosyphon works? If you understand how it works, it not only answers that original question, but may also help you make better choices (ie work better, cost less, less errors). Ask if you're unsure how it works and help will likely emerge here.

Why do you want a thermosyphon? If the requirement is only to not use power, a small DC pump with a small solar panel is another way to have an essentially passive system without thermosyphon constraints. Nothing against a thermosyphon - just exploring boundaries here.

If ultra cheap is critical, you might look at Sergiy Yurko's youtube channel. His experiments push the boundaries of cheap, though these are experiments and starting points rather than refined DIY plans... and the language barrier sometimes requires a little extra thinking. Here's a link to one of his videos to get you started.

Is solar the only option? For example, would you consider a rocket hot water heater for cloudy or short days... and do you have the wood resources for that to make sense?

Would you consider a pre-made solution like a camping solar shower? Would you consider a design like that for your own DIY?

If you found a local plumber with a castoff water heater that you could salvage the tank from (it's often the heating element that dies first in electric ones), do you have the skills to salvage it... and more importantly to mount it securely enough that your gravity feed tank won't become the piano that crushed the cartoon character in the shower? A decent sized trash can tank or water heater tank can easily hold 400 lbs of water... not counting it's own weight.

Thanks for the reply Ashley. Skills are not a problem here I do wood work , plumbing , DIY , electronics and repair my own vehicle and never stop learning .
As for budget , i,m trying to keep it low as poss. Have the occasional trip to the local dump and scrounge up some stuff and have friends in building trade here. I re-use old wooden pallets as the wood is perfectly good. Probably looking at 200 bucks max. Looking at copper tube 22mm for the collector panel but now thinking of the effort involved in moving a panel , so may have to make three panels of smaller size and couple them together , i think 25kg is the absolute max weight i want to lift even with handles on the boxes . If i make small panels i can always add on more . So have to figure the all in weight of the components of the collector box , including wood and absorber plate, no greater all up than 25Kg.

I have just looked on a government website and the table shows a person is allowed one lift per day of 25kg  !
Nice to know the factory i left a few years ago had me lifting these engineered components 20 or 30 times a day Gripe / rant over.

Yes so its also about ease of assembly and health and safety and i take your point about the weight of water believe me i do !
I chose thermo syphon idea as a starting point because it has no electrical parts involved and looked reasonably easy to construct so if thermosyphon works well . which i have no reason to doubt then a small pump should enhance the system as an add on.
I dont want to involve any other  added heat source yet , just the sun, this will give me a point of reference.
The other thing is how much water does it take to have a shower i rekon i could do it in three gallons Minimum, five Max as water is valuable here. So for 4 people = 20 gallons and double that as a reserve and for pressure up keep say 40 gallons so the closest to that is a 55 gallon drum. In litres = 275 .
I have achieved 60 deg C here from a 20mm black irrigation coil pipe of 30 mtrs at about 45 deg angle and it is steaming  hot , no box no glass top just clipped to a wooden backing and no storage tank!!! So i am looking to improve on what i have got
Yes i,m going to have to buy some materials and glass however i will look for ways to recycle . Looking at tempered glass off cuts at a local glaziers or even cast off double glazing panels . That is it .

Double pane replacement door wall or sliding door glass units are 30 dollars and you get two pieces of tempered glass 30x72.

If you could find commercial storefront type frames as salvage, those would make a great collector box and have provision for glass.

Rodale institute has some good diy plan materials and details on various collectors, hydronic, air, batch, heat exchangers, storage, etc.

Corrugated steel with the tubing laying in the channels works to improve collection while guiding the courses of risers straight. Small holes with stainless wire as a fastener is cheap and effective. Possibly the channels in the corrugated steel could allow the tube to be captured and pressed into contact and forced straight if running a horizontal tilt. If you go too far, you could turn poly pipe into silly putty!

Poly pipe or pex can be run in contact with the underside of a south facing roofdeck and even use metal conductor/absorber sheets that are simply stapled to the plywood. These are made for radiant floor systems and can easily be made in some fashion or use corrugated steel or just clamp/straps for the.pipe with short screws.

Yes , i dont fancy plastic tubes and container turning sloppy on me . It happenned last year and that was not even a system, it was just thrown together on the quick , so something in a glass covered box is going to reach even higher temps so i better start looking for high temp materials .
I might even discard the idea of soldering connections because i,m just building in potential failure points , i,m leaning toward the annealed copper tube serpentine method.  but als the flooring piping.  I,m going to check out the local builders yard as they have access to a lot of gear and often have a rubbish skip so its always a lucky dip.
Thanks for the link i will check the institute out

An easy hot water storage container is an insulated ice chest.  Igloo, Coleman come to mind.  They just need an out-flow pipe with a valve near the bottom to attach a low-flow shower head to. They will keep the water at about the same temp it went in at for an hour with the lid down tight, under warm-day conditions.   Not too big a chest so the water stays above the outflow pipe.  They are light weight, easy to clean, can be placed on a high shelf so the shower head is at about shoulder level.  

There are examples of this on YouTube.

Ok thanks for the tip. I had never thought of that one .

Malcom, in my earlier reply I suggested Sergiy Yurko's youtube channel as a source of super cheap solar designs. However, I just discovered that he has a video that's much more relevant to your specific project than the link I originally posted.

Here's the better link... To make Solar hot water supply: simple and cheap. This is his take on a solar shower. It's a bit more involved than many of his other collectors, but more applicable to your project.

Enjoy!

Many thanks for the tip. I will have a look. I,m experimenting with some copper tube i had lying around and hope to have it running within the next few weeks .