I have a garden shower straight from the garden hose that we use to rinse off after a swim. Often the first bit of water is wonderfully warm as it has been sitting in the garden hose. I would like to extend the time this warm water flows. One problem I have found is that water kept warm (> 25 deg and < 60 deg) can breed dangerous bacteria. For this reason I am thinking of some sort of heat exchanger, so that the fresh tap-water passes in a pipe embedded in a small solar-heated tank of water. This may get somewhat complicated with the tank and solar collector plus coiling the fresh water pipe in it. My latest idea is to combine the water storage and solar absorber into one thing. I am considering passing a small diameter black polypipe down the centre of a larger diameter black plastic pipe, such as a grey-water pipe. And then coiling this in the sun. The outer pipe is filled permanently with water. The inner pipe gets new water when you turn the tap on and this water hopefully warms up a bit before coming out of the shower. I only need the water a few degrees above its natural cold temperature. However, I then have the problem of keeping the outer pipe full of water over a long period of time with no evaporation or leakage. To solve this, I was wondering about somehow filling the outer pipe with cement slurry instead, coiling it in place (with inner pipe inside) and letting it harden. But I can't think of a good a way to get the slurry into the pipe which would be about 30m long. Any advice on this or other ways to get slightly warm water from the sun, very welcome.
Warm garden shower - advice needed
(5 posts) (3 voices)-
Johnnojack
MemberWhy use cement? Try it with sand only. Ever walked on hot sand at the beach? Imagine how much hotter it would get inside some black drainage pipe. Myself I would just use a roll of 20 mm poly irrigation pipe between the normal hose and the tap. This would give you about 5 times as much warm water anyway. As for legionella I think the risk is next to nothing as you are only heating a few litres at a time and using it daily. You may need however to set up a mixer ( using irrigation taps and fittings) as the water may get too hot.
Posted Wednesday 7 Dec 2016 @ 11:37:42 am from IP # -
ChrisG
MemberYes, dry blackish sand might work. It's certainly hot to walk on, on a sunny day. Now I think of it, I wonder if it needs to be black sand (I know you didn't suggest that) - perhaps the black pipe provides the solar absorption and the colour of the contents doesn't matter. In my case, this is at a holiday house that we use only every few of weeks, so there may be times when the water lays in the pipe for long periods, so legionella would still be a risk, I think. Of course I could flush it out when I arrive, if I remember. But there are also friends etc who use the house, so I was looking for a foolproof solution. Now to go dig some sand....
Posted Thursday 8 Dec 2016 @ 12:49:31 am from IP # -
Johnnojack
MemberI was going to suggest using used foundry sand ( which is black) in a bed under an old window pane, with the poly pipe buried in it. However it may be hard to get and can be contaminated with metal, depending on what it has been used for. If your little system goes unused for weeks the water will heat up well past the point where any bugs can grow and will be sterilised when you get to use it.
Posted Thursday 8 Dec 2016 @ 5:19:32 am from IP # -
munrre
MemberSounds overly complicated to me.
My outdoor shower has about 50 metres of black approx 1" polypipe hanging on a fence.
Gives about 10 minutes of warm water once the hot water subsides.In Summer the 1st flush is very hot and I'm pretty sure any bugs are history.
I have thought about laying it on a veranda roof and including a cold mixer line but not worth the effort for the amount of use it gets.
Posted Friday 9 Dec 2016 @ 3:31:22 am from IP #