Solar water collector design advice, please

Welcome to UKHIppy2764@2x.png

UKHippy is a long running online community and of likeminded people exploring all interpretations on what it means to be living an alternative lifestyle -- we welcome discussions on everything related to sustainability, the environment, alternative spirituality, music, festivals, politics and more -- membership of this website is free but supported by the community.

  • Hi everyone....:waves: I'm back online as I've invested (heavily) in a 4G sim tablet/laptop after my old one died :(. It does mean that I can sit happily in a field listening to skylarks and buzzards overhead...


    Like JonathanH, I've trawled through quite a few threads hunting for advice but I probably didn't look hard enough so apologies in advance if it's been staring me in the face! I want to build my own solar water collector, as my caravan's water heater is on its last burners and I don't want to fork out for a potentially expensive replacement yet and if we get a good summer, I feel I should make the most of the bright yellow disc in the sky and reduce my lpg consumption to the bare minimum.


    I've surfed YouTube and found various ways of doing it.. but most "Tubers" were in California or Florida etc... Has anyone made / know anyone who has made / direct me to a web page with a design - a small but efficient solar collector for the British climate which can be set up conveniently next to / on top of a caravan in "stealth mode" on a farm? There's only me and my water consumption is low...


    I've seen batch box heaters; parabolic curve designs; Fresnel lens - which looks quite dangerous! - a gazillion miles of black water pipe...evacuated tube systems which look very cumbersome. I've used the black plastic camping shower bags (batch) outdoors in the past but find they puncture quite easily - despite putting them in a "cage" to give them some rigidity...


    Any wisdom on the subject would be gratefully received...


    Thanks, Moira

  • Hi Hero..


    Thanks for the idea.. I'd have to find a titchy tiny one but I'm quite a good skip-scavenger! I wondered whether an alu beer keg would work? I've seen the odd one down at the local recycling centre in the past..


    Moira:waves:

  • Be careful with beer kegs - £2000 fine if the wrong person sees you with one.


    Kegs and casks being stolen for scrap was a big problem, then the law came in and most scrappies wont touch them with a barge pole.

  • The reason a lot of solar water heaters use miles of pipes is that it increases the surface area so gets hotter quicker , same as the radiator (leave a hosepipe in the sun for a few hours then turn the tap on,chances are it will be too hot) , dont see how a metal beer keg is gonna be any more efficient than a black bucket ?
    Simplicity is a piece of black board with a lot of black pipe fixed to it , tap at the bottom and a funnel at the top,leave it in the sun for an hour or 2 and you should get enough for a very good wash,then top up via the funnel ....

  • Hi Colin... and thanks for the tip, I hadn't realised that's what went on! Do they still sell those mini beer kegs in supermarkets, can't remember what they're called... and I'm going back many blue moons! Party 7s is coming at me from my last grey cell...??? :waves:

  • The reason a lot of solar water heaters use miles of pipes is that it increases the surface area so gets hotter quicker , same as the radiator (leave a hosepipe in the sun for a few hours then turn the tap on,chances are it will be too hot) , dont see how a metal beer keg is gonna be any more efficient than a black bucket ?
    Simplicity is a piece of black board with a lot of black pipe fixed to it , tap at the bottom and a funnel at the top,leave it in the sun for an hour or 2 and you should get enough for a very good wash,then top up via the funnel ....


    Hi Shroom... I thought people preferred metal to plastic because of the heat conductivity being higher with metal.. There's an army surplus store in Banbury and I thought I could rig something up in an old jerry can depending on capacity..


    However, tubing is probably what I will verge towards with super absorbant black paint on the backing board, but a small version... Would I still need a bit of glass / plexi over the top... ? I'm afraid of melting the tubing...


    My other question is regarding using my Whale pump to pump the water to my shower which has hot n cold mixer.. and my water current reservoir outside obviously pumps cold in from so I don't burn myself! ... Presumably I would have to pre-mix hot n cold in a reservoir beforehand to the Goldilocks temperature each time...? :waves:

  • ok , maybe go with copper pipe , but for weight and cheapness i reckon hosepipe. Black is optional but obviously best and bigger the bore the more water it will be heating ,my calc say that 1 metre of 40 mm waste pipe holds about 5 litres , so a metre square board could hold about 15 lengths each with 2 x 90% bends on the end (dont recall off hand how big the bends are), 15 x 5 = 75 litres of hot water :) ,how you incorporate that into a shower is beyond me ......

  • ok , maybe go with copper pipe , but for weight and cheapness i reckon hosepipe. Black is optional but obviously best and bigger the bore the more water it will be heating ,my calc say that 1 metre of 40 mm waste pipe holds about 5 litres , so a metre square board could hold about 15 lengths each with 2 x 90% bends on the end (dont recall off hand how big the bends are), 15 x 5 = 75 litres of hot water :) ,how you incorporate that into a shower is beyond me ......


    Wow, Shroom... you're a marvel! I'd never need 75 litres of hot water in one go though so it sounds as though I could reduce the amount of copper but use a bigger diameter pipe. I "rescued" a large bit of osb that the farmers had put on their bonfire this afternoon which I can get a decent piece out of.. Obviously hose pipe is cheaper than copper and I doubt I'll find some copper lying in a skip somewhere, so I'll have to do some sums... I've got some "rescued" single glazing if I need to make a cover to reduce wicking by the wind/(rain) etc but then I would probably need to insulate the back panel...or just get some intumescent paint? Thanks for your help :angel: Moira:waves:

  • I had in Spain a length of 6" pvc pipe, capped at both ends, with a fill spigot with vented cap and a tap at the other end


    Mounted on my roofrack and painted black, it held enough water for two good hot showers at the end of a day.....

  • You can't melt the tubing because it can only get as hot as the water inside.


    You want a flat collector like a radiator. A barrel has a low surface area compared to it's volume so would not be as efficient.


    Have you thought about a compost water heater?


    Paul

  • Hello everyone.... Sorry, I went a bit quiet whilst building my water heater! What was only meant to be a weekend project ended up taking a bit longer but I got there in the end... and I have to say I'm quite proud of my efforts! Was just about to insert a pic but realised I'll probably have to resize it before posting it... so back in a bit... or a bit longer or how long's a piece of string!


    PS No, Aman I've never heard of a compost water heater but sounds great... if you've got a big smouldering heap! ~

  • Hi again... I took a better pic today so you can see the workings inside...


    solar water heater resized 2.jpg


    If I let the sun do its stuff before I turn the low flow rate pump (200 lph - the size of 2 matchboxes!), then it comes out PIPING hot... but obviously cools down as it circulates, but it's still hand-hot when the pump's running. I only put about 20-30 litres max water at any one time I fixed just over 25m of 15mm barrier pipe, leaving a gap between the pipe to maximise the amount of pipe being heated. Have found some old single glazed window frames that I will try to take apart without breaking the panes, to lay on top of the secondary glazing panels. Still got some ultra matt black painting to do .... and put some insulation on the north-facing side and maybe concoct some internal method of keeping heat in rather than condensating on the double-glazed panel sitting on top.


    :waves:

  • I saw someone on tv use some big plastic coke bottles or similar to insulate their pipe. The cut the bottoms off and strung them together over the pipe. They painted the bottom half (when they are laying on their side) black to sbdprb the heat.

  • I saw someone on tv use some big plastic coke bottles or similar to insulate their pipe. The cut the bottoms off and strung them together over the pipe. They painted the bottom half (when they are laying on their side) black to sbdprb the heat.


    Thanks for the tip BF... I might put some painted bottles around the pipes from the heater to the reservoir...:waves:

  • Thanks for the tip BF... I might put some painted bottles around the pipes from the heater to the reservoir...:waves:

    Aluminium pop/beer cans work the same if not better as the aluminium absorbs and retains heat from the sun better. The cans are used end to end.
    I'm about to experiment with heating water using biogas. I bought two very old copper and brass natural/coal gas/town gas water heaters. They are basic with a limited amount of hot water produced in one go like solar, but a very well designed and made bras gas jet arrangement burner at the bottom and a copper cylindrical water boiling chamber, with the fume exhaust gasses passing through a empty tube space in the center of the copper boiling chamber. So all heat rises up through and along the boiling chamber before escaping out of the top. They also have a copper header tank built onto the side near the top. This has a ball cock valve fitted. The height of this header tank is crucial for header pressure, replacing any removed hot water from the built in tap on the boiling chamber, with the right amount of cooler fresh water. I want to build a biogas holding device and hope to become sustainable in small amounts of Hot (not just warm) water, when required. These units have a built in pilot flame tap which swings away from the main gas jets to ignight and then swing back into the jet area when the brass gas supply tap is turned on (avoiding any synged eyebrows by accident) for main gas jet ignition.
    Sorry to divert this thread, but I'm seeing much positives in cheap/free hot running water. Not having had any for almost six years now, I'm beginning to miss it.
    I will start a new thread when I begin to experiment with biogas production. Any pointers for DIY biogas storage systems appreciated. Link if it still works. http://www.ebay.co.uk/itm/Vint…253D&orig_cvip=true&rt=nc
    Ta fo nar ~ back on topic.

  • For the past eight years I've used a home made solar heating system made from two second hand radiators in boxes fronted with corrugated acrilic, normally used with corrugated steel as windows. This backs up my solid fuel stove which normally heats my hot water cylinder, but which isn't used in hot weather. I have 2 sq meters of heating area which is enough to fill my cylinder with enough hot water for a bath during a sunny afternoon. Total cost was around 450 euros, but something smaller would cost less. I live in the west of Ireland which is hardly the sunshine capital of Europe, so ought to work anywhere in the British Isles.

  • I was going to suggest a solar swimming pool heater kit as theyre reasonably priced and easy to adapt but i see youve made your system already...Congrats.
    Back in the 80's when i lived in Pembrokeshire i made a similar arrangement from old central heating radiators painted with black enamel like astartosteerby and worked very well.Used it mainly to heat a greenhouse at the bottom of garden in the cooler months.(I wasnt there long enough to try the system on the house).


  • I cant jelp but think a couple of properley positioned reflective panels ( Mirrors, shiny ally foil covered boards whatever) positioned around there would concentrate much more sunlight, n therefore heat onto those coils, and make the water hotter


    think solar oven!........


    - - - Updated - - -



    I cant help but think a couple of properly positioned reflective panels ( Mirrors, shiny ally foil covered boards whatever) positioned around there would concentrate much more sunlight, n therefore heat onto those coils, and make the water hotter


    think solar oven!........

  • Hi SootyF... I don't really want to start making it bigger...but I know what you mean. I've seen some hotter climes designs where the hose is coiled in a very large "bowl" for want of a better word. Mine's already 1m sq. I could put some foil on the inside edges of the frame, maybe, to reflect some light that way.


    What I did scoop up yesterday from the someone's boot, at the local tip, was a load of polystyrene sheets, destined for the incinerator. I've fashioned a couple to sit above the water level in the reservoir to keep more heat in the water.


    What I keep forgetting to buy is a decent thermometer, d'oh!!


    Also, I meant to ask Alice's Wonderland where "biogas" comes from... I was distracted by the construction of his heater (way too complicated for me) that I forgot to ask....


    Waving... :)