Innovative solar powered radiator - will it work?

Ok, so i live in a rented flat (apartment) in London UK. Its a small flat but its old and doesn't have a gas heating system so i'm stuck using expensive electricity especially as the windows are single glazed and winter is on the way! Brrrrr! I desperately need a cheap and effective heatsource Now I know solar water heaters can be suprisingly effective even in the cold and that got me thinking. I have a south facing garden. Couldn't I use the sun to heat the flat? Specifically, I was thinking, can I use a solar water heater to heat an insulated water tank, then use the tank to heat a radiator after dark? (See diagram below) Bear in mind in temperature during the day at the moment is 11 degrees. Will enough heat be generated to make the system viable? I.e. will the water heat the tank hot enough during the day to keep the room warmish for a evening? Other pressing questions: Do i need a commercial panel or will an instructables model work? Oil filled radiator or water filled? Will it auto-siphon or will i need a pump? cheers a million guys and gals!!!

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damianzuch2 years ago

I am in Canada and am looking forward to another chilly winter. I have been toying with an idea of building a copper or aluminum coil and embedding it in a housing of solid concrete. I want to use a large magnifying glass to heat a panel on the outside of the concrete block; the thought is that the heat generated would travel through the concrete block and then slowly give off radiant heat after the sun goes down.

Has anyone ever had any luck with a system like that?

knektek7 years ago
yes, this will work, but you will need to insulate the pipes with a good insulator, i was thininking : a copper pipe, then a few layers of foil (opt), then a few layers of tape, then a thick layer of something
NachoMahma8 years ago
. It should work, but I'm with Kiteman - your first priority should be to insulate as well as you can. You will be more comfortable and the solar heater won't have to be as large. . > Do i need a commercial panel or will an instructables model work? . If you can do all the other plumbing/&c involved in this project, building your own panel shouldn't be a problem. . > Oil filled radiator or water filled? . I'd avoid oil. A water/glycol mix is easier to clean up. An oil spill might have legal ramifications, also. . > Will it auto-siphon or will i need a pump? . If the storage tank is mounted above the panel, it will thermosiphon. If you are only using one radiator, you may get enough flow by mounting it above the storage tank. With the panel/tank, you'll probably need several feet change in elevation; with the tank/radiator, a few inches may work. . . There are quite a few solar projects here on Ibles and all sorts of info elsewhere on the 'Net. There are a few safety hazards involved (eg, water flashing to steam), so read up on all this before you get too far.
In my system the tank and panel were insulated and the pipes just PVC pipes. I did not bother to insulate as the pipes were very short The panels we have here seem quite efficient and thats how theyre built You have horizontal 2 pipes of 1in diameter in the top and the bottom Beween them you have some 15 parallel vertical pipes of 1/2in diameter So you get kinda grid of size 1.5 x 2 meter There is also thin metallic plate pressed on the pipes from the top but I think a flat plate welded on the bottom should be at least as well (be careful not to weld too much to not damage the pipes) All this is sprayed with thin coat of rough (not glossy) black paint (Graffiti paint is ok) Now all is enclosed in a thin wall metallic box. If you welded the metal plate put it with the plate down and the grid up Under the plate there is some insulation ~ 1 - 2 cm thick The glass is single plate of fully transparent glass ~ 3 - 4 mm thick or perspex (I think glass is better. Perspex is used in some panes cause its less breakable) It will flow on its own if you have enough height difference and pipes dont go up and then down etc
Tassle (author)  NachoMahma8 years ago
Will do nacho. cheers for the advice. I'm aware I need to look up pressure release valves or expasion tanks. Any recomendations warmly received tho!
starwing1238 years ago
You could probably get more energy from Fresnel lens heating up the water. USe the page magnifiers you get at staples in the us for 8 usd
Can you break the light with them as in to make a 1500 - 1800 angle in the light rays ? It would be possible then to tile them to few M2 lens and get all that sunlight in a single spot. Now thats gonna be hot !

Btw you made me think of - if you strech a plane of strong transparent plastic above the panel and fill a pull of water in it you get kinda huge lens too
110100101108 years ago
I tried to do this ~ 2 years ago with the Israeli standard 4 entry 150 L tank This tank is different from your one in the following - There is no coil. All 4 entries connect to the space of the tank - The hot out tube enters the tank from the bottom and goes all the way up inside Some things I figured out when building and experimenting - Hot water does not want to go down. Raising the radiator above the tank (or at least entry above entery) improves performance. It is essential if you cross the tubes on the radiator like in your picture so that hot water goes only up and cold only down - For the same reason take the hot water directly from the top of the tank and not from the tube that goes down inside the tank. In my tank I used the same tube as the return from the panel and used the top tube only as air exit to fill the system and connect the overflow tube (see below) - I connected the radiator straight (top to hot and bottom to cold) and not in reverse like in your picture - If you close the system it may blast (water expands when heating). Connect a tall tube to the topmost point in the system and point it up as high as possible. Fill with water until water fills that tube and exits from the top. leave the tube open - Make sure there is no air in the system. Tilt the radiator to get the air in its top out - I used the tube grid from broken solar panel as radiator. A real radiator may work better. Radiator from fridge seems to be excellent shape for heat spreading but tube is thin and it may not take enough flow to keep warm (water cools down on the way to the radiator or only top of radiator is warm) - I did not try that but laying the tank on the side should reduce the height differences needed for the system to work and allow its use on 1st floor too
Tassle (author)  110100101108 years ago
Cheers 110! (what does that actually say in binary????) How did you find the system? Did it work ok? Was it worth the effort? Would you recommend an open system like yours or one with a coil like my diagram?
The img above is the standard hot water supply system thats in allmost every home in Israel The panel is built as 2 horizontal pipes (top and bottom) and a grid of thinner pipes that connects them. Its all sprayed in black paint and enclosed under glass plate to make kinda greenhouse The tank is just a 150 (common sizes are between 80 - 200) L tank with 4 entries like in the img and 3.5 KW electrical heating element (The water is always hot in the summer and often warm in the winter too without using electricity) Some tanks have extra 2 entries with coil between them. The entries exit both from the bottom or one from bottom and one from the side near the other one. This kind of tank is uncommon and used only in homes with radiator heating system. The coil is connected to the system as radiator. This way if you turn on the radiators you get hot water in the tank too. The other 4 entries work same as in the normal tank The 4 entries of the normal tank are labeled as following In - enters from the bottom to the bottom of the tank. Sometimes there is a small plate welded over the end of the pipe to keep the cold water in the bottom of the tank. Without it if cold water flows in it can mix with the hot water in the upper area of the tank and cool it down Out - enters from the bottom and goes with a pipe inside the tank to the upper end. The pipe is often bent so it ends above the center of the tank (above the electrical heating element) and not in the corner To panel - enters from the bottom and ends there (without a plate like the in pipe) or sometimes goes for alittle longer inside but not much Fom panel - enters from the side at about 2/3 the height of the tank and ends there The tank is allways installed higher than the panel or at least so that the pipes connecting them have good height difference between the ends. This way the system is more efficient when working on solar and does not lose energy to the panel when working on electricity Tanks often leak in the area where all the electricity is (and too rusty to open the nuts to fix) and are discarded. The leaks usually are not severe to make it unusable for this project. You can try to epoxy the place and also try to out the tank upside down so the leaking place is on the top Panels are often discarded too cause of leaks and I think can be fixed with epoxy. I tried to fix one with electrical tape and duct tape on the bad spot and it worked nice as short term solution I tried to make this system just for the experiment of it on the roof of my home (having to climb on a ladder to get to the radiator - not too useful to heat the home). I used the existing tank and panel for the experiment and tried a grid from another panel (the one with the duct tape) and a snakeball of PVC garden hose as radiators. The grid was way better The water exiting from the tank after a sunny day is hot and you feel the radiator heat up in quite short time. In the beginning the radiator is hot and then cools down as the heat is lost I did not measure time but I think (it was >2 years ago) it was good for ~ 1/2 - 1 hour and somewhat warm for some more time I also tried to cheat by using the pipe from the top of the tank and emptying the water back into the home system while some1 was having a hot shower (the problem otherwise is how to get the hot water to flow down). With this cheat the top of the radiator was impossible to touch for some time and then it cooled down too Note that sometimes the water cools down evenly with time and sometimes quite suddenly. I did not figure out what caused the difference I did not try a tank with coil and dont know what to expect from it. If you do try both options - with the coil on the radiator and with the coil on the panel side You may try Use a radiator from the back of fridge. It has all that metallic net welded to it and probably makes better heat spreader Use electrical pump to drive the water in the radiator faster and also be able to use the pipe that comes fom the top of the tank
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