HereKittyKitty

just read through the other thread re:- gas & electric comparisons with UK and Spain. I did a previous post on these costs and am paying exactly £137 per month for both including charges over the whole year. Now Scottish Power have confirmed a rise which will put his up to about £150.00 per month for a 4 bed modern house, which I think is a disgrace! I really don't know how these companies are getting away with it.

Anyway...Hubby wants to install a solar panel on the roof to heat the water, and use a wood burning stove also. I wondered if anyone has done this and if it made a huge difference? I know it is an outlay to start off with But are thinking that we will benefit eventually?
P.S I should say for out home in Spain - not here!

bil

Wood burning stoves are a great option. They are ethical, burning carbon neutral renewable fuel, and if you pick one with an oven in the top, you can cook stuff too, for free. Plus, if it has a flat top, you can put a casserole on the top as well.

I've read warnings about putting central heating in old fashioned houses in Spain (I can't vouch if this is true) as it can cause problems. I can say this fits in with experiences I have had in the UK, where messing with old fashioned construction can cause problems by heating and drying material that was never designed to take those sort of temperature shifts.

As regards solar heating. They can be a bit expensive, and I am going to run some experiments to see if I can make something a lot simpler and cheaper. Crudely, a long coil of black hose will give a surprising amount of water warm enough to shower with, but I'd like to step it up a bit using a parabolic reflector and a hot water storage unit.

Bri and Katee

Old aluminium (for lightness if roof mounted) or steel radiators painted black and linked together will provide plenty of hot water. If you plumb two of these into a sealed circuit to heat a hot water storage tank, you would have clean hot water. Of course you would need a circulating pump in there as well, along with a blow off valve for safety, the water in the circuit especially during summer will quickly get overheated.

This system is ideally suited for use in large gardens (where they can be hidden behind hedging) for heating pool water!

bil

Yeah, the only problem with purely passive is that you need to run a pump, and the capacity is limited. How would you propose to store hot water for night time use?

The design I want to experiment with is as follows. Take a hot water tank. Either this is open construction, with a ball cock, and feeds things via gravity, in the which case it needs to be on the roof (thank goodness for a solid construction flat roof!), or else use a pressurised container with a relief valve, as you describe.

One single heating element works as follows. a copper pipe exits the tank at the bottom and goes out a foot or two horizontally. It then turns vertically up thru 90 degrees, and then goes to the top of the tank so that it is at right angles to the sun. It enters the tank below the water line at the top. You then construct a parabolic trough so that the focus of the parabola is the copper pipe, which is painted black.

A crude test model can be created using ply sections and a thin strip of ply that snaps into them. That ply trough is then lined with baco foil, shiny side out. Ideally cover the open side with horticultural grade glass to stop the wind cooling it.

The tube should heat up to quite a high temp, and the hot water will rise up the pipe and should create a circuit with cold water flowing into the tube at the base. Insulate all the pipework outside the parabolic trough, and the container itself. What will be interesting is how much hot water can be generated in unit time.

This can be quite crudely constructed and on a comparatively small scale for very little cost. This is just to give an idea of how much heat can be generated, and if the passive circulation works. It might be that 22 mm pipe would be better than 15 as the smaller the pipe, the greater the drag on the walls. Also, the smaller the pipe, the more accurate the parabolic focus needs to be. (It's more expensive, but you could split the pipe into four in the centre of the trough as that would give a better heat pickup.

If that construction works, then the troughs can be situated further out and bigger, and have several troughs, radially so that as the sun moves, one trough will always be pointing at the sun.

The height of the container can also be varied to boost heat input.

If it works, then the design can be tweaked, making the troughs from stainless steel (polished) and the supports for the troughs out of steel strip.

Bri and Katee

The reason I said that the radators heat a storage tank Bill is because the heated water has to be kept seperate from the hot water (potable) you actually get from the tap. In other words water in the heating circuit is self contained and goes round in a continuous loop via a coil of copper inside of your tank, to the rads (solar panel) via a pump. This copper loop heats the water in the tank via heat transference.

To just heat the water via a solar panel and use it as is, will lead to all sorts of problems, illness and worse.

bil

Well, the corrosion problem relates more to the central heating systems. I'm in a very hard water area, so I think a thruput will be more likely to fur up with calcite deposits than it it to corrode. I did quite a bit of research on this when I kept koi, concerning the risk of copper leaching into the water, but was reassured that a comparatively low KH (temporary hardness) was all that was need to give a protective layer to the inside of the copper pipes.

What health reasons were you thinking of? Water that hits 40C is almost always fatal to most bacteria, and I was thinking this would crank up to in excess of 80C.

I would only ever drink from the cold tap anyway.

TheArmChairDetective

HAve a look at this
http://www.anotherurl.com/therm/Self...ar/default.htm

or more up to date
http://www.lowimpact.org/courseoutli...buildsolar.htm

You might find that it's easier (or harder) than you thought

bil

Thanks for that. Not being hugely flush with cash, I can't really afford the full kosher version. Plus, I get enormous satisfaction from creating solutions myself.

For example, I think it should be feasible to build a large trough from ply, and line it with mirror tiles, which would give excellent reflection comparatively cheaply.

Plus, you could set it up so that the trough rotates around the central core, which would be made out of multiple lengths of 15mm pipe, because the mirror tiles throw a flat, unfocussed beam. Hmmmm. Actually, if the tiles were mounted on strips of wood, fixed at each end with a peg, they can be rotated as a strip to focus the light better. Obviously 4" tiles would be better than 6, unless the central core was more than 6 inches.

That would save the cost of ply, and make things lighter. In winter as the sun drops, the trough can be rotated so it faces the sun perfectly. It would need a pressure relief valve against overheating, and as it is pressurised from the pump, I could simply plug it into the hot water line in the bathroom, or even the kitchen as long as the service pipes were well insulated.

Mitzyboy

Blimey Bil
This is rocket science

bil

No, it really isn't. It's really simple stuff that anyone here can do providing they can do soldered joints in copper pipe. That plus a bit of third rate carpentry.

Go on the net and see how you make a parabola. Cut out of ply two such shapes and extend them a little to make the lid support. look at the parabola as a semi circle and extend it up a little like a capital U OK? Just make it big enough so that there will be enough square feet of sunlight to heat the water.

Mark the bottom of the U and move outwards marking it at 6-7 inches apart on a line parallel to the edge Drill a hole at each mark. Take a strip of wood, one for each mark, put a screw thru the hole and into the centre of the strip. Repeat at each end so you end up with what looks like a baby's cradle with parabolic ends. The pipe will enter and exit thru the centre point where if it were a semicircle, the point of the compass would go to draw it.

The pipe divides after passing thru the end, splitting and resplitting until a central core is made that obstructs totally all the light falling on it. Then at the other end they all come together and pass out. Make a frame to support it so that it can rotate, and align it along the solar axis. This doesn't even need to be on the roof.

Stick the 6 inch mirror tiles to the wood strips, and when the trough is aligned, rotate each strip so that it focusses the sun onto the central core. When each strip is aligned, fix it with a second screw the hole for that can be drilled when the first row of holes are made. Then staple rubberised cloth over the back to stop air blowing thru, and fit glass sheets to cover the top.

This should cost peanuts by comparison, and while it runs, you can get a steady supply of limitless hot water. If you want, a storage tank can be added to the system, but that would require a bit of planning.

Trust me. Rocket science it ain't.

jdr

You don`t need to drink it to get Legionairres desease it can be caught from tiny unclean hot water droplets being inhaled, the reason they shut down Benalmadena ice rink.

bil

Ah, were you seeing a hot water system as a source of Legionnaires'?

I'm open to correction, but I always thought that was a comparatively low temp colony of bacteria, with the risk being as you say, in the inhalation of aerosol particles. The system I suggest is sealed, so not open to contamination, and the water temps should be so hot as to be self sterilising. A hot water tank, even if not sealed, should be safe as long as the temp gets hot enough.

TheArmChairDetective

Of course, thats why I posted the link about the course

jdr

My brother got it on holiday and luckily survived.
The specialists said he could of caught it from air con in the hotel, showerhead, or air circulated in the plane, but who knows really.
When they opened the ice rink in Benalmadena it closed shortly after as three people living nearby died if it from the refrigeration process needed for the ice.

bil

Poor air circulation in planes is implicated in DVTs too.