Archive for Downsizer For an ethical approach to consumption
 


       Downsizer Forum Index -> Energy Efficiency and Construction/Major Projects
Hairyloon

DIY solar thermal?

I've been told that a suitably insulated, black painted radiator is fairly effective as a solar thermal collector, but I've also heard people say it is not worth the effort.

Anyone here tried it? What's the verdict?no smilies
gz

Friend in N Wales did that in the early 1980s when we lived there.
Worked ok, definitely use it indirectly,ie fill system with fluid including antifreeze. The Winter "take the chilly off" pre-heating cut bills massively.

If you are practically capable and have the components to hand, go for itno smilies
dpack

if you can put it in a "cold frame"type thing it will work better.

i would think sourcing some recycled double glazing panels and a few old radiators ,a tank with a coil ,pump and pipe would not be beyond a man with a van :wink:

the rcd for the pump and wiring might be best as new items but the rest could be from a scrapper or plumber chum.no smilies
dpack

ps the ch water goes through the coil and the solartherm water goes in the cylinder tank /black rads

it needs a header tank like an open ch system cos in summer the thermal expansion can be considerable

a similar thing can pre heat water for baths washing up etc

pps plenty of insulation to pipes and tank is good to avoid losing what you gainno smilies
vegplot

It's not very efficient but if you have a surfeit of radiators and Perspex or glass then it might be worth the effort. Your call.no smilies
Hairyloon

It's not very efficient but if you have a surfeit of radiators and Perspex or glass then it might be worth the effort. Your call.

Where does it lose efficiency?no smilies
vegplot

It's not very efficient but if you have a surfeit of radiators and Perspex or glass then it might be worth the effort. Your call.

Where does it lose efficiency?

You can't lose what you haven't got.

Google it.no smilies
perlogalism

It's not very efficient but if you have a surfeit of radiators and Perspex or glass then it might be worth the effort. Your call.
Where does it lose efficiency?

You can't lose what you haven't got.

Indeed. If I was going to the trouble of plumbing into a solar coil in a thermal store I wouldn't be wasting my time with some old rads. Buy a 30 tube evacuated array from Navitron and produce nearly all the hot water you want!no smilies
dpack

having had a look at the vac panels dont bother with rads/dg /box etc

made for the job seems like it is easier and will cover the cost quite quicklyno smilies
RichardW

If you have all the bits FOC, want a summer only system that has a back up then go ahead & have a play.

You can even make quite a good system just using a long hose.

If you want a system that will work for more of the year then get vac tubes.no smilies
Mistress Rose

We built a prototype back in the 1970s when all this stuff raised its head and before all the modern stuff had been developed. It will work after a fashion, although a coil of copper pipe fastened to a black collector in a double glazed frame will be better perhaps. Not very good, but using scrap you at least gain a little.no smilies Hairyloon

We built a prototype back in the 1970s when all this stuff raised its head and before all the modern stuff had been developed. It will work after a fashion, although a coil of copper pipe fastened to a black collector in a double glazed frame will be better perhaps.
What is it that would make it better?no smilies
mark

essentially efficiency in solar collection is

1) maximising solar heat absorbtion - you need to absorb the heat not reflect it
2) avoiding any head less by convection or conduction or re-radiation in the collector.

stopping air movement or using vacuum stops convection losing heat by convection (no use your radiators getting hot then losing all that heat to the cold icy wind blowing over them)

likewise with conductive losses - you need insulation.

But you don't want you insulation to stop conduction and convection to block any of the nice warming ways.. (the bubble wrap in a greenhouse problem)

Your basic radiator painted black is not efficient. Putting it in a greenhouse under glass makes it better. Putting it in a vacuum more so etc etc.

Also your piping conducting heat to the air (very well if its copper) so you need to insulate.

And so I could go on .. but I'm sure you are getting the plot by now !no smilies
vegplot

We built a prototype back in the 1970s when all this stuff raised its head and before all the modern stuff had been developed. It will work after a fashion, although a coil of copper pipe fastened to a black collector in a double glazed frame will be better perhaps.
What is it that would make it better?

Material
Manufacturing processes
Research and development
Quality
Science
...
...

This list look familiar.no smilies
Hairyloon

Mark's answer was infinitely superior.no smilies vegplot

Mark's answer was infinitely superior.

What is it that makes Mark's answer better?no smilies
Hairyloon

Mark's answer was infinitely superior.

What is it that makes Mark's answer better?
It contains actual answers.
Yours just says "the professionals do it better. Nyah nyah."no smilies
vegplot

Mark's answer was infinitely superior.

What is it that makes Mark's answer better?
It contains actual answers.
Yours just says "the professionals do it better. Nyah nyah."

I wasn't expecting a reply as the question was tongue in cheek.

But thanks.no smilies
Mutton

Go look at www.builditsolar.com.

All sorts of self-build designs and data on how well they work. Some include costs to build as well.

I've always had a fancy for a solar shed....... :)no smilies
Tavascarow

A lot of the professional instalers are going away from the Chinese evacuated tubes (Navitron) back to flat plates. Problems with maintaining vacuum.
If you can instal your panel below the tank so it works on gravity & fit a non return, so when the panels colder than the tank it doesn't suck the heat back, fairly cheap & easy IMHO.no smilies
vegplot

A lot of the professional instalers are going away from the Chinese evacuated tubes (Navitron) back to flat plates. Problems with maintaining vacuum.
If you can instal your panel below the tank so it works on gravity & fit a non return, so when the panels colder than the tank it doesn't suck the heat back, fairly cheap & easy IMHO.

Or perhaps installers breaking too many tubes? :wink:

I prefer the flat plate collectors. The may be less efficient but are more reliable and tougher they also look better IMHO.no smilies
Mutton

I worked with glass vacuum equipment a lot of years ago - not glass solar hot water tubes - but I spent a lot of my life leak hunting.....no smilies
       Downsizer Forum Index -> Energy Efficiency and Construction/Major Projects
Page 1 of 1
Home Home Home Home Home