heat pumps / ground source heating.

[biffvernon]

You'll have to wait till next summer for performance report. It's still 'work in progress' - not actually plumbed in. I did record an air temperature in the shade next to the copper pipe near the top of 85C after the sun had been out for half an hour. There's no water in the system yet but it will be plumbed into our existing heating system via a second indirect cylinder that will pre-heat the water before it reaches the existing cylinder that can be heated either by our straw-burner or an electric immersion heater. Really the aim is to have the solar panel providing most of the hot water in the summer when we don't run the strawburner. It will therefore substitute for the electric immersion heater. The ex caravan aluminium is the actual energy absorber so is painted matt black. Al is a good conductor so transfers the heat sideways to the water filled copper tubing which is held down with screwed clips and a thermal contact made with silicone mastic. The plastic top (not yet in place in the picture) creates a greenhouse effect. The total area is almost 12 square metres. The main cost was the copper tubing, the second copper cylinder, and the plastic glazing. There's a domestic central heating pump to wizz the water round that someone gave me, and a power shower pump that I got at a car boot sale. Someone on this forum gave me an old roll top bath and someone else gave me some pantiles for the other side of the roof and some quarry tiles for the floor. Bricks are similarly recycled and most of the mortar and timber frame was dug up or cut down in the garden. The windows, triple glazed in mouth blown stained glass are mine. The whole building has cost under £1500.

 

[Mark]

Ice are also claiming good results using solar linked in with the gshp - as i understand it they use the ground loop as a thermal store ? Might be worth asking - I dont think they are selling that yet, but it could bring the payback period down a bit further. On my list of things to do is the navitron solar stuff - its the cheapest I have seen evac tubes which give a worthwhile effect even in winter (i have spoken to some people who have installed it and they are very positive)
I know its more expensive than the diy approach but I hope that in the longer term the all year rpound efficiency will pay off.


Biff - what do you use between the glass in your windows ? Just air or do you buy in the units ? or buy in inert gasses ?
I want to both replace the upvc that previous owners have fitted and also look at modifying / secondary glazing som eof our windows.

Just had a week looking at property in France - Its amazing how little they have ruined stuff and how affordable it still is - even after the recent increases.

While im here Ill also comment about fireplaces - I have just taken out a recent fireplace and i'm in the process of opening out the fireplace to something more its original size - I am amazed at how much warmer the room is already despite the fact that the hole in the wall is so much bigger. All I can put it down to is the fact that the modern shaped fireback and lintel have gone. The venturii effect must be huge.

 

[biffvernon]

Biff - what do you use between the glass in your windows ? Just air or do you buy in the units ? or buy in inert gasses ?

I buy in the insulated glazed units. Their manufacture is a specialized job (if you want ones that don't mist up!). My supplier always uses argon fill - it is no more expensive than air fill once you are set up with the equipment. Argon is cheap stuff.

Remember that if you are adding secondary glazing it may be worth using a hard coat low-e glass such as Pilkington-K.

 

[skier-hughes]

WOW

 

[middi]

What a nice project Biff, very simple but inventive.

That should keep your calculator busy in future.


( You will probably be so pleased with it that the next " improvement on efficiency" picture you post will be one displying a doubled or trebled copper pipe run ).

 

[biffvernon]

doubled or trebled copper pipe run

You think you jest! It's spaghetti in my airing cupboard.

 

[NT]

doubled or trebled copper pipe run

You think you jest! It's spaghetti in my airing cupboard.

heh, thats the downside. Good job you dont have my electrics as well.


NT

 

[skier-hughes]

Anyone contacted Jon Maine recently?

I've tried emailing from his web-site, but the mail keeps getting bounced back as undeliverable.

I was wondering if he had any feedback on his GSHP yet.

Graham

 

[Penners]

You'll have to wait till next summer for performance report.

I shall be very interested to hear the results. And many thanks for all the technical spec, although I'm not sure I entirely understand the bit about the matt black ally transferring heat "sideways" to the copper tubes.

I had always assumed that a solar panel was simply (as you describe it) a thin "greenhouse" through which a lot of copper tube snaked - the copper being painted matt black to absorb heat. I therefore assumed that the base (ie: the bottom panel under the copper tube) would be reflective, to bounce the heat back.

Is that oversimplifying the idea?

 

[Penners]

doubled or trebled copper pipe run

You think you jest! It's spaghetti in my airing cupboard.

Italians never jest about spaghetti.

 

[MdB]

I had always assumed that a solar panel was simply (as you describe it) a thin "greenhouse" through which a lot of copper tube snaked - the copper being painted matt black to absorb heat. I therefore assumed that the base (ie: the bottom panel under the copper tube) would be reflective, to bounce the heat back.

Copper is the bit you want to heat but tubing is expensive so it is therefore difficult to get a large enough surface area. To save cost, Biff is using an alumimum sheet to act as the absorber. It has a large surface area and will be collect far more of the suns heat than the copper pipe will by themselves. It will transfer its heat to the copper pipes which then heats the water. Neat idea but I'm not sure how well silcone is as acting as a heat transfer mechanism.

Ordinary radiators painted black might be a better solution apart from their weight.

 

[Penners]

Would a steel radiator (painted black of course) absorb heat as well as copper?

 

[MdB]

Would a steel radiator (painted black of course) absorb heat as well as copper?

No, it is a poorer conductor of heat so the surface would get hot and reradiate before it has chance to conduct to the water inside. However, you try finding copper radiators for the same price as steel!
(if you really want to improve performance then the panel should be made from silver! and then painted black)

 

[Penners]

OK, MdB. If you were going to make a DIY solar panel, would you use an old (steel) radiator, tightly clustered copper pipes, the family silver salver, or what?

 

[skier-hughes]

I'd use Biff.

 

[MdB]

I'd use Biff.

LOL! I think I would too. Any one know how good a heat conductor he is? I wonder what the difficulty would be in getting a copper pipe through him.... Open wide Biff!

 

[Penners]

I wonder what the difficulty would be in getting a copper pipe through him.... Open wide Biff!

That'll bring tears to his eyes :x

 

[biffvernon]

Oi. Behave. :twisted:

Neat idea but I'm not sure how well silicone is as acting as a heat transfer mechanism.

Yeah, I looked into this. There are better conductors that are used in computers to stick the heat sinks onto chips but the cost is astronomical in the quantities I needed. Silicone is a lot better than nothing.

 

[Moo]

Would discarded hot-water tanks be a useful source of metal sheeting?
(I'd always assumed they were made of copper, but it's a while since I saw one).

 

[biffvernon]

Yes. (And yes.)

PS. Did you say dicarded? Copper price today is $6779.50 per tonne.