No - behind
Everything except the 1.0mm t&E I used to extend the array pt1000 sensor down to the airing cupboard. I had a roll lying around.
See previous post, Chinese panel
Solar coil is a flat pancake coil on the bottom of the cylinder.
I'll post any developments as and when. I'll try to give an assessment in twelve months.
Cheers
Not sure about your configuration but my tubes are vertical with a horizontal header at the top of them. The reflector behind the tube is fitted after installation but extends down most of the length of the tubes. How does your horizontal tube set up an internal convection to transfer collected heat to the header at the top? I simply cannot visualise your layout unless it has an entirely different arrangement/principal to mine
In message , cynic writes
You mean you have an ET system with an unpumped primary ?
Cheers, J/.
Yes - know what you mean...
OK. And cylinder ?
Navitron import ?
OK.
Thanks !
Cheers, J/.
The first stage in the collection is twenty vertical tubes with partial pressure fluid inside. These "plug-in" to a series of copper sockets sealed into a top horizontal manifold tube thus can be changed without depressurising if so needed. The manifold has a pt1000 temperature sensor which monitors the temperature and if the differential between manifold and cylinder is sufficient the controller runs the circulation pump. If the top region of the cylinder is above a set point the pump is inhibited. Among other points I am awaiting the right weather to study is the effect of long periods of sunshine with the cylindewr up to temperature. There is no heat dump facility but if needed I could provide one relatively simply.
Yes the cylinder was included in the price. Its a slim tall unit with solar coil flat to the bottom, a boiler fed coil about halfway up and an immersion boss at the top. Without going up and raking out the airing cupboard to measure i'd say about 400mm diameter and around
1700mm high with a thick foam insulation applied in manufacture.In message , cynic writes
Heat pipes I guess ?
Sounds standard.
Yes. Cylinder stat and solenoid valve, but maybe better just to let the pump stop and the water from the manifold displace to an expansion vessel ?
Cheers, J/.
Right, so with big collectors there is return. The ones I'm talking about cost hundreds of quid.
Orders of magnitude more cost.
Well, you've offered nothing with even comparable payback, let alone better.
ok, but I dont propose using it. Wood battens screwed to the outside wall, polythene stretched over and stapled on. Thats it. In winter the outside of the wall is warmer due to greenhouse effect plus insulation effect, so reduced heat loss thru wall, and in some cases a small heat gain. IIRC payback is good, but the issues are horrible. Looks like crap, very vulnerable, needs peeling off every summer, and complete replacement every 4 years.
I did calcs in full about 3 yrs ago, lemme go see if I've got them available...
no :( I didnt think it'd be on here. IIRC ROI was somewhere vaguely in the 30s % region.
I very much get the feeling youre not familiar with this tech.. Mesh absorbers have 2 or 3 layers of black mesh, and the air passes thru the mesh. The mesh is angled so that all the air against the front panel is air yet to go thru the mesh, which further reduces losses. The 2 or 3 layers of mesh means that losses from any but the frontmost mesh are partly recaptured. Air flow through the mesh maximises turbulence, maximising energy transfer from mesh to air. Couple this with the low temp output of air heating and you've got a panel that can run at 90% efficient. Flat HW panels dont get anything like that, their efficiency is way down when putting hot water out.
skylight contains IR too.
In that case I'm going to take a wild guess you may mean passive solar buildings. You must be aware that many techniques can be described as passive solar, your comment was pretty vague.
The above isnt much use for tens of millions of existing buildings, and ditto for many new builds. I think a cheaply fitted diy system with good ROI is of more utility myself.
Too expensive and complex to see widespread use or good ROI.
Its on the to do list, but too many other things are as well. The small solar setup at the last place worked well, but I just dont have the time here. Maybe one day.
NT
Yes, there is a return, but not necessarily a lot of rate of return.
Well maybe so, but that doesn't guarantee any particular rate of return.
Without seeing the costs, designs and performances of both systems, I don't think you can make any such assertion.
Hmmm... See what you mean !
OK - If you find them, I wouldn't mind a look at some point.
But 90% efficient with what temperature rise ?
If it's 5C outside and you need three air changes per hour, how hot will it get the air ?
I've spent too many January days looking at delta T values of zero to be very convinced.
Unglazed ?
Indeed, but there's always going to be a trade off between efficiency and temperature.
Maybe. If it stacks up I'm happy, but most of the examples of solar space heating that I've seen have not been well regarded in terms of rate of return, and may of them don't seem to elegant to retrofit because of the ducting required.
And you are right - passive solar building design isn't a retrofit thing, but it is generally a fairy cheap approach when you are starting from scratch or extending.
More expensive than you seem to have in mind I grant.
:) Know the feeling...
Cheers, J/.
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