Hi Jon,
Clue is in the address.
H

OK Herbal

I know the manufacturer I don't know the product type. At this point I think I'll give up the research.

CommentAuthorJohan CommentTimeMar 9th 2008 quote
Posted By: jon

How long has ET's been available? 10 year? I don't think that's long enough to say they are better then FP's. If in another 10 years the SAME tubes (no replacements!) are still running as good as they are today then you can start comparing them.

Thermomax - started supplying vacuum tubes in 1980 (that makes 28 years history) - Surely that is a long enough track record.

Posted By: antiriadCommentAuthorJohan CommentTimeMar 9th 2008 quote
Posted By: jon

How long has ET's been available? 10 year? I don't think that's long enough to say they are better then FP's. If in another 10 years the SAME tubes (no replacements!) are still running as good as they are today then you can start comparing them.

Thermomax - started supplying vacuum tubes in 1980 (that makes 28 years history) - Surely that is a long enough track record.

Absolutely! Sorry, I wasn't aware they had been in business that long.

"I am working on a 12V pump using a solar recharge to a battery,"

You might consider using a car pump second hand. You will find suitable pumps in some types of Audi's, Volkswagens, BMWs and the occasional Vauxhall

Horses for course I would say, depends what you want really. FP are reasonably strong and robust, simple too; but need 'gallons of sunshine' - permanently - whats the one thing we ain't got in this country? You all know that................gallons of sunshine!!

Whilst the ET are fragile (Ok its all glass but........) and most importantly don't need 'gallons of sunshine', still needs some mind!

Whatever it all costs money - this energy for free is a myth!! Like a lot of other things! Thought up by salesmen who haven't a clue what they are talking about but need to sell their products! Wether it's solar energy, garden peas or government!

I find our ET's (just coming into their fourth year) work fairly well most of the time - lashings of hot water between say March thro' June to October! Sod all in the winter (despite global warming - another myth)! Ah well we don't bath in the winter (smell a bit), or use loadsa' money on kettles!

So for me, whilst I prefer FP (cos I'm a simple soul) for practical purposes, in this country, it has to be ET's!

This response may provoke howls of protest, given the views expressed so far, but I feel I have to make it all the same.

I confess I haven't read all 72 comments posted before this one, (I gave up at about 30ish) but the consensus seems to be that ETs are the preferred solution. Whilst I'm sure the heat generating potential of ETs can't be denied, the basis if this poll is presumably to test the balance of thermal efficiency against other factors (including cost of purchase/installation).

I point out that I haven't read all 72 comments because it's possible that my thoughts have already been expressed by someone else, in which case - sorry!

On two previous houses, my father-in-law has installed home-made Flate Plate solar water heaters. In each case, he took a scrap copper water cylinder, cut the top and bottom off, cut down the side and flattened it out. Then he constructed a lattice of copper pipes with a top and bottom rail (outlet/inlet), and soldered/brazed it onto the flat copper panel. The whole assembly was then painted matt black.

He then constructed a wooden case from marine ply, lined it with insulation, placed the copper panel in the box and fitted a perspex cover (though a toughened glass one would have remained clear).

The whole was then plumbed into a dual coil cylinder, and provided all the 'free' hot water a family of four needed for most of the year.

Combining this with a biomass stove with back boiler seems to me to be the best of all worlds, and even scores on the recycling front!

From Ample: 'Total energy bill' ? Or total space and water-heating bill? Nevertheless, do tell.

Nick

Has to be ET for this simple reason. Replacing a vac' tube is as simple as replacing a lightbulb.
No draining of the system. Damage to an FP, replacing that, what does it entail and what are the consequences?
An ET panel can still operate with a couple of tubes out.

Mantra

Could I just paint some radiators black and put them on my roof, then hook them up to the rest of the 'proper' system - tank and pump etc? Or are manufactured FP specially made for the job and therefore better at collecting the heat?

A compromise is to make your own (as I've described elsewhere) using some copper pipe, and a scrap copper cylinder topped and tailed and split down the side to provide a large piece of copper sheet to act as a backing panel. My father-in-law's dome this twice before and been self sufficient in hot water for at least half the year.

OK then define total energy bill please

i had a comment regarding if flat plate was strong, the glass flexes by 30mm under test condition and a ball bearing is dropped from a meter away- in that case I have a picture with two men standing on a flat plate collector both are 14 stone each; if you would like to see this picture drop me a line.

Ample,

Thanks for the clarification. That's 'total space and water-heating bill', not 'total energy bill'. This is not for pedantry, but because so many claims are made without the hearer being sbsolutely sure what the base figure is.

Ample - ok, you have defined what you mean by "total energy bill". How have you managed to achieve a 60% reduction in space heating/DHW production using solar? I only ask because I am in the process of trying to come up with a system which is going for overkill in terms of solar panel area (FP type) with the idea of having some significant contribution from solar during spring and autumn.

Jeff