Solar Heating?

[Andy Hall]

No abuse at all.

I simply said that reducing one's carbon footprint (a nonsense term to begin with) via this method is naive.

That is simply a comment on a position not about any particular individual or individuals.

It's something of a stretch to turn such a comment into an accusation of abuse. Do you feel vulenerable about your position or something?

I think that the Chinese are quite knowledgable. Certainly in using the avarice of the West in terms of their trade arrangements while ignoring issues that are of concern to some in the West is very clever indeed. Alternatively, perhaps some in the West who like to speak about green-ness out of one side of their mouth while buying cheap goods from China out of the other are not as bright as it would appear.

Not very convincing.

[Stuart Noble]

The problem is sorted.....

[David Hansen]

On Mon, 10 Dec 2007 18:37:40 +0000 someone who may be Andy Hall wrote this:-

Nice try. However, completely incorrect.

Do keep it up though.

It may not be very convincing to some. However, it remains a fact.

[Andy Hall]

There's really no need. As soon as something is said for which you have no answer, you suggest that it's some form of abuse.

That it may be. Whether it is in the least bit important is something else entirely.

[David Hansen]

On Mon, 10 Dec 2007 21:35:16 +0000 someone who may be Andy Hall wrote this:-

Nice try, but just as incorrect as many of your other assertions.

[David Hansen]

On Sun, 9 Dec 2007 11:59:42 -0000 someone who may be "Mary Fisher" wrote this:-

The post at

some figures from another system, which included a few extras.

A 23% saving in gas. Most interesting.

[John Rumm]

Indeed, although what I think we were looking for were hard data for a change.

The carbon footprint stuff is nice in concept but fairly meaningless in reality. Unless you know the true energy consumption (and the carbon released during its generation) during the extraction of raw materials, the production, distribution, installation, and finally disposal of the system, you can't make any realistic assessment as to whether you are having a net positive or negative effect.

[Andy Hall]

Very. Especially valuable from the vendor of the system.

[Andy Hall]

So why raise the subject?

[Andy Hall]

Another cosy, fluffy thing where people can feel that they are "doing their bit"

[AJH]

I thought water was fairly opaque to a lot of the spectrum? My infra red thermometer seems pretty effective at measuring bath temperature.

AJH

[David Hansen]

On Mon, 10 Dec 2007 22:00:33 +0000 someone who may be John Rumm wrote this:-

I think one can make a realistic assessment without having highly accurate figures for a particular installation. That is what an assessment is. One can benchmark that assessment by looking at comparable figures. In the case of solar water heating such figures are available from the usual sources.

[David Hansen]

On Mon, 10 Dec 2007 22:00:48 +0000 someone who may be Andy Hall wrote this:-

You appear to be claiming that the person who made the posting is the vendor of the system, but that is not the case.

details of the system, which those genuinely interested in the subject may like to read.

[Peter Parry]

Most interesting indeed. He has a single solar collector virtually identical to the Thermomax one used in the DTI test (DTI/Pub URN

01/1292) tilted at a similar angle and with slightly less optimal alignment yet managed to get 5,400kWh in a year wheras the Energy Monitoring Company Ltd for the DTI could only manage 1,010 kWh from an identical panel in one year.

It would be really useful to find out how he achieved the fivefold increase in performance over a fully instrumented and monitored system especially as it appears to be about twice the amount of energy even falling on the panel in one year (from Navitrons figures which are similar to the DTI ones).

Global warming must be much more advanced than we thought.

[Pete C]

Hi Peter,

You need to read on a little, quote:

"Actual cost saving works out to around =A3120 year-on-year. But, also consider that as part of the package I spent a further =A3300 to improve the exisiting CH/DHW controls to meet full Part-L specification so not alll the saving can be attributable to the solar installation. However this included dual cylinder stats on separately timed zones to maximise the solar gain vs boiler operation."

cheers, Pete.

[David Hansen]

On Mon, 10 Dec 2007 23:15:20 +0000 someone who may be Peter Parry wrote this:-

The difference is that the DTI test did not involve systems fitted in real houses connected to a real gas boiler undergoing real draw offs. I don't recall the detail of what size of storage the DTI panel was connected to and whether they observed it reaching the maximum temperature and thus shutting down.

The author does not claim that all the reduction in gas consumption was due to the solar panel, yet you imply this would have to be the case.

[tom.harrigan]

Also, you have to get the right sort of insulation as the pipes can get quite hot.

T

[Peter Parry]

They involved systems fitted in a test rig with draw-off patterns which were representative of normal usage. The storage tanks were fitted in insulated equipment sheds maintained at a constant temperature so they were representative of a normal house.

No high temperature shut-off was used and from the data it wasn't necessary. The only overheating occured during a number of failures that occured with the panel installations throughout the test.

I may no more of an implication than you did when you said "A 23% saving in gas. Most interesting.".

Assuming the panel performance is more or less in line with the DTI test (which is reasonable as they are consistent with the amount of collectable energy and the panel efficiency. They are also similar to the results others have achieved in independent tests) then 80% of the saving is not due to the solar panel but the other alterations he made. From his description of them they wouldn't be expected to have made this much difference so I'm interested in how it was achieved.

[Peter Parry]

Of the 5,400kWh saving no more than about 20% of that can be attributed to the solar collector, there simply isn't enough energy falling on the panel to produce significantly more. This is nothing to do with how good or otherwise the solar panel may be - the energy isn't there to collect.

If 80% of the saving came from the relatively modest (in cost) alterations to the controls this obviously represents a far better way of spending your money but is a lot more than most authorities would estimate you would save. Its simply impossible for the panel to produce more energy than it can possibly collect so I'm interested in what did produce the observed effect.

[tom.harrigan]

As far as I recall, average insolation in Birmingham is about 100W/m2. The June average is about twice that, in December, less than a 1/5th.

T