Hi all,

Sorry to revive this discussion but having scanned through all the threads on the optimum angle for solar thermal, i am still struggling to get an answer specifically on the optimum angle for prioritising solar heating in winter.

I posted in late summer about having too much power in our first summer (we ended up covering some of the panels at times) but one of the pieces of advice from the forum which i am going to use was to increase the angle of the panels to reduce output in the summer and maximise in the winter.

To complicate matters, we are at 43.5 degrees latitude in SW france.

Does anyone have a tried and tested table of angles for various latitudes and for various priorities (heating/DHW/winter/summer and so on)

Finally does anyone know of flexible water pipes that can take up to 180 degrees temperature (standard ones are only rates to 100 degrees i believe) as my plumber can't seem to source any. These would allow us to modify the angle with ease in the future as our panels are on the ground and the frames allow various angles to be set.

Thanks

soar angles http://www.macslab.com/optsolar.html regards roger

As fostertom says your easiest solution is to use the PV estimation tool from PVGIS

http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php#

You can pick your exact location off the map and then input different panel angles until you find which angle gives you the maximum output for the winter months.

The same angle will hold true to get the max. output from solar thermal panels.

If you want to know what that output actually is you will need to perform the calculations in an estimation program specifically designed for solar thermal estimation such as PolySun or T*Sol, whoever supplied your panels may have this software and can perform the calculation for you or I believe you can get a 1 month licence for T*Sol for about €50.

I used the corrugated Stainless that seem to be the norm over here. Armalex do single and twin pre-insulted ones although it is possible to get uninsulated ones. Armaflex's insulation seems a bit mean to me at about 12/15mm, so buying the plain tube and insulating yourself may be a better option. The sizes seem to refer to the internal pipe dia. e.g. DN. 12,-16,-20. They require special flange fittings, 3/4" and 1" BSP, plus converters from copper to SS. I don't know French plumbing sizes, so you'll have to be careful with any conversion fittings. After many hours spent plumbing with copper pipe, working this SS stuff is a dream, just twist and bend it any which way. I've used it for some general plumbing applications where pipe alignment was very difficult.

Longest hours of daylight today, summer is on its way

Going to get a full 8 hours and it will peak at 16.4 degrees high.

Ahh, Winter solstice ST Is it 21 or 22 this year? Down in your corner the Druids will be getting ready for the Yuletide revelry, are they still wassailing? It must be my imagination but I always feel that the daylight continues to lessen until about 2nd week in Jan. Only then do you notice a difference.

Posted By: owlmanAhh, Winter solstice ST Is it 21 or 22 this year? Down in your corner the Druids will be getting ready for the Yuletide revelry, are they still wassailing? It must be my imagination but I always feel that the daylight continues to lessen until about 2nd week in Jan. Only then do you notice a difference.

All down to the angle of the earth's axis. What actually happens is that the length of the day increases but the sun rises later in the morning but sets later in the day for a couple of weeks. Shortest day Edinburgh, 6H59M, London 7H50m. The variation across the country is amazing. Have got a sun map installed and it is fascinating. Oh the December solstice will occur at 05:30 UTC 22/12/2012.

Posted By: fostertom............Posted By: SteamyTea...Longest hours of daylight today. Is that a misprint, or some quirk I'm not aware of?

No, as I thought it's ST on the wassailing rounds. Cider, breadcrusts in the apple trees, you know what they're like, they get muddled after a while, can't tell night from day.

Posted By: borpin..........All down to the angle of the earth's axis. What actually happens is that the length of the day increases but the sun rises later in the morning but sets later in the day for a couple of weeks.

Thanks Brian, so not my imagination after all.

Hi,

Thanks all - i'll look up armaflex and speak to my plumber about it. He will be able to cope with the imperial to metric as he is German and is used to clients bringing taps etc over from the UK.

It is always worth getting this stuff in the UK as everything costs double over here in France.

Cheers

Alistair

high temperature insulation is a must fot ET systems, generally available from solar suppliers.

stainless steel flexible or soft copper?

I'd have thought pretty much any motorsport-type braided hose would do the job easily. A typical PTFE hose with stainless braid will work at temperatures up to around 250 deg C and pressures of 150 bar or more. The stuff is available made up to whatever length you want by some of the motorsport suppliers, the only snag being the need to fit adapters to your pipework for the fittings, as they won't be BSP, in all probability they'll be JIC or unified threads.

Hi,
Stainless flexible will work fine but we can only seem to source in 20m lengths which is megabucks. The plumber is now looking for a price per metre.
We'll probably not move the panels again but it was to avoid modifying the copper pipes
Thanks all