Sensor placement

[Gixer]

Hi Gnidrolog,

Another way of putting it would be

your water (how many ltrs ?) was raised by 20deg using 2.71Kwh

That would be 2.71 Kw would raise your water 20 deg in one hour. hence the "h" in Kwh

Hope that makes sense?

[Gnidrolog]

Hello Gixer

I think I've got it now. The tank size is 117 Litre, checked it today, I think yesterday I said 115 Litre, but that was from memory. BTW my collectors are not Navitron, didn't find this forum until after I got the kit. Seems my supplier is well known to supply dubious tubes.

Regards

Gnidrolog

[Gixer]

Why dubious?

2.7kwh sounds good to me for what you are using.

I think most tubes are made in the same place, it's the panels that vary, but then again most of the headers look identical as well.

[Gnidrolog]

Gixer

There's been a lot said on this forum about a certain supplier on flea bay, probably best I don't elaborate. Anyhow I purchased 42 tubes (2 spares) from unsaid supplier, fitted the first 20 tubes to the SW using the 2 spares and 18 from the first box of 20 tubes, so leaving 2 from the first box of 20 as spares. Performance wasn't too good. So I decided to check the remaining 22 tubes by setting them all up, covered, then testing heat gain when all were exposed to the sun. The 2 tubes from the first box and 1 from the second only managed around 50c after an hour of exposure. The others reached over 110c in the same time, big difference! So I think it's likely that at least a few others in the SW collector are probably under performing as they came from the same batch.

My brother outlaw has since purchased a system from Navitron (yet to be installed), so I "borrowed" one of his spare tubes and did a similar comparison to one of my "good" tubes. The Navitron tube was much slower gaining heat at the bulb than my one, despite this they both reached 80c at about the same time, then the Navitron quickly increased to 110c while mine was still at 85c - another big difference! At that point I shut down. Don't tell brother outlaw, but I still have his Navitron tube in my SE collector 

Maybe all the tubes come from the same factory, but I'm convinced there are significant differences, possibly the heat pipes are of varying quality? I don't know, but I'm sure my SE collector gives better output than the SW one.

Gnidrolog

[Gixer]

Hi, my 2 east facing panels, heat up much quicker than my 3 west facing panels.

Not sure if it's the time of year but the sun seems much closer when east than west?
I'm not sure that it can be, but it certainly seems so.......

The rest regarding suppliers is best not talked about here for obvious reasons.

[Ivan]

I played around with a solar angle calculator a few months ago, and found that the sun's rising/setting position moves nothwards at different rates on the East/West side. Not sure if it would be enough to have any detectable bearing on your system though...

There is a lot of technology in the heatpipe, although most glass tubes are interchangeable and pretty much identical. The heat capacity of different heatpipe/tube combinations may vary which affects the heating up/heating down time, and type of fluid in the heatpipe also has a big bearing on efficiency and heating up time (slow heating up time doesn't affect overal performance). You also need to consider potential freezing of heatpipes and overheating - these also affect the choice of working fluid, and can have slight adverse effects on performance, but nevertheless much preferable to failing heatpipes - which then perform miserably!

[dhaslam]

Hi, my 2 east facing panels, heat up much quicker than my 3 west facing panels.

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How accurate is the measurement of east and west.    Not sure if the midday sun at this time of year is exactly south.  If it is then that should be the most accurate measurement.   Magnetic soiuth is quite a bit different. 

[Gixer]

After some more watching of the system I think it's more likely that the sensors pockets are different in two panels giving different results in rise and fall temps.

Last night I fitted two additional check valves above each pumping station.
Sure enough this solved by original problem of the east pumping hot water to the west panels and vice versa.
At the same time it showed that the check valves in the pumping station do not work as suspected.

but now I found another problem, when one side is already pumping, and then the other side starts, it can't open the check valve due to the pressure on the other side thus causing the panel to heat right up.

Ho hum, is an E/W system supposed to present so many problems?
Right now having two totally separate loops and tank coils looks favorable !!

The pump speeds were on min setting, I have now set them both to no2 speed to see how that goes.