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Author Topic: Solar Thermal Production @ Courtiestown  (Read 924 times)
linesrg
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« on: June 02, 2017, 12:56:19 PM »

Good Afternoon All,

Based on solar data from [url]http://www.efficientenergysaving.co.uk/solar-irradiance-calculator.html/url] we get 872kwhr/ m2 annually.

Using the formula:-

Annual output (kWh) = 0.44 x annual horizontal solar irradiation (kWh/m2) x aperture area (m2) = 0.44 x 872 x (1.26 x 3) = 1450kWh.

For the month of May this gives a theoretical average output of 233kW. According to the software in the heat pump we've actually had 228kW which is a pretty close correlation.

Regards

Richard
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16off BP380 on a Lorentz tracker/ SMA SB2500, 16off Chinese 80W/ SMA SB1700, 16off BP380/ SMA SB2500. CTC GSi12 heat pump/ Gledhill ASL0085 300litre EHS/ 3off Navitron 4720AL solar ET panels and an Immersun T1060/ T1070/ T1090 (+ planned 7off 235W panels).
Fintray
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« Reply #1 on: June 02, 2017, 08:43:25 PM »

Richard

That's a useful amount of energy each day, isn't your system also using this heat for space heating via the thermal store?
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linesrg
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« Reply #2 on: June 03, 2017, 09:18:44 AM »

Ian,

Yes all the energy goes into the EHS. At this time of year there is little demand for space heating. As I think I've commented elsewhere this leaves you with a 'deadzone' between 30 & 50 degrees in the EHS where you can't make any use of the energy.

More use will be made when the non-electric shower is installed next week.

Regards

Richard
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16off BP380 on a Lorentz tracker/ SMA SB2500, 16off Chinese 80W/ SMA SB1700, 16off BP380/ SMA SB2500. CTC GSi12 heat pump/ Gledhill ASL0085 300litre EHS/ 3off Navitron 4720AL solar ET panels and an Immersun T1060/ T1070/ T1090 (+ planned 7off 235W panels).
linesrg
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« Reply #3 on: July 03, 2017, 09:00:57 AM »

Good Morning All,

As I commented in the Solar PV section it has been the wettest June on record since 1910 up here in Scotland so not surprisingly both solar PV and solar ET output are down on expectations. According to the heat pump display we made 178kWhr against the 231kWhr forecast.

Regards

Richard
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16off BP380 on a Lorentz tracker/ SMA SB2500, 16off Chinese 80W/ SMA SB1700, 16off BP380/ SMA SB2500. CTC GSi12 heat pump/ Gledhill ASL0085 300litre EHS/ 3off Navitron 4720AL solar ET panels and an Immersun T1060/ T1070/ T1090 (+ planned 7off 235W panels).
linesrg
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« Reply #4 on: October 05, 2017, 10:09:47 PM »

Good Evening,

About two weeks after I went back to work i.e. the last week in July our system started producing some strange figures. Unfortunately through my being off California and my wife not really understanding the system an analysis of why this was didn't happen.

In early September I sent an EM to the installer detailing the problem as the heat pump was telling us we were producing silly amounts of kHr and this clearly wasn't happening. As it happened the heat pump manufacturer's representative was up in Aberdeenshire later that week and both were able to go over and look at the system.

They gave the system a once over and left having not determined the cause of the problem.

I got home last Thursday and having gotten various things done which needed doing I set about getting to the bottom of the problem myself.

I guess I'd better detail the issue. The Solar ET system circulating pump is meant to cut in when the temperature of the water in the system is 7 degrees warmer than the heat store. There was no doubting it was doing this. The pump kicks off at 100% and then modulates as it monitors the rate of temperature drop across the tubes.

Problem was the temperature wasn't reducing and the pump continued at 100% essentially continuously.

Switching the solar ET bit off and then back on did nothing. Switching the heat pump on and off didn't do anything either.

After a bit of head scratching this morning I pulled the insulation back from where the solar pipework entered the heat store and it was pretty obvious there was no hot water circulating anywhere - fairly obvious conclusion was that despite the pump running at 100% the system was clearly airlocked.

The heat pump determines the energy derived from the pump velocity and the temperatures recorded for the solar energy in and out of the tubes so as the temperatures weren't going down and the pump was running at 100% all the time clearly large figures would ensue.

I have spoken to the installer this afternoon and am waiting on a crew turning up with a charging rig to flush the system through.

I'm not sure how much useful energy has been 'lost' but on a relatively sunny day like today energy could have been gained in the heat store and used for the low level background heating currently in use.

I haven't named any names here and I'll leave you to form your own conclusions I know I have mine.

Regards

Richard
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16off BP380 on a Lorentz tracker/ SMA SB2500, 16off Chinese 80W/ SMA SB1700, 16off BP380/ SMA SB2500. CTC GSi12 heat pump/ Gledhill ASL0085 300litre EHS/ 3off Navitron 4720AL solar ET panels and an Immersun T1060/ T1070/ T1090 (+ planned 7off 235W panels).
dhaslam
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« Reply #5 on: October 06, 2017, 01:09:14 AM »

It is always useful to have a flow meter in the system to make sure that there is proper circulation.
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Heating  180,000 litre straw insulated seasonal store, 90X58mm tubes + 7 sqm flat collectors, 1 kW VAWT, 3 kW heatpump plus Walltherm gasifying stove
linesrg
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« Reply #6 on: October 15, 2017, 09:32:50 PM »

dhaslam,

The system does have a flowmeter, it is hidden in the CTC Ecosol unit which is up in the Utility Room attic space and doesn't lend itself to being easily seen. In theory somebody should be coming around to sort the problem out tomorrow......................................

Regards

Richard
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16off BP380 on a Lorentz tracker/ SMA SB2500, 16off Chinese 80W/ SMA SB1700, 16off BP380/ SMA SB2500. CTC GSi12 heat pump/ Gledhill ASL0085 300litre EHS/ 3off Navitron 4720AL solar ET panels and an Immersun T1060/ T1070/ T1090 (+ planned 7off 235W panels).
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