Monday, December 30, 2013

December 2013 Reports

Year Ending: The weather has been better during 2013 (after the rainy start) compared with the previous year, and the metering figures have become more steady, with the triennial figures (see below) finishing with where I wanted it to be, the PV being higher than the GSHP.
Peveril Solar Figures for the 29th Dec
  • House annual 5,266, biennial 5,352 kWh. 
  • GSHP annual 3,199, biennial 3,325 kWh, triennial 3,112 kWh
  • PV annual 3,104, biennial 3,070 kWh, triennial 3,173 kWh. Steady....
  • Sunbox annual 3,508, biennial 2,974 kWh. Still going up, and topped 3,500!!
  • Ground Temperature 10.7ºC - rising a bit.
Elsewhere... Russia released the Pussy Riot girls and the Greenpeace activists - a pre-Winter Olympics peace gesture, one assumes (and there were a number of bomb blasts in Volgograd Russia, giving Putin much more things to worry about.) Michael Schumacher is in hospital after an incredibly unlucky skiing accident, hitting a rock in what seemed like a smooth slowy slope. Britain was lashed by rain and windstorms, with many people flooded and more than 100,000 houses without power over Xmas. England were again beaten in Cricket with the Australians (now the Test series score is 0-4). Britain opens its doors to unlimited numbers of Romanians and Bulgarians (making many Macedonians and Serbians eligible). A Russian ship and other icebreakers are caught in ice in the southern oceans. Southern Sudan is still in a civil war that flared up in a week, and seems like the Ruandan one, with a number of massacres based on the tribes. A new island has formed volcanically off the coast of Japan, in the shape of the dog, Snoopy. Edward Snowden, the revealer of the information gathering of the US and UK governments, gave the Channel 4 Xmas address. Oh, and Mikhail Kalashnikov (inventor of the AK47) died, as did British comedian John Fortune. Closer to Nottingham, my own wife finished the year in hospital, being taken in on New Year's eve. 

22 Dec 2013: It's the run up to Christmas and the university term has ended, but things still seem to be busy.
  • House annual 5,281, biennial 5,345 kWh. 
  • GSHP annual 3,189, biennial 3,307 kWh, triennial 3,123 kWh. 
  • PV annual 3,101, biennial 3,070 kWh, triennial 3,173 kWh. Steady....
  • Sunbox annual 3,479, biennial 2,961 kWh. Still going up!
  • Ground Temperature 10.4ºC - the lowest this winter, after an overcast cold week.

8 December 2013: Elsewhere in the world, the biggest story of the week has been the death of Nelson Mandela at the age of 95.
Sport, England are 2-0 down in the Ashes, in Australia. Pollution levels in Shanghai have reached levels 25-40 times worse than UN safe health recommendations, so what hope for bioclimatic design using natural ventilation?
Scotland and England were lashed with strong winds of up to 100mph, but the worrying thing is that it coincided with a Spring Tide, so that some places on the east coast were flooded. The Thames Barrier recorded the highest ever tide level since its construction. Without the foresight to build this, the entirety of the Isle of Dogs, Canary Wharf and much else of east London would have been under the sea! See the potential flood diagram that has been widely circulated.

I won't print Peveril Solar update figures until next week. Ground Temperature was 11.0ºC, which is good.

1 December 2013: Elsewhere in the world, there was the helicopter crash in Glasgow and a derailment in New York. Energy prices were still a big topic in the news, but why don't people just switch to the smaller companies like Good Energy, who have frozen their prices already? Cameron and about 200 UK business people travelled to China, the largest visiting trade delegation in Chinese history!
How about the Peveril Solar House?
  • House annual 5,318, biennial 5,357 kWh. Very steady.
  • GSHP annual 3,233, biennial 3,321 kWh, triennial 3,191 kWh. 
  • PV annual 3,101, biennial 3,070 kWh, triennial 3,170 kWh. Steady....
  • Sunbox annual 3,473, biennial 2,946 kWh. Still going up, this is a maximum ever!
  • Ground Temperature 11.6ºC. After a sunny weekend, it's above 11 again!

Monday, December 9, 2013

Time to dump the Tubes

9 Dec 2013: It has been an expensive experiment, these evacuated tubes. My two Sunboxes continue to turn in good performance figures, but the tubes have never been good, even in the height of summer - 7kWh is the best ever (after two summers of testing), but the problems are greater than the benefit.
    On a summer's day, the tube ends can reach 130ºC and I dread to think of the effect this can have on the rest of the system if, for some reason, the pump isn't pushing liquid round to cool them. I don't want to build up pressure cooker pressures. All my problems with leaks started after these tubes were fitted. The simpler system of 40mm hose-joints etc cannot cope with sudden rises in pressure. Even after I fitted a heat exchanger, it worked better as two distinctive circuits, but the daily harvest was not improved.
   The performance boost from fitting ETFE to the main Sunbox was so big that it eclipses any benefits from fitting the tubes. The annual solar capture with the Sunbox 3 and 4 combined is now up to 3,470 kWh/annum, which is a better deal than the range  of 2400-3000 I used to get before.
   It is clear that tubes can get to higher temperatures if facing south, and should be used to heat hot water in a tank in a system that can cope with high temperatures and pressure. In a low pressure, high volume, low temperature circuit like the Sunboxes, the tubes are a hazard, and would be a greater one if facing south.

Postscript: as an end of the year action, I disconnected the electricity to the tubes on New Year's day, and will drain the pipes soon. 

Monday, November 25, 2013

November 2013 Reports

24 Nov 2013: Well, the winter is well set in, and the ground temp is 10.8º - in keeping with previous winter seasons. We are getting to the first anniversary of the installation of ETFE panels on the main Surya3 sunbox (coincided with getting the small roof mounted sunbox4 fitted), so I expect the rise in sunbox capture to level off. These were donated by Holscot, and what a piece of luck it was meeting Holscot at a small symposium on Vertical Farming!
  Elsewhere, there were talks in Geneva agreeing a deal with Iran over processing nuclear materials, but very few news sources mentioned the international talks at the same time in Poland over Climate Change..... ended with little, it seems, because of disputes over wording, and the usual claims by rich countries that it will hurt their economies. The can is kicked along the road to 2015.  Sebastian Vettel, already Formula One world champion for fourth year running broke all previous records by winning the ninth Grand Prix in a row in Brazil. This week saw the 50th anniversary of JFK's assassination and of the first edition of Dr Who, and the deaths of Aldous Huxley and CS Lewis.

17 November 2013: It's been a sunny week, with a weekend of cold, and more cold to come. Be grateful, we do not live in the Philippines or in Illinois! How is the house doing?
  • House annual 5,302, biennial 5,322 kWh. Very steady.
  • GSHP annual 3,219, biennial 3,283 kWh, triennial 3,242 kWh. 
  • PV annual 3,097, biennial 3,072 kWh, triennial 3,169 kWh. Tiny improvement....
  • Sunbox annual 3,442, biennial 2,936 kWh. Still going up, this is a maximum ever!
  • Ground Temperature 11.9ºC. Satisfyingly high for this stage of Winter, but the weekend was very sunny!
10 Nov 2013: It's been a week of mostly sunny but cold days. Metering figures for the year are pretty constant, except for the Sunbox 3 and 4 combo which is yet to reach an annual peak. It has just passed the 3,400kWh mark. The ground temperature is moving to where it ought to be for this time of year.
   Elsewhere, the Philippines have had a hurricane with the fastest wind speeds every recorded on land, 195mph. That is so strong, it is unimaginable to survive - buildings just get torn away.

3 Nov 2013: The Winter really has arrived with consistently below 10ºC temperatures, although my courgette plant in the Veg patch hasn't collapsed yet - waiting for the first severe night frost. We are having more sunshine than the same time last year, so the sunshine has been keeping the ground warm for longer than in previous years. Here is a chart of ground temperatures since 2009.
  • House annual 5,299, biennial 5,302 kWh. One down a bit, the other up....
  • GSHP annual 3,210, biennial 3,247 kWh, triennial 3,217 kWh. 
  • PV annual 3,085, biennial 3,057 kWh, triennial 3,167 kWh. No change.... 
  • Sunbox annual 3,390, biennial 2,907 kWh. Still going up, this is a maximum ever!
  • Ground Temperature 12.1ºC. True indication of winter - the heating is on!

Tuesday, October 29, 2013

Air source, Ground Exchange, GSHP, MVHR discussion

29 Oct 2013: Continuing the conversation, David R writes: "With the DHSS and some iterations of the Viking House solar/passive slab the earth store is insulated from the fabric of the building but is continuous at its base to the surrounding earth which would hopefully mitigate most of the effects you describe.
      Of greater concern to me is the size needed for effective storage; our build is a super insulated triple-glazed SIPS structure which should have relatively low space heating requirements with MVHR. On the Viking House site they indicate that some of their stores are sized sufficiently to cover the required number of heating days for the thermal load of the building, I was just not sure how accurate that would be?
   Thanks for the info re the boreholes, four shallow ones would certainly seem to be a way around the problem. Do you know how GSHP compares to ASHP in terms of power requirement? That seems to be one of the issues we have for our SAP calculations in that we need a load of PV to offset the heat-pump usage.
     As an aside re ASHP, for our MVHR unit we are installing a Rehau EcoAir Ground to air heat exchanger to pre-heat (or cool) supply fresh air to the MVHR. As ASHP seem to have a significant power penalty and COP loss due to de-icing during winter why do none of them allow for such a simple pre-heat fix as a ground buried supply pipe?"

David N-C replied same day: I don't have a comparable consumption figure for the ASHP although there is data on the web, e.g., the Mitsubishi Ecodan brochure shows useful information. We have one in one of the ecohouses on the campus here, but i enquired and nobody is keeping metering records for it…. so what is the point. Its lived in by PhD students who could be keeping records!!
     If the store under your Viking house is uninsulated downwards, I would merely have about a metre down drop of perimeter insulation, and let the underside of the store reach down to the infinite everywhere below. Perimeter losses are very seasonal and wasteful. Is the footprint of the house sufficient? Mine is two storey, with a footprint of only 9.6x7.2m2…. If the pipes below are unjointed and made of ground loop or borehole rugged plastic, then there is better security against fracture. They should still be buried as deep as you are willing to go. If you are actively solar charging the store, you can protect against a frost heave, and if the occupant (you and successors) have a temperature sensor in the store, you can turn the solar charging off if you have an extremely hot summer and are worried about over heating.
     Ground to air exchange is a good passive method for pre tempering your MVHR air and Rehau are the best experts in it, including the means of dealing with health risks etc. That will be around the perimeter? I have an undercroft below this house, and should have thought of using that as an air intake if we had a whole house MVHR fitted.
     An ASHP is a closed box in that it is not designed to be adaptable. A GSHP is really a general purpose device that could be adapted by being linked to solar panels, air to air exchanger or ground boreholes. the one we have included the water tank, so is inside the house, to shorten pipe runs.
     The reason that ASHP doesn't use ground air exchange is that the airflow rate is many times that of MVHR. The flow rate would be so fast that there wouldn't be time for a heat transfer, whereas the MVHR only requires 0.6 ac/hr. Actually, I have just done a calculation and that seems quite a lot of air! For my house of 600 cubic metres, that means 360 cubic metres of change, which is 6000 litres/minute or 100 litres per second…. which has to be reheated by the MVHR.
    An ASHP is flowing 50-100 cubic metres/minute of air through its fan depending on size. Taking 50 for a house with excellent insulation, that would be 833 litres per second. A larger model would use twice that amount. It needs to draw the air from the infinite everywhere and not be hampered by the frictional losses of a pipe with an air intake big enough for children and animals to get lost in!

PS, to most people DHSS is the Department of Health and Social Security... only a few thousand google hits before finding the one you mean!

David R replies: "Thanks for all your input... We have a bigger footprint (around 115m2) but I can still see this being marginal for an effective heat store unless the pipes are trenched in at some depth, which has its own health and safety issues. I think I will try to get some comparative costs for what would be needed as a sub-foundation store compared to a borehole scenario.
    With respect to using ground air heating to pre-heat an ASHP, I had suspected the flow rates would be the issue and your reply certainly puts that into perspective.... I think the badgers have a surfeit of available habitat around here without adding more artificially!
     I will let you know how things pan out, thanks again for your consideration!"

Monday, October 28, 2013

Enquiry about putting thermal energy UNDER the house

28 Oct 2013: David R writes: "I read with interest your blog posts as we are currently attempting to build a code 5 / 6 property in Northumberland, albeit somewhat remotely as we currently live in sunnier climes!
    I have been intrigued for a long time about the use of soil for inter-seasonal heat storage and followed the Viking House iterations in Ireland with interest. Your own endeavours with solar recharging of the boreholes seems to be a similar concept.
    As we are soon to break ground we really have to decide on the most appropriate (and affordable) technology and I am still looking along the lines of a below house thermal store. I saw you posted a link to the DHSS site and I have had some communication with them about their product, but they seem to be suggesting a huge amount of solar thermal tubes to dump heat below the building structure. We are already committed to a Viking House style passive slab for the foundation with 300mm of EPS insulation, so we could easily look at installing a thermal soil store beneath the foundations but my own grasp of the physics involved isn't good enough for me to work out if this would actually work in reality and whether the house footprint would be sufficient for a GSHP in this recharging scenario.
     I wondered if you had any thoughts on this DHSS type of set-up?"

David N-C replied same day: Thanks for reminding me of the Viking House. Very impressive. My project started with an existing house, so could not bury energy literally under the house and the idea started with thinking of a Future house under which we would do what you are thinking of :- putting solar energy under the house with a very well insulated floor slab to contain it. A few problems with that:
  • If you make the store insulated, its as expensive as building yourself an earth filled swimming pool (without the pleasure) and couldn't be big enough to meet the needs of a whole house. it would be well freezing by the end of Feb!
  • The house could need a volume of solid soil larger than the house itself if you have it enclosed with insulation.If it is smaller, you need to build up to a higher temperature, and cool down to a lower.
  • House could be designed to span structurally across the slab area so that shrinkage or swelling are not a problem, but this is expensive.
  • You must never allow the store to swell with frost heave. When the store reaches below 4degs, it might be moving to a point where it expands after it gets cooler - lifting the house! GSHPs can go below 4degs. You should avoid putting so much heat into it so that it becomes like a hard rock with large shrinkage cracks which tear your pipes apart and require abandonment when leaks occur - or which cause house to settle.
  • If it is uninsulated (like a borehole), this is safer, as the store has 'infinite' size and pulls energy in from outside in the cold spring months to stop it freezing. It is safer against overheating as the outside mass will stabilise it by allowing surplus heat to leak out.
  • For those reasons, we reason that vertical boreholes... comparatively easy and quick to drill... NEXT to the house.... are the best option, provided the soil below is right. Infinite size, no risk to the foundations, minimal seasonal heat loss, minimum cost, minimum land. Four shallow ones are better than one deep one if you include solar charging.

October 2013 Reports

27 Oct 2013: (Just remembered, it's my mother's birthday... ) Sebastian Vettel won the Formula One championship, Lou Reed died, and Britain braced itself for a hurricane. Angela Merkel complained about the Americans having bugged her private phone for over a decade. The biggest talking point of the news is the hike in energy prices by the Big Six, and by them blaming it on green 'levies' and then Cameron completely siding with them and demanding a roll-back of the green levies the largest proportion of which he has applied since 2010. The greenest government ever was a lying electoral slogan.
    On Peveril Solar house, we still have this agonising 32 kWh between the PV and the GSHP consumption (triennial figures), but this is closing slowly - its equal to 3.6watts, an LED lightbulb left on for the year. The GSHP consumption includes hot water, so for heating, we are well into credit.
  • House annual 5,316, biennial 5,285 kWh. Reducing.
  • GSHP annual 3,229, biennial 3,227 kWh, triennial 3,209 kWh. Reducing. 
  • PV annual 3,080, biennial 3,058 kWh, triennial 3,177 kWh. No change.... 
  • Sunbox annual 3,366, biennial 2,901 kWh. One up, one down....
  • Ground Temperature 13.1ºC. Amazing...still above 13!
20 Oct 2013: Its been a week of cold and rainy weather. No figures this week.... but the weekend was sunny, so the end of week Ground Temperature was 13.1ºC - a brief twitch of the summer, before it finally gets really cold. The last beans were picked, and the courgette plants are still producing vegetables!
    In the world outside, the US government shut down ended - at a huge cost to the US economy, and with not a cent being deducted from the salaries or the perks enjoyed by the Republican congress men who caused it.

13 Oct 2013: We've had a whole week of overcast weather, with a lot of drizzly rain. As the same thing was happening a year ago, things are pretty stable. The heating is on every day now, and my wife expects it to be on, warm. We cannot sit around shivering in woolly pullovers trying to improve my metering figures.
  • House annual 5,373, biennial 5,282 kWh. Steady.
  • GSHP annual 3,301, biennial 3,243 kWh, triennial 3,233 kWh. Reducing. 
  • PV annual 3,080, biennial 3,075 kWh, triennial 3,175 kWh. Reduced... 
  • Sunbox annual 3,323, biennial 2,921 kWh. No change
  • Ground Temperature 12.5ºC. Now going into winter mode.

Friday, October 18, 2013

Lecture to CIBSE North West

17 October 2013: I was invited by the CIBSE North West branch to do a longer version of my lecture about the Peveril Solar House. This was held at Blundell Hills golf club in Rainhill (closer than Liverpool, but requiring me to drive in the car). I completely forgot to take a photo, but here's a screen shot of one of the PPT pages. According to Steve, the organiser, it was a larger turnout than usual, but I put that down to the excellent preview he provided for the lecture in his website!
Click the image below to get a PDF of the lecture.

Thursday, October 10, 2013

Second PV array to feed electric car

11 Oct 2013: Somebody called Trevor wrote a comment on an earlier posting of mine and he has directed me to an interesting blog about his electric Renault Zoe car. (I don't care if he works for Renault, the posting is about installing PV).
He has PV fitted in 2010, and that is the usual grid connected system with the Feed in Tariff. He has recently added extra panels on the north roof, because the 2010 system took up his entire south roof. He has kept solar generating metering records since the start, and house electricity records since 2008. It isn't clear if the second PV panel array is added to the original 3.7kW system as a grid connected system, because as far as I know, this would alter the terms of his original F.I.T agreement.
As the blog is mostly about the electric car, I guess that this is to reduce his small running cost of the car.

Wednesday, October 9, 2013

PV on a Train station
I heard about this project frmoAlex Mungo of Eco Kinetics, St Albans.
Eco-Kinetics specialize in installing Solar PV Systems, Solar Energy, Solar Panels and Solar Power systems for residential and commercial entities. They were recently successful in winning a tender for the installation of a trial system at one of Network Rail’s maintenance depots, which along with other energy reduction measures will help to reduce energy costs and carbon emissions at the site.
With a tilt frame mounting, and some active decisions to modify the angles every couple of months, this should be an efficient system. 

Digital Self Heating Homes

9 Oct 2013: More detail will be added about

Monday, September 30, 2013

September 2013 Reports

29 Sept 2013: The 'last twitch' of Summer is lasting longer than expected - the weekend was sunny and warm again. There have only been short periods of heating in the last two weeks. The annual figures are looking good because a year ago, the GSHP had moved into winter mode by the end of Sept 2012, whereas the forecast now is for it to stay at moderate temperatures all week. The Carbon Zero difference between the GSHP and the PV annually is down to 54kWh, which is 6W, less than a bedside radio left on sleep.
  • House annual 5,384, biennial 5,259 kWh.  Reducing.
  • GSHP annual 3,369, biennial 3,227 kWh, triennial 3,239 kWh. Reducing. 
  • PV annual 3,128, biennial 3,089 kWh, triennial 3,175 kWh. Steady... 
  • Sunbox annual 3,324, biennial 2,920 kWh. Sunbox energy still going up. 
  • Ground Temperature 13.4ºC. The ground has never spent this length of time above 13.0º in the previous summers...

22 Sept 2013: I am now doing the number-summaries fortnightly, but as a passing note, we had a last twitch of Summer with a hot and sunny weekend. With no house heating and with bright conditions, the ground temperature is back to 13.8º, and the annual Sunbox capture risen to 3,253kWh.

17 Sept 2013: Winter has arrived, we didn't seem to have an autumn. I'm sure there will be another warm spell before the real winter arrives. Most of the annual metered figures below seem to have levelled off, and any future change depends on how different the coming autumn-winter is to the previous two years. 2011-12 was warm, 2012-13 was cool and rainy.... so the 2013-2014 season holds the casting vote.
Carbon Zero?
Strictly we are not currently carbon zero, subject to a difference of only 70kWh/triennium, equivalent to an 8watt light bulb being left on, or less than the consumption of the broadband modem... or the cordless phone...  so a small difference. If you take away hot water and consider house heating only, then we are substantially in credit, by hundreds of kilowatt hours. House heating is about 700-800kWh less than the total heat pump consumption, perhaps 2,500kWh, which is less than the PV capture of 3,173kWh.
Ground temperatures size we started in 2009.... this week's
temperature is the first stage of the winter turn-down
  • House annual 5,418, biennial 5,227 kWh. This now seems to be the stable average.
  • GSHP annual 3,422, biennial 3,210 kWh, triennial 3,243 kWh. This appears to be steady too. 
  • PV annual 3,114, biennial 3,154 kWh, triennial 3,173 kWh. Steady... 
  • Sunbox annual 3,223, biennial 2,906 kWh. Sunbox energy capture levelled off, perhaps this will be the new annual average. 
  • Ground Temperature 13.0ºC. The heating has been on for a few days, and I am relieved that it is still 13....

Friday, September 20, 2013

Possible solar earth charging installation in Norfolk

12 Sept 2013: Here is an image of a house in North Norfolk that I visited to consider a possible Heat Pump and Solar earth charging installation. The conservatory will be replaced with a flat roofed kitchen extension, and there is room under the bedroom windows for 6 Solarfocus panels, ranged across the 6.5m of wall. We discussed the installation with a heat pump installer and drilling engineer, and this system is more likely to use charging pipes that run alongside the GSHP pipe, thus keeping the liquids in the two circuits quite separate and at their own pressure and temperature.

Tuesday, September 17, 2013

Winter comes in like a late train in a hurry - whoosh!

16 Sept 2013: Thursday 5th Sept was incredibly hot, the hottest September day for many years, but we all knew from the weather forecast that things would change.
     On Friday 6th, it all went almost directly to conditions where daytime temperatures were close to what had been night time lows... with a lot of overcast cloudy conditions, although still not much rain. The drop in barometric pressure is impressive. We have had the heating on for several days now.
    This relatively early start to the heating season will be bad for my metered consumption figures, although one can hope there there will be warm spells in end Sept or mid October to compensate.

Friday, August 30, 2013

Inverter off again

29 Aug 2013: After a day, I had to turn it off as the Inverter was making an alarm call, the TV was off, and the web-router off too.... seems that the battery doesn't hold enough charge to survive even a day. I don't know what to do now... the PV panel is bought and installed... so is the next thing to buy a conventional lead acid battery?

Tuesday, August 27, 2013

Inverter running now

27 Aug 2013: I have, very cautiously connected the battery to a load. It has had three days of charging slowly from the single PV panel, days of mixed cloudy bright conditions. The battery rose from a starting voltage of 11vDC to 13.6vDC.
   I have started using it by running the water pump that operates the evacuated tubes, 72W power consumption. This consumption occurs when there is sunlight or brightness in the sky, so the 200W PV panel should be able to meet this load.
   If the battery is happy after a couple of days, I will add more load by connecting more appliances, e.g. another of the waterpumps.
   The regulator is quite good in displaying the current battery condition, and it allowed the battery to rise in voltage to 13.6vDC which is something the car charger did not allow. Once it is working under load, it levels to an equilibrium of 12volts.
   One thing I have added to the group of appliances is the TV aerial amplifier in the loft. This means that when my wife complains that the TV signal has suddenly gone weak, I know that I need to go into the loft and see what is happening...

Perhaps in winter, I will need to connect the appliances to the mains, as before.

Monday, August 26, 2013

August 2013 Reports

26 August 2013: Weather continues to be warm and dry, so different from a year ago.
  • House annual 5,407, biennial 5,223 kWh. 
  • GSHP annual 3,420, biennial 3,206 kWh, triennial 3,243 kWh. No change.... steady... 
  • PV annual 3,133, biennial 3,093 kWh, triennial 3,176 kWh. Slowly improving change.... 
  • Sunbox annual 3,120, biennial 2,839 kWh. Sunbox energy capture still improving, I wonder what the new top line will be. It is the combined figure for the two sunboxes, and does not include the tubes. 
  • Ground Temperature 13.5ºC. This seems to be a consistent summer temperature. 
12 August 2013: The nights are getting cooler and we have had hints of Autumn already! It's been a good summer though, compared with 2012. The days have been a mixture of overcast with sunny spells, but not much rain.

  • House annual 5,417, biennial 5,210 kWh. No change..... 
  • GSHP annual 3,427, biennial 3,202 kWh, triennial 3,244 kWh. No change.... steady... 
  • PV annual 3,102, biennial 3,096 kWh, triennial 3,166 kWh. No change.... steady... 
  • Sunbox annual 3,024, biennial 2,789 kWh. Sunbox energy capture is improving (with the help of the ETFE front panels), it has now gone past the magic 3,000kWh point! 
  • Ground Temperature 13.6ºC. This seems to be consistent temperature, there's been no significant withdrawal from the borehole store, but there must be some diffusion of the energy outwards.... until the heating season starts!

Sunday, August 25, 2013

PV Panel connected up

24 Aug 2013: I've been back to Maplins for the more powerful regulator and that is now up and running - charging the bank of Nicad cells.
A double light switch is used as an isolator for the panel and for the line to the battery. It is super important to get the positive and negatives correctly wired up - check, double check before starting it up!There are 80 1.2 volt NiCad cells riveted together in lines, and in parallel to form a 12volt battery. Let's hope this works.
I will not draw any load off this yet, until it has had another day of charging from the panel.

Saturday, August 24, 2013

PV Panel up but not regulated

23 Aug 2013: The PV Panel for the house extension is now mounted and the DC cables are threaded through the vertical duct. It is not working yet because the regulator I got for it is not up to the job, and I should have realised this as it was a cheap Maplins one. This one is for a low powered device like a caravan solar panel or wind turbine. At the moment, it is 40v DC in, and 40vDC out.... should be 40vDc in and 12v DC out for the connection to the battery.
     Maplins also do a regulator for solar panels up to 500w. This panel is only 200W, so I now need another trip to them to get the more powerful one.

Getting the PV panel ready to lift - it is only 15 kilos, so the biggest worry is how to avoid scratching the surface while handling it.The PV panel in place. Held down with only 3 clamps, I need one more M8 50mm bolt to hold down the fourth.
The panel is delivering a healthy 40 volts plus, but I can see that there is room for improvement, already even though it is not connected. The photograph shows two shading hazards straight away.

  • The solar-thermal panel next to it is 200mm higher so there is a shading hazard as soon as the sun moves to the West after 2pm.
  • The garden fence is an open grid, but that is enough to cause a shading hazard in Winter. The roof angle is 15º, and the maximum winter sun angle is 15º the other way, so there isn't going to  be much gain. With the shadow from the fence it will be even worse. 
However, I could build four aluminium legs and elevate the whole panel by 200mm. Another little building project on the way. It will also improve ventilation underneath the panel (marginal improvement in performance in hot air temperatures).

Sunday, August 18, 2013

Another PV panel coming

17 Aug 2013: There is one more space on the east end of the roof of the extension. Today, I had delivery of a single PV panel, 800 x 1600. It has to be narrow to fit the space remaining. It's been delivered by Chris Wheelwright of Solarheat UK, a Nottingham installer, but as it is not going to be Grid-connected, it's going to be my job to install it. 

Monday, July 29, 2013

July 2013 reports

28 July 2013: The last week of July has been quite mild with a regular mixture of sun and light rain. The most noticeable change is the productivity of the two Sunboxes - the Surya-3 with the ETFE front panels is simply bounding ahead of all previous expectations! When the month ends, I will publish a new energy and ground temperature graph.
Some House figures:
  • House annual 5,415, biennial 5,210 kWh. 
  • GSHP annual 3,427, biennial 3,202 kWh,  triennial 3,245 kWh. 
  • PV annual 3,128, biennial 3,096 kWh, triennial 3,166 kWh. 
  • Sunbox annual 2,922, biennial 2,744 kWh. Sunbox 3 improving rapidly with the help of the ETFE front panels.
  • Ground Temperature 14.0ºC. This used to be the highest peak ever possible, now it is a more consistent temperature over a few weeks.

21 July 2013: Ground temperature dropped back to 13.7ºC after a cool weekend at the end of the July heatwave. Annual PV grew to 3,170, and the annual Sunbox capture increased from 2776 to 2878 after some days of exceptional weather and performance.

14 July 2013: the month started with a week of overcast and rainy spells, but the mid period of July is the longest period of summer heat since 2011. I have had to cope with leaks (which have been fixed), but I still have anxieties. The biggest worry would be a leak underground. Let's not think about that! Glycol solution does not dry off quickly, so there are long lasting tell tale smears if there is one.
  We have had several days this month when the system has packed 59 kilowatt hours in a single day - three times in the last 8 days! This is a combination of electrical and thermal storage. Now, I have a new target, which is to see if we can pack in a full SIXTY!

World News later, here are some metering figures for the midpoint of the month. For the House and the GSHP there isn't much change because it's summer! PV, Sunbox and Ground are on the way up:
  • House annual 5,399, biennial 5,204 kWh. 
  • GSHP annual 3,424, biennial 3,204 kWh,  triennial 3,249 kWh. 
  • PV annual 3,132, biennial 3,081 kWh, triennial 3,163 kWh. Improving - in first two years of operation the average was 3,300 per annum!
  • Sunbox annual 2,776, biennial 2,653 kWh. Improving rapidly with three systems working, and better weather.
  • Ground Temperature 14.1ºC. This went up thanks to a warm sunny weekend. This first time in 4 years that I am seeing ground temperature so high.
7 July 2013: I'm doing house reports on alternate weeks during the summer unless something changes.

Sunday, July 21, 2013

Energy levels restoring

20 July 2013: It is some months since I produced an Energy Levels diagram, and since the tee-piece leak and the repair to the leak, it is time to do another. Just before the leak occurred, there was good sunshine and the levels were on the way up nicely. There was a period of time when I was waiting for the replacement tee, the scaffolding was up for a whole month. (The more recent leak of July was fixed so quickly, it doesn't cause a blip on the curve, because it was just equivalent to a couple of cloudy days.
Diagram: Produced by ArchiCAD, using author's data and algorithm July 2013
I'm not sure why the curve should drop so steeply at that point in May. Although May was cold, it wasn't cold enough to have the heating on, although hot water was still needed. It could suggest that the borehole had warmed up, but without the additional heat being added, the energy level was dispersing outwards because the temperature had risen to higher than would be normal for May without charging.
The Ground Temperature line looks slightly different. The recent winter was not particularly cold, but it was very long and dreary, so the winter curve is very wide, and the dodgy spring (combined with the leak in April May and the heat wave of July meant that there was a strange look to the curve climbing out of the winter into summer 2013. The fact that the ground temperature of 21.7.13 has dropped back to 13.7ºC reflects the energy curve (top), implying that the larger volume still needs more energy to be injected before equalling the energy levels of, say 2011.

Sunday, July 14, 2013

Record capture on sunny days, and another pump exchange

14 July 2013: The ETFE is so effective that the heat can build up almost too quickly in the big Sunbox. I've decided to leave the bottom vents open to reduce over heating risk. Although the black collectors are vertical, the liquid temperature will zoom up to over 70º if the pump is not running. If the pump is running, it is still too slow (at 2-3 litres/minute) to remove this heat and I have been tricking the GSHP into using its pump to work cold, just pumping liquid round without heating or cooling. This brings the Sunbox temperature down to about 40º on hot days.
These show the liquid temperatures in each
of the Surya panels
  I decided that it would be worth investing in a replacement faster pump, so I installed a faster speed Wilo pump this morning (only took about 20mins). This will get the energy down below faster, allowing the panels to accept more solar energy. This pump uses slightly more energy than the previous one, but during the day, it is powered by the PV roof anyway - costs nothing to run!
  Today, the total Solar capture was 59 kilowatt hours! 23kWh of this is Photovoltaic, 7kWh from the tubes (highest ever) and 29 kW from the combined Suryas (also highest ever, Surya-3 was 19 and Surya-4 was 10). The afternoon got slightly cloudy, so we havent yet had a totally maximum performance from the PV roof.
  Ground temperature is holding steady at 14.1ºC, boosted by the good weather, but also by the additional solar thermal systems added since last year.

Thursday, July 11, 2013

Refilling and checking for leaks

11 July 2013: The hosing is now fixed and I need to re-fit the lower louvre. It is a very sunny warm day, so we must not waste any more of this free solar energy 'raining' down on the house!
The ladder is held away from the window with a ladder brace that makes the whole process safer, and enables it to be rested against a window without risking damage to the glass or frame.

Instead of filling through the top-up bottle, it is easier to take off an air-vent and do it through that - about 40 litres being returned to the panels! Every small part of it is run through a strainer. 

Hose is secured!

Looking upwards at the
repaired hose and clips
11 July 2013: After two days of slow draining of the Surya-3 Sunbox panels (which hold many many litres of fluid), I finally moved that piece of hosing 10mm sideways so that it is now equal between the two panels. The Jubilee clips have been retightened and the panels are not leaking. 
This was accomplished by a combination of ladder work and reaching out of the bedroom window. The work has still saved £250 worth of scaffolding, perhaps I should spend something like that on an improved energy meter for the roof mounted Surya-4. 
 I would still like a pop-up platform scaffold or similar for this sort of light maintenance. I think the hosing got moved when I was doing the work to insert the Tee-piece and i had to loosen off the panels and hoses to give some flexibility for fitting the tee. In the end, I used a simpler leakproof tee piece, but must have forgotten to fully check all the other hoses. 
I hope it doesnt matter that the jubilee clip
isnt pefectly lined up :( It is still keeping the
junction leak-free
Now it's time to refill.... Will be a long job. Took 2 days to drain.

Wednesday, July 10, 2013

Improved flow to Tubes heat exchanger

10 July 2013: This is ironic after mean and dispirited things I wrote only a few weeks ago about the Evacuated Tubes. But at this time, when the two Surya panels are closed off waiting for my repair, the valving and circuit design allows the Tubes to continue working, and they are doing splendidly.
   A bit of determination to fix it has fixed it! New pump is working well, and on Monday, I replaced the flexible tap connectors with normal 22mm piping - reducing all restrictions on flow, other than the actual heat exchanger itself. This means that the position of the H/exchanger is fixed, but it hasn't needed moving for a year.
   I still believe that a low temperature collector is more effective for solar earth charging. They really only seem to do anything when there is direct sunshine. But when the sun shines and the tube circuit is not working, the tube manifold temperature rises to dangerous levels, like 135ºC, and I don't want an exploding steam engine in my loft!

Monday, July 8, 2013

Fixing leak - probably needs scaffold

8 July 2013: The gravel on the ground below the sunbox has a distinct pattern of wetness. There's no point in collecting it in the bucket because it will be contaminated, but the bucket shows the 'rate of loss' quite well. 

I'm trying to fix it from the ladder, but it's very difficult and rather dangerous. I am using a lifeline and the ladder is tied on, but one still cannot exert real force on a screwdriver or see clearly what is being done. The hosing between the two panels seems about a centimetre too short, and tightening up the jubilee clip alone may not be enough of a fix (it did feel slightly loose).

Ladder or Scaffold
I have been up the ladder and had a good look, and the problem is the lower hose section connecting the left hand panel-pair. It's not enough to just tighten the jubilee clip, because, somehow (perhaps during the tee piece fixing) the hose got moved slightly, and is off centre. It needs to move 10mm rightwards, then re-tighten. I might be able to do it without scaffolding.
   If you never hear from me again, I am in the Queens Medical Centre after falling off the ladder. Seriously.... I will  use a lifeline and tie the ladder on securely.

Another leak, in a new place!

8 July 2013: Oh dear, I should have left the old scaffolding up a bit longer to test this system in hot weather. I haven't had a problem with a jubilee clipped hose joint before, but I've noticed recently the need to top up the system recently. The leak is definitely happening, and it is easy to detect now because the ground is so dry that one can see where drips are falling. It's at the mid point between the two panels on the left.

Sunday, July 7, 2013

Murray wins!

7.7.13: After 77 years without a British winner, Andy Murray wins Wimbledon in straight sets!
   What has this to do with the Peveril Solar house? well, I had to keep nipping out to reset the GSHP to do another half hour of cold pumping. This being the hottest day of the year caused our house to store 59 fifty nine kilowatt hours of energy in the day - made me wonder how Andy and Novak could do anything in 40ºC heat of Centre Court, let alone play at full stretch for three sets.
    The ground temperature (after some hours of rest in the middle of the night) was 14.1ºC, the highest it has ever been!

Heat pump help with cold pumping

7 July 2013: The hottest day of the year and Murray is slugging it out with Djokovic and Wimbledon! Meanwhile, I am keeping an eye on my solar earth charging circuit.

The ETFE Sunbox fronts are so effective that the temperature in main Sunbox (Surya-3) has risen to over 70ºC! This is far too hot and I need to find a way to reduce it. Liquid flow of 160 litres per hour is just too slow to remove this heat, so I have turned to the GSHP to circulate cold. The pressure of this pumping pushes more liquid up to the loft area if there are two small pumps up there pulling it along.When the powerful pump in the GSHP is cold-circulating, the assistance it gives to circulation is enough to boost the flow rate more than 3 times, to 490 litres/hr. It boosts the kilowatt rate to over three, and lowers the highest temperature in the Surya by 30 degrees - that gets the heat down more quickly and enables the black panels to accept more solar energy. 

The power used by the GSHP is immaterial because in this sunshine, it is being driven by the large Photovoltaic array on the roof!
    I know what my evening project is!
  • I have to swap the recently-purchased faster pump to the Surya 4 circuit
  • Modify the heat exchanger circuit for the Tubes to have less flow resistance, and return the Tubes to using the weaker pump. 

Friday, July 5, 2013

Summer temperatures

Top controller is for the Surya-4 metal radiators
on the house extension. The lower controller showing 64.5º
is for the main Sunbox with the swimming pool panels
Friday 5th July 2013: Warmest day of the year so far, and Saturday is likely to be hotter, and Sunday likely to be hotter still! This photo shows temperatures at about 3pm, and demonstrates perhaps how effective the ETFE is. 
    The vertical panels of the Surya-3 Sunbox have a steep angle to the Sun, so I would expect the metal radiators of Surya-4 to be doing better - at 15º pitch. 
  • On the S-4, the Sun has to fight through 6mm of solid Polycarbonate to get to the radiators. 
  • In the case of 2 ultra thin skins of ETFE on the S-3, most of the solar heat is arriving on the panels, and this photo shows a liquid temperature 34.4 degs C higher than the radiators, and about 40 degs hotter than the ambient air temperature. 

Exchange pump for tubes

Friday 5 July 2013: Circulation in the Tube-circuit is a problem, so Step One, I took all the components off and checked each one in case there was a blocked strainer. Everything is clear, although the flexible connections to the heat exchanger are quite narrow in diameter. 
  The main problem is that the low wattage consumption pump was too feeble to push the liquid through the heat exchanger and the other parts, unless it was at maximum power of 45watts.
  I've taken Step Two which is to replace the Wilo pump with a more powerful model - 6m head instead of 4m head. And in the next week or so, I will probably replace the Flexible Joints with fixed piping. That means that the position of the Heat Exchange will no longer be adjustable, but that is a sacrifice that is needed for improvement to the performance. This is working but needs to be at 72 watts to be strong enough to push through.

On the main Surya Sunbox circuit, I have removed one of the check valves (replacing it with open pipe) as it is not really needed, and I notice that the flow rate has improved, with the low power pump.

On the tubes, I need to remove the flexible connections so that all further obstruction is removed. 

Tuesday, July 2, 2013

Restart the tubes

The wiring includes an energy meter (middle),
the Kingspan solar controller (bottom) and
a 3 switch 2-gang light switch which allows me
to force things on and off. Actually, I could
do with another switch plate for some other
control functions.
1 July 2013: My main problems with the Varisol Tubes are flow rate and airlocks. This was all complicated by the loss of liquid caused by the leak in the main Surya3 Sunbox.
    I've done some plumbing and electrical work in the last few days, and got them working again. Perhaps they can be brought back into use.

1. I removed a check valve to improve flow through the heat exchanger (that works). I put it there to stop 'improper' flow when the more powerful flow from the heat pump is working, but this risk no longer applies.

2. Modified the wiring so that I can force the pump to come on (so that I can check flow rate and working action) - partly done, right->
3. Refilled the system on both sides of the exchanger with fresh liquid so that it can run - and gradually work the airlocks out. I don't have an airlock remover at the highest point of the tubes circuit, but regular pumping around does seem to remove them gradually. I need a sunny day with both pumps working to be sure it works.

By the end of the day, I had a new reading on the energy meter!! Looking at it working now, I wonder why it seemed so difficult before!

The copper heat exchanger is contained inside that block
of pink insulation below the pipework.

Monday, July 1, 2013

June 2013 Reports

30 June 2013: World News later, here are some metering figures for the end of the month:
  • House annual 5,413, biennial 5,209 kWh. 
  • GSHP annual 3,422, biennial 3,202 kWh. Annual dropping very slowly.
  • PV annual 3,071, biennial 3,093 kWh, Triennial 3,160 kWh. Bad two weeks with rain and cloud. In first two years of operation the average was 3,300 per annum!
  • Sunbox annual 2,663, biennial 2,619 kWh. Halted by the cloud and rain of June.
  • Ground Temperature 13.2ºC. This went up thanks to a warm sunny weekend.
23 June 2013: I'm not doing house reports on alternate weeks during the summer.

16 June 2013: World News later, here are some metering figures:
  • House annual 5,420, biennial 5,206 kWh. Annual dropping very slowly. 
  • GSHP annual 3,427, biennial 3,200 kWh. Ditto.. 
  • PV annual 3,087, biennial 3,122 kWh. Rising slowly - not an excellent June yet 
  • Sunbox annual 2,669, biennial 2,631 kWh. Halted by the long time of no action in May-June. 
  • Ground Temperature 12.7ºC. This went up to 13.1ºC last weekend (9th) with some sunny weather, but the rest of the week was rather cool.
9 June: This is the week of no solar capture earlier, but I got the Teepiece fitted later in the week and got the system working. There have been some sunny days, including the weekend, so the ground temperature jumped to 13.1º on Sunday evening. During the summer, it's not really worth posting figures every week as there is so little electric consumption by the house or heat pump that there is not much change. June 2012 was grimly cloudy and rainy, so we will see how the figures improve. June 2013 has started well.
  World news wise.... it was the 60th anniversary of the Queen's Coronation - more horse parades. In the same week, the Queen opened the new BBC headquarters in Portland Place. The Turkish crisis rolls on with the occupation of Gezi Park in Istanbul. Syria dominates the news too with Qusair being recovered by the government.
  The story of global phone tapping has been broken by the Guardian. Who can be surprised that the NSA in US and UK government were performing statistical analysis on trillions of phone calls, emails and messages, Facebook and Google requests and all? With all the worries about global terrorism, and security, this seems inevitable. They claim that they do not read the contents specifically (unless keywords are used), mostly it is to check the linkages and frequency. We shall see.
  Tom Sharpe, novelist, died, and Nelson Mandela is looking dodgy having been admitted to hospital yet again with respiratory infection. Surely they can let him die in peace? LondonDerry (Northern Ireland) has been voted European City of Culture and had a large ceremony - it seems better to do this in June than to do it on 1st of January, as did Liverpool a few years back - having a large music festival in January in bitter winter winds coming off the Irish sea was a bit difficult.
  As an oddity, a man in Bolivia got what many see as a deserved end - buried alive. I am not sure if this was an officially sanctioned punishment, or villagers doing their thing. Having raped and murdered a woman, he was in custody, and the grave was dug. He was flung into the open grave and the coffin of the woman lowered onto him, and the grave filled in. It says something about the culture that rape is punished in this way, compared with some countries where a raped woman is ostracised or even killed because she is no longer 'pure'.
  Sportswise, Rafa Nadal won the French Open Tennis for eighth time, and Vettel won the Formula One in Montreal.
 For the Peveril Solar house, it is only worth publishing numbers every two weeks, as little changes during the summer.

2 June 2013: The month of June has started with very good weather, and it is frustrating that the Sunbox system is not burying solar heat while it remains out of use. I am waiting for one solitary Tee piece. The first one arrived from Anablep but it was the wrong size, a 30-30-30 when I want a 38-38-38 tee piece. I am still waiting for the right ones to arrive. It will only take an hour to fix up, and yet lovely days of sunshine are passing by!
  The ground temperatures chart below is interesting. With negligible heat being drawn up by the heat pump (a tiny bit of hot water only), and no solar heat being put down either, we seem to have settled on a stable summer temperature of about 12.4-12.5ºC. The Sunboxes have been out of use since the scaffolding went up, and while they were working there was a rapid upward acceleration of the ground temperature from 10.6 to 12.5º.

  • House annual 5,460, biennial 5,209 kWh. Annual dropping very slowly. 
  • GSHP annual 3,459, biennial 3,203 kWh. Ditto.. 
  • PV annual 3,026, biennial 3,148 kWh. Very static.
  • Sunbox annual 2,666, dropping fast because nothing is being put down.
  • Ground Temperature 12.4ºC. This seems to represent the summer norm (for this time of year) if nothing much is being put down or taken up. (I would expect it to rise with natural warming to 12.8º by July if the sunbox is not repaired.)
World News? Turkey has come from nowhere to be the biggest story, with the proposal to build a shopping mall (using a pastiche Ottoman style) over Gezi Park in Taksim Istanbul. A peaceful occupation of the park (to save the trees) turned nasty when the police over-reacted, inflicting excessive punishment over the tree-savers. In a more unexpected place, Stockholm has been suffering from riots, youth unemployment, especially in the immigrant communities has spilled over into violence. Beloved actor Bill Pertwee (Hodges of Dad's Army) died. It was the 100th anniversary of Stravinsky's Rites of Spring and of the death of Emily Wilding Davison, who leapt fatally in front of the Kings Horse at Ascot.

Monday, June 24, 2013

Dump the Tubes!

22 June 2013: Many of my problems with the system comes from the small circuit that goes to the evacuated tubes. Before they were fitted, the solar recharging system was very stable for 2 years. The leaks and bursting airlock removers etc happened after that. the tubes circuit has never recovered more then 7 kWh on the very best of days, and mostly less than one per day, even on good days.
       The lesson is that if you have one element that can make over-high temperature, it must be on its own closed high-pressure circuit. It cannot be on the same loop as the heat pump or the low temperature fittings. This was the idea behind fitting the heat exchanger, but I have had endless problems with the heat exchanger, possibly due to airlocks.

  As of this week, they are isolated with valves closed and the electricity to the controller turned off, but I might make the big decision to isolate them entirely, i.e drain the coolant, and disconnect altogether, and put stop-ends on the pipes.

Expansion Tanks
One thing I must do is make sure the existing expansion vessels are more effective. This is the primary method for preventing leaks. I read up on them recently and found the opposite of what I expected. They all have the bicycle valve (Schraeder) on top and for some reason, I thought that letting them off a bit would provide more expansion. If this occurs, more liquid flows in, and there is less air space for expansion. They are intended to be pumped up to about 30psi (about 2kg/cm2). 

Wednesday, June 19, 2013

Twin boreholes in the same hole: Calgary solar

18 June 2013: Robert from Norfolk sent me a link to a paper published in 2007 for the 2nd Canadian Solar Buildings Conference, Calgary, June 10 - 14, 2007. It is authored by Bernier and Shirazi. The link is:

Very interesting. I note that the abstract claims that their purpose is to find a way of reducing the depth of the borehole, which seems a small cost saving to aim for. It seems to be based entirely on mathematical modelling, I cannot find a mention of a real building being used as a case study. There are some very useful and deeply mathematical methods of calculating the borehole size.

That part of Canada has a 'continental' climate, and there's a very short summer, and a long long winter. See the above Degree Day graph to compare Calgary [blue] with Nottingham [red]. This degree day curve symbolises the amount of heat required for comfort. It's so cold in Winter that you would keep the heating on overnight, whereas a well insulated house like ours in Nottingham, England needs no heating at night. Even in winter, it is off from 9pm to 8am.
    Solar heat is 'interesting' in a climate like that, but with such short summers and long winters, its a tough call for it to be significantly useful - but one of the most famous examples in the world is Drakes Landing, about 30km south of Calgary.
Diagram by Bernier and Shirazi
It's useful to have that article with the formulae. It is also interesting that they propose to use an entirely separate but along-side set of pipes for the solar ground loop and GSHP ground loop. That is a good idea, if you are going to drill the hole:- make it big enough to drop two sets of pipes in, not one. This would avoid cross contamination, pressure variations, etc. The GSHP loop can continue on cheerfully, even if the Solar loop is discontinued or faulty.

Monday, June 10, 2013

Repairs to the Tee piece, done!

10 June 2013: The repair is done, and the system ran for many hours without any sign of a leak (the jubilee clipped hose joints have never ever leaked.)
I now have to close up the sun boxes and we are in business again. I forgot to photograph the finished tee close up, sorry! I don't see how the tee piece can fail now, but if there is excess pressure, it's a bit worrying that a fail could happen elsewhere. That's why there are 4 expansion vessels on this system!

The tee piece is in place and I have restored the centre panel cover, and the insulated ducting to the inflow pipe. Here is a view of the repaired tee piece, looking upwards!
The left hand outer ETFE panel goes on. I needed a helper, but managed somehow. The main problem was the risk of puncturing the ETFE by letting the panel fall against the sunbox sharp corners. Now the right hand panel goes on. 
I have another week of the scaffolding, so I will hope for some sunny days and monitor the performance of the system. After just one day of working, I noticed that the ground temperature has risen from 12.7º on Saturday to 13.1º on Sunday evening.
I have some numberplate lettering so I can have
on the panel

Monday, May 27, 2013

Work on the Surya3 panels - tee-pieces

26 May 2013: I have finally made a start on the re-plumbing of the panels (where the leak is occurring). I am glad I didn't start earlier in the week and then have the strong windy conditions of last Friday. Unfortunately, the system is missing several days of good sunshine, but that is all greater incentive to get on with the task. 

The first ETFE panel is lifted off and stowed carefully to one side.

Both ETFE panels are off and I can see where the leak is coming from. The 40mm compression joint was good for a year, but then it began to leak from one joint. This was a bit of 'working on the cheap' that worked OK for a year, but has now cost me a lot in wasted glycol, scaffolding, time, worry and lost sunny days.

Waste pipes are normally dry, i.e. the liquid flushes away and are not really good for a permanently filled pipe with occasional pumping or thermal pressures. I should have done more research on other piping solutions.
Here is the junction with all pipes taken out, and I need to insert a replacement Tee-piece.Unfortunately, the Plasson connector will not fit and gave me some hours of despair. I even considered taking the entire system down and relying only on the new roof mounted panel. 

When the panels were originally built (with a Plasson fitting) it was difficult then, but with all the polycarbonate casing and the metal, it is now quite impossible to get a Plasson back in. Taking the system down is inconceivable not just because of the holes that would be left in our wall, but because it it my research topic and the main purpose of this blog! It is proven to reduce the consumption of the heat pump, so it needs to continue working!

I spoke to a near-neighbour, Chris Bright, who also happens to be an engineer at Rolls Royce, and he suggested that there were other tee-pieces that I could find that would be good enough. I kicked myself for not having tried harder a year ago when I had weakly assumed that the compression waste fitting would be good enough.

This item is a 'rubber' tee piece that can be pushed into position, but needs a rigid pipe connector to the panels either side. Also, I don't need directionality of flow, nor a doubling of the number of jubilee clips.

This above is the ideal solution. With a 'male' tee-piece, I can have one flexible 40mm hosing connection to each of the panels at the side - fewer jubilee clips and reduced opportunities for future leaks.

By the way, it is only about three pounds! I have ordered one of these by post, and it'll arrive during the week. There is a local company, Tennant Rubber, who have a vast variety of rubber and plastic hose types, and I can choose more of what I used before, of the more flexible type.

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