Monday, January 28, 2013

January 2013 Reports

27 Jan 2013: A long grey week with the snow on the ground, but there was a lot of rain on Saturday night and warm sunshine all Sunday. Great for outdoor work, every trace of snow was melted, and my solar sunboxes were doing well. Solar capture in the day was 19 kWh, totalling both sunboxes and the PV.
   Elsewhere in the world... we had the outdoor inauguration of President Obama, Andy Murray made it to the Australian Open final, but lost in 4 sets to Djokovic. There is a breaking news story about a night club fire in Brazil. There's a big economic summit in Davos, Switzerland and David Cameron is digging himself into embarassingly deep snowdrifts with his In/Out European policy. The Mali situation continues. It was the 200th anniversary of the publication of Pride and Prejudice. Our new semester starts at the university, and we are running a dual channel of Tall Buildings and Wide Buildings. For the Peveril Solar house:
  • House annual 5,520, biennial 5,058 kWh. 
  • GSHP annual 3,506, biennial 3,048 kWh. If February is warmish, the figures will come down.
  • PV annual 3,011, biennial 3,203 kWh. Snow on roof all week.... 
  • Sunbox annual 2,416, biennial 2,745 kWh. Biennial going up a bit.... 
  • Ground Temperature  10.6ºC . It helped, having two sunny days at the weekend, especially Sunday! (Lowest this winter is 10.4ºC)
20 Jan 2013: Britain has been blanketed with snow all week, and I have published a stop-frame movie of the tobogganing just outside our house.
Collection of Twitter photos compiled
by the Telegraph, of the Helicopter crash
     Elsewhere, the world has been gripped by the story of the Algerian gas plant taken over by Islamic terrorists and many hostages held or killed. Barack Obama has been sworn in as President in a private ceremony and the big open air one is tomorrow on Monday. In or Out of Europe is being heavily discussed in England, but isn't it always? Lance Armstrong came clean about his drug-taking on TV with Oprah. A helicopter collided in low cloud with a crane on the new Vauxhall tower and crashed into the streets below - if he had held his course northward he would have been safe, but he got worried about the fog and diverted westward towards Battersea - causing him to hit the crane. Some climbers in Glencoe were killed in a snow avalanche - very sad seeing those faces.
     The snow has blanketed our house all week, and so we have terrible figures for PV, Heat pump and Sunbox. According to my iPhone weather, the next smallest glimmer of sunshine isn't expected for another 4 days! We just have to hunker down and hope for better in the Spring.
  • House annual 5,496, biennial 5,060 kWh. Groan, going up!
  • GSHP annual 3,505, biennial 3,055 kWh. Oh dear.
  • PV annual 3,019, biennial 3,202 kWh. Doh!
  • Sunbox annual 2,420, biennial 2,734 kWh. Nothing in the last week... 
  • Ground Temperature  10.4ºC . Squeaky bum time, I hope we have a bit of sunshine next week! Must not go below 10.0 !!!
13 Jan 2013: Weather has been cold and is predicted to get colder, but the house is snug and warm, and  the electricity consumption is still moderate while the energy level below is still good. I like sunny Sundays because it give the ground temperature a bit of help. Snow is falling lightly as I write.

Elsewhere.... the gun debate in the US went ballistic for a while when Piers Morgan and Alex Jones had a hilariously confusing debate on TV, and a gun loving idiot called James Yeager promised to 'start killing people' if the President brought in any form of gun control (look them up on Youtube). The Royal Airforce are supporting the French in missions in Mali. David Bowie produced his first new song for over 10 years. London Underground ran the very first underground steam train along the Circle Line. It has been lovingly restored by a Buckinghamshire Railway Centre for the occasion.
   Climatically, Australia has had a sequence of the hottest days ever recorded with continent wide averages temperatures of over 40ºC - with a flashpoint high enough to cause terrible fires. The US has had the hottest year on record, and still the majority of US population seem to deny climate change. 
   Energy figures are about the same as last week, with the main change being a consistent climb in solar capture from the Sunboxes.

6 January 2012: First report of the year, and so far, it hasn't rained! Well, not in Nottingham, anyway. In 6 days, it has averaged three sunny days, and three overcast days. In the US, the Fiscal Cliff was avoided, and nothing of note happened in the UK. With the weather being so mild, our ground temperature has gone up slightly, and consumption figures are looking better than I hoped.
  • House annual 5,426, biennial 5,029 kWh, and I will be soooo happy if this gets below 5,000.
  • GSHP annual 3,428, biennial 3,033 kWh. ditto if it can get below 3,000 biennially.
  • PV annual 3,035, biennial 3,209 kWh. No significant improvement yet!
  • Sunbox annual 2,451, biennial 2,757 kWh. Looking better.
  • Ground Temperature - 11.3ºC . It has gone up after the mild and sunny week, but I am sure there will be a cold spell before the Spring sets in.

Sunday, January 27, 2013

Sunniest day of the year 2013

27 Jan '13: We've had a day of strong sunshine after hours of overnight rain and the combination has converted the snow draped landscape back to normal! Good day for the solar panels too! This is a print from the Sunny Portal view, as seen by my iPhone - the roof is connected to SP in real time and the graph is built up during the day.

Sunday, January 20, 2013

Conservatory heat loss : good!

20 Jan 2013: Further to my question about the effectiveness of insulation, this seems to be to be a pleasing photo. We have had snow for 7 days now, and this snow on the glass roof reveals that we are not supplying heating to the underfloor coils in the conservatory floor - the valve doesn't work correctly, so we have a pound coin buried in the valve that keeps it shut! Also, it reveals that there is so little heat loss through the inner french windows that the conservatory hasn't had enough heat to melt off the snow. I'd quite like some more snow, actually! Apart from the lack of PV earnings, a bit of snow makes life more interesting, especially travel.

Saturday, January 19, 2013

The view from my window, time lapsed

19 Jan 2013: The hill behind our house can be annoying for solar reasons, because the sunrise in winter solstice is a whole hour later than for people living in the plains. But there are compensations, it is a great place for walks, and when the snow arrives it becomes West Bridgford's winter sports resort.

Insulation readings with infrared thermometer

19 Jan 2013: It's freezing and we are surrounded by snow, and the heating was turned off at 8pm last night. I did some testing of the temperatures next day at 8am, after 12 hours of no heating. I use an infrared thermometer, but it rounds all readings to the nearest integer degree. Sometimes, it flutters between two, hence the dual figures below.
    The internal walls and ground floor are 19º/18º, upper ceilings 18/17º, the external walls 16/17º. The house extension walls were 16º, and the floor slab (which has no heating pipes in it) 17º.
    For those considering an investment in triple glazing, the normal double glazed windows were 14º and the triple glazing surfaces were 15º. I don't have a single glazed window to compare with, but the exterior of the glazing was zero, so one guesses that its the same on the inside as glass is thin and conductive.

Matt F asked below about these Infrared Thermometers. Ones like this vary from £20 to £30, and perhaps there are some that cost more, but the one I have was £30 from Maplins. It would be nice to have one that shows tenths of a degree. This one has an illuminated display if you have to work in the dark, and has a laser pointer if you want to pick on a detailed object like a pipe, valve, lightbulb or lintel edge. The range is unknown, but it seems to work over 10m and perhaps 20m.
    This is better than paying £850 for a slightly better one from FLIR. It is scandalous how much thermographic cameras cost. We are in a time like the early days of digital cameras and scanner when they were very very expensive. Scanners collapsed in price after USB came in, and cameras collapsed in price once they were included in mobile phones. I don't even use a camera now, the iPhone does everything!
  Unfortunately, they believe that nobody will ever create a mass market for thermographic cameras, so they might as well maintain the high price. This one in the picture is over £10,000 I think, more than a car or motorcycle. That cannot be right!

Monday, January 14, 2013

Snow falling, check insulation

14 Jan 2013: First snowfall of the year, and it's a chance to see how good the loft insulation is, in our house and our neighbours. Well, it looks good at the north end, but the south end is disturbingly well melted. There is a thermal connection between roof and walls where they meet at the verge. I don't have the thermographic camera at the moment, but perhaps I can use my infra-red thermometer to get a few readings.

We are not going to get any sunshine today!!

Looking back:

Here is my photo from one year ago, Feb 2012, showing that the bigger losses are from the thermal bridges around the windows - which is normal for non-Passivhaus british construction.

Postscript 20th Jan 2013: After a week of snow on the roof, it is clear that the insulation is good. The reason for the uneven coverage on the first day was that there was a strong breeze from the south east and it was blowing the (then) very light powdery snow along the roof and it was building up at the north end. After a lightening of the breeze and a continuation of snowing, the coverage became even. 

PV for the year 2012

13 Jan 2013: The PV figures for 2012 were severely down on the previous 2 years, and you can see why with these images from the Sunny Portal. June was terrible. The rain that spoilt the Queen's Jubilee Flotilla and countless street parties across the country also cause a massive blip in the PV figures. Instead of being over 500, it was only 360 - and July was bad too. May was good.

Sunday has been very sunny, even though we woke up to see snow on the ground around the house. One day, about 4 days previous, the web router was accidentally unplugged, hence the impression that one day earned nothing. 

Sunday, January 13, 2013

ETFE Condensation

13 Jan '13: The Sunbox is doing really well with the midday solar angle being almost straight on, and the double-skin ETFE having far better transmittance than the old triple-skin polycarbonate.
   One thing I have to live with is that the sealed units have a permanent H2O population that takes different forms depending on temperature - today there is a haze, other times, they are clear with discrete droplets. Never mind, the greater solar visibility of the black collectors has improved performance. Solar thermal collection since 1st December to 13 Jan was 131kWh in 2010-2011, was 171kWh in 2011-2012, and this winter was 205kWh (including a small contribution of 20 from the new Sunbox)

Sunshine after the snow

13 Jan 2013: After a light covering of dawn snowfall and below freezing temperatures, Sunday has been true to its name, with lots of free solar energy pouring down, thermally and electrically!
View from the South westView from the South east

Someone called Linda asked me if the upper boxes cut out light to the bedroom. The boxes do not cut out low angled winter sun. Yes, they might reduce white daylight very slightly, but each room also has a large main window east or west. The overhanging boxes provide solar shading in summer, which is welcome.

Thursday, January 10, 2013

PV-Thermal evaluation by Solar Blogger

9 Jan 2013: There's an interesting article on the Solar Blogger website by Stuart Elmes. It's about PVT (Photo-Voltaic-Thermal) panels, and he has a more technical PDF linked to it. The link was sent to me by David B. of Newform.

PVT panels are, in essence, a PV panel with a mesh of liquid cooling tubes behind the PV surface. For higher PV capture, the panel is uncovered, but for a higher thermal capture, the panel has a glass cover over it and insulation behind.

   I am a great believer in PVT, but the only properly productive application for it that I can see is when it is associated with low-grade thermal storage and heat pump.
   It could also good for those who have a limited area of roof, and haven't enough space. If you have enough roof surface to play with, the best place for PV might not be the best place for thermal. Ideally, a house needs 28-30 square metres of PV to attain the 4 kW that is recommended for the Feed-in-Tariff in the UK - a smooth, unobstructed and unshaded area facing south is the best. PV arrays normally have an air space under them and they work best on sunny days with a cooling northerly breeze that can get under the panels.
   For solar thermal, the size can vary from 1sqm to 4sqm. Above that, it gets a bit silly unless you are addicted to hot showers all summer. So Solar thermal can often work well in smaller locations on hipped roofs, or large dormers, providing you can get a south aspect. Another criterion for best place might be closer to the optimum positions of a tank and the plumbing.
   The idea of PVT is that you get a larger area for thermal, and the PV element is cooled by the liquid passing under it.

   The paradox is this: for you to get useful heat to a water tank, you want the panel to run very hot, but for the PV panel to run well you want it to run very cool. Stuart's article explains the paradox well.

   So for a solar thermal water tank you want the circuit to run at 50-70ºC, and when the tank reached 60ºC, the circulation would stop. If you ran PV at these temperatures it would be unworkable. If you want PV to be optimised, the purpose of the liquid has to be to cool the PV, so it should be circulating at 15-20ºC. A normally air cooled PV panel reaches 40-50ºC surface temperatures on a hot summer's day, but the PV cells run better is the wind is blowing.
   If the water tank reaches optimum temperature and turns off the pump, the sun will make the PV even hotter, and as there would be insulation behind the PVT panel, there's nothing to stop the liquid temperature getting dangerously high. Stuart's article refers to the risk of temperatures as high as 220ºC. (I am informed by Newform that this might be a mistake, as Powervolt panels permitted to stagnate seriously haven't gone higher than 100ºC, although the glass topped Powertherms might get hotter.)

Therefore, for thermal storage for a heat pump, the panels running at 15-20ºC would be warming an infinitely large tank size, the earth, whose base temperature would be 10-12ºC, so there will always be a benefit. There is no risk of any of the system reaching stasis and turning off because earth has a vast thermal capacity in relation to the size of the panel array or the size of the building above it.
    Having a larger surface area than normal solar thermal panels (28sqm instead of just 2 or 4sqm) the solar thermal gain for the store - large volume of low grade thermal energy is going to be very good! One thing that my experiment has shown is that the ground does not get 'hotter', but the volume of earth that is warmed up to a moderately warm temperature gets larger.
    One thing about any of these systems, is that they must keep running. If the system circulates reliably everything is the right temperature. If a future owner of this house just turned the solar circulation off in summer, there would be problems if temperatures rise and there isn't sufficient capacity for expansion of the liquid.

In this house, we were within a gnat's whisker of having PVT, and I had already emailed Newform with preliminary arrangements for delivery and invoicing. 
Four reasons we changed direction: 
  • My wife rebelled against the cost of the PVT, when we have no real need for the extra electricity, 
  • I had problems with the battery I intended to use for the PV power, and 
  • I was offered a large amount of polycarbonate, aluminium and two large radiators, an offer so good, I had to accept it. I also had a good collection of OSB and timber, enough to make an entire sunbox without buying any materials other than plumbing connections.
  • I considered my research priorities, and the general thrust of these are to prove the efficacy of a black collector in a polycarbonate sunbox. With only 4 sqm of roof to choose from, there is only space for ONE more device - had to be a Sunbox.
If I was starting this house again, with the knowledge I have now, I have no hesitation in saying that I would use PVT panels in association with the borehole and heat pump - instead of the existing array. But these were not available or known to me in 2009.


Tuesday, January 8, 2013

Aluminium eaves detail

7 Jan 2013: Here are some more aluminium strips, cut and shaped to form the eaves detail. Nearly finished.

I have supplies of the 0.7mm aluminium left over from the roofing. This is ductile enough to cut and shape nicely.

Nearly finished. The eaves sheets have been pushed under the roof sheets, and there are metal tabs under to which they are finally riveted. Then bend them straight. This detail doesn't look quite right, it needs pushing in a bit on the left! Main thing - it keeps the rain out perfectly!

Saturday, January 5, 2013

Winter Sunbox capture

5 Jan 2013: The Sunbox annual solar capture figure has been lower recently, due to two things. 1. the months of the spring when I had a leak in the system and it was off for a month, and 2. the rainy grey weather that we have suffered from April 2012 to the present day. I sometime regret having changed the profile of the original sunbox from vertical to sloping. The later decision to use ETFE means that I might have been just as well to stay with the vertical fronts, and because there is better solar radiation on the black panels inside, it could have stayed as the two boxes instead of one.
     The peak annual capture of the sunbox system was 3,090 kWh at the start of March 2012 and the worst was 2,419 kWh at the start of December 2012. It is climbing steadily now, and here are some figures that cheer me up. I also have a far more accurate and reliable meter, the Sontex Supercal 440.

[Updated 13 January]
I have been sampling a winter period from 1 December to 13 January in the last three years:
  • 1 Dec 2010 - 12 Jan 2011: 131 kWh
    (with the vertically fronted 6mm single skin Sunbox)
  • 1 Dec 2011 - 12 Jan 2012: 171 kWh
    (with the sloping fronted triple skin Sunbox)
  • 1 Dec 2012 - 12 Jan 2013: 205 kWh
    (with the ETFE fronted Sunbox and 18 kWh from the roof unit.)
It will be a long climb back to the glories of an annual figure of 3,090, but this is a very good start, and let's hope for sunny weather in 2013!

Friday, January 4, 2013

Finishing work on the extension

4 January 2013: The only slating to finish is the sill-bit below the large window, but I can't do that until I can buy more aluminium angle, and the Faculty Engineering stores don't re-open until 7th Jan. The East and West walls are finished, and I have now fixed down the aluminium roofing

There are some slates temporarily fitted to keep the
battens dry, and the green metal sill is now fitted.
I had to make a component for each end, like this, that provides four tabs that the folded over aluminium roofing can be riveted to. It is a 25x25x3mm T-section, with 1.6mm aluminium bent tabs riveted to it. The tabs are over long, and get trimmed back to size.Night photo of the edge section, tucked in below the overhanding roof panel. The 0.7mm aluminium sheet roofing is lifted briefly, for the photo. I tend to work in the evening darkness a lot, and use a headlamp. 
Daytime photo of the west end, showing the edge section, one of the four tabs, and the long screw about to fix it through to the structural OSB panel. All this aluminium is made from scraps in the metal scrap box, or recycled from earlier projects.
I have a philosophy, which is, that if the thing you need doesn't exist, DESIGN it, MEASURE the site precisely, and then MAKE it!
I calculated at the builders merchant that I would need 200 slates. Because they only sell them in packs of 15, I considered getting 195, but they are not expensive, so I bought 210. The work is completely finished. So how many have I got left, unused? well…. there are TEN, meaning that my estimate of 200 was precisely calculated to the exact number! I didn't have any lost or broken slates, and tried to make double use of slates wherever possible (i.e 2 small pieces can come from each end of one slate.)

The Sunbox4 is at the east end of the extension for four reasons.
  • It gets rain shelter from the Surya sunbox above it, 
  • it leaves space at the east end for a future PV panel, 
  • it means that the pipes supplying it have the shortest possible run to the vertical conduit, and 
  • I can examine it from the bedroom windows above to check for leaks or any other problem.
The West end with the aluminium roof sheeting finally riveted down. Neat job!

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