Friday, December 31, 2010

Graph of the Year 2010

31 Dec '10: This is a good time to summarize the year. In short, the graphs show a good story.
• The vertical line shows the date of the installation of the Sunboxes.
• The blue mound representing the deep ground temperature is clearly hitting the end of the year about 3 degs C higher than it was at the same time last year.
• The performance of the GSHP (yellow line) is far smoother and logically related to the air temperatures (red line).
I hope this results in a cost saving in electricity over the entire year, when we reach March, the anniversary of the Sunbox installation. If not, don't forget that we have had a very severe winter so far - this has not been a typical winter, in fact we have had the equivalent of 2 winters within 2010.
  Also there is the long term vision. The ground chilling effect is one that takes place over 5-10 years before it reaches a low steady state. If this system has the effect of maintaining a consistent warmish temperature every year instead of letting it chill, then it will have succeeded! But we shall never know how cold it would have got without this. Simply, if I knew someone else nearby with a GS heat pump in a similar sized house, one could test their ground temperatures as a comparator.

Ground Temperature
  Later in the evening, during our New Year's Eve party, I did a meter recording, and when the guests had gone I did a deep ground temperature test.... the result was 10.3º (higher than last week's 10.0º). I am assuming that this slight rise is due to the reduced rate of extraction, as the entire week has been above freezing, foggy and cloudy. No solar heat put down for a while week, but not so much heat required from the ground.
  In case you are wondering why there is more fluctuation earlier in the year, I can also say that as time goes on, I get more strict about standardising the procedure. I now let the heat pump sleep a full 4 hours after it has last done a heating cycle before running the temperature test - so I might turn it off at 9pm and test it at 1am, and the ground temperature has evened out. The test is run for 15-20 mins, and the reading taken after that time.

Tuesday, December 28, 2010

Charging is visible on Mobiles

28 Dec '10: I just discovered that it's possible to view this blog (and the others that I do) using a Mobile device. Normally, you need a phone with a large screen and very good reception to pick up a full web page. Most of the heavily used sites like the BBC, Eurosport, Guardian have Mobile versions.
   Well thanks to Google blogger, we have too! If you have a mobile phone, try this site with your iPhone or Android phone. (I hope it works for you).
  I already use my iPhone as the hand held device for my PV roof, now it is even more useful, for checking my various blogs!
  I notice that the iPad is treated as a computer, not as a mobile, even though it's using the iPhone OS. Up comes the full display, not the mini-mobile one.

Friday, December 24, 2010

Energy meter misreading

24 Dec '10: Doh! Just before the Christmas break, and with the Sun shining brightly and quite visibly pumping heat into the ground, I see that the Sontex Energy flowmeter has gone wrong. It is still displaying volume pumped, and the clock is still working, but the energy display is showing Error 2.
So I may be able to work on an estimate, based on previous readings.
 I don't know if it's the unit, or just the return flow sensor. But it's holiday time, nobody will be open till new year, and the readings will just have to have blank entries for a while, sorry.

26 Dec '10:  Got back from Xmas in Norwich to find that the energy meter was displaying Energy rating again, and the figure shown is reasonably compatible with the last recorded figure (i.e. related to the number of hours run and the amount of sunshine in the last 3 days). It must have missed a bit, but not too much..... At this time of year, there are same days with zero.

I still want to know what 'Error 2' is on this meter... Hmmm.. I just found out from the manual, it's an error with the second sensor. On Thursday, I packed insulation tightly round the piping in the attic, and that included the second sensor, and perhaps there was a bit of pressure on the wire causing it to lose connection. On Friday, I removed the insulation, and freed up the wire that runs into it... and it's working.... phew! Repacked the insulation, but less tightly...

28 Dec '10: Another Doh! There hasn't been any sun for three days running, and none likely till 3-4 days away, so no chance to really see how that Energy meter is working. It is no longer showing an error message, so I will be patient.

Thursday, December 23, 2010

Adding Gas?

Dec 23 2010: We have had gas in the house since it was built - we asked the builder to omit it, but he had already paid the Gas board to install it, and as it had to be included, we decided to have a neat minimal fire that could be in the living room and be a blessing in case there were power cuts or severe cold - especially as we had no experience of living with a heat pump or underfloor heating.
    As it happened, we have hardly ever used it, and our total bills since 2007 have added up to about £5.40. - less than most people use in a single day in a gas fired house at this time of year. We tried to get it working recently to lift the air temperature : it would possibly reduce the workload and consumption of the heat pump because the carpet in the living room reduces the effectiveness of the underfloor heating. Not having been used for over a year, it would not light. The piezo worked, but the pilot would not light up. We had some guys in to check it, and £50 lighter, we now have one that works. I am not impressed that a new product is going wrong after only £5 worth of gas, but the problem is that if you don't use some mechanisms, they get stuck. This needed the front panels taking off, the burner unit, lifting off and then a good vacuum cleaner to get dust out of the pilot light nozzle. I know what to do next time!
    I have now included the gas consumption in my meter readings, so will not use it to reduce the electricity consumption and not let all the readers know! But at 3.5p per kWh, it is unfair to deprive my wife of the warmth that it gives on these cold nights.

Wednesday, December 22, 2010

How 'Large' is CO2?

CO2's Volume: It's very difficult to imagine GASES by weight, as they do not appear to weigh anything when considered in the atmosphere at sea level.
  You could imagine a large balloon of gas orbiting in the vacuum of space - that would definitely have a mass and momentum. How large would a tonne of that be?
  A plastic bag full of water floating in the sea is suspended weightlessly - lift it out into the air, and that bag becomes very heavy! A bag of pure CO2 in the atmosphere would fall gently, as it is 1.5 times the density of air, plus the bag would have some weight. Hot air balloons can rise or fall gently, just by varying the temperature of the gas inside compared with the cooler temperature of the same gas around the balloon.
  Another way of thinking about it is through wind forces - gas has momentum when it moves, and acts on things it meets - trees, building, people! A 5 metres/second wind on your building is like having 6 kilograms being thrown at every square metre of your building, every second! (that is only about 10 knots, by the way).

  The density of CO2 gas is 1.98 kg/m3 at atmospheric temperature and pressure. So one kilo is a sphere of nearly one metre diameter or a cube of 800mm dimension. A tonne of CO2 would be 1000 of those (would be 10x10x10 bigger), therefore a cube of 7.96m dimension, or a sphere of 9.88m diameter. Doesn't seem so large until you consider the next paragraph.

  The next problem is that pure CO2 cannot exist unless contained - it may be heavier than air, but it doesn't settle out into a simple layer, it wants to dissolve into the air it is released to. For many centuries, the CO2 concentration has hovered at 260-280 ppm, but the high present day CO2 concentration is 390 parts per million, and if it goes above 450 ppm, then the planet will have runaway Climate change. So at 390 ppm, a tonne of CO2 dissolving into air would require an air-cube of 110m dimension, or an air-sphere of 135m diameter. Considering that the air it is being released to already has this much CO2 in it, the volume required is even bigger than that, unless a conveniently close Rainforest can remove all that CO2... but there are declining numbers of them!

PS, I am grateful to Ted and Klaus of the Navi tron forum for elucidating some of these points, especially, as they took it a lot further, with Avogadro's numbers and Mols, bringing back memories of GCSE Chemistry lessons in the 1960s!

Further thoughts on ground loop

22 Dec '10: Some way back, there was a discussion of Ground loop, Horizontal, defrosting the ground.

If I had a garden or estate big enough for a long horizontal ground loop, I now know how I would do it.

Solar earth charging really is working for me, it is producing wonderfully consistent performance from the GSHP. But we all recognise that a horizontal loop would lose too much heat up to the atmosphere during the winter to hold any summer charge.
    If I had my chance to lay a horizontal ground loop, the first rule is to lay it as deep and as long as possible - that is agreed by all. But now with charging in mind, I would also lay, buried at a depth of about a meter below the final top surface and a meter above the slinkies, a slab of 100mm polystyrene along the length, using 1.2 x 2.4m rectangular slabs. This is so that sunbox injected solar heat would build up below and take a longer time to escape. It doesn't need to be thicker as the delta-T between charged and uncharged ground is not large. The lower surface would have to be very well levelled, or the foam would break up when the upper soil was rolled back and compacted.
    The greater solar heat that is the basis for all ground source heat pumps would easily rise from below the foam once the winter is set in and the region immediately under the foam is chilling. For a shallow horizontal ground loop, the chilling from the winter atmosphere above is much faster than that from the house - so Insulate!
   A similar requirement applies to Energy Foundations. If one is heating the ground below the slab, I would advocate putting a 'trenchfill' of foam around the perimeter - heat can build up below the slab and heat loss sideways would be reduced. There is no chance of it getting direct solar heat except that which is systematically injected. But when the injected heat is exhausted, the volume below the slab draws heat from the wider volume beyond. If the sizing of solar panels is well calculated, there is less risk of it being exhausted.

How much CO2 is this saving?

22 December '10: I have been trying to work out how we calculate CO2 savings, as this is the ultimate judge of success, not kilowatt hours.  KWh are a guide, but they are different for each fuel, as for example, Gas is burnt in your own boiler and turned directly to heat, but electricity from a gas powered station meant that gas had to be burnt elsewhere, converted to electricity in turbines, then posted 20 miles through a series of stepping up and stepping down stations until it gets to us - it is very efficient when it's in our house, but it may only be 1/4 the efficiency of the original gas, which partially explains the 1 to 4 ratio in the gas to electricity price.
  Used well, and generated from renewable sources, electricity is in the long run more efficient once it is in your house.
  The Peveril Solar house (during this coldest December since 1910) is using 27-29 kWh / day to provide space  heating and hot water for this house, and a neighbour with a well insulated house of similar size, but with gas central heating and DHW is using about 120-140 kWh / day of gas to achieve the same comfort.

With regard to Climate Change, what matters finally is the amount of CO2 you emit from heating your house and other activities, such as transport and food purchasing decisions.

Quote 16 Dec: 'A Task Group convened by the Zero Carbon Hub has delivered a report to the Minister for Housing and Local Government setting out its recommendations for carbon compliance levels for new homes from 2016. Carbon Compliance – that is, on-site reductions in emissions – form part of the Government’s overall plan for achieving zero carbon homes; the other part comprises off-site "allowable solutions."'
for the details.

Their recommendations are that the 'built performance' emissions from new homes should not exceed:
  • 10 kg CO2(eq) /m2/year for detached houses
  • 11 kg CO2(eq) /m2/year for other houses
  • 14 kg CO2(eq) /m2/year for low rise apartment blocks
What does this mean? The Carbon Trust site gives some help from a table published in 2009:
Conversion to CO2e (gross CV basis)
  • Grid electricity: 1.0 kWh =0.544 Kg CO2 per unit
  • Natural gas: 1.0 kWh 0.184 Kg CO2 per unit
On this basis from the kWh above for heating and hot water:
  • Peveril house is costing (during these coldest winter days) 27-29 x 0.544= 14.6 - 15.8 kg/day
  • Neighbour's house in the same time period 120-140  x 0.184 = 22 - 26 kg/day
This is in no way a criticism of my neighbour, it's a technical comparison. He has just invested thousands in a south facing PV roof that is doing a lot better than my roof, and he has replaced all his 25yr old central heating radiators with modern efficient ones, with insulated backing and thermostatic valves to reduce heat loss through the wall. We are all trying our best here!

During the year 1 Oct'09 to 1 Oct'10, our House Space Heating requirement was 3,000 kWh = 1632 kg of CO2. For 120 sq metre house, that is 13.6 kg / sqm / year. considering that this is a developer built house with insulation only slightly better than the current building regulations, and not having MVHR (Heat Recovery), that is pretty good!
The Passivhaus requirement is for 15 kWh /sqm/year or 8.16 kg of CO2/sqm/year, so we are still far from that target.
 Our PV roof generated 3,325 kWh in the same time period, which was all either used by us or sent to the Grid for others to enjoy. This is equivalent to reducing CO2 emissions by 1809 kg/year.

Monday, December 20, 2010

Jonathan Porritt and the Scourge of Denialism

I went to a lecture by Jonathan Porritt on December 14th, and he is always inspiring. The subject was 'The Scourge of Denialism', and the lecture was in the new Science Park buildings at Nottingham University.

We are mostly aware of the news of the  Republican wins in November. The unfortunate consequences of that event is typified by this quote from Fred Upton, who is now the Chairman of the House Committee on Energy and Commerce, which goes something like:
"God created the world and its climate, and if God wants to end it by changing the climate, that is God's Plan. That's ALL you need to know about Climate Change." Therefore he will do everything in his power to oppose pro-environment legislation.
See Huffington Post report Nov
See Huff Post Jan 1 '11
His own website doesn't sound so extreme, but he is a firm advocate of large scale nuclear development, plus exploiting Alaskan and other tar shale deposits of oil. Any investment in 'green technologies would result in losing American jobs' Hmmmmm...

What cheered me up is that Obama's Energy adviser, Professor Steve Chu has devised a brilliant new strategy for countering this, which appeals to the most hardened of American heart... goes right to their wallet, and fully justifies massive investment in Green Technologies.

I have written up JP's lecture and remain only to add in the Question and Answer session at the end. He has written a book recently, and any serious correspondent should get this.

See a precis of Jonathan's Lecture, Part ONE
See a precis of Jonathan's Lecture, Part TWO
See a precis of the Q&A session after the lecture (not yet written)

Winter and delta T

19 Dec '10: Before the sunboxes injected summer heat into the ground, in previous seasons, I noticed that the GSHP worked regularly at about 3.6 degC delta-T between outgoing and returning temperature.

I have got worried recently that it is consistently working at about 2.0 degC delta-T.... even in this wintry weather.

Having phoned Ice Energy they tell me that this is not to worry about, it is a sign that it is working well, and finding the heat it needs... doesn't need to drive the outgoing glycol too low. A word from Ivan on Navi tron seemed to confirm that. But both also mentioned Pump Speed, as did Chris Wood commenting below... So I checked pump speed and found that the ground loop pump has been running on the fastest speed setting of the pump. So I shifted this to the middle speed and the delta-T steadied at about 2.6ºC.

Having discussed it with Chris in the comments below, I have been tempted to reduce pump speed further. The result of lowering it seems to be that GSHP needs to refrigerate the outgoing liquid more. Yes, this means the heat pump has to work harder to refrigerate more.... but it reduces pump power consumption, and this could be useful - deepening the outgoing liquid temperature would help the thermostat to be earlier at triggering sunboxes into action when there is any useful heat.  It would make the energy flow recordings of the Sontex a bit more accurate, as a delta-T of 2.0 is too small for that particular model to measure accurately, considering its margin of error. 3.6 would be larger than twice the possible margin of error.
    David Atkins recommends aiming for a delta-T of 3.0-3.5ºC so this would indicate reducing the ground loop pump speed more. So I have tried doing that, in the early evening, and after a while, it settled down to a delta-T of about 3.5º. (So maybe the pump speed got fiddled with in the early autumn, and I forgot.)

If anybody wants to know more about the progress of the chocolate teapots with the diddlysquat  mirrors 'perpetual motion machines' (as they have been derisively referred to on the Navvi troll forum), here is an update.

The Sunday 19th Dec 2010 deep temperature is 10.30ºC.

Note: This has been the hardest winter since 1963 and we have had few hours of sun in the last week, and I have set time-clock to start earlier and end later than in previous winters (because Mrs N-C demands it), and an extra degree on the thermostat. So a much increased heating load, but the GSHP still using less than 30 kWh/day.

One year ago, on the 19th Dec 2009, there had only been two evenings with below zero temperatures in the entire winter (-0.2 and -1.50). It was very mild. I was just beginning to drill holes in the aluminium rails and brackets. The black slabs were stacked in the garage. My daughter and son-in-law were staying having just got back from Istanbul and Athens.
One year ago, on the 19th Dec, the deep ground temperature was 7.10ºC

I now notice that the daily consumption is consistently proportional to the daily temperature (with slight improvement if there is Sun) whereas a year ago it was inconsistent.

In fact, the Weekly Consumption of the house from 12 Dec to 19 Dec makes an interesting comparison.
13-20 Dec 2009: House 233 kWh, GSHP 168.79 kWh, Avg evng temp 1.88º
12-19 Dec 2010: House 226 kWh, GSHP 170.59 kWh, Avg evng temp 0.22º
Something seems to be working here! The GSHP figure includes the circulating pump for the underfloor heating system. It means that at this time of deep winter, we are meeting our Space Heating and DHW requirements with an typical figure of 0.225 kWh /sqm / day.

This seems to me to prove that the earth charging works! But it doesnt necessarily prove that in its first year there is a financial return. If our intention is to prevent chilling over 5 or ten years, it could take that long to prove it. We shall be preventing a major loss of inefficiency in five years, maybe we are merely keeping the machine running as if it was its first efficient year of operation.

   This is like planning for climate change or population control... for a future problem that won't show if the policy worked for the following 25 years.

   So if we prevent chilling in five years time, and the earth does not chill, we will never know what the GHSP would have been performing like in 5 years time without the charging. There might then be a significant cost difference from what it would have been. In fact, after 10 years, we would be blaming the performance on the machine and demanding a replacement - when it is the heat in the ground that needs replacing!

  The fact that during this deep freeze, the power consumption of the GSHP now is about the same per week as the same time last year with mild above freezing weather suggest to me that when temps and sunshine hours improve in the spring, our overall annual saving will be measurable.

26 Dec '10 Postscript: The ground temperature is on 10.0º, despite this continuing long cold season! Just holding in there, in double figures, and I hope for some sunny days as the days draw out into Spring, and we get a bit of recharging from winter sun. The deep ground temp a year ago was 7.50º.

Friday, December 17, 2010

Weird days on Navi, and Immosolar!

16 Dec '10: It has been an utterly surrealistic day with a swarm of bees breaking out suddenly on the Navi Groan forum, more slagging off of me and my 'chocolate teapots'... I now think of them as navvy trolls! It quite ruined my day and took up most of my morning, and even when not on it (such as driving) it seemed to be taking up about 90% of concentration... but somehow, with some goodwill from a kind person called Mr Gus, and a little backing down of angry parties (including me), things calmed. So I am grateful to Mr Gus, and to the antagonists for calming down.
    Really... with this densely grey cloudy weather, snow and rain, there is Nothing to talk about! The sunboxes are dormant, we are hunkered down for the Winter at this time of solstice, we are collecting and storing data, that's it! There will be sunshine Friday - something to hope for.
Image from Immosolar's movie, showing
Summer ground charging

 Towards the end of the day, one of the Navvy moderators, billi, sent me a marvellous link to a site of a german company Immosolar, with an excellent video of what I have been trying to do, but they have highly customised and engineered all the components, working in intermediate storage tanks, foundation design.... I have to study it more, but for the moment, here is the link,
Maybe I was over optimistic to imagine that the germans wouldn't have thought of this before, with their decades of leadership in solar technology and applications....

Thursday, December 16, 2010

Misleading headline in the Telegraph

16 Dec '10: I was listening to the Today programme and hearing Chris Huhne (Energy Minister) rebutting a leading article in the Telegraph claiming that Green Energy would add £500 to everyone's bills. Thankfully, he did a good job, and I hope it will have allayed fears.
On the Good Energy website, Julia Davenport writes a good article, rebutting this scare-mongering:

If you see a previous article on the Rushcliffe Solar blog, you see that price rises in electricity were nil or reversing during the 80s and 90s due to abundant finds of oil and gas - but they have nearly trebled in the 9 years since 2001, and show no signs of reversing.
 Any country that does not invest in green energy is going to face even higher price rises as oil gets more scarce. Does not the Telegraph consider the larger societal costs that have already been incurred in Carbon capture research, and that will be incurred in future in Nuclear station building and decommissioning?
  Even the Saudis at Cancun 2010 were making that case that their oil were finite and were asking the developed world to promise support for the Saudis once it gets to the point that the last remaining oil has to be left in the ground for longer term needs - a bit like preserving pockets of Indonesian rainforest. What a sick joke!  
   They and the Qataris presently have the highest per capita consumption of oil, burning almost 40% of their own oil, even though they have a tiny fraction of the population compared with the USA - showing no signs of conserving the oil in their own economy.

Oh dear, another storm on Navi tron

16 Dec '10: Oh dear, they're at again. Moderators of the Navi tron forum suddenly having another rush of feeding frenzy to slag off my project. Criticism I welcome, Slagging off, I don't know how to deal with, other than to feel depressed or angry. This is Trollism, not Tron....
What is it with these people? The thread is in an area nicknamed Bodges, Inventions, Ideas, harebrained ideas! Why did the moderators call it that if they crush discussion of any private experiment that isn't done by them?

I tried to answer some of martin's questions very politely, but he comes back clearly not understanding some basics - unable to understand why boreholes aren't insulated, or the microclimate effect of a glass box... Wow, on a larger scale, that is what Global warming is about, heat getting in, and not able to leave. ....not understanding that heat pumps cool the soil in order to heat the house, they do not post heat below. (If we lived in a hot climate, this is actually what reverse cycle heatpumps do, and why not? )
Name calling.... is there any need to refer to me derisively as "Mr Professor" ?
   They don't seem to recognise that I am always the first to be self-deprecating either for humour, or for a rethink of the direction of the project.  When I mentioned amicably that for a future experiment I might try to repeat it using evacuated tubes, it was leapt on triumphantly by martin as an admission that my Sunboxes were not up to it. This is yaboo clever clever stuff which is proof that he wants to kick at any soft spot he can find rather than discuss.

It's all very well for those with landed estates who have managed to live off-Grid to sneer. I wish I had a river in my property to run hydro off, or enough land to grow honey, or lay out long slinkies, or convert barns to thermal stores. It really is very admirable to be able to combine a plurality of systems so that collectively, the house or estate can be off-Grid. Such people deserve great credit, but it looks and sounds UGLY when they cast scorn on others who do not have so much land, and whose experiments are far more limited - and more amateurish than their own.

Simply, I am doing the best I can for an on-Grid suburban house with tiny plot and a microclimate that is too sheltered for wind.

For space heating it is better than Carbon Zero, and now I am trying to do better still.

At this moment, the 'chocolate teapots' are doing nothing, that is the whole idea!  On grey cloudy days, there isnt enough sun or delta-T to wake them up. Enough heat is below to enable the GSHP to operate efficiently on grey days, and considerably more heat is down there than a year ago.

Friday, December 10, 2010

Charging the sidewalk!

9 Dec '10: Interesting article in about Snow-Melting Sidewalks, and 'Hydronics' the conveyance of heat using water.
   There are a variety of suggestions for preventing roads, sidewalks and paths by using solar heat that has accumulated during the summer to warm the ground that you wish to defrost. This has to be done when the sidewalk is laid, and the ground can be charged with enough heat in summer to help it stay ice free through the winter - it all depends on how you get the heat down there.

Thinking more about this..... 
   Logically, solar panels could deliver heat much deeper down (3 m down) in the summer, and during winter, another loop would run between the deep zone and the zone under the pavement. Easily done with thermostats.
   You would not need to go down so deep if using some insulation. e.g. Summer deep pipes about 1.5m deep, a 200mm layer of polystyrene, then the Winter pipes in the half metre below the sidewalk. A small inspection chamber every so often would contain the manifold that switches from summer to winter mode. And nearby, attached to a building or pole, a small solar thermal collector.

Effect of Pump speed

8 Dec '10: In further discussion of the increased performance, I must say that the total quantity of heat downloaded is of course smaller in Winter. We sometimes have sequences of days with no heat from the boxes at all. The difference has been in the heat PER hour. Part of this is down to mirrors, but part is down to pump speed and hours of operating.

  • In the Winter, the GSHP is much more proactive, on for longer hours, driving down the glycol temperature, pushing liquid through at 18 litres/min, getting the heat in fewer hours, then closing the valve.  
  • In Summer, the GSHP is largely asleep, leaving it to Sun and air temperature to drive the boxes - far longer hours of operating, and only 5 l/min flow rate. It does get more heat in summer, but needs more hours to get it. 

  The only way to know is to continue, and then test the daily harvest of heat during Summer 2011. As we all know that Solar Cookers work best in Africa and India, it's fair to hope that the daily thermal harvest will be higher in the summer sun with the mirrors diverting extra heat onto the collectors - higher than the unmirrored ones were in Summer 2010.
    Logically, I should continue with the high delta-T requirement (6.0º) that I am now using, so that it really only runs when there is something to run for.... and when it does run, have a higher pump speed to increase capture - when this occurs in summer, there is likely to be plenty of PV power to match the pump requirements. For last summer, the summer pumping rate was 30W, approx 5 litre/min - next spring, it will be time to try the middle speed, which I think is 45W.

Tuesday, December 7, 2010

What is the effect of the Mirrors?

Rendering of mirrors before they went up,
including the vertical corner ones
7 Dec '10: For the last few weeks, I notice that when there is sunshine and the GSHP is demanding heat, the SBs always work at over 2 kW ! Even at this cold time of year. (I am so glad that the black collectors were contained in glassy boxes, not left naked on the wall.)

  As an assessment of the contribution of my 'diddly-squat' mirrors', let's look at total kWh divided by total number of hours, from the time that I installed the hour-timer in mid-April. This rules out freak results from single exceptional high or low days, by having time periods that are measured in months, not hours.

The average capture of the Sunboxes:
  • with No mirrors from late April -mid Sept, nearly 5 mos =1.11 kW
  • with Top Mirror only from mid Sept -mid Oct, 1 mo =1.43 kW
  • with both Top and Bottom Mirror from mid Oct -early Dec, nearly 2 mos =1.93 kW
Now I have fitted side mirrors, but these are going to be of marginal effect, intending to kick start the boxes on summer mornings by directing early morning heat into the boxes.
As Chris points out below, the increase in kW is also connected to pump speeds and hours of activity of the GSHP, which we discuss in the comments, and I add a bit more in a posting of 8th Dec.

Even if the bigger idea of interseasonal charging does not produce an improvement in the COP of the heat pump, I think and hope I have the confidence of my immediate technical group (Chris, David A and Blaise) in the general idea, and time will prove us right or wrong.... by next May for getting through the winter, and by next October for assessing the summer build up. So far, the results of my deep ground temperatures are proving me right, but I need longer to know if the electrical consumption of the GHSP will be reduced annually.

  But let's rejoice at small victories...
....with the months of testing before and after, I would declare the Mirrors to be a success.

Final Mirrors up

7 Dec '10: Despite the perishing temperatures, I managed to get the ladder up and fix the final side mirrors on the Surya Sunboxes. We had brilliant sunshine, but the air temp according to the GSHP was minus 7.0º outside. Earlier in the day, people had been writing Facebook updates about it being -10º and -14º in some places!
  The side mirrors are more for summer mornings and evenings, to capture the side sunlight, but they will also help with midday sunlight in winter. Just a few mins handling aluminium, even with gloves on, is very chilling for the paws.

Just a few readings from the sunboxes today, which are helping the GSHP to operate safely in the plus temperatures range, even on such a cold day.

Times 1100 1145 1215
SB temp 23.0 22.2 21.0
Air temp -6.9 -6.9 -6.9
GSHP outgoing 3.7 3.4 3.0
from SB down 5.7 5.7 4.8
GLoop return to GSHP 6.2 7.2 6.6

At this time, more heat is being pulled from the SBs than from the Groundloop! The SBs come on if there is a delta-T of 6 degrees, so they only work when there is a clear advantage. There have only been two days so far in this half year when GSHP consumption exceeded 30 kWh.

Monday, December 6, 2010

Ground Temperature is still holding up!

The filled area represents the ground temperatures
The fine line is the external air temps from 1 Jan to 7 Dec 2010
(Temps are usually taken between 8pm and 10pm)
(System for recording deep ground is more systematic now)
I will replace this with a Dec 31st graph when the time comes.
5 Dec '10: I am deeply surprised.... now that we have really got into this long period of wintry weather, I had reconciled myself to the ground temperature dropping and our charging of the summer beginning to run out. We have had many days without sunshine, with low temperatures. I have rigged up a time-clock activator so that has extended the operating hours of the GSHP to be 3 hrs per day longer than before. I have raised the target temperature in the house to keep it more comfortable for Mrs NC.
   So I had half given up on doing better than last year.... :)

Au contraire mes amis! I did a ground test on Sun 5th Dec and it was 10.8º.  What!? Sunday has been a good day for sunshine, with 11 kWh banked by the Surya Sunboxes during the day at an average of over 2 kW per hour of running. The weather forecast is suggesting several more days like this, a foggy start finishing with good sunshine.
   We have had no good sun since end of November, but I had a hint of this performance benefit on a sunny Sunday morning of 5th December, when observing the system at work. Just before I had to go out at 11am, the GSHP was busy heating the house:
  • External temp: 0.4º. 
  • Sunbox air temp: 24.5º. 
  • House air temp 20.0º. 
  • The GSHP was pushing glycol up to the boxes at 2.0º, and 
  • it was coming down at 4.9º - disappearing into the ground.... 
  • and returning to the GSHP at 5.7º. 
  • So the GSHP is getting a very favourable delta-T with little depletion of the ground heat, and working above zero degrees.
  Exactly a year ago, with a much milder autumn and no sunboxes, the ground temperature was 7.50º.
Seems to be working!
Next year?  I am fully prepared for it to go under 10.0º, or even below 9.0º for much of January and February. The graph of the ground temperature for 2010 has looked like a soft mound shape, part of a Sin wave... but I wonder what shape it will take as the spring sunshine takes effect?

6 Dec '10 Postscript: Monday was even sunnier than the day before, and the sunboxes banked 13kWh during the day despite the ambient air temperature falling to the lowest of the year. The daily consumption of the GSHP managed to stay under 30kWh and the temp of outgoing glycol to the ground loop remained above Zero.
Looking at the diagram above, it seems amazing that we all thought of Spring 2010 as a 'severe winter'. It now seems a mild period compared with the present month of December 2010.

12 Dec '10 Postscript: Deep ground temperature was 10.4º , after a week of continuing cold but thawing temperatures. We have had a good run of sunny mornings, banking 48 kWh of Sunbox heat during the week. Exactly a year ago the deep temperature was 7.2º .... when exactly will the dividend from this greater reservoir cut in, I ask?  I don't know! Let's hope it is after the New Year celebrations. At face value, it doesn't look so good, as our GSHP consumption for the last 52 weeks has been 4,235 kWh and when computed in 1 Oct, it was 3,996 kWh. This is entirely explicable by the earlier starting and extra-cold autumn-winter. The current 52 week block includes two unusually cold winter semesters, whereas back in October, it only included one.
   One dividend I notice is that the GSHP consumption is more closely related to fluctuations in air temperature, whereas it was more erratic a year ago. Put it another way, the consumption reduces if the air temperature rises, proportionately and promptly - I hope that is because it finds the heat below more easily. So as the weather warms, I hope to see that annual figure sinking back to and below 3,996 kWh!

19 Dec '10 Postscript: The ground temperature is on 10.3º, despite this long cold season! There was some sun at the weekend. One year ago it was 7.1º

26 Dec '10 Postscript: The ground temperature is on 10.0º, despite this continuing cold weather! Just holding in  there, in double figures, and I hope for some sunny days as the days draw out into Spring, and we get a bit of recharging from winter sun. One year ago it was 7.5º.

Wednesday, December 1, 2010

Peveril in Snow

1 Dec '10: Well the snow has been down for some days, and today it was added to by a continuous light dusting of fresh snow. We live right next to West Bridgford's best winter sports location, and when the schools are closed and the snow is down, there are hundreds of children using the hill.
 (Grumpy note, and leaving broken plastic sleds all over the hill, but they will not be cleared till the snow melts...)
Left, our PV panels are completely covered. The neighbour down the hill has south facing panels and they had enough hours of morning sun to melt off, and give him a power harvest.
Right, it was about 0930 this morning with the Sun right in front, the children coming out to play, and the snow encrusted sunbox mirrors framing the top of the picture.

Ground Temperature holding up....
  I am glad to see that with sufficient heat down below, I have not yet seen the GSHP sending glycol out at below freezing. It is close but not that low yet. If returning temperature is low, it has to lower the temp of the glycol going out to the ground loop. We have a sunny day forecast for Friday, so lets hope for a bit of winter recharging then!
  May I say, for those who do not believe in this, that today I was at home and able to observe the GSHP's behaviour and this was the FIRST day I noticed the outgoing glycol having to be below zero.

PV Still working!
Despite being completely covered with snow, as in the photograph, my PV roof managed to earn something, 0.25 kWh of power...

I have now built the Corner mirrors, but I just have to find a good moment to get the ladder up and fix them. No hurry when it is snowing like it has been, they will only be functional in sunshine. I managed to get some 18mm long pop-rivets which mean that the mirrors can be fixed without having to open the sunbox fronts. I got one corner mirror fitted on Sat 4th Dec, but need daylight to fit the other one.

Timetable change
Now that I have fixed up a B&Q time-clock that can turn on the heating as and when I wish I now find myself subject to democratic decision making (i.e. I do what I am told) and we will start the heating up at about 7am in these extreme winter mornings, and leave it on till about 2330..... makes getting up a bit easier. Even with that, the GSHP consumption is not as bad as it was in the bad old days of last Jan and Feb when the ground had run out of heat and GSHP having to supplement it with the immersion heater function. From the sunboxes, we had nine kWr on Friday 3rd Dec, very welcome for restoring some heat to the ground, and immediately recycled as heat in the house. This system works!

Navi tron afterthought
I can live with the hostility of some, this is the effect of the mob, and  thankfully it's quietened down now. But why the Disbelief and the constant demands for Proof? Why to tenths of a degree when my major variable is 48 m deep soil of partially unknown quality, and weather conditions that are unprecedented and unpredictable?
  It is only 2 months since October 1, and January 2011 not arrived yet, and May 2011 and Sept 2011 still some way to go.
  There is disbelief that this can work for an obvious reason - this is the only single domestic system known. The only domestic ones remotely like it that have been discovered by the experts are Anneberg, Sweden and Drake's Landing, Alberta. These are for settlements of 92 and 50 houses respectively. Drakes has a massive district heating centre to handle the load, and Anneberg is topping up the heat below with supplementary heat. No one is doing it for one house, in the simple but effective way that I am. If there was another, I would by now have been told in the spirit of "haha, someone else did it before you!".

   There is an air of "If the idea worked, someone else would have done it by now - so it must be a hoax." (a 'scam', 'chocolate teapot', 'crackpot invention', 'perpetual motion machine' and many other rude or ruder words.) The silliest one is that it is 'stealth marketing of a commercial product'! Imagine the market research into the number of potential GSHP customers that could justify making more of these! Like watching a goalless draw!
  The scorn from the engineers - with detailed plumbing or electrical knowledge - is the most striking of all, like a grid-locked motorist being annoyed at being overtaken by a cyclist on the bicycle lane.
  The real test will come this winter and through the summer and to 1 Oct 2011, when we compare the progress of ground temperatures, weekly and compare with them now. If I am wrong, you will be the First to hear it, here, and them there!

Floor pump Thermistor on a Timeclock

1 Dec '10: I now managed to get both the heat pump and floor circulating pump to switch itself on and off due to time as well as to temperature.
   Although the GSHP has its own timeclock to turn it off at night, that doesn't stop the floor circulating pump from whirring all night if the external air temperature is below 15º. A few months ago, I rigged up a 2 way switch that we could use manually, so that we could fool the GSHP and the floor pump into thinking that the temperature externally was 25º - so that neither could come on. I did this by installing a fixed resistance of 4.7 kohm which is what the external thermistor would return at 25º.
   With these cold days, we have been wanting the GSHP to start a bit earlier than usual (like 8am), and not wait for us to get downstairs for breakfast. So I have taken a 220 vac line to the original switch, and from there, it goes to an Omron relay below, and this has a 2-way switch function, so it can switch the temperature sensing between the real external thermistor and the fake one. Now, with a little B&Q timeclock, we can have the sunboxes and the GSHP+floorpump turned off and on at the same times.
  Please, Navi tron expert critics, do not attack my wiring, this photo was just after I got it working, and I will tidy it up. And yes, I don't like using an adaptor but it is only driving 50 watts. And the little wires around the Omrons are mostly datalogger cables.

Tuesday, November 30, 2010

Anneberg, an inspiring example

29 Nov '10: Sami (of Finland) just pointed me in the direction of Anneberg, a district near Stockholm which is an inspiring examples of interseasonal storage - better than I have yet seen (even more than Drake's Landing), and a huge vindication of what I have been doing here as a solitary adventurer, much maligned by some who don't believe it is possible. Chris Wood (who mentioned it to me a few weeks ago, but I didn't hunt down the details) points out that it has been going now for eight years.

This scheme uses interseasonal storage despite the much higher latitude - colder winters and lower sun angles in summer. There is a deeper technical discussion on this site, in english with some good diagrams:

  Quite remarkably, they are trying to do this without heatpumps, I guess trying to store enough energy to support their underfloor heating, and using electricity as a backup. The house designs are hugely dominated by the absolute imperative to face south and maximise the solar panel area.
  One of the most interesting diagrams I have seen is their attempt to guess at the losses underground and to provide enough solar thermal input to overcome this heat loss. This could be because their panel area is far larger per house than mine, and their expected ground temperature far hotter - the delta-T between their hot zone and the surrounding infinite ground will be far higher and encourage much faster leaking.
   As with mine, this cannot be measured, it can only be guessed at. My panels produce so little by comparison, that last summer, the maximum deep ground temperature reached was 14º, not significant enough for a large loss. I look forward to seeing next summer how high this goes, and will try to evolve a similar diagram with some estimate of loss. The earth should reach higher than that, as the mirrors will enhance the sunbox performance and the earth will be making a better standing start, assuming that the ground temp in March is higher than it was in 2010. Presently, it is more than 3 degrees better than in 2009.

  I have since learnt that Anneberg did not work well initially, mostly to do with technical problems from leakages, and the consequent reliance on direct electric heating. The decision to try to heat the ground to the temperature of a hot water tank so that there would be no need for heat pumps is bound to have problems, transmitting high temperature fluid a long way from each house to a distant store, and back again, and then doing the same with the fluid that is actually heating the house. It also accepts a far higher rate of loss to surrounding soil than I would be prepared to accept. 
   My sunbox system here is heating only the soil immediately below the house using existing pipe runs, and never higher than 25º even in summer. Re: using houses without heatpumps, I believe that it would be very difficult to market a house that had no heating system - its better to put something in that doesn't have to be used too often if the house performs well, but is there if it doesn't.
   However, I have also heard that the Anneberg system is working for some years now, since solving these teething problems. I have had enough problems too and it is all part of the evolution of a technology.

Sunday, November 28, 2010

Is this a perpetual motion machine?

28 Nov '10: I am having to take a helluva lot of criticism from people on the Navi tron forum, and I really dont understand why people do not let my experiment continue, and patiently wait for the result like I am having to do.
  This system has had only 2 months of the winter so far, starting from October 1. It is too early to be crushing the author with excoriating criticisms, everybody has come in for it, myself, family, children, students, job, Phd student, Datataker, Sontex... nobody has been spared.
  Come on, give me some time to test this, and to improve my expertise! This is a piece of Plumbing for crying out loud! Ground charging schemes need 5 years to get up to speed (see other articles), and some artificially boost the ground in the first few years until the sun has provided enough to reach steady state.
   I am not trying to sell them something, or compete with the company who hosts the forum, I am an individual, and a prospective customer for future projects. I am not submitting it for 'peer review', I am reporting on my findings. If a product comes out of it, NT might be the right company to take it on. So be patient!
   It is my research fund that has been expended on it, not theirs, nobody is buying anything, so what is the aggression for? I have been accused of 'not presenting it clearly' - well I am not doing a 3 minute pitch on the Apprentice, I am not selling anything, I am testing and discovering something. The blog is a 'diary' format, and key points worth presenting are stored in the Tabs at the top of the blog. There seems to be real resentment that I report on it using a blogsite, but this comes from the old fashioned pre-blog days when one might have used the forum to report every twist and turn.

   Things have been quiet recently, and I have enjoyed discussions in some areas, such as high rise, passivhaus etc. Suddenly last weekend there was an eruption of real nastiness. There is a particularly critical individual called Chris who writes:

'What David claims to have managed is another perpetual energy machine. He's in some pretty good company, but at the end of the day he claims to be warming himself at the expense of , well what...? Could it be the warmth of his wall? could it be temperature of the soil in the garden? I don't know, but certainly any attempt to refine the question is being met with increasingly aggressive responses. Sadly this is another characteristic of the Perpetual energy community. The reference to their own integrity over provable data and the anger are recognised characteristics'

'And there in lies the community skepticism. Because I don't believe this is a malicious hoax, I believe it's simply an individual outside of his own area of expertise, worried because he has started to realize some of the flaws. Having re-read the 'mirrors' thread in light of the beast it has become, I'm surprised by how much consideration was given. The original premise of mirrors seems to have moved from the top to the bottom upon suggestion, and it is interesting to note both Martin and myself worried about wind blowing things off, independently, but the overriding approach has been similar to a spoilt child, I'll take my toys away if you don't play my way, wait till winter is over and how dare you question me?, cos I've got lots of massive projects waiting, and you'll lose all these orders if you don't act nice.'

  By the way, he hasn't told me anything about what he is doing other than that he has '30 tubes' - what does that mean? Evacuated tubes, doing what precisely? Heating what? I have asked more than once, and still he doesn't reveal.
  His posting isn't the only one.  He claims that he speaks for the entire 'skeptical community'. So hostile is the attitude, that I have taken to referring to my system as the 'chocolate teapot' with the 'diddly-squat mirrors' as a form of humorously self-deprecating self defence because they were calling it that enough times.
  He says he doesn't believe this is a 'malicious hoax'. We all know this is double speak of the sort "I don't believe you are a wife beater but...." that plants the idea in the mind of the reader, and followed up by his link to, there is no further doubt as to the degree of malice intended.
   As for worries about my mirrors 'blowing off', I don't think he has examined my solid aluminium brackets. His reference to 'martin' was an item suggesting that the mirrors would scare passing jet planes - which I took as good humour. Martin is a gruff knowledgable person with a sense of humour.
  As for the reference to 'large projects'.... well I am doing some. As to asking whether I am heating the house from the soil in the garden, the answer is YES YES YES! Am I recycling heat from the wall back into the house, NO NO NO!
   He claims to be a moderator, but how can a moderator on a forum of a company retailing ground source heat pumps not know that heat can be lifted from the ground?
  Anybody who has seen a Stirling Engine on YouTube powered just by a cone of metal reflectors facing the sun will see what appears to someone like Chris to be a perpetual motion machine - mirror reflectors driving an engine?? Well, the news is that it stops when the source of power stops, after sunset.
  What is wrong with waiting till Winter is over? This isn't a time based computer simulation which can be speeded up, it's in the real world with a real family in a real house, and Time is the only way to test it. Other projects I have looked at, eg Anneberg, Sweden require 5 years to settle in, and Xolar in Austria require 7.
   I won't know fully how the GSHP has performed in its first real winter (using charged ground) until May 2011, and I won't know if the mirrors have changed things until a summer has completed by Oct 2011.

My reply on the forum, here's much of it:

'There are some who will continue to think that ground source heat pumps are perpetual energy machines, and funnily, I agree with you completely. I still meet people who assure me that there is no need to recharge the ground as there is 'infinite' heat down there, and so we can all cheerfully have heatpumps and draw heat up for ever. I contend that theres nothing infinite about the ground, because our boreholes are fixed in position, and can only reach a finite distance. Ground temperatures in Arizona cannot reach my house, neither can heat from under the Nottingham Forest ground.... therefore it is not infinite.'

'There is another more obvious perpetual energy machine available to us, it's there for another billion years or so before it burns out... called the SUN. It appears every day, even during the winter, even though it is often hidden behind clouds.'

'I am surprised that there is someone left on this forum who doesnt realise that the sun is a source of energy that lasts longer than our lifetimes - but Chris, welcome.'

'We are not talking about volcanic heat, that is far deeper down. We are talking about solar gain by the earths crust. Actually, I live on the edge of the city with a large open field behind me and a north-south oriented tarmac road alongside. so, yes, we could get solar. But others live in denser areas, or east west roads, where the ground is shaded by the houses and trees, and little opportunity for summer sun to penetrate. And what happens if all the neighbours have boreholes too?'

'I very much wish I had kept metering records from the time we occupied this house. I would be more sure about whether the GSHP progressed steadily for its first three years, or if it was better in its first year, and declining each year due to borehole chilling. Having made the decision to have one, it now seems crazy not to have kept records. I think there is a mentality with GSHP owners to think "Oh, we are getting all this free heat from the ground, we can cheerfully turn up the heating or have plenty of hot baths"'. 

'Having become aware that the electricity bills were far too high, I made the decision in August 2009 to record electricity meters every day, and at the same time had the thought, that logically, the ground must get colder every year. It doesnt seem credible that my deep ground can recover fully over a short summer after a long winter of depletion.' 

'As a quick aside, the present situation is:
 External air temp -5.0º
 Sunbox air temp is 23.2º 
 Heat pump heating the house, putting glycol up to sunboxes at 3.5º at 15 l/min
 Returning from 4 sqm of sunboxes at 5.2º, going down to the ground,
 Returning from ground at 7.5º, from the twin 48m boreholes.'

'Last sunday night, after 4 hours of 'resting' the deep ground temperature in my boreholes was 11.3º How many other people with GHSP at this end of November with the coldest November weather since 1993 have boreholes in double figure temperatures? We are three weeks from the solstice, and the boxes are reducing the chilling - simply that.'

'If you can get solar heat directly pumped 48m down in pipes which already exist (their embodied energy now paid for), using low powered (30W) pump powered by PV panels, what is there not to like? It is not a perpetual motion machine because the sun is the power source and it only shines in daytime, when it is not overcast. 
But this brings in the age old principle of Storage - you store things for using later. Its as old as Genesis.'

'Last year the heating of my house required 3,000 kWh.
Last year, the PV roof generated 3,325 kWh.'

'There are many ways to measure carbon neutrality (and I reject all based on offsetting or tariff tweaking), but what is there not to like about the two figures above? 
Using the grid as a store. Above that 3,000, I need power for DHW, lighting, cooking and appliances.'

Actually, storage is older than Genesis, there are examples in early cave dwellings of food stores and water stores, long before the invention of writing. Some of the earliest evidence of human activity are pots or broken pots, which would have been used to store grain or olive oil.
   I didn't start this as an engineer knowing fully what he was doing and willing to subject it to peer-review. I set out as a householder and architect-academic with an interest in plumbing to follow a hunch that I could improve things using second hand materials : the pump, thermostat, flowmeter and black panels are donated from previous experiments by others. If it works, I shall undoubtedly tighten up the monitoring regime, although people who have seen my spreadsheet think it's already sufficiently OCD!

Feb '11 postscript: If there is anything 'malicious' here it is truly expressed in the contemptuous and moronic utterings of this Chris Wyleu characters. He then embarked on a smiting campaign against me later in February, and got me banned because I objected to being smitten so much. 

Friday, November 26, 2010

Phase Change Materials

25 Nov 2010: I am awakening my interest in Phase Change Materials.
I had a parcel given to me in the School office, but it was mis directed. When I opened it, it turned out to be a package for a Mr Ciu in the research labs (only a minor misspelling there!) and it contained some cuboids that contain phase change material that has a change at 26 degrees C.
This is very interesting! The 480 balls that I have in my loft have an unknown phase change and are also difficult to stack - they would need to be buried in a water tank.  So I still don't know what to do with them.

These cuboids have circular holes through them, so you can thread plumbing through them, and stack them tightly, avoiding the need for liquid or even for a tank! Or just allow liquid to permeate though those holes.

I shall send them to the correct recipient, but will contact the supplier.

Phase changing at 26 degs is exactly what we could use for underfloor heating using solar panels! 26º is low enough to be right for solar panels to stack heat into them, and yet high enough to operate as an under floor heating source in a well insulated house (backed up by a few radiators to top up air temperature).

The other purpose of the PCM could be to be a buffer against overheating - if we used evacuated tubes in a future experimental installation, there is a danger that if the system was static for a while and then turned on, we might be getting glycol landing into the ground loop at 100 degs C - far far too hot! If the liquid runs through a Water tank, this might also get too hot. If it is run through a large crate containing PCM blocks, it would cool the liquid to a safe level but not lose any of the heat, it would simply delay it until later when the sun was not shining.

Passivhaus Highrise in Linz
25 Nov '10: The Power Tower: This remarkable 19 storey tower in Linz, Austria is the highest building that could be considered near to Passivhaus standard, requiring no fossil fuel burning for its energy requirements. It's designed by Kaufman and Haas.

As the PDF above says: "The new group headquarters of the Upper Austrian power utility, Energie AG Oberösterreich, is currently under construction in Linz. Known as the Power Tower, this is no ordinary office complex – even before completion, it is setting the benchmark for energy efficiency in large buildings. With its nineteen storeys, this will be the first high-rise office building in the world that uses renewable energies to meet almost its entire energy requirement for heating, cooling and fresh air."
   The tower has 46 x 150m deep boreholes for ground source heat pumps, plus it has 90x10m deep concrete piles with thermal loops. 6,900 metres in all! An inexhaustible source of energy!
   There is an immense amount of PV in the facade (700 sqm for 42,000 kWh/year). They are not using solar thermal  panels to recharge the ground with heat. They are doing some summer cooling of the office areas with water brought up from aquifer. Tall buildings generally have high internal heat gains, and these are even greater with highly insulated walls - so there is plenty of heat being put down in the summer - in a sense, the whole building is a solar thermal collector!
Media press release 2008 

Wednesday, November 24, 2010

Examples of Earth Charging

24 Nov'10: Here are two notable examples,
IKEA store in Tempere, Finland, the 37,500 sqm store will be heated from the ground, 60 200m deep boreholes, to be used for cooling the building in summer, and for drawing heat in winter. The article focuses on the technology of drilling through such deep rock, so I am not sure if they also use solar panels in summer. But commercial buildings produce a lot of internal heat from lighting and other internal gains, so if this is stored underground it's better than just blowing it into the atmosphere.

Xolar's roof
(image from their PDF document)
Xolar Group, Eberstalzell in Upper Austria, are a company making solar hot water systems so they are obliged to get it right in their new headquarters. It's a 21,900 sqm building that will eventually be totally passively heated and cooled. They have a huge number of solar thermal panels on the roof to provide thermal energy. The building is nearly airtight, so heat recovery is possible.
The perimeter of the building below ground is deep insulating walls, and they are charging the ground below with heat. The solar panels are charging the ground and the target temperature is 22º. For the first seven years, they are using 3 biomass (wood pellet) boilers to maintain the rate of charging through the winter. After 7 yrs, the ground should be at a steady state, where regular solar input can keep the ground topped up, so the biomass boilers can be disconnected and sold.
They are aiming ultimately to run the building at 10 kWh/m2/annum, less than the Passivhaus standard of 15. There is a very large buffer tank of water at the heart of this, and the thermostats decide whether to use biomass or solar heat, depending on the season.
The article says that in Upper Austria, 32 percent of gross energy consumption is provided by renewable energy sources, biomass being 13% (I guess a large part is hydroelectric).
See also, PDF document.
PS thanks to a friend on the Navitron forum for alerting me to these.

Monday, November 22, 2010

Ground Temperature is holding up!

22 Nov'10: A year ago today, the deep ground temperature was 8.10º. Tonight, while taking the usual Sunday night readings for the spreadsheet, and letting the GSHP pump glycol round for 20 mins, the deep temperature was 11.3º. I want it to be high, but this is far higher than I expected because the last week has been dire.... a small amount of sunshine last monday, followed by days of low fog and cloud with periods of drizzle.
   Perhaps this interseasonal charging lark is working!

   Because we seem to get quite a lot of sunny days in Feb and March, I am hoping that the usual springtime drop of ground temperature will not occur because the sun will come in early enough to prevent frosting. The lowest was in 10 January, 4.70º, with an average daily GSHP power consumption of nearly 30 kWh/day. Even if there are sunny days, we don't get much of them, due to Sharphill looming high to the South East of the house.

24 Nov: Higher consumption?
 My all time annual low of 3,996 kWh for the GSHP and 6,075 kWh for the house was achieved on 1st October'10, and since them the weekly-corrected figures for annual consumption have gone up, not down.  
   Some things are causing our consumption to be higher than last year... the calculation of the annual consumption is re-computed every Sunday. As each week is being added at the head, a week at the tail is snipped off, and I am snipping off a very warm autumn of 2009 and replacing it with a week of very cold autumn.

  We had an unusually cold Spring in 2010, and now, we are having a far colder autumn in 2010, with a cold snap in October and evening temperatures in single figures for most of November. It is still November, and a heavy fall of snow is predicted for the last week of this month.
  Another reason is that I have a deal with my wife (who is disabled and unable to exercise) to raise the thermostat to 22º whereas it was 21º last year. I am also allowing the room thermostat to have 'more influence' in the thermal algorithm of the GSHP (compared with the liquid temperature). One degree difference can greatly add to the annual heating load, perhaps another 180 degree-days.
  I will reduce the activity of the Sunboxes on non sunny days by raising the Triggering Delta-T to 6º C, instead of the previous 5º. This is from observation, that when temperatures are lower, the earning from the Sunbox is reduced, and a fast pump flow does not pick so much heat up. So one can reduce excessive pump hours by making it activate when there is a greater delta-T - either when the GSHPs' ground loop is much colder, or when there is a winter sun.

Sunday, November 21, 2010

Jussi Mirrors in Finland

21 Nov 2010: Sami from the N-tron forum pointed out to me that he knows of an installation in Finland by someone called Jussi, (Mr Juha Kirjonen) which uses mirrors.
  Finns have a short summer season with very long hours of daylight at a low sun angle so they need to try every possible trick that will help. These are self-built panels, and seem to use central heating radiators as collectors. I hear from Sami that winter temps are so cold up there that you have a risk with above ground liquid circuits, even with anti-freeze. As the winter photo here shows, there probably too much snow for them to work even if you did have plenty of anti freeze in them!
   Aurinkovoimaa is Finnish for Solar Panel. Well done to Jussi for believing in the power of the mirror! His other albums have pictures of boat restoration projects, car and heat pump reconstruction, and more. He seems to have a very large workshop.
    His Picasaweb album has pictures of the whole thing being built in the workshop - the link is:

Feed in Tariff finally paid!

20 Nov'10: I was glad to see that suddenly our bank account looked larger than usual, and I found it had just benefitted from £1015 of Feed in Tariff - Good Energy's payment from 1 April to 1 October. Actually, I shall have to complain (I don't want to sound ungrateful), but it is less than the hoped for 41.3p/kWh.

The amount over the winter will be less than one third of that, as October has been poor, and who knows what March will bring. During the winter months, the Sun is hiding behind Sharp Hill and shortening our solar hours by as much as 2 hours a day :(

Friday, November 19, 2010

Tea with Ken Clarke

Ken shares tea with Jenny
19th Nov '10: As part of NEA's Warm Homes Week, various MPs have been visiting projects in part of the country so see examples of energy saving or generating. The Rushcliffe Solar team were honoured to be chosen as NEA's example for Rushcliffe, and nominated one house for a visit from the MP for Rushcliffe, Rt Hon Kenneth Clarke. We visited the house of Jenny Johnston.

  As he is currently Justice Secretary, Energy policy is not top of his priority list, but he showed supportive interest in what we had been doing, and it was good of him to take part in the national week of action.
  As it was a Friday at the end of a very busy week, it was very relaxing for him to end the week with a nice cup of tea, non political chat, and only a walk away from his own home.

Thursday, November 18, 2010

360 degree sunbox for Finland

17 Nov '10: I have had an interesting conversation on Navitron Forum with Sami, who lives in central Finland, and has a problem with very deeply chilled deep borehole - 210 metres deep serving his ground source heat pump. It is getting well below freezing every winter. His part of the world has no sunshine at all from November to February, but during the summer he has virtually 24 hour sunshine - with very low Solar Altitude angles coming from a 270 degree sweeping Azimuth this is a real challenge.
   With such a short summer and such shallow angles, how can solar heat get deep down when the ground a metre below the surface has been frozen for months? - and most of that solar heat is used in overcoming the thermal load of thawing that frost.
  There is this very short summer season, so there is a short time to pack a lot of heat down below, so a highly efficient device is needed that can work from 2am to 10pm!

  This design idea is scalable - for a small installation it could be say, 1 metre high, but it could equally be twice as big or more in every direction (i.e. eight times bigger). The central element would have to be black and cylindrical cluster of pipes carrying glycol, and the shape of the square box would be rotated at 45º to north, so that the NE and NW faces get direct sunshine. Every face is surrounded by large bright mirror finish metal, so that there is maximum harvesting of the sunshine, even at very low angles.
  In this model, the central black cylinder could be larger. The whole thing is scalable, and it would be great to build a prototype. As I have found, it can do no harm to defrost one's borehole, even if the direct efficiency increase can take 2-3 years to measure numerically.

Tuesday, November 16, 2010

Centre Mirrors are now installed!

16 Nov '10: I have now managed to handcraft the centre mirrors, and these are now in place. I wish I had thought of it when the scaffolding was up - so much upping and downing of that ladder, not good when you also have a slight pulled muscle in your back.

  With luck these will remain reasonably clean and reflective. I notice that my upper mirrors are still very clean, but the foot mirrors are coated with atmospheric dirt and a bit of bird shit after only a month. Still, as they are not so high, they are easier to clean, and could be a task for every alternate month. I was hoping that at an angle they would be more self cleaning. Perhaps they can be coated with Wax to make the dirt stick less effectively.

  Now that the centre-mirrors are fitting snugly, I may go on further and cover the upper pipes with aluminium box enclosure.
   Also, I have yet to fit the outer corner mirrors. They are made, but still on the ground as I have to build the special hinges for them. The best angle will be 45º in summer or winter, so they do not need to swivel once established. They will stay clean for longer.
  The centre-mirror assembly you see here is of pop-riveted plates, and is not screwed in as there is a good gripping base detail with a strong Push-Fit detail at the top.

Energie - house heating from Sun, Wind and Rain!

16 Nov '10: I have just been directed to a very interesting product that is very similar in some ways to the Surya Sunbox principle. This is the Energie system from an underfloor heating company called Thermal Reflections. The system uses efficient unenclosed aluminium black collectors, open to the air, which in enough number can be the sole source of heat for a ground source heat pump. Because they are the sole source, they have to be open to the wind and rain, and the heat pump sets the appropriate delta-T to manage the heat collection, even in the dark. They can be roof or wall mounted, like mine as they need most of their heat in winter.
  My criticism would be that they would be very very effective in summer, but have nowhere to put the surplus heat, whereas my humble sunboxes quietly pump solar heat all summer long at 5 litres/min into a fifteen storey deep hole, from where I am now getting the heat for my house during the winter. Mine are an augmentation system that defrosts the ground, a similar technology but differently applied, but it is pleasing to see that the general idea, including the plumbing is very close.
  I take heart from this, and hope to get one of those panels sometime, to test. Apparently, the panel manufacturer is in Portugal. One of those panels, enclosed in a transparent case, might be more effective than our polypropylene collectors.
  The detailed document about them is:
Below this item, Chris Wood has posted a clarification of how these work: apparently they are in effect part of the heat pump because refrigerant goes to the panels.

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