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."'
Read: http://www.ukgbc.org/site/news/show-news-details?id=350
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

Immosolar
 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,
http://www.immosolar.com/en/systems-a-products/video
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:
http://good-energy.typepad.com/greenenergyrepublic/2010/12/the-true-cost-of-greening-uk-energy.html

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 Contractormag.com about Snow-Melting Sidewalks, and 'Hydronics' the conveyance of heat using water.
http://contractormag.com/columns/eatherton/cm_column_632/index.html
   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...

Mirrors!
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.

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