Sunday, February 27, 2011

Weekly summaries include annual assessments

27 Feb '11: At the end of every week, I enter the current readings for everything, and I also put in the reading of exactly a year ago. This means I get an annual update every week.
This diagram is compiled in March, showing
completed graph including February
and deducting power use of DHW and underfloor
circulating pump
  My initial yardstick was 8,500 kWh total consumption for the house for both the years of Aug'07-Aug'08 and Aug'08-Aug'09. I know not the breakdown of the figures, and we didn't have PV then, but let's assume that the house consumption was 3,000 and the heat pump 5,500.

  I moved my yardstick assumption to Oct-Oct as this is the start of the winter heating season and it is the date of our Photovoltaic installation.  For 2009-2010 with the help of the PV roof and more careful management of the GSHP, we managed to get down to a lowest ever of 6,080 kWh for the house and 3,996 kWh for the GSHP.
    As the winter progressed, we remember how cold November and December 2010 turned out to be, and these figure became more and more remote, reaching a new 'bad' of 6,302 kWh (house) and 4,245 kWh (GSHP)
   With the warmer weather of Spring 2011, the annual figures are getting better and better and by next month, I am predicting the annual figures to be a new 'good' of 5,600 kWh (house) and 3,600 kWh (GSHP).
  I don't expect to get the GSHP down to as little as 3,325 kWh (the amount of our PV roof last year) because our Sunboxes will have their anniversary in mid March, and therefore the warmer summer figures will be working under similar conditions.

Sunboxes and Mirrors
  As for the Sunboxes... based on their averages of last year, we should have reached 3,000 kWh earning by now, but this spring has been a combination of cloudy and warmish weather, just what is needed to stop them working!
   We should make 2,950 kWh by March 7, the anniversary - close, but not on the nail! Blaise made me turn the Sunboxes off for three days, May 13-15 2010 and these were unfortunately some of the sunniest days of the month with very high scores on the PV roof. We did this to record performance to the datalogger without the influence of the Sunboxes. These would have made us the extra 40-50 kWh we needed to make the magic figure of 3,000 kWh in a year.
    I am often being encouraged to do things like 'take the mirrors off one box and fit an extra energy flow meter to each box, so that they can be compared.' I don't really want to miss out on any of the free summer energy, just to prove a point to those who do not believe that reflectors help - my hunch is that they do.
    Also, and without doubt in my mind... if we had had the mirrors from the start it would have been a different story - a much higher score. Prior to the mirrors' installation, the Sunboxes averaged 1.1 kW from March till September 2010. Since then, with the mirrors installed, they have averaged 1.91 kW in Oct'10-New year, and 1.92 kWh from New year to the end of Feb'11. Although I know that this is a Winter semester, it's clear from their behaviour that they have caused an improvement, and I am sure that the Summer figures will be good enough to enable us to hit the 3,000 kWh annual target next year.

Visit to East Leake - it leaks

27 Feb '11: I visited the installation at East Leake. This has been underperforming at less than half the capture rate of the Peveril installation. We have checked the electrics and plumbing and sensor positions etc and they are perfect, and David has insulated the flow and return pipes, so we have done what we can with the 'internals'. Since the mirrors were fitted, the Peveril boxes average 1.9 kW when they are running.
     Climbing a ladder to check the 'externals', there is a large air gap at the top at the rear because the plywood got damp, and it has gone into a curve, opening up a gap. The boxes were built last October-November and we didn't get the plumbing and electrics done till the pleasanter weather of February.
    This gap was rectified with a hardwood wedge (temporarily), but we will need to fit a flashing, and fit a bracket to secure that curved section permanently. The top polycarbonate level is too shallow (250mm) and it is letting rain in at the rear, and it is letting it in at the front too, the junction with the vertical polycarbonate is tooooo flush. It needs a good overhang as the site is very windy and rain has been getting inside and running down the inside front face. This should not happen and never happens to my Peveril boxes. So I will order a new roof piece, about 290mm deep, and fit it to the same aluminium angles.
  (Sorry, I forgot to take a picture of the boxes....)

Passive Skyscraper at EcoBuild

27 Feb '11: Above, The layout of EcoBuild 2011. We have our  stand, at the North west corner of the main hall, conveniently next to the Coffee space. This is the MultiComfort House stand, provided by Isover, and we will have seven of our Passive Skyscraper designs on show. These will undoubtedly be the highest building designs of the whole show, most likely the highest ever displayed at EcoBuild.
    All the schemes show the Solar Earth Charging technology adapted for high rise, as has been researched on the Peveril Solar House. In the tall buildings we shall have large stores of PCM wax instead of using the ground, as it has a thermal capacity equivalent to about 25-100 times better than Water or Clay (depending on how it is used and graded.

Another Weathershield would be good

27 Feb '11: During this Sunday before I go to EcoBuild, I am thinking of what else could be done to improve this system. Well the pipes which leave the sunboxes are well insulated, but there is a question of how much weather and sun the black tape and adhesive can take. So it would be a good idea to build a weather shield for them too - I have enough Aluminium for the job!
   So expect a design for this corner soon.
   There are also small airgaps around the pipes. Now that I have established the importance of airtightness, it would be worth an investment in some clear Silicon filler for these gaps. 

Weathershield in place

27 Feb '11: I made the piping weather-shield a couple of weeks ago, and made a padded insulation lining for it a week ago. It fitted nearly perfectly first time, with only a small amount being filed off the left hand side for it to fit cleanly into place. It's designed to reduce long term wear and tear on the exposed pipes, but I hope that the thermal insulation wrapping around the pipes will have a tiny benefit in reducing system losses.
  It has always been a benefit that the Sunboxes are strong enough to lean a ladder against. And I inherited the ladder from my Dad - and am so glad that when he bought it, he included this demountable safety feature of a safety frame at the top. 

Thursday, February 24, 2011

Geothermal in Newcastle! Quake!

24 Feb '11: Just to distinguish deep geothermal from shallow geothermal, this project in Newcastle UK is drilling down to levels where there is real heat coming up - water at 80 degs C, hot enough to make a hot cup of tea -
  The heat we are using in ground source heat pumps goes nothing like as deep and the contribution from the deeper heat below is too small to quantify. The GSHP's heat comes from Solar heat falling on the soil during the years and soaking in to many metres deep. Thus a ground source heat pump can run out of easy warmth if the soil around the building is heavily shrouded by trees or other buildings.
  Interesting to see a counter article in the website claiming that a significant fraction of recent earth tremors are not 'acts of god', they result from man's interference - ultra deep mining (perhaps as deep as 5,000 metres), fracturing of the rock, pumping gas under high pressure into the rock.... some of these activities are believed to have cause tremors or quakes. A 1989 quake in (of all places Newcastle, New South Wales) was thought to result from deep mining, and caused damage at the surface more costly than the value of the coal extracted in the life of the mine.
  As reported in Live Science website some projects may have been abandoned once the risks of earthquake became known. An earth tremor in Basle in 2006 is still causing legal action, years later, due to the damage at ground level.
  Even though we all know that there is plenty of heat down there, it is clear that we have to be careful about how it is extracted.
(Many thanks to the good people of the website for finding me those references, a lot friendlier than the Navvy - trolls.)

Saturday, February 19, 2011

Under performing in East Leake

19 Feb '11: We are not getting such good figures from the new installation. Although it should do better than the Peveril house, in theory, this demonstrates the better feedback one can get from a real life real time installation.
   From 2-16 Feb, the Peveril Sunboxes captured 90 kWh, and the East Leake ones only 46 kWh. There is a difference in the plumbing layout, but I don't think that should be the reason. We are trying a number of things:
1. Reduce system losses. Need to fully insulate the pipes from the sunboxes to the heat pump now that we have checked for leaks (and there are none).
2. Check that there isn't a lot of cold air getting into the box somehow, eg the back of the box is against a slightly uneven wall and there is a case for some duct tape to do some sealing.
3. Check that the two sensors are correctly positioned. I am not sure if the Cold sensor against the ground loop is strongly enough taped with thermally conducting paste. Perhaps the warm sensor needs to be positioned higher in the box, so it detects a rise in temperature more quickly (eg when the sun comes out from a cloud) On my system, the sensor is at the highest point of the box where heat rises first, but has a foil hood to stop it being triggered by direct sunlight.
4. Reduce the pump speed. If it is slower there is a more distinct temperature difference between the flow and return, if it is too fast, then the energy flowmeter isn't precise enough to measure the temperature difference. In my case, it can run at middle speed, as the pipe length is longer and the volume is about 60 litres. In E Leake's case, with the compact radiators and small pipes, the volume is smaller.
     As if that wasn't enough we also had the Energy flowmeter stopping recording for a few days, it was showing an error earlier in the week and with a bit of tapping and shaking, it worked again.... new technology, huh!?

Postscript 27 Feb '11: I visited the site and the main problem seems to be a large gap at the top letting warm air escape. There is a smaller gap at the bottom, and rain penetrating from the top - needs a flashing.

Friday, February 18, 2011

Walthamstow Interseasonal Charging

Walthamstow Fire Station
photo rendering
17 Feb '11: I am always glad to find other examples of Interseasonal Charging and here is a goody!  
   Walthamstow in London is getting a new Fire Station, due for completion in late 2011. They are installing 188 square metres of 132  PVT panels - PV with liquid cooling, a combination of solar PV and thermal. The heat from cooling these panels is to be buried under the building for use by the ground source heat pump. the panels will be the Solimpeks (that I wrote about earlier) installed by NewForm Energy.
   The statistics are impressive, if it finally gets built this way:
  • Peak Electrical should be 20.46 kW, and Peak Thermal 89.76 kW. The effect of liquid cooling is to improve the PV capture. 
  • Over a year they are hoping for over 22 megawatt hours of electrical energy and over 76 megawatt hours of thermal energy
A main fire station is a high consumer of hot water, with showering and cleaning of machines and equipment, so this heat is worth capturing, and will reduce power station fuel burning. I just hope that they stick to their promises and don't cut this bit out as a short term cost saving.

Thursday, February 17, 2011

Abstract accepted for SET 2011

17 Feb '11: Wow! I had an email accepting my abstract for SET 2011, in Istanbul. This gives me till May 2011 to write it up in more detail, although still limited to 6 pages - which is good! As I have just written the material for the lecture of the 15th Feb, I know I have plenty of material, and know what I need to add to sharpen it up more. It's great to have this to aim for!

Pipe cover fabricated from aluminium

16 Feb '11: With summer on the horizon I want to add more weather protection for the exposed external pipes connecting to the sunboxes. This one will go over the central supply pipe between the boxes.
   I should have done this before the Winter, as there is also a chance to stuff some insulation around the pipes as a tiny contribution to reducing system losses.  In Summer, there would be heat gains through an uninsulated pipe, but I am also considering ultraviolet degradation.
  This is knocked up using 1.6mm aluminium alloy, same as I used for the mirrors. Many thanks again to Mr Makita, and the maker of my Angle grinder and pop riveter. Will try get it up there at the weekend.

I ought later to do ones for the return pipe at either end.... I have enough spare alloy for the job.
 The cover is for this tee junction, on the right, the photo was taken when the polycarbonate still had its protective plastic skin.

Tuesday, February 15, 2011

Lecture about 'Charging'

15 Feb '11: If you have want to hear more about the 'Charging the Earth' project, there is an evening Lecture 15 Feb 6pm in the Trent Building of Nottingham University - in the Graduate Centre. Arrive at 5.30pm and there are some eats. Parking may be better down by the Djanogly Lakeside theatre and walk up.

This is about adapting the idea of Solar Cookers to collect Solar heat and pump it 48 metres below the house for retrieval by the Ground Source Heat pump. The combination of this and a good PV roof have made the house Carbon Zero for heating.

PostScript: Well I gave the lecture. Thanks to all who attended. Thanks to Heba Al-Sharkawy who organised it. And thanks to Chris Wood who helped me out on a few confusions of kiloJoules and Watts etc, while I was at the dentist having my teeth drilled for root canal treatment, so that I could finally get my head around some of the issues of thermal capacity. It completely distracted me from the drilling! I wonder if the dentist realised I how much I wanted to stay on the phone at the moment his injection was going in! I can save a copy as a low-res PDF if anybody is interested

Saturday, February 12, 2011

Temperature samples sunny spring day

12 Feb '11: Although the weather forecast said cloudy, we had the pleasant surprise of a bit of sun on Saturday morning. I took pictures of the thermostat and recorded the sun and temperature patterns from our weather station on the roof.
  • External air temperature 10º
  • PV panel surface temperature 19º
  • Air temp in Surya Sunbox 30.0º
  • Pumping glycol into borehole at 15.3º
We hope to see more days like this as the Spring continues.
An hour after that photo was taken, outdoor temp was the same, but the sunbox temp was over 35º and pumping glycol down at 19º!

Friday, February 11, 2011

Photovoltaic and Solar thermal - Solimpeks

1102-2011 : I see that PVT - Photovoltaic and Solar thermal is coming one step closer with this Volther product from Solimpeks. The Building Green blog does a good write up of them:
and the Green Optimistic does a good write up too with a better picture:
The document from Solimpeks themselves is:
I want one!!! Or a few..!
At the moment, I am not aware of one that is on the market in the UK, although the company EcoMerchant may be a source. and then click in Products for 'Solar Thermal'. There are two types, the PowerVolt and the PowerTherm. Each of them majors on one technology or the other according to name.

  • Powertherm would be better on very small roofs where you judge that thermal is important. The panels have a gloss top and I guess, an insulated back. The thermal part of these would work longer into the equinox and winter.
  • PowerVolt - On a larger roof where you can go up to 20 square metres or more, you would not need such a large amount of Thermal, so you would use PowerVolt, maximise your PV harvest and then take advantage of the large thermal capture that would come from this only during the summer (no insulation or glass cover).

Liquid cooled PV is ideal if such a thing is available and MCS approved, imagine having 20-28 sqm of PV, and all that being thermal too. A bit of a plumbing nightmare, but if installed at the time of new build would be incredibly effective. The PV would have increased production (ours always does better if a cold north wind blowing on sunny day) and the same area of thermal instead of our puny 4 sqm. However, we do quite well by using the greenhouse/ solar cooker effect.
   From my point of view (being interested in Solar Interseasonal charging) they could be ideal because in summer, most normal tank based systems reach stasis quickly. 20 sqm of thermal panels would reach stasis extremely quickly if the only store is a 300 litre tank. The earth charging process doesn't suffer from stasis as the thermal capacity of the boreholes is close to infinite, and there will always be a delta-T that is beneficial. Thus the PV panels will be well cooled in summer no matter how hot the weather because the liquid coming up is sure to be cool. Imagine how much heat would go down if we had much more than our present 4sqm. Without the glassy sunboxes over them one would get little capture in winter, but the summer storage would be so comparably colossal that this would compensate. I have a temperature gauge on my PV panels and know that their surface temperature goes well above 50 degs C in summer, in fact, they go off the scale! They need cooling!
[Many thanks to David Hill of Carbon Legacy for alerting me to this and to Walthamstow.]
He also points out to me that the new replacement for Walthamstow Fire Station will have 188 sqm of these panels, giving them over 22 megawatt hours of electricity and over 76 megawatt hours of heat, all to be buried in the ground, to be recovered by a heat pump. It's wonderful to be finding something that is so directly and confidently doing what I have been trying to do, in my lonely furrow.

Mark Brinkley's Blog - Denby Dale

1102-2011 : Mark Brinkley is author of Housebuilder's Bible, and writes a lively blog on house construction and energy issues, Home 2.0. I advise readers to view this occasionally.
   He has earlier promoted the Denby Dale passivhaus, and recently wrote an article on how Denby Dale passivhaus had weathered the Dec 2010 month. They have done well, although it draws two things to my attention.

 1. They have an efficient gas boiler, but also use gas for cooking and DHW, so they have difficulty knowing exactly what gas is used specifically for heating. This could be solved by getting a gas plumber to fit a meter to the pipe that feeds the boiler, so they can at least remove the variable of Cooking. It is also possible to fit a water meter on the Hot water pipe so that it can be measured, as we do at Peveril.

 2. There is a different calorific value for Gas and Electricity - what really matters in the end is the amount of CO2 this is equivalent to. Electricity means burning fuel in a power station somewhere else, and transmitting 30 miles, whereas gas is piped to your house and burnt at home. Hence the difference in Cost of the two fuels and the difference in CO2 equivalent. I wrote more about this in December:

I am glad to see that the Govt redefined the 2016 standard in kilograms of CO2, not in kWh, as that makes it easier to calculate the real energy cost.

For December 2010, here, our GSHP used 768 kWh, but if you take away the consumption of the floor circulating pump and the DHW, that is about 645 kWh for the month, for space heating. Our PV is always bad in December due to the large hill to the SE of the house, so we have to drink heavily from the grid during December. Despite this, and with the help of 109 kWh from the sunboxes, the deep ground temperature managed to stay just above 10º by New Year's Eve.
 For our 120 sqm house, 645 kwh is about 5.4 kWh/m2/year or 2.9 kg of CO2/m2/year, which is about right as December was about 1/5 of the entire degree days for 2010.

Itho propose ground charging?

11 Feb '11: Chatting with David Hill, I recently discovered a company called Itho who are Dutch, although they have a British subsidiary. It seem that their main business is whole house ventilation, heat recovery etc, although their main website is in Dutch.
     This page has a movie on it that demonstrates a whole house working, with underfloor heating working with a heat pump and with MVHR.
     What fascinates me is that they seem quite comfortable with the idea that in summer, the solar panels return solar heat to the borehole, that is then recovered for water and space heating in winter. No great trumpeting about it, just a component of a larger picture of how the whole energy system can work. From the english translation of their literature, they are clearly using a reverse cycle heat pump that can cool the underfloor circuit during the summer, sending heat down below. The movie shows the underfloor heating assisting this, but it could also be using heat from the solar panels on the roof.
     If it is only putting heat down from the underfloor heating in summer, I would question it. The number of cooling degree days a year in the UK and Netherlands are few and are easily dealt with using natural ventilation and decent thermal capacity, and therefore the amount that could be put down is too small to count. (they will be at EcoBuild in March 2011 if you or I want to ask.) Also, I think this is a theoretical proposal, there is no case study to prove that a full working house has been built that does this.

Hitchhikers can help too!

10 Feb '11: I gave a lift home to one of our Polish students who was worrying about getting some parts of her model back to Lenton in the light drizzle. As we were going towards the University gate, she checked her email on the iPhone and said "Hey, I see you're going to give a lecture in the Trent Building next week!"
   Aha! I had not quite forgotten, but hadn't realised how widely it would be circulated, to the entire staff and students of the Engineering Faculty and perhaps beyond. Lawks a mercy! I had better get on with the Powerpoint!

East Leake Clocked!

Clock and Neon are in the photo, top left.
10 Feb '11: I have been out to East Leake again to fit a Digital Clock and Neon light to the control unit. The data that we are collecting from it is of less than half the desired value if we can't record the time. Now we will know Litres/hour, KilowattHours per hour (i.e. kW), pump power consumption and more. I also filled out the spreadsheet a bit more, as they have been recording the readings on a paper grid. In future the readings will become more meaningful a few days, weeks and months after the clock is running.

While I was about it, I got two of the clocks, and added the second clock to my Peveril system, to record the number of hours the compressor is running. I had to fit up a relay last year to inform the datalogger when the GSHP compressor runs, so the new clock simply records when the relay goes on and off.

The only addition required now at East Leake is a top mirror, and a little flashing behind to help keep out a small amount of rain.

Thursday, February 10, 2011

Graph of Sunbox versus PV capture

9 Feb 2011: Blaise came round to collect more data from the datalogger, although we think it ran out of memory as November and December didn't seem to be there. Never mind.
   One thing that complicates the calculation of COP is that the underfloor heating circulating pump draws its power from the  GSHP, adding about 55 kwh to the monthly winter consumption figures. He tried to explain how to calculate the COP, but this is going to take a bit of work. Having datalogger sensors on the internal compressor helps us to be more accurate.

Blaise has found the recent set of graphs produced from my Peveril Metering spreadsheet very useful, especially the ones comparing Degree Days with Heat pump consumption, and the one showing the deep ground temperatures.

Here is another, comparing the capture of the Photovoltaic and of the Sunboxes. This will be updated monthly, and I hope that the SBs with their reflectors do better next summer. The mirrors were only installed in the autumn, and notice the brief rise in Oct'10. Thereafter, we had our cold cloudy Nov and Dec'10, so both curves went down. Due to the hill behind our house to the south, the PV capture is significantly reduced in the winter months. The Sunboxes are less affected by this, as they face south and are driven just as much by demand from the GSHP as they are by sunshine during those months.
The blue curve is compensated
by deducting DHW and floor pump

  Also, I have had to point out to everyone viewing the comparison of Degree Days and GSHP consumption that the GSHP figure includes hot water and floor pump, so here is another version of the graph with those overheads deducted.
  By removing those overheads, you see an even clearer distinction in the heating curves between Winter 09-10 and Winter 10-11.

Wednesday, February 9, 2011

Interseasonal News from Sweden

8 Feb '11: I heard from Tommy in Sweden, the one I mentioned earlier who has being doing some experimental interseasonal charging on his house.  He runs the heat from his solar panels directly to the heat pump (well, the liquid is circulated to the panels). When there is no Sun, the GSHP uses the ground loop as normal, and when the Sun is shining and the GSHP asleep in summer, he can charge the earth, for future use.

That's interesting, and I would be able to fiddle with the plumbing here to do this (I have sketched a layout establishing that I would would need at least three three-port solenoid valves) but we would be hesitant about doing this as this IVT heat pump would not accept hot liquid directly from a solar thermal panel - it assumes that if the return from the loop is in the 20s, something has gone wrong and shuts down.
   So for the moment, my very simple 'Trickle-or-Whoosh' system using one 3-port valve is working well, and for the system in East Leake, we are using 'Trickle-while-we-work' layout with a 2 port solenoid valve, both cheap and effective.
  In the Swedish environment, being a lot further north, Tommy's system would have a lot to offer, if you can get the control mechanisms right.

He writes:  Our system is somewhat different from yours, as we are using the sun to heat the house and the hot water directly as much as possible. In order to do so we have a control system especially designed for us.
  When the sun hasn´t been able to heat up the solar panels enough for us to use the sun directly (when there is a need), we use the solar energy to preheat the brine before it enters the heat pump.
  During winter this is the only possible way for the control system to use the solar energy, as there are so few solar hours. When the heat pump is not running the bore hole will be recharged as in your system. For example my 14m2 of solar panels where recharging my 70m bore hole for about 3 hours during the fantastic winter day yesterday.
  As we are using the solar energy directly we cannot use “pool solar panels”, instead we use Solar Keymarked solar panels from Watt ( ). “Pool solar panels” are effective during the recharging cycle, but for direct heat they are not useful.

See below, some interesting follow up comments from Dr Chris Wood one of my colleagues at the University.

Adding more PV power

8 Feb '11: I enquired of EvoEnergy today about adding additional PV to my roof. My motivation is to make the house Carbon Zero, not to maximise the Feed in tariff - so I want to generate more electricity!

Another system is really impractical. To work in the FIT system it would need another inverter and grid connection - as this would have to be on the West facing roof, it is not worth it, because that is tilted to the north, and shaded by a dormer at the south end of the west roof.

  If I added a couple more panels to the existing roof, it would push it to 4.32 kW, and the Inverter is probably rated only for 4 kW - although it faces east, there is a possibility of the roof exceeding 4 kW on early midsummer mornings. With the feed in tariff reducing to 36.1 pence/kWh, there would be a drop in income, but this is not a problem for me as I primarily want to go for a higher annual total.
   However, the Sunny Boy Inverter would seem to define the limits of expansion. 
   I have my spare PV panel which my wife would like me to remove from the conservatory. I am tempted to fit it to the south wall, for battery charging, which could power some of the night time functions in the house. I already have a regulator and a 600W inverter for this purpose. If it doesn't make enough power, the PV panel could be replaced with a new, higher output one.

'Active House' is that better than Passive?

8 Feb '11: I met Julian Marsh, one of my architect friends today, who was visiting the Dept of Arch and Built Environment. He has a self designed house in Nottingham and is the architect of the highly excellent Green St houses in the Meadows. He promotes the idea of the 'Active house' as better than Passive house, a sort of cheerful British interpretation of the slightly joyless German ideal.
    That is more like my house, where you don't have to live in a airtight box, dependent on a fan for breathing. You make sensible use of the PV and a heat pump, open the windows in summer for ventilation, have a sunspace with openable shutters, allow the occupants to make sensible energy saving decisions such as solar shading by day or closing curtains at night. 
    Like me, he has been monitoring his energy figures, to try to get below carbon zero. I will invite him as a speaker to one of our West Bridgford Ecohouses meetings in the future.
    I gather that Julian's house is about as carbon zero as the Peveril house, i.e. is covering the heating, and more than that, but with the 4kW limit on PV panels in the British Feed in tariff, he doesn't have enough PV to cover the entire electrical consumption. With being on a corner site, he has two party walls, so has fewer external wall surfaces to lose heat.
   He does have a small amount of MVHR, but not on the whole house - uses it on the most lived-in zones of the house. This is a pointer to how I could use it - it is too difficult to instal a Whole House system, but I could have an exchange between the Kitchen area and the main Living space. The articles in the links below provide additional information.
  Another my friends, Gil Schalom has a eco-upgraded victorian house in West Bridgford and has zonal MVHR rather than in the whole house.
In 10 March 2011, the Architects Journal devoted a long feature article to Julian's house. (Unfortunately there's a paywall on the AJ website, but if you are a subscriber it is visible)
also visible are these links:

Sunniest day for months!

8 Feb '11: I'm just basking in the figures from solar power today, the sunniest day since 20th October 2010.
It was cold,  between minus 1º to 9º and back to about 3ºC most of the day! That coldness helps both ways, as the PV works more efficiently in the cold, and the Sunboxes also work better if the GSHP is working harder to heat the house.
Today, we scored 9 kWh on the PV and 16 kWh from the Surya Sunboxes!
   Before the metal reflectors were fitted, there were only a tiny number of days last summer in which 16 kWh or more were achieved. So I have good hopes for the coming summer!
   My original prediction that we would get about 3,000 kWh from the sunboxes in a year is 145 short of the target with one month to go, to March 7. I was encouraged by high averages through the spring, summer and equinox.
   So I hope for some more sunny days! November'10 brought in 194 kWh, so this does seem attainable.

Tuesday, February 8, 2011

Skyscrapers in New York

8 Feb '11: Isover have now published thumbnails and larger images of the finalist in the Isover competition.
All of these are using, to varying extents, interseasonal solar storage to supply heat to heat pumps, using a composition of solar thermal panels and PV panels on the south facade, with thermal stores on the north face or in mechanical floors.

Monday, February 7, 2011

Ground Temperature Upcurve

6 Feb '11: Ground Temperature: I run the GSHP ground pump for the usual 20 mins, hopefully mixing the glycol up a bit as it goes round, and ensuring that it's a reasonable representation of the deep ground temperature. At today's date all three of my indicators (the Sunbox thermostat, the In and the Out temperatures of the GSHP) average at 11.4º. Last year it was 6.8º, but we were having a cold Spring.
   One of the major motivations for this is to prevent the deep ground from chilling. We are defrosting it in winter and charging it with additional heat in summer.
  During the winter of 2009-2010 I suspect that my measuring may not have been as rigorous as it is now, because of the more frequent oscillations, but the trend is quite visible. The sharp deeper troughs are probably when I didn't give enough time for the ground to recover after turning the GSHP off.
   Since the sunboxes were installed in mid March '10, the ground temperature recovered quickly to a higher point at the end of July '10, and has been pretty stable ever since. With the weather improving in Jan and Feb'11, the temperature has actually recovered slightly. I would dearly like to see the summer peak rise higher than in July '10.
  When there is demand from the GSHP for heat from the Sunboxes, there is an average delivery of about 1.80 kW from them, so there is still regular heat coming in, even if the Sun is not shining daily.

Sunday, February 6, 2011

Don't count chickens... unless they hatch

5 Feb '11: In my conversation with Dr Chris Wood a couple of days ago he reminded me of the importance of searching for ways to prove that there are real efficiency savings from the Surya Sunboxes.
    If you will permit me to use another Animal metaphor, I remember saying in an earlier posting that a ground source heat pump is rather like a hungry dog gobbling at its food. It just greedily sucks up heat without discriminating where it comes from - it only takes the heat it needs for heating the house above and no more, so why would that make it more efficient? This is the point he was making. If some of that heat is from a solar panel, and some for the ground, it does not automatically follow that it will make the GSHP more efficient! and would it save enough electricity to justify the cost?
   The general theory is that a 1 degree rise in the temperature of the primary source can add 3-4% to the COP of the heat pump. My deep ground is over 10º and rising gently when at the same time last year, it was about 5ºC and rising gently.   It does not necessarily follow arithmetically that 5 degree difference automatically multiplies that 5 times... although it might do - it is hard to verify, especially when I fear that the datalogger memory is full and therefore the real numbers for last Nov and Dec might be lost.

Timescale: Ground chilling is something that occurs over 5-10 years, and it would take that length of time to be really sure, to see if the performance in 5 years time is as good as when the machine was new. Our intention is to defrost the ground, not to make it hot!
  We installed the GSHP in Feb 2007, and should have started this then - who takes records that early, and who keeps records that long? I wish I had done so from week one! Doh!

Graphic representation: I showed him this diagram which is an unusual graphic interpretation, because it combines Degree Days with Kilowatt Hours on the same chart. They are different units, but proportional. The diagram is extended every month. It started from 1 October 2009 and currently ends at 31 Jan 2011.
  The diagram clearly shows that in a milder winter of 2009-10 (red curve), the blue curve of the heat pump consumption was vastly greater than it has been in recent months.
  There is a small inexactitude, that is to our credit, in that the blue curve also includes DHW and floor pump consumption. The Heating part of that would be lower than shown, and zero during summer.

Immersion Heater:  Another point is that most heat pumps have an emergency function which is a direct electric heater in case they are unable to retrieve enough heat from the main source. If this comes on, the electric consumption soars, because it is direct 1:1 heating. Our heat pump had to do this for the equivalent of 220 hours in 2007, and 220 hours in 2008, and in the winter of 2009-2010, it used 110 hours, mostly in the Spring when the ground was exhausted.
  In the winter of 2010-2011 including the severest December in recorded UK weather history, our heat pump has used only ONE hour - and that annoys me, how did that happen and why? I think I know, because this IVT model has a faulty algorithm that overheats the water, repeatedly, trying to pasteurise the water every day instead of every 3 weeks.  I have now beaten this by fitting a small Danfoss thermostat that stops it heating the water beyond about 58º.

Sunday 6 Feb '11: Electric consumption: This will always be a primary decider, because it can be directly balanced against the power generation of the Photovoltaic roof - electric kilowatt hours balancing electric kWh - and it can be directly costed in Pounds and Pence. It is also a final decider of whether we are 'Carbon Zero' or not.
   Every week, I do a meter reading and compute the full consumption of the House and of the GSHP. I am glad to say that we are advancing into unknown territory, seeing consumption levels lower than ever previously witnessed. The House annual consumption is less than 6,000 kWh (5,970), and the GSHP annual consumption is below 4,000 kWh (3,957) for the first time ever.
 (as each week of the cold Feb 2010 peels off and a warm week of Feb 2011 is added, this is not surprising. So I ask, will we stay below this line for the rest of the year?)

Saturday, February 5, 2011

Navitron ban

If this isnt 'fair comment' after the way I was treated on the NT forum, please explain.
I took this posting off for a month, but after repeated requests to be re-instated on the forum have gone unanswered, there seems no more reason to keep this article concealed.

5 Feb '11: Oh dear, those nice people at NaviTron have done it again - antagonised me to the point of having to say something about it, and then when I do, it is followed rapidly with a Ban but with no pre-warning.
  On Thursday I was enjoying browsing the forum, and feeling how comfortable I now was with it, and enjoying the variety of discussion threads when I realised that someone was suddenly 'smiting' me. I could see the count rising, and only 'moderators' can smite like that, 200 during the day, and while I was watching, 20 hits in 5 minutes. One of the 'moderators' 'billi' taunted me asking me if I needed a 'blowrag' (look that up in Google to see what sense of humour these people have), and posting a photograph of a grown man weeping, and labelling the illustration to ensure that it was for me. Not nice really.
   Of course, I had to reply to that, who would not?
   Shortly after, I found myself banned completely by 'Jack' without warning, even though I had an exchange of very sympathetic emails with Ivan of Navitron (although only through their system email, so I cannot continue with this). They have done it to all my IP numbers, so I cannot even read threads as a non contributing guest. I did not get a private message warning beforehand.
   They have deleted all of my discussion threads about the solar sunboxes and earth charging, and the high rise buildings.  How destructive! there was some excellent technical discussions in there amongst the malicious gossip. The company is good, but the forum is mismanaged by people who have appointed themselves as 'moderators' but who taunt and aggravate members without giving them the right of reply.
   It offends human rights that they can be discussing me and the project on the forum, and I cannot even get on as an external browser to see what is said.

   Back in October, my whole project was repeatedly doubted especially on engineering precision matters, by the very same people, even though the thread was in a group called 'Bodges', subtitled 'hare brained ideas' which suggests to me that one is entitled to be a bit experimental.
   I had to fend these doubters off with promises to report back in January and February. (by the way, the doubters included attacks on myself, my job, my children, my students, all posted in a public forum and nothing to do with engineering - the project was termed a chocolate teapot, a scam, and even at one point inferred as a 'malicious hoax'.). There is a moronic moderator who claims that getting energy from the sun is 'perpetual motion' - well, Chris, yes, it is! for a few million years we can get energy from the Sun, dumbass!
   I kept my promise this week, reporting new data from the end of January which is indicating that the project is now successful. My deep ground temperatures and the other key parameters - electricity consumption - have all proved it to be good. Every week, the annual consumption of the house and of the GSHP are re-computed, and every week, that figure is dropping to never before recorded lows, despite the two severe winter seasons we have recently suffered. The ground temperature is now rising slightly, whereas a year ago it was more than 5 degrees colder.
     One of the reasons given by Jack is my failure to place an order with Navitron for a large housing project which I have mentioned periodically. He clearly doesn't know the timescale and cost of a planning application for such a large number. He doesn't seem to know that participation in the forum is not conditional on buying kit.
   As I have said before, it doesn't pay to piss off the future customers. I have to meet Navitron at EcoBuild because we will both have prominent stands near to each other, and yes, I am working on a development of 128 dwellings all of which will have heat pumps, PV panels and evacuated tubes. My last email to the boss of NT promised him that NT would play a part in this, but the ban followed a few hours after.
    I want back in, I don't want an apology for the smiting, I just want the threads restored, delete this article, and to get on with discussing Sustainable Energy Technologies.

I would like to say to some of the genuinely nice and helpful people at N-Forum, that I am missing you, and sorry. (eg biff, Mr Gus, Ted, Klaus and Ivan and Stuart, and even Hiccup....) if you read this and you have been missed out, (I cant scroll through remembering all the names) please notify me by email...

PS: One reason that Jack says for the ban is: Someone starting a new project asked if he should start up his own blog, and I strongly recommended him to do so - it is fun, and it is up to him to do the editing and illustrating. If his sole recording of the project is on the Navitron forum, then it will gradually be buried under the vast river of threads and contributions, so he will be unable to trace a history in a years time. Also, the entire project is subject to the capricious whims of the 'moderators' who can smite and delete without the chance of reply, making the life of the originator a misery, like they did to me. It looks like I was totally right, a whole years worth of work could be destroyed by vindictive smiters and blockers, as has happened to me.
The last laugh is mine, in that my project is very successful, with wonderful results, and I can continue leaving this here to tell you what a deeply depressing place that forum is.

Solar storage under roads to reduce effect of Salt and Ice

4 Feb 2011: I have recently been interested in 'solar roads' of which there are quite a few google references. It was also stimulated by reading that the UK was running out of Road Salt and having to important thousands of tons.
   A system of solar heat storage that could be used to defrost roads would save hundreds of thousands of tons of salt every year, plus all the cost of damage it does to the water table, and the vehicles that drive over the same roads, and cost of the vehicles and crews that have to do the salting.
    When roads are relaid, it would be good to add this system. Underneath roads there are many other things, such as the sewers gas and water, and electrics for traffic lights and street lighting, and telecoms / TV coaxial cables. The local authorities know what is under most of the urban roads, so that know what is there when they have to dig.
   I have heard of this system used in Scandinavia or Holland, but would be difficult to remember where this was. I found that ICAX who were mentioned here some while back have done some experiments with ICAX solar roads using summer thermal storage underground, and circulating liquid. They have laid some prototypes.
   There is another system called Solar Road which is a lot more sophisticated with active lighting systems, power generation etc. but that is in a different league of cost and expectation. What I am writing about is simply defrosting roads to reduce the risk of ice.
    It doesnt need heat pumps. Just a small pump serving each bank of pipes, to recirculate heat, moving heat from the road in summer to deeper down, and during the month of Dec and Jan could be thermostatically activated to circulate again, this time bringing deep ground temperature to the surface. It would melt off the ice.
   We have had five winters in succession, each getting progressively colder, since 2005. Will next winter bounce back? Or will this continue, as part of the climate change trend whereby as other parts of the world may get warmer (eg the Canadian Arctic), as the UK gets colder?

15 April '11 Postscript: I see that Heathrow Airport is considering this system, and it is on the front page of the Guardian! See the article - I will write about it in this Charging blog in the April section.

Friday, February 4, 2011

Discussion about System First

(Image from RB website)
4th Feb 2011: I was lucky enough to have a chance to talk to Dr Chris Wood today, who has just been awarded one of the Rushlight Awards, in the category of Ground Source Heat Pumps - against tough competition from some very good competitors. His particular research has been in 'energy foundations', a system of piling developed with Roger Bullivant that is another way for GSHP to get energy from the ground using the structure,  instead of a single deep borehole.
   Key to this is solar recharging of the ground under the building. It is based on the RB System First piling system, but it adds ground source loops into the piles. Typically, these would be 8 metres deep and with solar charging would form a bulb of heat under the building (reaching more deeply than some horizontal slinkies) benefitting from the high insulation of the slab. There might be 20 such piles under a typical house, quick to drill with RB's high speed rig, and causing the minimum of spoil compared with traditional trenches or trench fill - and using less concrete.
   I am designing some houses and flats at the moment for southern England, and am pretty determined to use this system, in tandem with Surya Sunboxes.

   Chris is also interested in the proposals for the skyscraper design in New York. One benefit of the RB energy foundations is that you have some comfort from the near infinite quantity of soil under the house. The natural energy content of the soil overrides the many variations such as the amount of heat gained or lost from the ground near the surface. If you wish to, you could add more solar panels.
   In the case of the skyscraper, with insulated thermal stores at high altitude, much more exact calculation is required:
- the matching of the area of solar panels incorporated into the facade
- the potential system losses from the delivery piping
- the volume and phase change temperature of the store
- the means of returning heat to the apartment
- allowance for heat loss from the store, or how to deal with overheating
All these have to be perfectly balanced, or there would have to be some direct electricity used to supplement the heating system which would undo the whole purpose of the scheme. The HQ building in Austria assumed it would take 7 yrs of solar heating to get the infinitely sized ground store up to steady state (in which heat gain equals heat loss and withdrawal). In the case of the skyscraper, with heavily insulated stores of finite size, there has to be a means of bringing the store up to temperature, depending on what time of year the building is commissioned and occupied. Because the stores are insulated, they would get to steady state within one full year. Perhaps there should be ancillary stores. Also, the temperature of the ancillary stores can be boosted with non-solar heat by using them to cool public spaces and other parts of the building in summer.
We hope that Chris will be available in March (after EcoBuild) to help us take this further.

Wednesday, February 2, 2011

Skyscrapers using Surya technology!

Here are thumbnails of two schemes, each of
which were presented in 3 A0 panels.
2 Feb '11: The skyscraper designs produced by our students have swept the board in the UK stage of the Isover competition.
  The students of the unit submitted 9 schemes, and 7 were chosen as finalists, and the remaining 2 were highly commended. Only one other scheme from the UK was included in the total of eight finalists.

Phil and I set the students the task of designing the upper residential sections with ZERO energy cost from any form of burning - no gas, oil or direct electricity! They have all designed apartments with heating based on the Surya interseasonal technology of my Peveril Solar house, with solar thermal panels on the south elevation, and large thermal stores on every floor, or every fourth floor, and underfloor heating from heat pumps in each apartment.
  At a height of 200 metres, it is too distant to send heat to and from thermal stores deep below the underground parking so the geothermal stores have to be 200 metres high too. As we could not use vast amounts of clay at that height, we would use large water tanks or stores of PCM blocks. The stores have to store an entire summer's heat, and it is clear from my own system that there is additional real-time heat in equinox and winter to avoid total cooling of the store during winter. More of this later. At the second stage, we will get engineer colleagues to validate the quantities required.
  We shall be showing these schemes on our model of New York - all nine of our designs - at Ecobuild 1-3 March 2011, Excel Centre in east London, on one of the largest stands of the show. Please call in!
The best three from the UK will be invited to Prague for the final in May, so at least 2 of our groups will have an invite and a prizes.

April 2010 Postscript: the one illustrated top won the FIRST prize in the UK stage of the competition, and the one illustrated below came 4th as decided by the competition judges, but was declared FIRST choice of the public attending EcoBuild.


East Leake running now!

Photo taken in a sunny day November 2010
2 Feb '11: I took a trip out to East Leake to programme the thermostat, and get the system running. The last work by me was done on the system in November 2010 including all the wiring. David Hill completed the plumbing bits some time in December. Then we had a succession of things like snow and ice or me going to Austria, or the University being busy which stopped me getting out there earlier - we haven't missed much as December'10 was cold, and January'11 has been quite grey apart from one bright week.
      I am glad to say that once the AKO thermostat was programmed, the system immediately began to work - activating the solenoid valve and pump. As the day was cloudy and grey, I had to pop the sunbox sensor under my tongue just to make sure that the warm temperature activates the pump, and to check that there is a good hysteresis. We have labelled each part of the system to make it easier to understand.
     When several days of readings are taken, they will be on a spreadsheet. As the weather conditions, and the surface area of the panels will be identical to those of Nottingham, it will be an ideal comparator with the existing Surya Sunboxes on the Peveril Solar house. You can see from the photo that there is a shading problem in the late afternoon, and there will be partial morning shading from the trampoline. But we can live with that - the boxes can endure partial shading OK.
    These black collectors are steel, with convection fins at the rear - a very high total surface area and better admittance than plastic, so we have hopes that this system will outperform the Peveril sunboxes.
    David's system has boreholes supposedly of 60m deep, but he is not sure if he has two or three! Even if it is only Two, he has greater capacity to send and receive free solar heat. He has also been running his heat pump for some years with a house twice the size, so the deep ground offers a better delta-T for any warm liquid we send down.

Tuesday, February 1, 2011

January update

31 Jan '11: End of the month, another update: the weather was much milder with only 373 degree days during the month (base 15.5) and the consumption of the heat pump was proportionately reduced.
  The best thing for me was that the ground temperature maintained above 10.0 degrees C, most recently 10.6º, and rising slightly since the end of December.
  In addition, the total annual consumption of the house has gone down to its lowest ever. In 26 Sept '10, it was recorded as 6,075 kWh, in the coldest part of December '10 it rose to 6,302 kWh, and on 30 Jan '11, the annual consumption worked out at 6,063 kWh. Let's hope that downward trend continues. I really want to see it below 6,000, and the GSHP consumption below 4,000 kWh.
  The graph illustrated here now includes January 2011, showing the downturn in both lines, which follow each other faithfully. Remember that we now have the heat pump on for more hours per day, and a higher thermostat setting than last year (at the request of Mrs N-C).
Explanation: The Red curve is degree days and the curvature symbolises the heating requirement of ANY building in the Nottingham area, derived from weather stats from the nearest international airport EMA. The Blue curve represents the Kilowatt Hours used by the GS heatpump
Note: Although DDs and kWh's are not the same units they are proportional to each other, and numerically similar, so I feel that it is legitimate to overlay the two curves. 
Also: the Red curve represents the heating requirement of the building, whereas the blue curve represents the combined requirement for Heating and Hotwater, hence the blue curve continuing through the summer, just above the red curve.

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