Saturday, January 29, 2011

There may be another solar charger!

29 Jan '11: During the ArchiCAD Winter school, many have shown interest in the solar earth charging, and one person, Johann from Stockholm tells me that he has a friend who is doing something similar in Sweden. I have been aware of a few district heating sized systems (Canada and Sweden), but have not been able to find information about single houses being done this way. If I can make contact, I would like to write an article on his system, or provide a link to a website he may have about it.
   It takes an almost unique combination of someone who had a Ground Source Heat pump, Boreholes, a South facing wall or roof, and the interest in trying out a new technology that does not yet have a proven commercial return. It does not require a lot of money if the other components already exist.
    Sweden has a very high installed base of GS heat pumps, but it has almost twice the degree days of Nottingham (colder!), and lower sun angles but longer summer days than we have in the UK Midlands. To me that is all the more reason to try this, if the capture in the longer sunny days of summer can be optimised.
   One problem is that if you are too far north, the summer sun spends hours in the North East or North West, and the problem becomes more 3-dimensional - a simple north wall mounting may not be ideal, a roof may be better.

Thursday, January 27, 2011

Where is DNC?

28 Jan'11: If you are a regular visitor, you may have noticed that I have not posted for a week or so, and the meter readings are a week out of date. I am in Austria on a skiing week.... yes, I admit that I am using up my carbon credits with a Ryanair flight and the electric ski lifts, but so is everyone else here and they are not living in carbon neutral homes.
  It has been grey and dull in Nottingham for the last week, and here in Kasberg, it has been cloudy with perfect fresh snow every day. Still.... the first day was sunny, and the weather forecast promises sunny for the last day, and for Nottingham too.
  Still.... I will be back on metering duty next week, and will hope to extend my graph of heating performance after the month's figures for January are completed.

Friday, January 21, 2011

Comparing Daily Averages

Jan 2011 : One of the benefits of metering for so long now is that it is possible to reflect on the performance of the systems at different times. At the moment, the average daily consumption of the House and the Heat pump can be calculated. This shows the house and pump to be using substantially less electricity than in the two previous months of comparison - and this is despite our starting the GSHP 1.5-2 hours earlier per day than we did last year, and having an extra half degree on the thermostat. It has used less than in the same time a year ago.

Jan 2011 - This month - is a warmish month, with 373 degree days.
Dec 2010 - this was the coldest Dec month for more than 100 yrs with 499 degree days.
Jan 2010 - this was a colder month with 441 degree days.
Dec 2009 - this was a warmer month with 387 degree days.

Average daily for house:  
This month: 27.60 kWh in Jan'11
Dec 2010: 33.22 kWh : 5.62 more than Jan'11
Jan 2010: 35.26 kWh : 7.66 more than Jan'11
Dec 2009: 30.49 kWh : 2.89 more than Jan'11

Average daily for GSHP:  
This month: 20.26 kWh in Jan'11
Dec 2010: 24.65 kWh : 4.39 more than Jan'11
Jan 2010: 25.83 kWh : 5.57 more than Jan'11
Dec 2009: 22.62 kWh : 2.36 more than Jan'11

Multiply any of these daily figures by 31 to get an idea of how much that saves monthly.

Tuesday, January 18, 2011

Interseasonal Thermal Storage - High Rise!

This is NOT an aerial photo, folks, it demonstrates how good
Earth Google has become, that the models are fully textured.
Our design site is over the parking garage where
the Brooklyn tunnel emerges.
18 Jan '11: One unexpected product of this research has emerged this semester, as my Tall Building students are doing a Passivhaus based 60 storey multi-use tower for New York.
  What started out as a very private project for me on my own house has ballooned into a key technology that can be applied to tall and super-tall buildings. One of their requirements is to heat and cool the apartments without any burning! This would be truly passive if the heating and cooling can be done with a combination of no-fuel methods such as thermal capacity, phase change materials, triple state heat pumps, localised geothermal stores etc. Much of the south facade can contain a mixture of PV and solar thermal panels (or tubes) and these can store to enough volume to meet the heating requirements of very well insulated apartments. This requires some very good design to make a 'smart' facade, and very high insulation standards applied to each apartment.
    Because geothermal heat pumps are a prime way to heat the apartments without burning primary fuel, where is the 'Geo' in geothermal? The real 'Geo' is a very long way down, too long to overcome system losses from pumping vertically and insulating. Also it is already complexified by the NY subway and subway entrance running under the building, and old sewers from previous buildings - and about 5 storeys of underground parking - and deeper down below that it is rock! Winters are too cold to consider air source heat pumps, as the degree days every winter are similar to the December'10 that Britain has just experienced, indeed, during the same month, Manhattan itself was brought to a halt by extreme weather conditions.
    So they are, in effect, having to build the 'Geo' at high altitude. Some will suggest water tanks, some will suggest PCM material stores, and these will either be on every floor on the north side, or will be larger elements every 4-6 floors. There will be localised heat pumps either in each apartment or serving each floor, with liquid underfloor heating to each apartment.
    I will publish some illustrations after we have had an appraisal of their work, which is due on 19th Jan, and then we hope that some of the projects will be on show at EcoBuild in Earls Court, in March 2011.

20 Jan '11 Postscript: We have now had the crit and seen the work of the students, and they have until 24th Jan to tidy up and finalise and then finally submit to Isover. I will be able to post details of them on here after 1st Feb, but at low detail. They have all used interseasonal storage, with slightly varying ideas on the best way to collect the heat, position the stores and distribute the heat.

Monday, January 17, 2011

Deep ground still good

17 Jan '11 : I am somewhat amazed at the ability of the ground to recover, thermally. Although we haven't had much sun recently, we haven't been drawing much heat out of the ground either, due to the mild weather. So the ground has not been chilling hugely. However, since the turn of the year, the ground temperature is gradually rising. From nearly dipping below 10.0, it has been warming, 10.2, 10.4 and now 10.6 degrees in successful weeks. It has been a slight coincidence that on the Sundays when I take a reading there has been a bit of Sun showing, and therefore some activity from the sunboxes, but these have not been more than 6 kWh in a single day - and always in winter time mode, i.e. driven by delta-T and well below 10 degrees while running.
    If they run, they are effectively restoring temperature more quickly if the holes have chilled. i.e. If the sunbox temp was 12 degs,  they might run liquid down at 5 degs for some minutes after the GSHP had dropped the loop down to -0.4 degs.
   My measuring conditions are strictly identical, the machine turned off for 4 hours beforehand to allow temperatures to settle down.

Without Hot Air: Mackay

17 Jan '11: David Mackay who wrote 'Sustainable Energy - Without Hot Air', has made it available free on the web - for some time it has been available as a large PDF or as a set of html pages readable on line. It is a very realistic look at all our sources of energy. While I can't agree with everything in the book (for example he is somewhat scathing of wind power) the overall message is clear - it is our Energy Guzzling habit that is the biggest problem. All the efforts to exploit new technologies like wind farms and heat pumps don't get away from the fact that as a society we use too much. Natural processes like vegetation cannot convert all the new CO2 that is caused by our energy consumption, especially if we are de-foresting as part of human activity. The inhabitants of the Los Angeles region drive the equivalent of 140 million miles every Day!

In particular he mentions that doing only a little, like not leaving mobile phone chargers plugged in will only achieve a little. Bigger gestures are required. Some need cost nothing. Turning down the thermostat by one degree could save 10% of annual heating costs. In everything he discusses, he is not polemically pro or anti anything specifically, fundamentally, he is pro-Arithmetic, and the logic that that carries with it. This is the opening quote from his statement to the House of Lords committee, Jan 2009:

The public discussion of energy options tends to be intensely emotional, polarized, mistrustful, and destructive.  Every option is strongly opposed: the public seem to be anti-wind, anti-coal, anti-waste-to-energy, anti-tidal-barrage, anti-fuel-duty, and anti-nuclear.

We can't be anti-everything! We need an energy plan that adds up. But there's a lack of numeracy in the public discussion of energy. Where people do use numbers, they select them to sound big, to make an impression, and to score points in arguments, rather than to aid thoughtful discussion.

Cutting our consumption is the priority. But what can governments do about energy generation? He concludes by discussing what is possible at the large scale, such as very large wind farms in the north and very large solar farms in sunny regions, with high capacity long distance cables.

Friday, January 14, 2011

SET 2011 Conference abstract

15 Jan '11: I have been encouraged to work on a paper for the Istanbul SET conference in September 2011. I had a poster at the SET in Shanghai in August 2010, but it was too early to be doing more with it then - we didn't have enough results.
  It probably isn't 'engineer speak' enough, but there is no harm in trying, and it would be co-authored with Blaise.

Tuesday, January 11, 2011

Some things one does at other times

11 Jan '11: Every so often I get to do something completely different, and here is an image of a project, this for example is a model of the US Coastguard ship Eagle, commissioned by the architects for the navy docks.
 It's a partially parametric model, you can set it on different angles to the wind etc.
(Below the waterline, there is a bilge and propeller, by the way)
This model will be on sale at Objects on Line shortly.
  Theres a bit more to add, lifeboat davits, and some handrails, perhaps - there's nothing to stop people falling off :). There's a lot more rigging than is shown here (when the real ship tacks, there are about 200 ropes to be adjusted). The original was built in 1936 by the German Navy, as the 'Horst Wessel'. In 1946, it became part of the US Navy as reparations, and was renamed 'Eagle'

Monday, January 10, 2011

Cylinder thermostat fitted

9 Jan '11: The Heat Pump still seems to have a periodic problem of pushing the water temperature too high - and it often then displays a panic red light when the water temp goes over 60º. Having already had the REGO controller replaced in July, I don't know what more I can do. Ice Energy tell me that IVT are not likely to change the ROM for a while, and that IE are aware of an intermittent problem with the HW temperature - the one I seem to have. Most people, it seems don't seem to care much, but I do! and I am trying to set a new low for energy consumption in the coming year.
   Another reason I care is that if the red light shows too often, the GSHP stops fully, awaiting the user to hit 'Acknowledge' before continuing. If this happens when we are away for a week during a cold spell, it could be serious.
   After a year and more with my whole earth-charging experiment - yes, this entire thing started with my attempt to tame this heat pump - I have tried another idea. I've attached a Danfoss cylinder thermostat, £15 worth, to the metal cylinder, and there is a bell wire to a terminal (bottom right in the photo) that simply turns off the hot water heating if the temperature goes above 56º. I shall have to calibrate it through observation and adjustment, as the thermostat goes from 30º to 90º and it's a rotating switch, not digital.
   My one thing to remember will have to be that I should turn the thermostat to high once a month, to allow the GSHP to pasteurise the water, by going past 60º.

Question about the whole thing?
So you ask... is the whole thing futile? Well not exactly. The heat pump is performing far better than last year, and has done so through the coldest December on record. The quickest-to-show criterion of success is the deep ground temperature. One year ago it was 4.70º-5.0º. Today it was 10.4º. Although the last week has been grey and dull, it has not been too cold, and in the last two days, it got colder but with good sunshine in the morning. I am delighted that we have managed to keep the ground above 10.0º.
 I have also improved my procedures for testing. I leave the heating off always for the same length of time, 4 hours, before testing. My results one year ago may have been tested with a shorter rest time, I cannot remember.
  The research has been good fun. I don't know if the annual saving will justify the expenditure, and provide a payback calculation for doing this to other heat pumps, but I am determined to give it a try.

Postscript: This is going to be more difficult than I thought. The water jacket surrounding the water tank has to get hotter than the tank to heat the water within. The thermostat is fastened to the outer jacket, not the inner tank wall. I need trial and error to see how hot the jacket gets when in a heating cycle, to bring the inner water tank up to the correct temperature of about 50º-54º. On the first day of trying, it seems that 70º-72º on the waterjacket seems to be about right for 55º in the tank. (Surplus heat seems to be drawn from any surplus to contribute to heating.).

Saturday, January 8, 2011

Nottingham Evening Post writing about DNC !

8 Jan '11: I am delighted to see that the Nottingham Evening Post has published a large article about my house and I, on page 18 of the 8th Jan Nottm Evening post - as an 'Eco-champ'.
They have also published an editorial about the house on page 14.

Thankyou Evening Post!
Can I just say, that there is one significant mistake in the article where Bryan Henesey misunderstood something.
I told him that the average UK house uses 3,300 kWh for Power and Lighting, and he wrote it into the article that it was for Heating.
Of course, Heating is more consumptive, the average UK house uses about 21,000 kWh ! That is because it requires a lot more gas to achieve the same effect. At this time of year, most of my neighbours' houses have a wisp of steam coming from their boiler all day long. I am glad to say that our heat pump is still finding times to sleep between heating cycles.

The Peveril Solar house annually costs 3,000 kWh of electricity to heat, and the PV generates more than 3,300 kWh so for that, the mathematics are simple.  Our house is Carbon zero for heating.

The Sunboxes store 3,000 in the earth, and the heat pump pulls up 9,000 (so a net amount of 6,000)
...but there were so many 000's flying around in the conversation that he got mixed up.

If you go onto the Evening post website, could you post a supportive comment, there are the usual moaners writing about it, saying that global warming is a hoax, and some of those need to be replied to.

The article about me doesnt mention climate change or global warming. My prime motivation is the coming Energy Famine, and the need to save energy, and thus reduce carbon emissions. It has been part of a personal target to make the house carbon zero.
 I am still trying to think of what to do next.... any ideas? (apart from jumping in the Trent...) whole house MVHR won't pass the marital approval test. More vegetables from the garden in 2011. Heat reclaim unit for the Kitchen only, perhaps.

More on the Energy meter, and Pump speed

7 Jan '11: It is obvious after some sunshine earlier in the month that the Supercal energy flow meter was not working again. But today the sunshine was strong and warm and the Surya Sunboxes were working well. Clearly, I could see from the AKO thermostat that they were pushing heat down into the ground, and the GSHP was benefitting.
   It has been stuck at 12548 for over a week, and I went up and wiggled the wires a bit, and suddenly it worked again - jumped to 12549 suddenly - it finished the day recording 7 kWh in a few hours on Saturday.
   There is a joint in the wire to the sensor that is done up with blue tape, and the wire is too tightly wound around the unit, so I think I will carefully unwind the tape, and check to see if there is a dry joint in the sensor wire, solder it back again, then retape it. As there is a tiny clock battery that keeps these things going for 5-10 years, the voltage on the sensor wire must be extremely small!
   I am tempted to just buy another one. Error 2 is one that the manual says 'Return to dealer', so perhaps a new one with a guarantee would be good, especially as this one was given to me, and was already old when it was given.
These DMS people do them for £ 185, so it might be worth splashing out.

Pump Speed
This was discussed earlier. I have increased the pump speed, so it runs at 45 watts instead of 30 watts. That is still very economical (and mainly only running when the PV roof is supplying power). It means that when there is real heat up there, it will download it more quickly, and if that works, then the thermostat will stop the pump - so overall, the electrical consumption will be balanced out - and our effective kW per hour of running might be slightly better.

Article for the WSSET Jan 2011

Jan 8 '11: I was invited by Prof Riffat to submit a quick 300 word article to fill a space in the next edition of the World Society of Sustainable Energy Technologies, to meet an urgent publishing deadline. So, along with three key illustrations (which he can use, crop, resize or omit as he wishes), I sent this, approx 302 words:

The Peveril Solar house in Nottingham has a photovoltaic roof and a ground source heat pump. It is a small detached house built in 2007 with a very small plot, so the GSHP is working to twin 48m deep boreholes.
The house is Carbon Zero for its heating requirements, by combining:
• Good insulation,
• Energy efficient lifestyle,
• Renewable energy from ground and sun,
• Photovoltaic generation, with a 4 kW array.
It meets Passivhaus requirements for retrofit houses, with 25 kWh/m2/year, even without a heat reclaim system. The heating consumes 3,000 kWh of electricity and the PV panels capture 3,300 kWh annually. Solar thermal ‘sunboxes’ capture 3,000
kWh/year and the ground provides about 6,000 kWh/year.
   Since March 2010, the house is a test-rig for an innovative heat pump add-on technology. South facing ‘Sunboxes’ charge the boreholes with solar and summer-air heat. The sunboxes use 4 sqm of black swimming-pool panels in clear polycarbonate
solariums boosted with 2 sqm of aluminium mirrors. They will prevent cumulative deep ground chilling over consecutive cold winters.
   Annually, the sunboxes are likely to put 3,000 kWh/year deep into the ground. They heat the ground in summer and equinox times, but the heat is planted so deeply that it does not have time to escape before winter comes. The heat pulled up is 9,000
kWh in total, so the earth is acting as a thermal battery, with about 8,000 tons of clay for storage.
   The idea of interseasonal storage is not new, but the known examples all seem to be office buildings, or district solar heated housing estates in Canada or Sweden. The implementation on a single domestic house remains a unique combination of glazing, plumbing and electrics created by the researcher, a lecturer at the University of Nottingham, UK. 
David Nicholson-Cole January 2011

Thursday, January 6, 2011

Animal water in winter - solar charge it!

6 Jan '11 : I met a farmer in Screwfix who is doing a PhD part time in our department. He is an organic livestock farmer, just a few miles outside Nottingham. He has had a bad time over the winter, as the animals need a supply of fresh water, and any external water containers were freezing solid in the prolonged cold conditions. The main water vessel is a 1,000 litre metal tank that froze through, and they had a troublesome session with blowlamps to free it up - very energy intensive!
   I proposed a simplified Solar charging solution that would be cheap because he already has a digger, and no heat pump is needed. Simply the ground temperature itself is sufficient providing it has been topped up during the summer. Using a 3-port valve, one can design two loops that combine into a single ground loop that can run out in a horizontal trench protected against freezing with foam insulation.
The Sunbox itself can be a metal radiator or a spare one of my swimming pool panels, enclosed in a ETFE or Polycarbonate box. As this is just a water tank, not a house, one such panel should be enough. One AKO thermostat could manage both loops, and only one pump and solenoid valve would be needed.
  Mind you.... if he just insulated it efficiently, that might have reduced the risk of freezing solid. The cold snap was so prolonged (not much of a 'snap') that it would probably have frozen through any amount of insulation.
  He was very enthusiastic at the time, but hasn't replied to the idea, so perhaps I needn't have bothered. But it was an exercise in thinking.

More about Heating Degree Days

6 Jan '11: With my new found interest in finding historic data for weather records, I have managed to get further. The very kind people at (provided by Bizee Software) have given me extended access, which goes beyond the normal three years worth of readings. Please visit their site if you are at all interested in energy statistics.
As the site allows you to calculate Heating and Cooling, and to set your own Base temperature, it really is VERY useful for the researcher. I have an interest in New York as well as Nottingham. I am working on ideas for interseasonal storage from sunboxes on a skyscraper in New York. Can one really store enough heat in the hotter summers to get through a New York winter?
It has been misleading for me that the two recent Nottingham winters have appeared to be as cold as New York. So plotting back ten years, one can see that averaged over that time, the New York winters are much more severe. The reality is that the typical New York winter is as severe than the one we are now living through. The two graphs are at the same scale.
The figures for NY for Jan and Feb 2011 will be interesting, as they have had much deeper snow than the UK. The figures for Nottingham will be interesting too - is this winter going to be followed by a very soft spring, or will some of the severity continue?

Wednesday, January 5, 2011

PV Harvest for 2010

5 Jan '10: As this is a time for reviewing the previous year, here is a diagram of the PV harvest for the year. Although the specific roof is facing east, the general trend of 'sunniness' is indicated, including some clear groupings of low or high readings when we had extended cloudy times, or sunny spells.
 Our total harvest from 1 Oct'09 to 1 Oct'10 was 3,325 kWh which is a lot more than we were led to expect from the PVGIS site, from which we expected about 2,850-2,900 at best.
  At this time of writing, in Dec and Jan, we are living through a time when we think that that 2.5-3.5 kWh is an extremely good capture.
  In the best times of mid summer, we are regularly over 20 kWh.
  If we lived in the south of England, or had a roof that was more south facing, it would be even better.

Comparing Degree Days and GSHP

4 Jan 2011: This Degree Day exercise has been very useful in reinforcing my confidence in this project.
  The chart compares the kWh consumption of the heat pump and the degree days of the same month. They are not the same units, but there is a linear proportionality between them.
  The GSHP meter was fitted in the last week of Sept 2009, so I have records from 1 Oct 2009, the same date as the start of the PV roof.

The Winter of 2009-2010 shows that the heat pump consumption for that winter was much greater in proportion to the degree days, compared with the winter we are now going through.
  The Surya Sunboxes started working in the first week of March 2010, and March was quite sunny. There is a steep fall in the GSHP consumption to bring it much much closer to the degree day curve. There was a brief cold spell in May 2010 which is reflected in both curves. During the cold months, the GSHP figures also include about 60 kWh per month for the circulating underfloor heating pump.
  During the summer, there was no space heating requirement, but the GSHP has to heat water, so it has a small workload. Other houses may have needed a small amount of heating in summer, but ours did not as the good insulation and thermal capacity ensure that it performed passively.
   In late September, the heating season started. The Oct-Dec'10 degree days curve reveals a much colder half winter that in Oct-Dec'09, but the heat pump's consumption is tracking it more smoothly, and the consumption peak at the end of the year is never as high as it was at the start of the year.
Weather data from
   Our energy efficient lifestyle hasn't changed, and if anything, we use more energy because we start the GSHP in the mornings nearly 2 hours earlier than during the winter of 09-10. May I be permitted to interpret this improved efficiency as being a sign of better heat resource in the boreholes?
  The graphs on the right show temperature records for Nov and Dec 2010.

Degree Day comparisons 2008, 2009 and 2010

4 Jan '11: Now we are in the first week of 2011 and still enduring a long winter, it's a good time to compare this year with previous ones. The wonderful weather site wunderground has a spin off, and this carries weather records for everywhere with an airport, it seems, and more besides.
    Degree Days are a good way to assess the thermal performance of the month and the year as they record the number of degrees during how many days that heating systems were required to bring the building up to a desired temperature. We normally use 15.5º in degree day calculations on the basis that incidental gains are enough to make the temperature comfortable. This is a bit approximate, as in the recent winter, there has been little sun through windows, and with energy efficient lighting, appliances and cooking, the incidental gains are less than hoped for. Incidental gains in equinox times are perfect, but in December and January? Not much!
  The figures above show the degree days on a month by month basis for Nottingham, for the last three years. 2008 was a very typical year, whereas 2009 was somewhat milder. The year of 2010 was truly more severe by 20%, with the very cold spring and the very cold winter occurring within the same calendar year.
 I have split the year into 3 blocks which equate to the times I use for metering, Jan-Mar, Apr-Sep and Oct-Dec. As these figures are monthly, I can relate these to the consumption of the heat pump, and generate a sort of index of performance.

What does this mean graphically?
Well, it shows that there has been a cooling trend annually. Do not be deceived into thinking that this disproves 'global warming' because climate change globally is about change, AKA chaos. It does not result in every place getting warmer. Britain could get cooler if the Gulf Stream is affected by melting polar ice.

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