Thursday, December 31, 2009

Happy New year

Dec 31: Happy New year to all the kind folk who have been reading this Blog....

     the project isn't finished - but its moving along.

           Now, I must get up to the loft and do more plumbing! I am now working on the vertical descent from the loft to the heatpump on the ground floor. It is very difficult working through an underfloor heated floor, with the risks of losing sand or cutting a plastic pipe.

Rushcliffe Solar now has a blog!

31 Dec : The Rushcliffe Solar campaign now has its own RushcliffeSolar blog and its own email. More articles will follow about that on the new blog, including parts of the original powerpoint to Rushcliffe, with images of solar roofs, tables and details.

Moving the Rails - get it right!

31 December: Thinking harder about the problems of the position of the panels, I decided that a thoroughgoing approach was required - take two of the panels and rails off,  drill new holes in the aluminium for refixing to the wall, and then to refit the panels from new with the main rails perfectly plumb, and 3cm to the right. This was forced on me by the fact that the polycarbonate panels are perfectly square and require perfect squareness in the rails.

This was a difficult decision, but made easier by a visit from Chris McCabe, a builder (and contemporary of my daughter) who has helped other families in our West Bridgford friendship group. He stayed for a couple of hours - it is much nicer and more decisive working with someone on scaffolding in freezing temperatures, a lot quicker, and we finished with plenty of daylight left.
Later in the evening, I got more plumbing done in the loft - it's time to do the vertical piping to the ground floor! The photograph above may not look different from earlier ones, but close up, and millimetrically speaking, it is perfectly plumb and ready to fit the glassy boxes!

Tuesday, December 29, 2009

Better harvest from the Solar Roof!

There is one benefit of having passed the winter solstice...  bit by bit we shall see improved average harvest from our solar roofs! (although for a couple of weeks either side, the sun's altitude only varies minutely).

My roof is performing better than predicted by the JRC solar calculator, even allowing 10% efficiency losses. The harvest is 7 percent better in Oct, 40% better in Nov and so far, 45% better in December..... (December has been sunnier than average) .
This is pretty good, especially as our winter sunrise is a full hour later than the real sunrise due to our being so close to Sharp Hill. The morning is our only chance for harvest. Air temperatures are colder than average for December, so has this been enough to improve the performance of the panels?

Thursday, December 24, 2009

A day of adjustment - fixing errors


23 Dec : a Horrible day, entirely my fault, although the nice thing is that the sun shone all day and made the work warmer. I wish I had been more precise about measuring the centre of the group of panels, I just worked from the centre-pipe which I thought was central. But it shows yet again how important accuracy is. The left hand array should have been 2 cm to the right, and the right array would have been better if it had been 4cm to the right. In each of the arrays, the pair would have been better a centimetre closer to each other. Seems small, but matters a lot when trying to fix all those bulky 40mm pipe fittings and stiff rubber hosing, with all the jubilee clips required.
   I was close to taking the whole lot off and drilling yet more holes in the rails, to refix them.... but thankfully, there was enough 'give' in the fixings to move them sideways, enough to fix the stiff rubber hosing.  By now it was dark, and I hope all those Jubilee clips work well! They certainly make it easier to fix the hoses!
   Later in the evening, back down at ground level in the conservatory, I fastened aluminium angles to the Polycarbonate front panels (large!) using pan headed screws... this all went well, although its difficult to handle such large panels on my own.

Monday, December 21, 2009

Four Panels up!

21 Dec: Four panels up now. The curvature is because they are dry inside, so the front is expanding thermally, but not the back. It's lucky I have 8mm bolts holding them on in 14mm holes - so there is enough play for expansion. Also, the panels have compressible foam backing, and rubber washers on the front so there is further play for expansion. The bolts are not done up tightly - Nyloc bolts ensure that they are secure even if left with easy movement front to back.

Actually, I am glad they are loosely fitted, as I need to shift the far left one a centimetre to the right... this is possible. It is alarming how precise things have to be with metal and plastic. One is used to the easy tolerances of brick and timber, but metal and plastic need millimetre accuracy, like modelmaking. I had about an hour and a half re-plumbing something that I did too quickly the day before and the pipes were a centimetre too short when projecting from the wall.. it seems better to make things oversize.... (and cut back if too long).
As the technology here is a prototype, one has to be so careful and methodical. It is all modelled in ArchiCAD first - this has made it possible to make detailed cutting lists for the panels and metal sections. When the whole thing is complete, I will draw up a list of components and dimensions, so that it can be replicated.

Solstice sun

21 Dec 2009: Well Dec 20/21 are both Sunny Days! A great time to calibrate the roof performance. Dec 20 had a short period of cloud which modified the PV harvest to 3.99 when it should have gone over 4.0.

Sunrise in Nottingham is 0816 on Dec 20/21, but the annoying thing about living in the shadow of Sharp Hill is the late sunrise in Winter. I watched the sun rise, but Peveril-sunrise didnt happen until 0918, 62 mins after the real sunrise. We get daylight in the mornings, but can only sense sunlight in the sky, but not see it on us!

GAISMA seems to be a really good site, with predictions for sun angles and declination, both in tables and in good diagrams. Plus info on insolation, wind and temperature. (the word means 'light' in Latvian)

By 0925, when the sun has fully cleared the hill, the roof is generating 310W, and by 1018, an hour after Peveril-Sunrise, its getting 1240W. We pass our peak at about 1030, so at 1118 the power was 1120W..... at 1200 was 800W.... and from now it's downhill for the rest of the day :(

Sunday, December 20, 2009

First Panels go up!


Dec 20: The sun shone all morning, so I got all four panels up.
Just as I finished, the sky grew dark and filled with snow, so I don't have a photo of all four, but here is one of the first panel going on.
All the panels fitted well and the biggest problem was fixing the stiff rubber hosing to join them together. The panels immediately responded to the sun, and you can see how this one curves as the front face is hot and the back face cold - when liquid flows through, the temperature will be more even.

The sunshine of the morning gave us an excellent haul of 3.99 kWhr and by the time the snow came, the sun was well round to the west. As today is the Solstice, this gives a good calibration for what the PV panels can achieve. Lets hope we have sunny days on June 20/21, Mar 20/21 and Sept 20/21.

Addition of three tracking panels?



I have in mind to increase our PV installation, but instead of more on the roof, there is room on the south wall for 3 more panels which are tracking. I could design and build the tracking frames.

I would like to know if or when there is a change in the kW rating assessment for banding of the Feed-in tariff. ie is it globally 31p if you go a step over 4KW, or if it is progressive (ie any amount over 4kW is at the lower tariff). Presently, the 36.5p per kWhr applies to systems 'nominally' under 4kW, not actually under. Its not known what happens if you install 4.4kW nominally, but because 4kW of it faces east it would never generate that amount in reality. Does the whole lot go to 31p or only the amount that exceeds 4kW?

Only three panels - 540W nominal, would generate a massive 583 kWhr in a year if tracking - eg one would change the angle every 2 months to maximise the harvest (easy to work out the perfect angle.)
The two windows open inwards, so one can simply open them and adjust the angle with bolts. Here you see a Winter, Summer and Equinox setting, from left to right.
I have written to EvoEnergy to ask. I wish I had thought of this earlier and had three fewer on the roof. I am keen enough on this idea to think that if I really am limited to 22 panels, I will have three moved from the roof to the wall.

Saturday, December 19, 2009

Rails go up onto wall


19 Dec: The Forest game was at 5.20pm which was great as it left all the daylight for getting some outdoor work done. I have had the Rails finished for some days now, so was desperate to make more progress. The Eight holes were drilled, and the rails are now held firmly by anchor bolts, all in the correct location.
I have been slow because I realise the need for extreme accuracy - almost like modelmaking - the spacing of the holes on the panels gives little scope for mistakes, and I already have 8 unwanted holes that I drilled last week and then realised were in the wrong place. So accuracy is essential, even though it is time consuming. I am building a prototype, so have no precedent to work from. I have to think it out through design, and then cut or drill accordingly.
Let's hope that the Polycarbonate panels (when they arrive) are cut accurately by the suppliers and need no further trimming. If so, they will fit perfectly with minimal cutting and a lot of accurate drilling.
By the way..... Forest beat Preston 3-0 at home. I think that is the 14th unbeaten game in a row.
Another By the Way..... we seem to be weather-lucky as the forecast for the 20th-21st Dec is for a clear sky and high pressure, meaning that we hope to get a classic solar bell-curve indicating the maximum PV harvest possible at the moment of the Winter Solstice.

Thursday, December 17, 2009

Making the metal rails

Dec 16: I have picked up all the aluminium angles from the University engineering stores, and have borrowed a platform drill. So the evening was spent enjoyably building the metal framework to support the panels - in freezing temperature....

I feel a sense of liberation - its been 46 yrs since I last did any metalwork, and with the right tools, it feels like a creative task - and now I am well into it, I feel less anxious about it. Also... one feels that one can make anything that one can invent - [I might make a metal gate for the house next, as it's impossible to find ready made gates that are the right size.] Many thanks to Adrian Harms for the loan of the pillar drill.
The Polycarbonate is coming soon, so that will be challenging - two glassy boxes 1.8m x 1.65m is quite an undertaking to build, and another challenge is to lift them 6 metres.

Dec 17: I have also realised that the temperature inside the polycarbonate boxes could become so excessive - perhaps 40º plus which could affect the liquid tightness of the joints, or overheat the plastics.....  - that I need to have a precaution for this by permitting Ventilation. So the bottom panel will have vents, and the top panel will become a tilting panel, with settings for Winter, Equinox and Summer, allowing appropriate amounts of ventilation. There was a chance to buy an automatic solar powered ventilator fan, but this would be automatic, so I did not get it (saving £ 80).  I prefer to try ventilation settings and see the results.
For research, I prefer to have manual settings that I can experiment with, and measure resulting temperatures, at different times of year. Using a Trombe wall based on this construction, and a MVHR (heat reclaim ventilation) you could go a long way towards heating a house using this method.

Dec 18: Still very frustrated that the Polycarbonate has not arrived... I am told it will come on Monday.

Sunday, December 13, 2009

Drilling holes for the metal structure

Dec 13: This is a view from behind, of the panels and the Polycarbonate boxes. The holes have been drilled in the wall for all the anchor bolts. I will have 50x50 angles top and bottom, which can support the panels and the boxes. I was going to make the boxes of pure polycarbonate using 8mm with patchplate brackets, but have now ordered 6 mm (for lightness and greater transparency) and will have small Aluminium angles at the corners. I will now have the boxes completely closed (including a soffit along the bottom), and the only ventilation is around the entry/exit pipes. This will build up a good temperature inside.
   I hired a diamond tipped coredrill to make the 32mm holes through the wall for the glycol pipes.
    Only disadvantage of the glassy boxes is that I shall have to sense the temperature of the panels by checking the pipes in the attic, as the glassy surround will stop me reading the temperature externally with an infrared thermometer.
    The same effect keeps the heat inside as the panels cannot lose heat by radiating outward through the polycarbonate. They will radiate back to the brick wall. I have contemplated facing the brick wall with reflective foil, but on balance there is a beneficial thermal storage effect from allowing the wall to get hot, and this will keep the space warm after sunset.
I have a difficulty picking up the metal angles, as the car is being repaired at the moment. I have the scaffolding now till early Jan, so there is time to do it well.

Dec 14: spent a while in the Faculty of Engineering stores deciding on the final cutting list requirements for the aluminium sections and the bolts - which can be collected later in the week.

Saturday, December 5, 2009

Scaffolding goes up in one hour!

Dec 5: these guys don't hang about! The 30 cubic metres of scaffolding was up in a flash on Saturday morning, I had time only to make them some tea and take some photos, and it was all done!

And Emperor Scaffolding of Leicester were kind enough to leave some old planks for me to use in the Veg garden. I have the scaffolding now till the first week of Jan.
And I now feel slightly guilty that Forest hammered Leicester 5-1 on the same day! :)
(still... football is more important than Life and Death, as Bill Shankly said famously)

Electrorad offer Solar Geocharging fence


5 Dec: Here is a product that is specifically linked to solar earth charging, although its too new to appear on Electrorad's website. It's called ThermoSolar Fence. [ Electrorad.co.uk ]

As this is specifically for Heatpump, I guess my friends at Ice Energy should add it to their inventory. I would recommend it - now we are reaching the solstice, I suspect my heatpump will using increasing amounts of immersion heater instead of ground heat. This fence is another good idea, although it should not be overshaded by nearby bushes or trees.
A few metres of this, above and below ground, and not overshadowed, would probably be enough for a whole house, combining the benefits of air-solar with the battery effect of the ground - saving the cost of deep boreholes.

Thermosolar on World Architecture News
(its important to look at the smaller pictures which explain it well)
Greendiary page on the Thermosolar fence

Perfect December curve

4 Dec '09: We had a cold but sunny day, without a single cloud all day. So the solar harvest is short but very clean, and represented a total of 4.5kWhr, the best that a December day will do. We have a hill to the south of us, which explains why the bell curve is so steep at the start. Normally when sun rises, it is starting in a haze and the bell curve rises smoothly. In our case, the sun in December has already risen, and it peeks suddenly over the hill at full strength - so the curve is nearly vertical. After noon, the power is coming from the bright sky, not directly sunlight.
The best day in October was 13 kWh, the best in November was 7.6 kWh and the best in December 4.5 kWh. So, of course, I am looking forward to seeing the figures improve after Dec 21, as we move to the spring and summer.
Total for October was 184 kWhr and we got 109 kWhr in November.

Friday, December 4, 2009

Red Light Immersion panic

4 Dec : Every so often, the heatpump seems to malfunction. I had set it so that the immersion heater should not come on, but there must be ways in which it overrides that. Today, it had a redlight moment in the afternoon (possibly not getting heat quickly enough) and then the Immersion heater comes on... it was on for FOUR hours today, more than in all the autumn. As a result the power consumption was 10 kWhr more than usual. And when it is on, the heat pump does not circulate to the ground at all.

This underlines how important it is to get on with this installation of the solar-air panels.

Scaffolding and Polycarbonate

Dec 2: I have booked the scaffolding for Saturday - for the south wall. I feel that progress is stopped until the panels are up.
   Had a tutorial with Joel Carter of the MEng course on Monday, and evolved the design further - we had a thorough discussion of the benefits of putting a glassy screen in front of the panels to foster a microclimate that would increase the air temperature around the panels - a sort of Trombe wall effect.
So in the evening, i have researched the stock sizes of Polycarbonate sheet  and worked out the optimum sizes for a sort of glass box that can surround the panels - if I leave it till another year, we would need the cost of scaffolding again, so it's worth doing all in one go.
    There is an interesting discussion between me and David Brook just below this posting, discussing the idea of glassing in only one of the pairs of panels, to compare their performance.

In the image above, the South Wall panels are rendered in ArchiCAD and photoshopped onto a photo of the house and PV roof. So we are hoping to capitalise on the 'Greenhouse Effect'.

Postscript Dec 10th: I have now ordered the Polycarbonate, more than 400 quids worth!! enough to make two large boxes, as above, and it will now be very closed, eg there will even be a Polycarbonate soffit going in, to make the air inside very hot. The outer leaf of the brick wall will get hot in Summer, which will prolong the thermal benefit long after sunset.

Thursday, November 26, 2009

Solar Rushcliffe Initiative Idea


25 Nov: On Dec 1 I am going to Rushcliffe Borough Council to present an idea about making a Solar Initiative in the borough.
I am doing a pilot study, developing a methodology for what could be a larger project, done by volunteers. I am evolving a Filemaker database structure, with the fields that would be required such as area, orientation, location. We could create a website that people could go to, to get information and register their interest.
    I am using Map-Photo analysis, combining Googlemaps and Bing.com aerial photography, and Digimap vectorised OS plans to map the roofs of West Bridgford, (and a bit of local knowledge) assessing them for building type, roof angle, kilo-wattage that could be installed. Main buildings, plus streets, plus some individual houses. Using local knowledge wherever possible. Perhaps identifying 500-1000 prime targets for PV generation. Nottingham Forest, Rushcliffe CC, Notts County Hall, ASDA, the Tennis Centre, Trent Bridge CC, some of the churches, and suchlike are all good for Larger installations. But then whole streets have house that are suitable… and many streets have hipped roofs in which none of the houses are suitable.
    The end result would be to have an informative website, and to write a very clear colour leaflet setting out the benefits, payback and costs, and then an individual form letter from the database to the householders declaring that their property has been identified in the research project as extremely suitable, and inviting them to ask for further details with a view to having their roof done (with a grant if before April 2010).
   To keep this simple, it is focused on Solar PV – which needs clear roofs. [Solar thermal can be fitted with little 2 sqm panels on any roof, and merely supplements existing heating systems.]
PV is answering the longer term need which is to reduce coal and gas burning for grid electricity.

Wednesday, November 25, 2009

Big Decision about the Battery

25 Nov : Also, after much agonising, and much time spent on design I have had to make a decision about the battery with the phase change spheres. I have at least two, perhaps three students dependent on me for a dissertation now, and I am aware that the battery brings two undesirables to the table: a big Delay, and excess Complexity - both of which are bad for them, and bad for me too.

To prove my basic hypothesis that the ground can be warmed to counteract its heatloss, the best route is PLAN ONE, which is to take the solar and air heat directly to the boreholes.

The other reasoning behind this decision is that the Delta-T between the Solar-Air panels and the Ground is perfect. For the battery idea to work perfectly, I would really need a high temperature flat-plate solar panel, as I would have if using a large tank of water. If I did that, I might as well go the whole hog and have my original idea (of a large water tank), which would also have reduced the cost of warming the domestic hot water. With the PCM balls in the battery sticking at around 23º, the panels would not often be hot enough to send warmth to the tank - whereas when comparing with the ground temperature of 8-13ºC, the Delta-T is favourable for most of the year, even at night.

Since a part of my idea is to see if the low-cost low-temperature air panels will do the job of warming the ground, then the use of a battery or tank introduces a level of complexity that is just too confusing. I will retain the balls and consider making the battery in a year or two. (The balls can be stored in the loft until then, and it will be easy enough to plumb in the battery in two summer's time.)

More solar collectors arrive!

Nov 24: Back to the Solar Earth Charging.
I have been waiting a while for the remaining two black 'Solar Focus' panels, and they arrived today, in an Ice Energy van - so I now have all four and can get on with the next stage - scaffolding the exterior to set them on the wall and connect to the interior piping.
     I will probably use the same scaffolders as did our house for the PV solar panels. Apparently a normal contract time for the scaffolding is a few weeks, so that gives enough daylight hours to get the holes drilled, etc.

Tuesday, November 24, 2009

Solar Surfing the Web!

24 Nov : The SunnyPortal website can be very revealing, if not fascinating. It leads me to think that it could lead to a dissertation topic in itself - by revealing 22 thousand sites all over the world, there are a wonderful range of systems all reporting themselves to the web - not just domestic roofs like ours, but others more revealing or experiemental.

There are combination ones (so you can compare wind and solar on the same site with the graphs combined). There are some experimental structures (eg solar panels on trees of metal tubing, motorised structures, or ones that build mirrors alongside the panels.) A student with enough patience could identify many interesting installations, and then follow up by contacting the owners for more detail in the case study.

RS485 Nightmares and Web Talking


Nov 24 : Our system has been talking to the web for a week now, by sending data to the SMA Website. The SunnyPortal.com compiles the data into graphs. We lost a few days of data over the weekend when the data cables pulled out of the plug when modifying the way that the unit was screwed to the wall (although the roof kept on working of course). As the colour coding of the strands was unusual (check RS485 on Google), I needed to experiment with the colours, and ask EvoEnergy a few questions. Got it working by Tuesday lunchtime after three very frustrating hours of trying.
    Now I am having interesting times configuring the pages on the SunnyPortal site, because you have limited desktop publishing abilities to very the appearance of the graphs - bars, XY points, lines, polygons etc. We have also enjoyed the addition of a sensor that gives Daylight levels, surface and ambient temperatures. Sometimes, this can allow one to reflect, eg when the surface and air temperature are close the wind is less, and when a strong SW wind is blowing, the temperatures diverge.

Tuesday, November 17, 2009

Peveril Solar roof is on line!

Nov 17: Kevin and Dan from EvoEnergy spent a bit of time at the house completing the installation of the link from our solar PV roof to SMA's ftp site on the internet, with Dan doing the hard work of reading the manual, and trying to work all the network settings.
     The Schuco inverter and SunnyBeam transmitter box come from a German company called SMA, and now there is now a live information feed from our router to the SMA server. SMA's website then stores and re-broadcasts the info to anybody who cares to see. So here is the graph of our roof, http://tinyurl.com/peveril-solar-roof. The info is blocked to quarter hour intervals, and takes about 45 mins to be compiled to graphics (and seems to show continental time). But it's great to have a display that builds up the calender of previous days, weeks, months and more.
It has been hard to manage without the hand held unit, and it is a sorry fact that the inverter doesn't allow one to use Both the Handheld and the Web display. But we went for the Web connection, as the widely visible display and record keeping is more important.
I see that our installation gets a mention on the EvoEnergy wordpress Blog.

Monday, November 16, 2009

Let the Plumbing begin!

Nov 16: For some weeks, I have been working out the lengths and dry jointing pipes in the loft. This weekend I finally soldered some of these, so the arrangement of panels is now fixed! These are all at the South end, and the panels will be on the external side of the wall. Yes, maybe they are a bit rough (all soldered, no Yorkshire or compression fittings...) but I don't think they will leak.
    I also began making one of the copper elements for the thermal battery, although in some ways, I wish I hadn't discovered those PCM balls, my life would be simpler if the Solar-air panels were just directly connected to the ground. It is isolatable, so if the battery never works, it doesn't matter hugely, as the system can run as originally intended. I feel so strongly curious about it, that I am prepared to build the thing, and see what happens.

Wednesday, November 4, 2009

3D Model of the thermal battery

Nov 4: I have been working on a 3d model of the 3D battery and elements, not just for fun... but it looks better for illustrations on the blog, and will help me in the fabrication process. It helps in finally deciding the positions of pipes - the copper elements have to be fabricated outside the tank and lowered through the holes in the lid.... and must be designed so they won't settle in the tank, or get air bubbles in them.

The outer pipes are 28mm copper, and the cross pipes are 15mm, to give some distribution of glycol, without having a short circuit. Also, the cross pipes enable me to fix legs which will keep the elements at the right height and slope.

December postscript: I have returned the plastic water tank and ballcock to Screwfix, but will retain the spheres and will have a go at this in summer. I will put in Ballvalves at the point on the pipe where the battery could be inserted.

Tuesday, November 3, 2009

Discussion with Ice Energy: Bottles

Nov 3 '09: After meeting Chris, I had a phone conversation with David Atkin of Ice Energy. I explained the changes in the plumbing for the panels which he seems satisfied with. He had some important points to make about the positioning of Expansion bottles, air release valves and Glycol top-up bottle on the plumbing diagram.
   The new plumbing arrangement gives more equal share to all the panels, but one can also control this with Valves (normal screw down ones) which is how a plumber balances heat distribution in a central heating system. The diagram and panel arrangement now equalises all the panels, so that there is no need for controlling valves which would present yet more restriction for the liquid flow and cause more work to the pump. In this diagram, hot glycol from the panels can never get directly to the heatpump, it has to circulate through the boreholes first, or through the battery of PCM balls, depending on the setting of the valves.
I only have two of the Solar Focus panels, so I need to visit Oxford to get the other two, or have them shipped up to Nottingham.
Another question will be about the speed at which to run the pump. Sluggish, or quick?

Meeting Chris Wood: Diurnial, Interseasonal and 5 yr cycles

Nov 3: in my meeting with Chris Wood, we also discussed the way that heat stays or moves in the ground, relative to the boreholes. He has done tests with sensors at different distances from GSHP borehole pipes.
Diurnial: We drew a diagram, a bit like ripples on a pond of the heat moving out from the borehole centre to the surrounding layer, showing that on a day-night basis, the daytime harvest of heat has nowhere to go than back up in the evenings, and any surplus moves out through the rings. The thermal curve is modified and will be added to this blog soon.
Interseasonal: This is very interesting, as we both know that the ground immediately around the pipe gets cooler month by month, and in Feb-April when the ground is at its coolest, the heatpump is having the most difficult task with cold ground - this is when the immersion heater element of the heatpump comes on, and ruins our Coefficient of Performance (CoP). During the long summer (with heatpump only drawing a small amount of heat for domestic Hot water) the ground recovers. However, in this spring period the sun is shining on the surface and if we can send solar heat down directly, the curve is changed. (See diagram - the area around pipes gets colder).
During the remainder of the summer when our solar heat is put down enough to exceed the heat taken out for hot water, some of this surplus heat may fortify the ground for the long winter.
5-10 year cycle: Chris explained how the ground gets colder year by year. It can be represented by a declining SIN wave. After each year, the highest temp that the ground recovers to in summer is never as high as in the previous year. Eventually it reaches a new stasis - this could be 5-20 yrs after installation, depending on the conductivity of the soil and the size of the house pulling heat out.

If the Solar Geocharging raises ground temperature, this will be remarkably successful, but is unlikely. What is very desirable is that the SIN wave has the same nadir (bottom) year after year (instead of dropping), and perhaps we might achieve a higher zenith - if this occurs, and we discover that it will maintain or improve the heatpump's CoP at that of a new machine in new ground, that will have been worth achieving.

Meeting Chris Wood: Panels and Balls

Nov 3: I had a meeting with Dr Chris Wood (recently of our Department, and currently on Knowledge Partnership project with Roger Bullivants). He is very interested in the project and has many pertinent comments to enrich the project, both for Solar Geocharging and for the use of a Thermal Battery.

Balls: He took away one of the Phase Change spheres to conduct some tests on, eg to use a testing tank to estimate the actual thermal capacity of the ball and the phase change temperature. As we dont know where they came from (we think they came from China for a chinese PhD student to use for research) we can use his tank test to discover their specification retrospectively. If the Balls are unsuitable, we can use the Thermal Battery using other phase change material such as brickettes of Wax, Water, or PCM emulsion from BASF.
Panels: We discussed the flow through the panels and although I now have a 'parallel' flow through all of them, this is going to favour the western most panel (left hand) too much, risking a short circuit that leaves the rightmost panel cold.
So, we redesigned the plumbing to make a more equitable arrangement, grouping them in two parallel pairs, each pair being sequential in flow. All the panels exit and enter from the top end, with airlock valves in the loft to prevent air bubbles.

Post script with hindsight written 22 April 2010: I am trying to work out when the polycarbonate boxes first appeared - it is clear from this elevation that they were not in the frame in early November 2009.

Thursday, October 29, 2009

Circuit diagram, with battery

Oct 29 : I am venturing to put this diagram on the Blog, although its not finalised. I have to discuss it with friends and experts.
As we don't know if the thermal battery will work, this is a dual system - either 2 circuits using the battery, or one circuit, bypassing the battery. It has to be manually changed with 4 lever-ball valves next to the battery.
     It been suggested that I could clean it up by using a 3-way battery (although have already bought the ball valves). However if the 3-way valve can be activated by an electric switch, that would be good.
There are Flowmeters to record all the volumes of liquid in circuits. All the pipes are 28mm, being laid to fall, with airlock release valves wherever needed.
The warmed glycol never goes to the heatpump first - it would shut down if getting glycol hotter than somewhere in the 20s. So glycol from the battery or the solar panels has to go to the ground first.

Wednesday, October 28, 2009

More Pipes, and Sasie discussion

Weds 28 Oct: installed more pipes in the loft and also worked on the drawings for the circuit and the design of the copper piping for the heat transfer elements in the thermal battery. The copper pipes are being laid dry (unsoldered), for which I am glad, as I am making a few amendments as I go.
    Had an interesting afternoon with Architect Mike Siebert, PhD student Nina Hormazabal (Nott'm Uni) and Engineer Mo Kelly (of Sasie, a company covering most of the renewable technologies, including Solar PV, Solar thermal and GS Heatpumps). Mo is interested in the wider applicability of our project. He has worked with reverse cycle heatpumps, putting heat down below to cool the building. He has looked and projects like the idea of 'renting roofs' for shared PV projects. Mike showed a website of ICAX (a company whose link is in the links section of Blog).
   Mo was interested in our thermal battery idea and the use of the low grade solar panels (good because they avoid overheating the battery or heatpump). The circuit is designed so that all heat goes to the ground BEFORE it goes to the heatpump - this is necessary because the heatpump's self protection would shut down if it received over-warm glycol directly.

Tuesday, October 27, 2009

Thermal battery update

27 Oct 2009: I think the balls I have contain Phase Change Salts, not Wax. That's not a problem as their thermal retention can be even better than paraffin wax. See the Wikipedia on Phase Change (PCM). Having discussed with BASF experts, it seems that good old WATER is still the best medium for conveying heat from the copper element to the PCM balls. There's plenty of it, we have rainwater butts full of it.
   It may need some antifreeze for the winter, but BASF have a product called Glythermin P44 which can be mixed in solution with water, and is a non toxic antifreeze, and supports heat transfer to the balls. I am more worried about a heat build up in the summer causing the water to evaporate. I shall have to check the water level regularly, and could fit a Ballcock to the tank to trickle water in, that would keep it topped up. (see interesting discussion, US patents). It will be covered and insulated, and the balls will cool the water, and some of the evaporation will condense on the lid and fall back.
    I have purchased some ball valves, so that the piping can be dual use - allowing the solar panels to charge the earth direct (as previously intended) and by changing the valves, to allow the solar panels to charge the battery, and the heatpump to draw heat from the same battery, with a different circuit.
My earlier advice to myself was to keep things simple and not introduce so many variables that proper data analysis becomes too difficult - so I ought to take that advice. Therefore, I could work with the same 4 panels as originally intended, and have the ability to switch the battery in or out just by moving the lever-ball valves.
Illustration from Colin of BASF. He writes:
"Below is a table of typical values for specific heat capacity, thermal
conductivity and freezing point for various fluids at 20 deg C. Some are more accurate than others. Water, ethylene glycol, propylene glycol are defined liquids so the values are pretty accurate. Mineral oil and vegetable oil are generic terms, and for example the specific heat capacity of linseed oil is 1.84, olive oil is 1.97. You could expect bigger variations between the many grades of mineral oil, paraffin has a specific heat capacity of 2.13, the mineral oil in the table at 1.67 is probably a typical lubricating oil fraction. The Glythermin figures are from BASF data, the glycerol data are extrapolated from published values. What can clearly be seen is the higher the water content the higher the specific heat capacity and thermal conductivity."

Sunday, October 25, 2009

Thermal Battery dilemma

25 Oct : I feel I can't turn down the use of the PCM balls for a Thermal Battery, it is too good luck to ignore. I have 480 balls, each 7.5cm diam., and these will fill a 250 litre tank perfectly, with room for two copper piping assemblies as the heating element. I can get the tank into the loft if I take out the ladder and lift it somehow, then restore the ladder.

But its problem is that it complicates things.

My original idea was beautifully simple, the low grade solar-air panels to send heat deep into the ground - the delta-T (temp difference) would work perfectly  because the ground is always cold, and the circuit could be a single large circuit. Easy. However, the idea is principally useful to people who have deep boreholes, ie. very very few. And it's fair to accept that some or much of the heat will drain away, as all my doubting friends say.

The thermal battery idea is very good (although it's a different idea) and could be applied to hundreds of houses, perhaps many more in 5 yrs time. So it's worth researching, and worth prototyping.
However, it needs a high temperature delivery, eg perhaps a pro quality flat-plate solar-thermal panel, so that there is a clear delta-T between panels and battery. The swimming pool panels would only be significantly hotter than the battery in summer and when the sun shines.

It also requires to redesign the circuit into two looped circuits with the battery as the hub (each circuit with their own pump), and thus prevent the heat-pump simply moving heat from the battery to the outside air. Using ball valves, I can change the circuit so that the battery is either connected, or the circuit is a single one as per my original plan. (I have designed something, but need to draw it an put it on the blog - also need to discuss it with the dissertation students.) I cannot depart too far from the original idea as I would leave them with a topic different from the one they started with.

I could just make my life easier and keep the 4 panels as proposed (and some of the piping is in. However, its worth considering David Atkins' earlier idea and have a mixture - two of the Swimming pool panels, and a single 2 sqm Flatplate solar-thermal panel.

For the thermal battery, I will use Rainwater as the sharing medium for the balls in the thermal battery, although BASF are interested in helping with a Micronal emulsion, and I also know that cooking oil would not evaporate - but it might get smelly. Water is easier to dispose of if that is necessary, and is adequate for proving the concept, and is free, and therefore more inspiring and possible to others as an idea to emulate.
I would test the amount of evaporation weekly in the summer and know if water is unsuitable.

Saturday, October 24, 2009

Water Tank for the Balls

24 Oct : Now that I have the PCM Balls - two dustbins and a small crate load, I have to think of how to use them. Having first thought of making an insulated plywood crate, then it was suggested to me to consider a 200 litre rainwater butt. But it would be hard to put the copper coil in through the top opening. So I have moved onto the idea of a Cold water tank, which will fit through the loft hatch. 50 gallons (240 litres 1090 x 610 x 500mm) will be enough for almost all of the balls - and being long, would be easier to make the copper piping for.
     I met a group today in the Marmont cafe who are from BASF, and they suggested that I can get liquid phase change wax emulsion  to pour in around the balls. My first idea had been to put sand in, but dry sand isn't conductive enough. Wet sand is better, but I thought it would dry out, be too affected by the temperature change and be too heavy. I am presently thinking of catering packs of cooking oil (eg Rapeseed) to bind the sand and avoid evaporating. The Micronal phase change liquid wax would undoubtedly be best, if it doesnt cost a huge amount.... either on its own, or mixed with coarse sand. Hmmmm.... think on, DNC!

Sept 2010: Update: This tank was returned to Screwfix after I decided not to use the tank or the balls.

Thursday, October 22, 2009

Plumbing and Phase Change Balls

Oct 21: I spent part of the morning laying pipes in the attic - 28mm copper pipes. I did much of the cutting to length and positioning, so they can be soldered another day.
Now that the panel positions are finalised (with flexibility provided by using rubber hose) I can now finalise the indoor plumbing and the location of 5 holes in the wall.
     Later, at the university, I was walking past a skip in our department and the technicians were wondering how to dispose of a large number of balls. They aren't allowed to put the balls in the skip as they are unsuitable for landfill. I offered to take ALL the balls as the balls are actually spheres of Phase Change Material, ie a special formulation of Salts or Wax that is suitable for use in buildings. They were left over from some lab research in 2008 into phase change materials.

 I had been wanting to have a thermal buffer in the attic to include in our experiment, but a water tank would be extremely inefficient and over bulky. A crate of PCM balls would be vastly better as their melting point is high, and they dont freeze. So the Heatpump can GET heat from the balls (which are at about 23ºC) and at other times the Solar panels can PUT heat into the balls (which remain at 23ºC). The balls will never heat to melting point because the panels are low temperature, and surplus heat will go down to the boreholes. They cant freeze as they are already solid. And I can get them through the loft hatch!
There are three dustbin sized containers of them, probably enough to fill a large wheelie bin. So a custom cubic container will have to be filled with the balls and ultrafine sand around them, with a zig zag of copper or plastic pipes going through them. This loop could be set with valves and thermo-couples to the input and output, so the performance can be measured, and the cube can be isolated if we need to do maintenance on it.

Wednesday, October 21, 2009

Immersion Heater kicks in!

20 Oct 2009: It brought home to me how valuable this exercise could be today. The Heatpump's Immersion heater function came on in the morning - the outside temperature was about 9º and inside 19.7º (so not really a lot to do), but it chose to accelerate the process with some one-to one heating - because the underfloor heating is so slow to make a real change. I noticed because the OWL meter suddenly said the house was using over 4 kilowatts! The meter reading at the end of the day was  22 kWh for the day, the highest I have seen since I started recording. (It coincided with a very overcast day and almost no PV generation).
    If Solar Geocharging can reduce this consumption - this switch from a CoP of 3 to no CoP at all - then it will be worth doing. (I had better go up to the loft and get on with laying pipes!)
If I am advising a client about a heatpump again, I would say that Underfloor heating is still best overall, but in rooms with a carpet, and in the location of the thermostat, there should be a modest sized low temperature radiator or hollow skirting - for the first to speed up the warming process, and for the second, to allow the user to tweak the valve so you can 'fool' the thermostat effectively. Our thermostat is in the hall, and if someone comes in the front door, it activated the heatpump far too quickly.
http://tinyurl.com/peveril-metering is the site for our daily metering.

Tuesday, October 20, 2009

'Planning' the FOUR design

Oct 19: I had a meeting with two of the dissertation students Robert-H and Joel-C, and one of my colleagues, Dr Rabah-B, who is a supervisor.  I also had an email from David of Ice Energy commenting on the layout below.
His comment was that we would be better to keep it simple by having them upright back to the wall not projecting out on a complicated metal frame. This will be cheaper and look better.
   He also asked if we have planning permission, and the answer is that we do. About 2 yrs ago, we had the idea of fixing a wind turbine on the south wall - and Rushcliffe refused (on spurious grounds, but I am now glad that they did) and offered by way of compensation to let me have a bunch of solar panels on the south wall.  So having paid about £170 for the planning application, I agreed rather than let it be wasted, never imagining that this permission would actually be used.
   He also suggested that we might consider 2 of the solar collectors and one Flatplate Solar panel in place of the other two, to catch more heat when the sun really shines. We could not do this as it would be too confusing for the students and for me to model the combination of two types of panel, as well as the fluctuating benefits from the PV roof. In an experiment, you try to shut out unpredictables or external variables so that the data from the experiment is credible and repeatable.
   One of the long term ideas is that this idea can be packed up as an commercial add-on to a heat-pump installation, so it needs to be proven.

Sunday, October 18, 2009

Timescale thoughts - December!

18 Oct : I am keen to get on with this project, but also have realised that there is a benefit to doing meter and temperature readings without the benefit of Solar Geocharging as we move into the winter. Ideally we should wait an entire winter, so it can commence the charging during the summer, and compare with next winter.
However, this would not be a help for our 'one-year' research students who would like to see the diurnial benefits in April/May 2010. It would mean another winter of higher fuel bills (and more carbon emission as we use more coal burnt power). So I will work in a relaxed kind of way on this, until at least the solstice... so there is time for real thought on the plumbing and installation details. As there is little sun in December and January, we won't expect great things of this until the sun shines more in February and March.

New arrangement - FOUR panels across

18 Oct : I had a visitor from Mike Siebert, an architect friend who has built a few houses, and we discussed the best layout of panels. There are five things I want to do:

• One is to find a way to increase the number of panels so that the geocharging effect is measurable. Two would not be enough, in the judgement of people I have talked to.

• Two is to keep the plumbing in the loft simple and accessible and free from airlocks.

• Three is to find a way to tilt the panels to increase their harvesting in Summer - perhaps 15º.

• Four, to keep them high enough to be free of interference from trespassers and shading from the nearby tree.

• Five, to ensure a good glycol flow through the panels, avoiding the build up of 'dead spots'.

My previous layouts were somewhat constricted by my desire for access by ladder. If I am prepared to pay for the scaffolding to put the panels higher, it seems very clear that the best arrangement would be high above the south windows, where there is space to have FOUR panels across, and I am able to get a good flow, and get the pipes plumbed easily. The 15º tilt will give some solar shading to the upper windows at the height of summer.

In case anybody doubts my sanity on this experiment, I am getting clear indications that the temperature of the soil below the house is cooling as the heatpump draws more as we move to winter. Temperatures are affected by the fact that the upper 5m of soil varies, but the trend can be observed. While I was getting soil temperatures of 12.8 in summer, I am now getting 10.7, a 2 degree C drop.

Thursday, October 15, 2009

Struggling with Panel arrangements


I have started putting pipes in the loft, but stopped for a good think.

  • The Top Left is what I have near enough agreed with Ice Energy , two verticals, horizontally arranged.
  • Bottom left is more economical in piping and fits better between the window and the corner, and needs a longer piece of 40mill pipe, and needs a curvy hose or two elbows to connect the panels.
  • Top Right is an Extension of that, with the panels still vertical, but with three, as one of my colleagues thought that 2 such panels as we have will not make enough impact. I would need a third panel and more piping.
  • The Bottom Right is interesting - it's the best fit on the wall and uses the least amount of joints and piping. However, I guess the panels are designed to be used upright, and may not work well on their sides. Putting them on the side like this puts the widest parts of the panel vertical. My colleague thinks the glycol will find too quick a path through the panels, and leave dead spots at the opposing diagonal corners.... or is it possible that things will even out, and if the opposing corners warm up more, they will mix faster? would a slower or faster pump speed make a difference here. does maximum efficiency matter when we are simply dumping the heat, not trying to nudge up the temperature of water?
If you click on the illustration, it will enlarge.

Wednesday, October 14, 2009

Welcome to three students!

14 Oct : I have been discussing the project with colleagues in the Dept of Built Environment, and it is likely we will have 2, perhaps 3 students to study the project and make use of the data I have been recording.
1. We hope to have a BA student, looking at the project non-mathematically, mainly as a case study in the light of the new feed in tariff scheme, policies and economic arguments for renewable technologies, code for sustainable homes targets, etc.
2. We also hope to have an MEng student taking a more mathematical modelling approach, comparing computer models with actual data. As the BA and MEng are only working on it till May 2010, they cannot look at interseasonal thermal storage, but will be able to monitor Diurnial thermal storage, i.e. in the March-April equinox period we hope that daytime warmth will return in the cold evenings.
3. We also hope to have a PhD student, who will have a 3 year term of work on this. Although the first year is often spent on literature research, the data will continue to be collected, and the total of three years will reveal the full effect of three summers and winters alternating to see if there really can be interseasonal storage that makes an economic benefit (as well as recording the diurnial benefits.)

It is a complicated equation trying to work out if Solar Geocharging is noticeably reducing electricity consumption if at the same time, you have a PV roof that is doing just that, and has varying performance depending on the weather. Our prime target is to reduce the previous 2 yrs of energy consumption of 8500 kWh per annum.
The PV roof is giving us free energy for life, so you could say we do not need to do the Solar Geocharging... but hey! this is Research! Mrs NC and I and Ice Energy and my Professor Saffa Riffat, and my friends in EvoEnergy and Rushcliffe Borough council have great faith that this will demonstrate a chance to improve the performance of heatpumps.

Work continues: insulate, and pipes...

14 Oct : Yes, anybody reading this in recent weeks must think I have forgotten about the Solar Geocharging project. Well yes, the emphasis of the last few weeks has been on the PV, because it is such a major novelty (and expenditure!) But with the prospect of 3 students taking this on as a dissertation subject, I have to go ahead!
   I got the solar-air panels from Ice Energy in mid September, and they were in the garage for a few weeks. This week I decided to get back to work on the project. So I have recently bought some Loft insulation and have been topping the insulation from 20cm to 40cm. I use large insulation mattresses from Knauf, 1.1m x 3.6m, which unroll to cover the top of the rafters. This establishes the optimum height for the pipes that will go from the south wall to the north wall.
   I went to the plumbing merchant and bought £300 worth of 28mm copper pipes, elbows, tees, reducers, pipe insulation, and other essentials. The idea is for me to install the long pipes dry, and get a plumber later, for the glycol filling and connection to the heat-pump loop.

Tuesday, October 13, 2009

Perfect sunny day...


Sometimes you get almost the perfect day.... see the handheld meter - totally sunny in the morning with an unbroken bell curve... and only breaking up a bit in the afternoon with some very late light fluffy clouds, by which time the sun was well round to the west. It intrigues me how the roof picks up power, both by reflection off the clouds, but also by some sort of diffraction - when the sun is clearly round to the west and having no view to the east facing roof, and blue sky above it (nothing to reflect the light), the roof still picks up power and the meter notices when clouds float across.
Of course, if the roof faced south, the bell curve would be symmetrical with a higher zenith. I will photograph the curve at monthly intervals. With the sun low, the bell curve zenith must move to an earlier time of day eg 10am GMT, and in the summer I expect it to move closer to the centre, eg 11am GMT.
For this reading the OfGem meter actually recorded 13.01 kWh for the day, which must be as good as anybody can do for mid October. The handheld meter samples every 30secs and tots up an estimated aggregate, whereas the OfGem meter is always on.

Saturday, October 10, 2009

Green Energy Republic

10 Oct : I am just signing up for a beneficial tariff that goes through to next April 2010. This is provided by Good Energy, 15p per unit for every kWh we generate, even before we use it to send to the grid.
  We know we pay more for grid electricity with them than with the cheapest, but they are the only electricity company generating entirely from renewable sources. What we pay helps to support other home generators. See the BLOG called Green Republic which is a wonderful source of ideas and advice.

Friday, October 9, 2009

Fear of steep energy rise

Today, 9th October, one of the hottest talking points in the news is the OFGEM report on future Gas and Electricity prices. Both of these will rise steeply in the next ten years (even without taking account of inflation). Every time the prices go up, the urgency for householders to become small generators increases, and the payback gets quicker. There are different strategies for the next ten years, Dash for Growth, Slow Growth, Green Transition, Green Stimulus etc, but the only one that will keep prices stable is more of the Green Stimulus, where the government actively provides incentives to push people to being green faster than mere dissatisfaction with the size of energy bills.
It is an irony that one of the factors that will slow the increase in prices of energy is the increase in renewable sources, balancing against the increasing cost of fossil fuel.
Read more about the report in Greenwire.org.uk

Reply to Rushcliffe Reports Enquiries


I have had a few enquiries about the article in Rushcliffe Reports. One difference since the article is written is that we will use a cheap Swimming pool solar panel, not an expensive Flat-plate panel. The panels can be tee'd directly into the glycol loop using their own small pump and a non return valve (no need for an intermediate water tank). The solar panels are still in my garage; we have been focused on getting the Photovoltaics up first. The Earth Charging panels will go up next. The other enquiry is about the balance between Gas and Electricity - whether to use a Heatpump. Quick answer: You cannot be carbon zero if you use Gas. My regular answer to enquirers would go something like:

"If you can afford it, the combination of Heat-pump and Solar PV is a winner, we shall have free heating, hot water, cooking, lighting and power for life, plus an annual income (tax free), plus all our money back when we sell or leave to our children - even without the solar charging. The Solar Earth Charging idea is to see if the COP of the heat-pump is significantly better by finding warmer soil below - hence reduce electrical consumption. Even if it doesn't work, it's worth trying... but my professor boss says it is a wonderful idea and will work. It costs almost nothing because we are just using swimming pool panels, ideal for the temperature differences involved. Running cost is nothing, because the pump will only activate when it is warm, and our photovoltaic roof is earning enough to drive the pump."

"The house is so snug that it is almost boring, always 21 degC, and I could sleep in a summer duvet all the year round... except that my wife is a fresh air fiend and wants to sleep with window ajar, hence the need for an equinoctial duvet (medium tog) in winter... but we will never need a winter duvet unless there is a power cut for a prolonged time.. but then everybody will be in trouble if that happens."

Tuesday, October 6, 2009

Feed-in-Tariffs news

We have installed our Photovoltaic system entirely on trust that the proposal on feed-in-tariffs will actually be enacted in April, near enough as the proposal has been framed. There is a site telling you a lot about it - http://www.fitariffs.co.uk/ . There are a number of issues not finalised and the public have until Oct 15 to add more opinions. Some issues are:
• Existing systems should not be excluded
• The tariff levels are set on the low side
• Some renewables get a lower return than others
• Some types of renewables have been omitted
• Issues like taxation and index-linking have not been defined

I have sent in a reply to their request for consultation with my own choice of key observations,

• There is a need to increase the tariffs to a level that will encourage more participants. Even with a potential payback for my roof of about 7.5%, some people still think I am taking too much risk. It should clearly be enough to show 10% to push the public into making this investment.
• They should clarify the tax implications of the tariffs, and whether they will be index-linked. If the UK has a period of inflation, and it costs £30,000 to buy a sandwich then the tariff (presently framed at 36.5p/kWh for domestic PV) must logically be linked to the electricity price, e.g. something like 2.8 times the maximum price (presently 13p / kWh).  As the income for domestic householders is confined to 4kW, it will always be small, so it should not be reduced by being taxed.
• There is confusion about the 4kW limit for domestic PV systems. This is designed, for good reason of electrical safety to stop the DC output rising above 17amps. However, this could only be achieved on a south facing roof at 36º at midday in summer. I have a 4kW nominal system on an East Facing roof and even if we increased the nominal output to 4.5 kW (ie 25 x 180watt panels) we would still never be able to generate 4kW at any time of the day or the summer. So I hope they will allow a larger number of panels, provided that their angle and azimuth is such that the output could not exceed 17 amps.

Sunday, October 4, 2009

Rushcliffe reports!


Just as our first week of Photovoltaic living is completed, Rushcliffe Reports is published with an article about us on Page 11. Wow!

Actually I drafted this for them about 2 months ago, and the emphasis then was on the solar panel for earth charging. By the way... this is still going to happen, but one can only do so much at a time, and we focused on getting the PV panels up first. The solar panels for earth charging are in the garage and it's going to be a while to get them fixed on the wall and linked up. I have to find some 28mm pipes and lay these in the loft, ready for a plumber to make the connections. These are more difficult to find than I expected.

PV Solar Panels in Action!


The Photovoltaic panels are in action now, and generating electricity.

One psychological problem that I have realised I have to live with is that if you instal in October, you are going to see your system decline in performance for the next 4 months! It's like spending seventeen grand on a new car, only to see it performing worse and worse, until three months after buying it, it's only as fast as a bicycle! I can see why the new tariffs will start in April, it would be too depressing to have them start in October!

In its first week, we have had varied performance from it, from 4.5 kWh on a cloudy gloomy day to getting 11.5 kWh today (Sunday 4th) because of a bright sunny morning with fast moving clouds. I can see that there will be times when I am angry over a cloudy morning, followed by a sunny afternoon and evening... Let's hope those are balanced by days like today.

Friday, October 2, 2009

Displaying the results


We have a Schuco hand held display that picks up a wifi signal from the inverter in the loft. This shows the amount being received at that very moment, plus a graph of how it has varied between sunrise and sunset.
Even when cloudy, you get power so long as the sun has not set behind the clouds. They get no power in the daylight period after sunset.
The handheld unit shows the whole month at a glance, revealing a weather record of sunny and overcast.
This moment here shows the situation at 0920 on Oct 2nd with 1.4kWh already harvested under a cloudy bright sky.

Wednesday, September 30, 2009

Inverter in Loft

30 Sept : I always like it when people enjoy their job. This is Julian, the electrician putting the final touches to the electrical parts in the loft, under the panels. The Sunny Boy box in the middle is the inverter, and below that are two isolator switches, one for the DC from the Panels, and one for the AC to the meter downstairs.

We have a handheld display unit picking up a Wifi signal from the inverter so we can have that in the kitchen, dining, or even next to the bed - so you can wake up on Summer mornings wondering how much your panels generated before breakfast!

Tuesday, September 29, 2009

Sharp MonoCrystalline

29 Sept : People will want to know which panels we have used. There are cheaper panels but you need more of them, and we have only a limited roofsize for the electricity we want to generate.

The Sharp 180NUSoE3E seems to be the ideal choice, and fits the roof as if it was designed for it (the Velux positioning was designed for it) The spare roof space between veluxes will be ideal for a future Solar thermal flatplate if we decide to fix one.
The NU180, at 1 metre x 1.3 metre is an ideal tile size for using in assessing other people's roofs for their fitness for photovoltaic installation.

PV Panels are up!


29 Sept : The Sharp PV panels are up, they went up incredibly quickly between lunch and teatime on Monday 28th. Tuesday has been a day of fixing the internal electrics, meters, inverter etc. Pity we cant leave the EvoEnergy van parked in the drive, as it would be a good advert for them, seen by all the walkers who pass our house on the way to Sharp Hill....

In the photo, DNC, the EvoEnergy van and the redoubtable Eddie Muriel, leader of the installation gang.

Sunday, September 27, 2009

Scaffolding up for the PV Panels

27 Sept : On Friday afternoon, the scaffolders turned up and did a wonderfully efficient job, getting the whole rear of the house done in just an hour, including building a bridge across the glass conservatory. I nearly reduced the total of panels to a line that would not be above the conservatory - simply because I didn't trust the scaffolders to get this up without breaking one of the panes - how wrong that was!
   The 22 we have ordered will cover most of the roof, offering some space at the south end to add a further 3 sometime, if we are permitted to within the terms of the Feed in Tariff. At the moment our proposed 22 equals 3.96 kW, but only if facing south.
Haha don't worry, the house isn't really bending. It's the Panoramic-Photo effect that joins several pictures together. If the camera is slightly tilted upwards, you get a bending effect.

Wednesday, September 23, 2009

Solar Power in KobnHavn

Sept : I have an architect friend in Copenhagen reading this blog and considering PV on a 6 storey office block he is working on.
I am not sure of the tariff in Denmark,  but in the proposed German style tariff for the UK, it's definitely worth fitting.  So I replied that:
For us as an all electric household in the UK, we have in effect a season ticket for 20 yrs (the guarantee period of the tariff, but this is extendible)

For a one off payment (to Instal PV on our roof), we have:
Guaranteed TWENTY Years
 of NO HEATING Bills
     NO HOTWATER Bills
     NO COST FOR COOKING, LIGHTING AND POWER
On top of which, our roof will earn some money, because we generate more than we need. All we have to do is clean it annually (with a long wet brush) and make sure all the electrical connections are in good order. We will have meters, and can check if there is any falling off in performance due to atmospheric dust etc.
The cost is about the same as a medium size car. In 20 yrs that car will have been scrapped, in 10 year it will be worth not even £1000 and we would need another.
In 10 and 20 yrs, our roof will still be earning money, providing totally free heat, light and power, and if we are still here and had to move, the panels have a resale value, and can be assembled on the next house, or add value to the house we are selling, more than they cost in 2009. The EPC system in the UK will add value points to houses with energy efficient systems.

For his 6-storey Office building, I replied:
There is value in fixing it to a vertical facade, as you get less power in summer, but more in Winter when you need it more. And a wall is more self cleaning - and high enough not to be shaded by neighbours.
Overall though, with the tariff arrangements, its better to harvest more in summer and sell it, but its difficult to arrange that on a facade. For Kobnhavn that would need to be 38º
See this table for 4kW worth of panels... (for your 6 storey you could have a lot more the 4KW. and you do SAVE on the cost of rainscreen cladding, as solar panels do that.)

How close to south can you make the wall? with a NEW building this is more important as you can design it to be optimal, instead of just attaching to an existing wall that is not in the right direction. For an Office building it's good to reduce the amount of South Window, so have more windows to north (for workspace daylighting), therefore have more wall with solar power on the south, reducing solar gain and reducing air-conditioning costs.

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