Sunday, November 27, 2011

Other constructions: Gate and Cloche

above is the work in progress on the Cloche, with my helper, Henry NC.
27 Nov 2011: Other things I have been doing:- the old Sunbox provided me with quite a lot of spare 6mm structural polycarbonate, so I have been finding ways to use it. First, in September and October, I did some work to make a Gate for the side alley, using minimal amounts of recycled aluminium. I decided to make it a fixed gate, with butterfly nuts and bolts if I need to open it on rare occasions. Then this weekend, I worked on a Cloche for the vegetable patch, which is causing the minimal possible waste of polycarbonate combined with a reasonable height of 450mm.

Side gate, and you can see down the alleyway
where the proposed extension will be.

November Reports

For those just arrived, I do a computation of the ANNUAL performance every Sunday, by subtracting this evening's meter reading from the same one, exactly a year ago.

End of the Month: Well this has been a remarkably warm month, with fewer heat pump hours than in March (spring Equinox).  The effect of Sharphill is now reducing solar PV capture significantly. Sunboxes were slightly higher in 2010, probably due to more sun-hours, and greater demand from GSHP)

  • House meter 534kWh, GSHP meter 270kWh, GSHP hours 123hrs
  • (2010 - 705, 477 and 233 respectively)
  • Solar PV 79kWh (2010 - 96kWh)
  • Sunbox meter 167kWh (2010 - 194kWh)
27 Nov 2011: Well, it's the week in which Mark Webber won the Brazilian Grand prix (end of the season), Gary Speed (manager of Wales) unfortunately died at 42, the Leveson enquiry went further with revelations of the hacking crimes of the British tabloids (and revealed that Hugh Grant's middle name is Mungo), the amphibian Newt Gingrich begins to draw ahead of the ragbag candidates of the Reptilian party, Egypt and Syria are in ferment, the Mars rover 'Curiosity' blasted off on its 9 month journey, and nothing much seems to be likely to come from the Durban Climate Change conference; meanwhile, I have to tell you about my metering exploits. Well, as usual, we are breaking records yet again, and in the same week, two of the key performance indicators have gone below even what I could have expected!
  • All time Records Falling: House 4,967 kWh, GSHP 2,972 kWh, GSHP clock 1,381 hrs. These have now fallen below 5,000 and 3,000, and of course, most of this is down to the continuing mild autumn. I accept that if the weather turns, these figures have to turn to, but I hope they never return to 6,000 and 4,000 respectively. (A year ago, annual was: House 6,213 kWh, GSHP 4,162 kWh). 
  • PV 3,364 kWh (I'm happy if it is above 3,300) SB clock 2,423 hrs
  • Sunbox 3,030 kWh (I'm happy as long as it is above 3,000).
  • Deep ground temperature was 11.9º. A year ago it was 10.8ºC. 2 yrs ago it was 8.2ºC. 
20 Nov 2011: So, in the country that Herman Cain can't identify, Libya, Saif Gadaffi has been found, and in Spain the government has changed. I and most of the population have lost track of what is happening to the Euro, so I'd better change to the matter of Metering. We are in the second half of November, and yet the heat pump hasn't used as much as 12kWh in a day since last March! Note, that if we left it on 24 hrs, it would be much higher, but we have a strict timeclock regime to ensure that it only heats when we need it.
  • All time Records Falling: House 5,040 kWh, GSHP 3,053 kWh, GSHP clock 1,430 hrs.
  • (A year ago, annual was: House 6,164 kWh, GSHP 4,104 kWh). It will take a week of v. severe weather for these not to fall to below 5,000 and 3,000 by next Sunday.
  • PV 3,367 kWh (I'm happy if it is above 3,300) SB clock 2,427 hrs
  • Sunbox 3,032 kWh (I'm happy as long as it is above 3,000). Low because GSHP activity is so low, with this mild weather, and only one sunny day in the last week.
  • Deep ground temperature was 11.7ºC. A year ago it was 11.3ºC. 2 yrs ago it was 8.1ºC. This shows that we are well into the heating season. I wonder when the graph will bottom out.
If I might hark back to the the news, the more serious one long term is the failure of the rich countries to do anything about Climate Change (in advance of talks next week in Durban) and to postpone most major decisions to 2020. See the Guardian Environment report of 20 Nov.... showing how important it is for us to do our best to combat energy shortage and reduce carbon emissions (but showing at the same time, how futile it is to do it one house at a time, one country at a time.)
   Looking at the chart below, one can see the winter starting up again and the GSHP tracking the degree days. They will never entirely meet as they are different units. But is it good to see the curves getting closer to each other.
Degree Days (weekly) against GSHP workload (including DHW+floor pump)
13 Nov 2011: So Silvio Berlusconi has finally retired, we've had Remembrance day, and the most palindromic day for 100 yrs (11:11:11:11:11:11), England beat Spain 1-0 in a football friendly, James Murdoch admits that he doesn't know what's going on in his own company... and need we mention the parasites, faux actors, neo-nazis, zombies who think they can be the Republican candidate for the US? No, because it is time for metering news. Another mild week, but mostly very cloudy. Not good for PV nor for Sunbox capture, and the mild temperatures stop the GSHP from being busy.... so another weekend of all-time records.
  • All time Records Falling: House 5,102 kWh, GSHP 3,106 kWh, GSHP clock 1,452 hrs.
  • (A year ago, annual was: House 6,115 kWh, GSHP 4,061 kWh)
  • PV 3,368 kWh (I'm happy if it is above 3,300) SB clock 2,427 hrs
  • Sunbox 3,027 kWh (best ever was 3,094). Low because GSHP activity is so low, with this mild weather.
  • Deep ground temperature is 12.0ºC A year ago it was 11.4ºC. 2 yrs ago it was 8.1ºC.
The higher ground temperature is probably because by this time, the 2010 winter was beginning to 'bite'. However, the autumn-winter of 2009 was similar to the current period, so 12.0 is good compared to 8.1.
6 November 2011: So the G20 leaders spend time in Cannes, Sir Alex Ferguson completes his 25th year at Manchester and some unfortunates on the M5 see a firework display and are caught up in a flamy pile-up. Meanwhile, I have to tell you about my meter readings.
Yet again, the weather continues to be mild after the mildest October on record, and the systems continue to yield some record readings.
  • All time Records Falling: House 5,123 kWh, GSHP 3,156 kWh, GSHP clock 1,475 hrs.
  • (A year ago, annual was: House 6,096 kWh, GSHP 4,046 kWh)
  • PV 3,384 kWh (Another record) SB clock 2,444 hrs. (highest ever)
  • Sunbox 3,065 kWh (best ever was 3,094). Low because GSHP activity is so low.
  • Deep ground temperature is 12.2ºC. A year ago it was 11.7ºC. 2 yrs ago it was 9.2ºC.
Water note: I have recently added more columns to my spreadsheet and can see a cumulative calculation of the annual Water Consumption. Cold water annual seemed to hover about 61 cum/yr in 2010, but in 2011 it is hovering around a figure of 55 cum/yr. The Hot annual seemed to hover about 21-22 cum/yr in 2010, but in 2011 it is hovering around a figure of 18-19 cum/yr. The only reason I can think of is that Henry (our son) used to stay a couple of nights every 2 weeks in 2009-2010, but moved his job to Wareham in Dorset and is not staying regularly. 
Gas note:, we are still using the Pilot light in the evenings (not the fire) and this is using about 2.0 cum/week. I am recording the consumption and will feel duty bound to include this in future heating computations, small as it is.
Weather note: During sunday evening, I have been watching a TV programme about weather, and there seem to be people predicting a tough cold snap coming up - maybe it will come in the New Year. I know that this continuing pattern of all time records being broken every week has to end soon, but I am wondering where this will bottom out. If the weather continues mild into December, the consumption figures will continue to fall.
    My dream scenario would be for the house meter to fall to 4,999 kWh annually and the GS heat pump to 2,999 kWh annually, but surely, both of these are surely an impossibility? If the mild weather continues for a couple of weeks, this might be achieved because the same weeks last year suddenly turned very cold!

Sunday, November 20, 2011

Progress on Extension

20 Nov 2011: I've been making further progress on the idea of an extension. Here's a slightly updated picture of the proposal with 2 PVT panels on the roof.
    I had a meeting with Mike, an Architect-Builder friend who was one of my tutees years ago, who I would trust to build it. We discussed the idea of building the SIPS panel ourselves, as a summer vacation project.
   I've also written to AnafSolar, volunteering to instal two of their panels on the roof - as an additional solar heat supplier to my ground loop. It would need its own energy flow meter, pump and thermostat.
  I've been skyping with a friend who works for Rationel, a high performance Danish window company with a base in Bicester, Oxon. The South and East window will be triple glazed, argon filled, of course. The SIPS walls will have a U Value of 0.15. The window will add to the heating gain, because it will be clear and intended to admit more heat than it loses (and there is a solar shading device for summer).

Tuesday, November 15, 2011

EPC for Peveril Solar House

15th Nov 2011: Ive had an Energy Performance Certificate (EPC) for the house. We had a visit from Steve and Ed of last Friday. They said it was a very high assessment, but it still comes out at 91 which is a high B+ rating. It is a bit disappointing but I know why.
    I know that we start out with a disadvantage, being Brick/block with double glazing, and being detached. The existence of a Gas fire (that we have only for the pilot light and for emergencies) knocks 5 points off the rating straight away. I didn't expect the software to understand the process of storing heat throughout the summer in an earth store. The guys are very sympathetic, but this is the way the EPC software rolls it out.

The actual metered performance of the house does not get included by the software, there is a box ticking exercise that then assumes the contribution that each component makes.
     So, having a GSHP is a credit, but quite how efficiently it performs is not included. Having the PV on a 40deg pitch, not a 30deg pitch is a negative. Not having a Wind Turbine is a negative, as is not having a conventionally installed solar thermal panel and tank. We couldn't have either of these. Rushcliffe BC don't give planning permission for WTs unless they are below the roof-line, and a solar thermal tank would be a major legionella risk for my dear wife - and thermally it would be redundant as we are sending enough heat already into the main thermal store.
    As a result the software assumes that we use 45 kWh/sqm/yr for heating and hot water, whereas the real figure as metered is 26.6 kWh/sqm/yr, and the heating alone takes less than 20 of those.
    I'll have to accept this philosophically - his mention of 'Time and Zone control', refers to systems in which programmers can manage each room separately - for which there seems to be no need in a very small box-like house with good insulation values, and no swimming pools, libraries or granny flats.

Ed writes: "The specifics of the property do fair much better than what is assumed in an Energy Performance Certificate.  However, I am still impressed that without the use of the gas fire, the house manages a score of 96 which is absolutely superb!
     "I’ll just provide you with a few scenarios with the current setup and the impact they would have on the EPC.  The practical impact would be different however…  This is based from a starting point of 91 points.
  • Add wind turbine – 94
  • Time and temperature zone control – 92
  • Without gas fire – 96
  • With conventional solar water heating – 93"

Sunday, November 13, 2011

Small maintenance jobs

13 Nov 2011: The weather gauge is working well, but at this time of year, there is nowhere for the temperature sensor to hide from the sun on sunny winter days - giving false readings. So I have built an aluminium sun shield that will protect it from direct view - it's the first time up the ladder since June or July 2011, and I quite enjoyed it! The construction all looks sound, and although the fronts are designed to hinge openwards (this is what took more of the time than the main construction) I have no reason yet to open the fronts for maintenance.

Airtight construction?:  I also examined the side panels of the Sunbox and decided that after all the work I did to make it airtight (around the leading edges) and well insulated, I should consider leakage at the sides where the box meets the wall. There are, in fact, many small places at the side where the bucket handle joints in the brickwork are letting cold air in. Cumulatively, that adds up to a lot of unwanted heat loss. So I bought some clear external quality sealant, and this has been fixed up during the weekend. There is still some ventilation along the bottom surface, but this is manageable.

Friday, November 11, 2011

Idea for an Extension

10 Nov 2011: We have been thinking for a while of a southward extension to the Dining Room. This seems odd as there is almost no space, but even a metre would improve the spatial quality of that room. We have in fact 1.1m of side alley, and I don't want to uproot the existing retaining wall. So, one idea would be to build it over the alley, and cantilever part of it over the sloping flowerbed.

Here is a first view of the idea. This could be constructed using SIPS construction, and would almost be cantilevered from the house - I am thinking of merely some props under the corners, either rubber blocks, or even a couple of car springs. The path would be lowered slightly to go under the extension.
There is a chance to fit some liquid cooled PV panels, probably from Anafsolar. The extra thermal surface area would be plumbed in to supplement the ground loop, and the PV surface would provide additional electrical power. The thermal loop would have its own enter flow meter and pump and thermostat. The PV would be working to a large battery, and powering certain devices in the house.

Tuesday, November 8, 2011

Another solar charged house!

Illustration from Geotherm website
8th Nov 2011: I was forwarded this link by someone who works for Geotherm (Italy), and it's a paper by David Maritan about the efficacy of solar charging. Geotherm as a company is a reseller of IVT, the same heat pumps as in the Peveril Solar house.
   He is a big fan of the 'Compact Collector' a grille of pipes that is hung in a trench as deep as you can plant it, and is a substitute for a borehole - although it still needs more space than our garden would allow (it is also an IVT product). It addresses a smaller volume of soil than a borehole, so he strongly recommends solar charging.
Link to D.Maritan's paper
  This illustration off his website shows an example, although it doesn't show a solar panel. His paper was written in 2008 and reports on data collected since 2004. The addition of the solar panels (and array of evacuated tubes) had a significant effect in smoothing out the deep ground temperature over the seasons. It was on a building in Soave, NW Italy, of 160sqm, larger than the Peveril Solar house - and with a larger roof surface area.
  If you look at Geotherm's web page on GSHP with different collector types, you should use Chrome as that will translate it into English. There's nothing I can find on his website about the Solar charging experiment, but I have emailed David Maritan to ask for more details of the house or building, and to find out if the project is continuing.

We would have had a compact collector if it wasn't for the tiny size of our garden and the closeness of the collector to the foundations. We consider ourselves lucky to have had a borehole because it still buries the heat efficiently, and avoids ground swell. Solar charging wasn't in our thoughts when the house was built in 2006-7.

Saturday, November 5, 2011

Want PV? Soon you will need an EPC!

5 Nov 2011: After April 12th 2012, it's likely that PV-hunting householders will have to get an Energy Performance Certificate (EPC) for their house to be eligible for the 21pence Feed in Tariff. The EPC should be grade 'C' or better. Without this, you may only be eligible for 9 pence/unit.
   This is going to need clarifying, because it seems to be bad news for people in historic buildings who are unable to bring the buildings up to grade C, or those who have to erect panels in the orchard, garage or uninsulated outbuildings because the house is historic, listed or is encrusted with chimneys and dormers. You need EPCs in order to sell a house, so there is now a small industry of EPC assessors. Google "EPC" and you will find loads, including some companies based in West Bridgford/ Rushcliffe. If your house does not yet meet grade C, then you will get advice from the assessor on how far it can be taken.

How do you get an EPC?
• EPCs are explained further on the DECC website,
• It costs between £30 and £70 to get an EPC evaluation, there are many companies offering to do one. See this page:
• Here's an example of a EPC for a house in 'AnyTown'

Does the Peveril Solar house have one? No, not yet, it wasn't required when we built it, but perhaps we should do so, if its only £30-£40 to get one. Although the PV makes the house Carbon Zero, the requirement is for the house itself without the PV. Our insulation is very good and the annual heating requirement is low, being about 100 kWh/Sqm/annum base requirement, but because we use an efficient heat pump, it is only requiring only 26 kWh/Sqm/annum to space-heat and provide hot water. On heating alone, it is only requires 20 kWh/Sqm/annum, which is better than the Passivhaus requirement for existing houses. So it should be A rated, but I will get it rated independently anyway.
    I've made a phone call to arrange to have one done in the next couple of weeks. The assessor says that PV is taken into account, and their rating includes recommendations for the 'potential' grading providing the basic house underneath gets improvements in insulation.

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