Friday, November 30, 2012

Floor Tiling and Sunbox mounting

29 November 2012: Chris and Alan (McCabe and Huddleston Builders) came for another day's work putting down the floor tiles. The extension screed was levelled based on the middle of the floor, but we see that the original tiler ramped the tiles slightly towards the skirting so new tiles could not cleanly butt up to the existing edge. 

Chris and Alan have to cut back the first line of tiles, and we ordered enough tiles to do this. (Great Builder's Bum, Chris!)First, they had to cut out the tiles which were slightly sloping, and they used an angle grinder along the joints, then levered up the tiles. Very dusty!
Chris applying the adhesiveAlan working the tiles up to the skirting
Its looking good now and after the tiles have set, they will be grouted.There is a niche waiting for something to fill it...
While I had some muscle on site, I got Chris and Alan to shift the Sunbox container to the correct position on the roof. This required some modification to the scaffolding.Then we lifted the two metal radiators up. They weren't so difficult to lift, but it helps to have two strong guys to do it, and we didn't have to modify the scaffold.
Up goes the first one, and Chris lifted it over the handrail.Here, it was lifted below the handrail and was a lot easier to raise.

Now the box is laid on the roof, I have some work to do!

Roped down in case the wind gets up! Hasn't yet, but it's damn cold and not going to be fun plumbing out there. But we have had sunshine for a couple of days.

Thursday, November 29, 2012

Slating, Battery and Plumbing

30 Nov 2012: I have recently pushed further ahead with slating, and have nearly finished the east wall. The forming of slate around an opening, close to a wall junction, requires a lot of measuring and cutting. I am keen to reduce waste, and to ensure that slates cannot easily be snapped or blown off. 
The slating has now gone up the left hand side and across the top, and the final aluminium trip is installed along the edge to secure the edge slates. That's me reflected in the glass.An hour or so later and I've got down the right hand side and managed to rivet in the final aluminium trip. 
Looking at the overall end wall, the slating is complete up to a proposed gutter level and I have to think of the best solution for that. Meanwhile, I have also finished building the battery and have 80 cells all joined together, giving a total potentially of 160 amp-hours at 12 volts. Unfortunately my car Battery Charger doesnt work, so I cant charge it up yet. 

It is also time to make a start on the plumbing for the Surya-4 roof mounted Sunbox, so I have to make progress with that. Here's the start. A Wilo 15W pump and a check-valve. More to come.

These are the 15mm pipes rising from the roof mounted Sunbox, and they will change to 22mm inside the loft. The curvy wire is the 3-core cable that will provide 12V DC to the lighting in the new extension.

Wednesday, November 28, 2012

Plasterboard is now skimmed!

26 Nov 2012: We had to go to Bristol for the day, but Chris and Alan came in on Monday and continued with the work and got the whole extension skimmed. 

Bonding out uneven or deep areasScrim tape all joints to prevent cracking
Mixing. A pro quality Paddle Mixer ensures perfect consistency in the mixture. Experience tell the mixer when the water-powder mixture is perfect.Second Coating to the thermalboard on the brick wall.
Tackling the ceilingEssential break to let skim go off. After 30mins setting you can return to the work and smooth it off to perfection.

Skimming finished, it's time to tidy up and feed the cat.

I've been to collect the floor tiles, so work will continue later in the week.

Tuesday, November 27, 2012

Solar Fraction - how are we doing?

27 Nov 2012: I am occasionally asked how we make the claim to be 'solar heated all year round' and perhaps that can be explained with the concept of 'solar fraction' - comparing what power we can capture from the sun with what we need to provide heating and hot water. Typically we are averaging 120% over the first 32 months of the Sunbox installation.
    There are some interpretations of Solar Fraction, but if you Google the expression, this seems to be the most frequent answer. See for example the 'Encyclopaedia of Alternative Energy and Sustainable Living'.
    As we live in an electrically heated house, it is possible to read the meters, deduct from the previous year's reading and then calculate the solar fraction precisely to a decimal point, because it is kilowatt hours against kilowatt hours.
   We do not have gas or biomass boilers or wood burning stoves to confuse the issue. Of course, we are getting thermal energy from the ground (which comes from long term solar originally). The whole point of using a Heat pump is to have a coefficient of performance that is better than 1:1 heating. It's classed as a renewable technology because it is drawing heat energy from a renewable source, and we aim for between 3:1 and hope to achieve better than 4:1 using the solar charging technology.

    In doing this calculation, I am simply looking at metered quantities: Electrical Energy we can generate annually divided by Electrical Energy we must use to heat the house and hot water.

Before the Sunboxes were installed, the Heat pump averaged 4,800-5,600 kWh/yr.
(This can vary by 800-1,000 simply depending on averaged weather over the year.)
The PV has averaged 3,300 kWh/yr in its first two years.
This would give a Solar Fraction range of 59-68%. (depending on weather)

Since the Sunbox was fitted, contributing its direct solar heat to reduce the GSHP consumption, the figures have improved significantly. 

The best ever solar fraction was in February of this year, when the sunny months and mild temperatures of 2011 had their good effect, by increasing PV capture and reducing heat loss in the house, thus reducing heating demand. At this moment in 2012, we are at a bad moment in time after a year of early winter, continuous rain through spring and summer with only the odd days here and there of sunshine. The only prolonged sunny periods were a bit in March, a bit in May and a short bit in August.
  • Since the Sunbox was fitted, the 'Best ever' solar fraction was:
    PV capture 3,450 kWh / entire Heating+hot water 2,625 kWh = a solar fraction of 130%
  • At the moment, we are struggling after the year of rain and the solar fraction is:
    PV capture 3,050 kWh / entire Heating+hot water 3,350 kWh, giving a solar fraction of 91%
  • Averaged over the 32 months from 11 April 2010 to 25 November 2012, the figures are PV 9,050 kWh, GSHP 7,567 kWh, giving a solar fraction of 119.6%.
We cannot enlarge the PV as this size is set to 4kW, as defined in the Feed in Tariff table. We can increase the solar capture of the Sunbox by adding in the Surya-4. The extra 2 square metres will contribute a fraction of better performance, but are not expected to make a huge difference overall - the purpose of installing them is to rehearse the installation difficulties and methodology of the roof mounted unit. 

Saturday, November 24, 2012

Progress with Plastering

23 Nov 2012: Progress has been slow with raining weeks, dark evenings, and my putting more priority on getting the external work done first. We decided to bring in Chris McCabe and Alan Huddleston to finish off the interior. they are quicker and can do the work more professionally than I could, with their plastering and joinery skills. I have to try to get the Sunbox working as soon as possible, so I accept that we have to have help to finish the extension. Chris and Alan's website is: I was impressed at how well they got on in the first day. 

Chris and Alan arriving on Friday morning…. cup of coffee and then get on with it! I had to go to the University all day, so Chris took some progress photos and emailed them to me in the evening.

The brickwork over the opening has to be faced with Thermalboard to prevent thermal bridging because this same wall is also the outside wall. If you want to glue board to brickwork you have to prime the brickwork with adhesive, and here, the PVA is going on.

The boards lining the brick opening were a bit wobbly and Chris thought it better to take them off and continue the Dab and Plasterboard around the pier. It is also cheaper than doing it with Plywood, and less painting in future.Walls are being checked for flatness and verticality…. I hope they passed! Chris read the blog before coming so knows about the 'Time Capsule' behind the yellow insulation!

A lot of dabs going on for the thermal board above the lintel.

Good progress made in the first day, all surfaces are boarded and waiting to be skimmed next week.

Wednesday, November 21, 2012

Flashing and Slating

22 Nov 2012: With all this rain we have had recently, it's urgent to get the building more waterproof and I have been fixing up a permanent lead flashing. There is a 10mm groove in the wall for it to slot into. Real lead (as opposed to self adhesive Flashband) is very heavy and if you try to push it into the groove at one end it falls out of the other, and if you try to push it in the middle, it falls out of the ends. The answer was to cut it into 1 metre lengths and then each was perfectly easy to handle.

Initially, the flashing stays in place using temporary wedges made of slate, then permanent small wedges of lead have to be pushed into the groove and hammered deeply in so that they hold the flashing firmly.  I had exactly the right amount of lead for the job, so I was reluctant to cut it into sections and lose some in the overlap, and even more reluctant to cut some off the end to make little wedges - which are tightly rolled up pieces of flashing. I have to use lead not aluminium because of long term electrolytic corrosion of two different metals adjacent. 
While the lead is held in by wedges, the groove is filled with mastic sealant specially for beadwork - durable and weatherproof. However, it will take about three of these cylinders to fully fill such a long groove, so the flashing is held in with a first fix of lots of dabs of mastic, and more will be added soon. I got Douglas, one of my tall building students to come and help with the slating, and although it was raining lightly all day and very windy and cold, we got plenty of battens up. 
The battens are at 250mm intervals, screwed firmly into the OSBoard.We got started with the slating, but starting wall slating is very tedious - the first few courses are all cut-slates and are covered by later ones. Getting started with the disc-rivets is also difficult, but once we get to full size slates, it gets quicker. 

I continued late into the evening (by flashlight) and got at high as I could do until I ran out of battens and completely out of 30mm self drilling screws.

Sunday, November 18, 2012

Surya-4 raised onto the scaffolding

18 Nov 2012: We had a lot of people round for lunchtime drinks, and for the sale of Save the Children christmas cards. When people asked about the "box in the garden", I realised it was a good moment to get help as the raising of the components is a 3 man job not a 2 man job. Jamie Boyer (near neighbour) and Hugh McCormack (friend for 40 years, the first time I met him was helping to lift furniture up 4 flights of stairs) offered to help. By the way, sorry that there was a piece of white paper partially blocking the lens of the iPhone.

We got the polycarbonate front up without photos or a lot of fuss but the box element was more difficult. Heavier and not so easy to hold. We removed a scaffolding pole to make and easier route for it to go.With operations like this it's better to take plenty of rests, and think out the next stage.
Our system was to hold it in 'portrait' format, and have two lifting from below and me above pulling it up and stabilising it at the resting stages. We took out the scaffolding handrail, temporarily.We fixed steel handles onto the OSB board so that the box could be lifted safely.
With the scaffold handrail removed and a handle screwed to the box, it only needed one more heave for the box to lift up onto the main scaffold deck. Jamie is giving a cheerful wave to wife Liz who was wielding the camera.

I turned my attention to getting the huge detail to work, but the sun set and the rest of it was finished in the dark with a helmet lamp.

Tuesday, November 13, 2012

More plaster boarding in the extension

12 Nov 2012: Final Plasterboarding - ceiling goes up. Now I need to get someone in to do the skimming. I have never been able to work out how plasterers do ceilings - when I try, it mostly seems to end up on me. There is still the Thermal boarding to do on the brick wall, that's another pleasure to come. It has been raining much of the day and the thermal boards are so large, they have to be cut up outside the house.

Here is the remaining space to be boarded.
It is so much easier to put the dabs on when the board is on the table.The dabs would not be enough to old the board up alone unless you prime the surface so the same mix of glued is smeared with a 2mm thickness all over the wood surface.

Further work on the NiCad battery

12 Nov 2012: All the NiCad cells have been moved up to the loft and they are now being riveted together in the final arrangement intended for them. A few of them are imperfect, but I will try to make it up to 80 cells, giving a theoretical total of 160 amp-hours.

The cells are all rather unstable if stood up by themselves, so the box must be partitioned to keep them stable and upright, and I happen to have some scrap thin plywood in the garage of exactly the right size. 
56 are now in, a few more to go yet. 

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