Friday 28 February 2014

"Always something there to delay me..."

...as Sandy Shaw famously once never sang.

Despite the Solar Fence project being started back in December, with the panels mounted well before Christmas, they still aren't connected to the grid! There are two reasons for this (three, if you count my laziness): First, the hideous, wonky patio we inherited from the previous owners of Chateau Lessgrid was apparently laid by gentlemen with horses and stetsons. Consequently, it sits too high against the house and, while not breaching the damp course, it is perilously close. Close enough to warrant digging out and relaying a good few inches lower. Secondly, ever since discovering the aforementioned patio problem, the effects of climate change appear to have singled out our garden for special attention and rarely has there been a dry day. (Well, there have been a few, but we've buggered off out for a walk when that's happened. Too nice to stay at home digging...) Anyway, it's all conspired to delay installation of the main cable between panels and house, which will be running under the patio. Nevertheless, I am still hopeful that the installation will be complete before we lose an ice cap.

Lavender doing well

On a happier note, plans to turn this previously neglected end of the patio into a micro nature reserve are ticking along quite nicely. January saw an explosion of snowdrops under the panels and now, as February draws to a close, daffodils are about to put in an appearance. It looks like the ground under the panels receives a good amount of dappled sunlight, which should be good for shade-tolerating woodland plants. Plans to plant the area in front of the array with lavender are in hand. Deb has got a propagator on the go and already we have plenty of seedlings appearing. We're growing Hidcote and Munstead strains, both chosen for their compact size and fragrant, bee-friendly flowers.

World's first solar powered bird box?

Finally, a couple of weeks ago, in a fit of sudden, uncharacteristic activity, I stuck a spare bird box to the end of the timber array frame. The local blue tits have been in and out on a daily basis ever since, so I am hopeful that we will see a pair take up residence when the nesting season gets underway.

Wednesday 18 December 2013

Solar Fence - phase 1

You know that moment, when you begin to stir from your slumber and, for a second or two, dreamworld and reality become entwined? I blame that. Anyway, for whatever reason, I'd decided that dangling some solar pv off the (south-facing) fence between us and next door would be a great idea. The fence panels needed replacing anyway...

There was some method behind the madness:
- Our 3.7kW on-roof solar pv system could potentially dump around 14A onto the grid when running flat out.
- Under UK guidelines for connection of small-scale generation, we are allowed to connect up to 16A of potential export without seeking prior permission from the grid operator. That's 2 whole amps to play with!
- We currently dump excess solar generation into space heating (a 400W panel heater currently, and a 1.8kW storage heater in the process of being hooked up), so as far as generation goes, the more the merrier.
- Everyone needs a hobby...

The new system wouldn't qualify for the Feed-in Tariff, so it was important to keep costs down. This was done by judicious choice of components and by collecting the bulky stuff from local suppliers where possible, thus saving a fair bit on shipping charges.

The initial idea was for a couple of cheap 250W crystalline panels mounted at approx. 60 degrees inclination (to both maximise winter generation and take up less space) connected to a dinky Mastervolt Soladin inverter. Output would be knobbled by shading from the house until mid-morning, but from then until virtually sunset, the panels would be in full sun. A bit of computer modelling in PVSyst showed it was a goer. I then came across Solar Frontier's 150W thin film panels, available from Dulas. Thin film technology works better in low light conditions and is more shade tolerant than crystalline technology. Three Solar Frontier 150's came in at a similar price to a couple of typical 250W poly panels but, according to PVSyst, would far outperform them. I could also collect from Dulas' warehouse in Welshpool... and they look better than crystalline panels... and are a little shorter (which helps with positioning). Job done and three panels were soon sat in my garage awaiting somewhere to put 'em.

Solar Frontier 150W thin film panels

Ubiquitous Mastervolt Soladin - perfect for small systems


I soon discounted mounting the panels directly off the concrete fence posts, via some dodgy framework of dubious strength. Instead I plumped for a more traditional ground-mount frame, using treated timber. A few rough sketches later and something resembling a frame was soon knocked up in front of the fence (ropey fence panels first replaced!). Panels were attached to the frame using a traditional aluminium rail and clip system. This was sourced from the ever-helpful people down at REDtip (STF Fasteners) in Bilston, a handful of miles down the road. Driving home with 3.2m rails sticking out of the passenger window of a van with a 2m long load bay was 'entertaining'. Fortunately no pedestrians were impaled. 

Framework up. Very sturdy.

Rails and clips in place, ready to take the panels.
My dad was roped in to give me a hand positioning the panels and these were soon clamped up, tested and terminated in a DC isolator, mounted to one of the timber uprights. Phase 2 will see the inverter mounted and the electrical connections made.


Panels on. Ooh, shiny.

The new ground mount system beneath part of its big brother
The new system occupies a previously unused end of the patio. However, we will be planting the strip of ground in front of it with some bee and butterfly friendly lavender and adorning the timber frame with all manner of insect and bird friendly habitats. A small 'water feature' to the right of the panels will hopefully encourage more wildlife and I might even see if I can get some sunflowers to grow up the gap between panels and fence! Should look nice in a couple of years, when everything has established.




Tuesday 8 October 2013

This year's entry to the Wolverhampton's Warmest Landing Competition

Finally managed to rig up the Solamiser, to divert excess solar pv generation into space heating. I even managed to run a new circuit, from the garage-mounted consumer unit to the panel heater on the landing, without knocking half the house down and with minimal swearing (first time for everything). So far, we have the Solamiser on a dedicated 16A circuit feeding a solitary 400W panel heater. I have employed a modular 'plug & play' design to make provision for future expansion (which roughly translates as "there's a junction box in the cupboard under the stairs").

Solamiser fitted discretely above the consumer unit in the garage

Well, it works. The moment pv generation exceeds demand, the Solamiser kicks in and the little neon on the panel heater begins to flicker, denoting that the heater is receiving less than it's rated power. As the pv output ramps up, the flicker lessens until the heater is running at full power. The landing is nice and toasty and our electricity meter hasn't moved since I last put the kettle on.

As I write this, at 1pm on a bright, partially cloudy day, the heater is running flat out and we're still exporting between 1 and 2kW. More heaters needed. We're now on the look out for a second hand storage heater or two, to maximise the potential of this free heating system.

Friday 4 October 2013

The rain in Spain falls mainly down the drain...

...and it did here too, until we finally got round to sorting out a couple of water butts. One of those jobs that we've meant to do for a while. The recent inclement weather has managed to divert a bit off the flat bay roof and into one of our shiny new green plastic tanks, while the other languishes in the garage until we decide where to put it.

The grape vine embraces its new neighbour

 Anyhoo, it's got us thinking about rainwater harvesting and, following on from that, re-using greywater (the stuff that goes down the drain after a bath or shower for example) to flush the toilet. It's as a bit odd that the water we literally flush down the bog is prime drinking quality - what a waste. Especially the amount that seems to, erm, pass through our toilet in a week. At 6 to 8 litres for the average flush, it soon adds up. Using harvested rain or greywater for flushing purposes makes perfect sense. It's a relatively straightforward DIY project, involving some water butts, some pipework, a pump (solar powered of course!), a loft storage tank and some control gear. Greywater, though more plentiful than rainwater (hard to believe at times) does require some sort of treatment and filtration prior to unleashing it on the porcelain, so we'll need to weigh up the pros and cons of each approach.

We've been meaning to get a water meter fitted for ages (we've been meaning to do a lot of things 'for ages'). A meter should dramatically reduce our bill. Flushing the lav from harvested or recycled water should reduce it considerably more.

I knew my allergy to washing the car would prove useful one day...


Incidentally, most local authorities and water companies have special offers on water butts. What you may not know is that pretty much all these offers are handled by one company, Straight plc. - the same people who supply your council wheelie bin. We found that one of Straight's own webshops was offering better prices than our local council or Severn Trent, so it's worth shopping around. We bought from evengreener.com and the stuff arrived within 2 or 3 days.

Wednesday 2 October 2013

Talkin' 'bout my generation

As any solar pv system owner knows, more generated electricity is usually exported to the grid than is used around the house. Even on dull days at this time of year, we are generating more than we use during the average day. With affordable storage solutions still a way off and our export payments deemed at 50% of total generation regardless of how much we actually wave bye-bye to, we were left with three options:

1. Do nothing.
2. Get an export meter installed (probably at some cost) and get paid accurately for everything we export, rather than the assumed 50% of total generation.
3. Use as much of the generated electricity (usefully!) as possible, while still getting paid for the assumed export of 50% of total generation.

1. & 2. were quickly discounted on the basis that we were buggered if we were going to give away our lovely, fresh, organic electricity for free, or at some discounted rate, just so that we could buy a load back again in the evening at three times the price. Option 3. it is then: Use as much, usefully, as we can while still receiving export payments for half of it, whether we export or not (I stress the word 'usefully' again - tempting as it is to waste as much as possible just so the energy companies have to pay us for nothing, me no like waste).

The usual way to use up a surplus of electricity is with one of many devices now on the market that dump the excess to an immersion heater, to provide hot water. Such devices monitor export and, by controlling the power to the immersion heater, never use more than the available surplus.

We have a gas-fired combi-boiler, therefore no hot water tank, therefore no immersion heater. I considered using a 15l unvented electric water heater I've got lying around to preheat the cold water feed to the boiler, but Worcester Bosch told me if I did that, I'd break it. However, they did tell me I could spend a fortune on one of their new models, which would accept a pre-heated feed. Er, no ta. Due to the way in which the power diverter devices work, they can only supply a resistive load, ie. a heating element like that found in the average immersion heater. Fortunately, this means they'll also work with electric panel and storage heaters (but only the basic 'no frills' ones without fans, timers or electronic controls). The plan is to therefore divert our excess pv generation into space heating. I've already sourced a snazzy, slimline 400W panel heater which I've installed on the landing and which should hopefully work in conjunction with our 'fresh air' positive input ventilation system, the outlet diffuser of which is located in the ceiling above the heater. I'm hoping for a mixture of pre-heating and destratification, as the two work together to waft gently warmed air around the house. Seems to sort of do something resembling that, following some initial trials.

Slimline 400W heater for 50 quid. Bargain.

 The main business will be taken care of by a couple of 1kW or so storage heaters located in the downstairs living areas. We're currently on the look-out for a couple of suitably cheap, used units to be added as and when. We hope they will be able to take a bit of demand off the gas central heating system.


That only leaves the power diverter device. I have installed quite a few Immersun units for customers with immersion heaters and this high quality, well thought out bit of kit works very well. However, it is far too sophisticated (and expensive!) for our needs. A bit of seasonal space heating will be nowhere near as cost-effective as year round hot water so a more basic alternative was required if this project was going to be worthwhile (not that we've bothered with such trivialities as working out the financial benefits!). The answer came in the shape of the Solamiser, a trimmed down controller with none of the Immersun's bells & whistles. More Aldi than Waitrose, if you will. Still, at a fraction of the cost of its flashier cousin, I am hoping it will perform as good a task. Hoping to get it fitted in the next week or so.

The Solamiser. I might buy a bell and a whistle to pimp it up a bit.








Tuesday 1 October 2013

Wolverhampton calling.

Morning all. Watch this space if you are interested in a not-terribly-scientific approach to lessening your dependence on the utility companies and generally greening up your life (by which we hopefully mean 'spending less money'). All views expressed within these pages are purely our own and do not necessarily constitute fact of recommendation. Copy any ideas at your own risk!!