My new fusion-powered house
The sign of the modern-day sun worshipper
Powering your house with million-year old dead trees is so last century. What you really want is a toaster that’s fuelled by a massive ball of nuclear fusion!
With that in mind, I’ve had a 2kWp photovoltaic array nailed to my roof. The roof needed work anyway, and the window of opportunity for the government’s more generous level of Feed-in Tariff was about to close, so we thought “what the heck!” and got the cheque book out.
So far I’m really pleased with the amount of power it’s producing. It’s designed to produce 2oooW of power on a sunny summer day, but you get somewhat less if it’s cloudy or winter. Nonetheless it’s been putting out well over 20kWh of energy a week, which is pretty good going for Feb IMO. According to PVGIS it should produce about 1600kWh per year, and the idea is to try and grab as much of that as possible for use at home. That can be easier said than done, on a sunny day it easily outstrips what you can use at home. That’s not a biggy though, you get paid for all the power you produce, whether you use it yourself or not. As an investment I feel pretty happy that it should pay out quite well in the long run, it’s basically a government-backed, index-linked income for the next 25 years which is a lot better than you’ll get putting your cash in the bank these days.
Really happy with our installer too, both the PV dude and the roofers were excellent, so if anyone in Kent needs a roofer I can recommend a good one.
All-up it gives me a warm fuzzy feeling to be micro-generating, and it’s got my brain ticking over about knock-on projects. First up is a decent power monitoring system, probably a gnarly DIY solution like this. After that I’d like to look at optimising our use of the power we’re producing, probably something along the lines of automatically using hot water storage as a dump load. That could be bit tricky though, as we’ve got a combi boiler. Open to any suggestions on that one…
Buy an unvented direct hot water cylinder similar to this (90 ltrs should be enough)
http://www.plumbnation.co.uk/site/gledhill-stainless-lite-direct-stainless-steel-unvented-hot-water-cylinder/
Get one that uses a standard 11 inch immersion heater(cost £7) (Megaflow use a proprietary one, cost £70)
Fit it somewhere, attic maybe. Divert the cold mains that goes to your combi to the cylinder then the hot out back to the inlet of the combi. Now your water is pre-heated and will save loads of gas.
Cons. If it is in the attic you will need to run three pipes to it. 2 x15mm for hot and cold and 1x 15mm for the pressure relief valve which could be run into the gutter drainpipe or the soil waste pipe. Put the tundish where you can easily see it,
Or build the wife an airing cupboard and site it there
The plan is to do something exactly like that Jamie, using one of these (http://openenergymonitor.org/emon/node/217) to make sure that it only uses power that would have been exported anyway.
Most combi manufacturers will tell you their boilers can’t accept pre-heated water, but there’s no technical reason they can’t if the preheat is kept down to sensible levels. Maybe fit a thermostatic mixing valve?
[...] For example, on a couple of mornings I’ve had enough sunshine to run the heat pump off my modest little 2kWp PV system at least some of the time, even in November. During spring and early autumn I’d expect [...]