As expected, it's changed my thinking. For a start, one of the most impressive speakers, David Hilton, suggested that if you have a gas supply it would be perverse not to use it. I later spoke to him and he explained that RHI probably won't cover you if you have access to a gas supply, so one argument for a ground source heat pump goes for a Burton. I don't think this was the sole reason for his stance - I think he was saying the research shows its the lowest impact fuel source, but I'm still attracted by the idea of severing dependence on fuel that somebody else sets the price of.
I also found out that if we had a heat pump we wouldn't need a gas boiler as they can produce water at up to 55 Celsius, but we'd probably have to dig trenches in the entire garden. A few holes, okay, but the entire garden looking like the frontline c.1917? And if we try to squeeze to much heat from it it could freeze your garden. I think the moral is ground source heat pumps are a fine solution to a challenge, but don't make up a challenge if you don't have one.
Better to make use of the almost infinite supply of wood on site, and I'm now thinking what's the best wood burner that could pre-heat water for a gas boiler when it's on, but doesn't cause problems when it's not. It also, I think, diminishes the risks of having different people supply different bits (I asked the panel about the risks of mixing n' matching but I think they hedged). Still, we have a site meeting with EcoEnergy this week, so we'll see how my thinking's swayed after that.
Solar PV was on everybody's lips (to the extent that practically no mention was made of wind turbines - I think a similar session three years ago would have majored on them), to the degree that I caught the end of the session by the man from Glow-worm gamely answering question on PV. Glow-worm have nothing to do with PV. Unlike not using gas if you have it, the unanimous view is that the economics of solar PV means that if you can use it, do so.
Another of the more thought-provoking speakers, Bob Harris, twice Builder of the Year and now university lecturer, put it to me that it would be better to store the output of PV than sell back to the grid. His suggestion was to use it to heat water. I'm still trying to get my head around that one as I can see a lot of water being heated in summer when I don't need it. He also recommended
My postman's going to hate me as I got very carried away with their laser-click-a-barcode-request-a-brochure machines. But a few items not related to the workshop stood out as worthy of further investigation:
- Colourcoat Urban roofing by Tata (http://www.colorcoat-online.com/en/products/exterior_products/colorcoat_urban) - looks good (from a distance) and was pushing the 'affordable alternative' line
- Roto roof windows (http://www.roto.co.uk/index.htm) - like Velux, but hinged a third of the way up
Our system combines solar thermal, lpg, wood and electrical heat sources with a thermal store. Mixing fuel sources is no problem, though you do have to plan your house layout somewhat as wood burners and thermal stores in particular are bulky devices. It benefits to avoid long pipe runs as well (something we failed to do).
ReplyDeleteWe're still commissioning parts of the system, but I'm a big fan of solar thermal since we've paid next to nothing for hot water since April. As we specified the system before FITs, we avoided the costly accreditation route, bought the solar kit from Navitron and installed it ourselves. Saved a fortune in the process, but don't get any cash hand outs.