Small domestic level oil engine CHP plant - Charlbury Mini C

Fri 29 Dec 2006, 05:45

OK, too much pain to sleep tonite, gee, tomorrow's gonna be a fun day. So some Sustainability Musing.

I'm toying with designs for a small chp plant to heat and power our house during the "heating months" and sell back excess lekky to the grid. Chinese and Indians are making decent single cylinder diesel/oil engines that output approx 3kw lekky and 6-7 kw heat if exhaust and cooling fluid and overall waste heat is captured.

Or find an old Lister engine in a barn somwhere (let me know if anyone knows of one rusting away in an old shed, please!!!!).

Some good homebrew open source rectifiers and grid supply circuit designs becoming available using stock electronic components upon breadboards from "the colonies" where a lot of people are off grid, so easy soldering iron work.

The merit of these old style engines is that they can use just about anything to fuel. Waste veg oil being most obvious "niche" fuel for minimum co2 footprint, a valuable if small component of carbon reducing jigsaw of energy options.

CO2/energetics if get heat capture right pretty impressive. Waste heat capture and heatsink storage is of course the key to the whole thing!!

An effective low cost interim measure until one can get PV panels at affordable prices - and persuade planners to allow effective external insulation of these outlying estate fake cotswold stone grotboxes with small rooms (which louse up internal insulation potentials).

Anyone else interested in this sort of homebuilt thing?

A few of us could import a container of engines and generator heads and basic spares at a very low price.

Engineering is such that maintenance with crowbars and lump hammers is common practice ;) and basic plumbing and welding with scrap materials will do the job for the heat exchangers, as will generous quantities of polyurethane insulation spray-on material for wrapping the whole lot up in a cosy bundle.

Might as well put it into a good size greenhouse as some heat loss will be inevitable, and keep oneself in fruit and veg VERY locally grown compared to air shipped carbon dioxide miles from the coop... even better if greenhouse is full height lean to attached to complete sunny side of the house - with a heat sink under the floor of course. In summer use the height and heat differential top to bottom of a full eaves height greenhouse to drive a passive evaporative heat pump air conditioning system for cooling the internal rooms - i.e. no need for electricity) which can also be made out of recycled piping. (NB no point in running the CHP engine in warm weather, energetics only work when waste heat is captured).

Even these small engines are probably too big output for a single house, so why not share with the immediate neighbour or two via an insulated pipe and some armourmed cable in a little neighbourhood cooperative?

Heavy(!!) cast iron construction and heat capture cladding makes them very quiet, and they are low revving and hence very long service life if well polished before final assembly for use. Veg oil gives very low pollutant nasties emissions compared to dinosaur diesel too, and can't see any reason why an automotive catalytic converter couldn't be tacked onto the initial part of the exhaust as part of the heat exchanger, it would be always running nice and hot and hence effective at hitting the few NOx's that do form (little does given the combustion chamber conditions of these engines though compared to automotive engines, but what the heck, if one can afford a couple of hundred extra quid for a cat why not?).

Too much of the energy saving stuff "for sale" is aimed and priced at well heeled early adopters with high disposable incomes and little technical ability at the "fingernail dirty" level. And in my opinion hugely overpriced and way out of our personal reach and many others who will be hit hard by future very large energy price increases due to low disposable incomes...

But for those with a modicum of skills and imagination host of ways of doing stuff using low tech equipment and recycled materials.

I'm working on the design of a permanent "generational" battery in thick glass "bathtubs" and hand hammered lead sheet that will last millenia and be infinitely recyclable. Shed tucked into a hedge with a bit of a bund around it (just watch out for keeping spillages down, don't want that stuff leaking into the ground, but if contained carefully, harmless).

Meanwhile we await photovoltaics prices to drop in a decade or two - we've enough roof for a theoretical 25kw with current technology, but alas a lack of 40 grand to pay for it at current prices whereas I reckon I can put a chp oil engine and genhead online for less than a grand and a quantity of elbow grease...

And also wait for planners to wake up to reality of only ways to insulate these nasty 60s and 70s grot boxes is external application of insulation coatings. But their "stone character" fetish will take a while to change I fear. Tho' personally I don't think that ground up powdered cheap limestone dust mixed with low quality cement fools anyone as a Cotswold character... and has lousy thermal latency properties as well so sod all thermal buffering benefits winter or summer, either.

Historic core areas there is a point in preservation, of course.

Future is going to be a weird mix of hi tech and the most primitive of infinitely repairable and maintainable machines, eh.

I'll resist stripping the Church roofing material for my battery bank, that would be a bit antisocial really and probably upset some of the locals... or is that roof copper sheeting? I've never really looked...!