This page was last updated on September 25, 2011
Forum replies
Useful comments and observations from various forums. Edited to reduce space. (my italics)
Question How to stop ring gumming - already water inject.
Check the injector!
--it was on the tip of my brain when I was posting before but I couldn't get it out, have you thought about one of those hydrogen boost thingies for cars ?
they're supposed to give more power/boost mpg etc. etc.
that stuffs a load of rubbish... but it will give you a cleaner burn and keep the engine free of carbon build up / ring gumming ?
only flicked through it, but i saw an independent write-up a while back where they agreed the extra mpg/power was a load of rubbish, but when they stripped engines down the ones with the hydrogen boost thingies were all spotless inside !What about feeding in steam direct?
Question What is the best size of pipe for heat transfer underground.
I used 22mm barrier pipe. My run to the shed (outside the house) was about 11m each way.
I found that I could fit some 19mm foam insulation that would then fit down the centre of a 68mm black plastic downpipe (Wickes). These were burried in a trench lined with scrap pieces of celotex. The trench depth was between 300 and 450mm.If I were to do this again I would probably use 15mm barrier pipe, and use insulation with a thicker wall - say 25mm.
I'd use 10mm plastic pipe - there's a load of different plastic pipes to choose from. The reason I say 10mm (or there abouts) is 2 fold...
*the dead leg, when you start up your pump, there's going to be a lot of cold water in 80m of pipe - you'll use up a lot of heat when you flush that out and back to your engine, and then there's the pipe to heat up after that....
*less surface area.... the less surface area you have, the less area you have to loose heat through.... so you really want to use the smallest possible tube that will let you shift the amount of heat you need to shift....
At what rate do you want to move the heat? the smallest pipe that will just do the job will have the smallest heat loss. 15mm will shift up to 6-7KW with a standard CH pump, 22mm pipe will shift 20kw.
Question What generator should I use?
The permanent magnet generators designed for wind turbines operate at low RPM, in the low hundreds. Consequently they have more windings and are more expensive for a given output. If you go for a more conventional PMG that give maximum output in the low 1000s RPM it will be less expensive. The grid tie inverter should be OK as long as it doesn't receive more than it's maximum voltage so the generator needs to be able to produce the required output within the safe voltage range for the inverter, usually about 50 to 500 volts.
actually... what about feeding a 24v GTI from a lorry alternator ?
they're easy to find, cheap, and reliable... ?
can always connect in a couple of batteries so help even out any ripple etc... ?
I've used a Navitron wind turbine alternator - designed for 450rpm - so easy to gear from the Lister CS. The advantage of low rpm is much longer lasting bearings etc. Also, if you use a v-belt drive you will find they fail often (again, check out Frotter's thread). I used a timing belt on mine - designed for much longer life AND it's much more efficient - vee belts get hot and sap power.
If you buy a Navitron wind alternator, it'll probably be cheaper than a PM generator designed for higher rpm.
I'd steer clear of low voltage stuff. For the reasons already mentioned, and also because the GT inverters available don't like going much overvoltage (ie range=24-65v), whereas the high voltage units give a large range of operating voltages (eg 200-600v)
Ii think that at the 3kw mark it's much cheaper to go with a wind turbine(generator) and a GTI than any other way... I've read up a lot on (knowledgeable) people trying different cheaper systems and they've always given up in the end and and gone with the wind turbine (permanent magnet generator) and a suited GTI
How should I use the heat in the house?
The heat exchanger (my origional idea) looks a lot of work with the car rads....you can pick up the proper heat exchangers really cheap, or even scrap. They used to put them in council houses and when people buy the house, first thing they do is rip the warm air system out. I think I would stick with a water system and something to top it up as needed, like your solid fuel rayburn.
Is your (solid fuel) Rayburn not connected up to any radiators ? (yes)
it would be much easier to add a heat exchanger to the coolant line and use that to heat up your central heating...
Thoughts on the shed.
make sure you leave about a metre all around the Lister to make servicing easier - no point working in cramped spaces. You might also wish to consider a permanent hoist running on an RSJ in the ceiling to make maintenance and manoeuvreing of the Lister easier. Don't make your bunker so small that you can't get some sort of a engine hoist in there somehow.