I wish you well with your search for the Merc industrial diesel. I have often thought that those refrigeration systems were just waiting to be re-assigned. A friend in Switzerland has a 3 cubic metre (795 US gallon) hot water storage tank, heavily insulated and built into a special room. It had several draw off points, and heat-exchanger coils so that water could be drawn for different purposes and the tank could be heated by different heat sources. You’ll need a big house for an 800 gallon tank!

Now onto Stirling Engines.

The Viebach engine is rated at half a horsepower – but they could be built in pairs to produce a 1 hp genset. Viebach experimented with pistons and bores from various compressors – because that’s really all the Stirling engine power piston is – a gas compressor/expander.

There is no reason why these engines should be so expensive on a cost per watt basis. It is only the lack of a mass market application which has hindered their progress. Viebach has a strong following of amateur engine builders – especially in Germany.

Unfortunately it appears to be German language only, but please do take a look. There are good photos of the overall engine – plus a new integrated 450W generator. Looks like Dieter has been pattern making again! The technical specification is quite easy to deduce from the German. The castings set costs DM1490 ($700) and the generator castings are $182. Carriage overseas not included. Because of the high cost of German labour a complete engine will cost $4250.

I bought casting set No 50 from Dieter Viebach, and one day intend to put the engine together. You need access to fairly large machine tools, and the heat-exchangers need a lot of fabrication work in stainless steel. This could be semi-automated using spot welding and electric resistance seam welding techniques. Expect to pay around $2000, $2500 for a complete engine excluding labour costs.

I keep saying that we should get the Chinese to bang these out for $500 or less. It would really suit their small engineering shops, machine shops and foundries. It needs someone to introduce it to them and get them started. I am in Hong Kong in early October – I will try and make a few contacts and steps in the right direction. This is a product that would sell in the West if only it were 1/10th of the current price.

Yes, the cost is ridiculous — I found those sites this afternoon, looks like pretty nice work, but the price! I think you’re right about the best hope would be getting China to build them, although I hear really bad stuff about some of the stuff coming out of there, like diesel gensets and tractors. You know, I’ve been fixated on getting a diesel and/or woodgas cogen system set up for so long now, and just this afternoon I started thinking that what I really should do first off, right now, is build a babington burner, put the hydronic baseboard heaters in the greenhouse, grab (or make) a small boiler of some sort, even just a used gas hot water heater, and start playing with that, burning WVO. And once that’s going good, perhaps pipe it into the house, and start looking at either a steam engine or a Tesla turbine. The TT really intrigues me — if it’s as easy and cheap to build as it looks, and anywhere near as efficient as claimed, it would sure be neat. And, as John was telling us earlier — simplicity is what we should strive for, the TT is much simpler than a stirling even. And I imagine even quieter. Hmm, so I guess I need to start gathering bab parts.

What about 2nd hand automotive diesels. A year ago you could buy a Toyota 1800cc diesel for R3000, and sometimes R600. (US $350, $75). They are imported from Japan as container lots of mixed engines, but the diesels do not sell as well as the petrol ones.