Small CHP Unit

This "Combined Heat and Power" (CHP) unit is designed to run on natural gas (or biogas), however I think the same principles would apply to a rocket stove heating core.

https://www.viessmann.com/com/content/dam/internet-global/pdf_documents/com/brochures_englisch/ppr-micro_chp_boiler.pdf

Found the maker of the engine. At least I think they make it. They're evidently working on a pellet-fired boiler that integrates CHP.

http://www.okofen-e.com/en/engine/

This is very cool, now to build one:>)
To get 1kw of power out of a sterling engine is pretty impressive.

There are plenty of commercial ones out there that produce several kW. Do a Google search for "Philips Stirling Generator" to see one that used to be produced commercially (I think in the 1950s). They're museum pieces now, but there are some YouTube videos of people getting ahold of them and getting them running.

This guy did essentially what I'm thinking of, though while his target was 1 kW, he "only" achieved 400 W. That's still quite a bit of energy, and I suspect a little bit of refinement can push that number right up. http://peterlynnhimself.com/LSM_11.php

So, here's some energy math for you (I worked 8 years for a local electric utility): a 1 kW generator running 24 h/day produces 24 kWh of electricity. At $0.10 per kWh, that's $2.40 per day, or $72/month of income, or $876/year for a continuously-operating system.

That's not a break-even number if you've got to buy the fuel for the stove, but if you're producing your own fuel (woodlot windfall, shop waste, etc.), it's a viable income stream, albeit a small one. And, the vast majority of the heat is retained; only what gets converted to actual energy is lost, particularly if the "cold" side of your stirling is in the space you're trying to heat.

Just something to think about.

Cheers.

JD

theres better than the phillips version out there now the one thing with phillips it used saved pressure inside of its frame to start up

I learned today that helium as a working gas provides an amazing amount more energy than air or nitrogen. Unfortunately, helium being what it is, it's hard to contain for long periods. Many of the He charged units are completely sealed, which takes way more skills than I have to manufacture.

I found a calculator that tells you what the output of a Stirling engine would have given some design parameters as inputs: http://www.bekkoame.ne.jp/~khirata/academic/simple/simplee.htm

One Megapascal (MPa) is about 145 p.s.i. (ten atmospheres, I think). I used parameters of .5 MPa (around 72 p.s.i.), 4000 cm^3 (which is four liters), 650 C (1200 F) for the expansion temp, 204 C (400 F) for the compression temp, and the default settings for "permitted values". I came up with 730 W max output for air, 1621 W when using helium. Going back to air and doubling the pressure to 1.0 MPa, I get 1622 W output. So, now to figure out how to make an air-charged system that I can put 145 p.s.i. into. Standard engine rings hold back 160 p.s.i., so it shouldn't be too tough.

I'm aiming for a 12" diameter piston with a ~3" stroke. The 12" piston should sit nicely on a standard shop heater rocket stove (I'm thinking of ppotty's builds).

ive posted these on forum before



still photos

spoted this one

http://news.mongabay.com/bioenergy/2007/08/engineers-develop-small-scale-biomass.html

A consortium of European research organisations has achieved an engineering breakthrough by developing a compact, highly efficient combined heat-and-power (CHP) plant based on stirling engines and fueled by biomass. Until now there were no biomass CHP technologies available in the power range below 100 kWel. The engineers succeeded in optimizing and scaling down the technology to a power range of 35 kWel and a 70 kWel. The small scale plants are hyper-efficient with an overall system efficiency ranging between 85 and 93%. Because the CHP units are so compact, they can replace existing but far less efficient traditional hot-water boilers. Alternatively they can operate in decentralised and autonomous energy systems in off-grid places, particularly in the developing world. Given that it is fueled by renewable and carbon-neutral solid biomass, the system is one of the cleanest energy concepts available. wrote:

Did you see the comment at the bottom?

Quote :

The information in this article is a few years old. The technology is now commercially available. The biomass boiler plants discussed in this text are sold through Mawera in Austria. The engines are produced by a newly created Danish company "Stirling Danmark Aps" who also offers turn key plants based on gasification of wood chips and the 35 kW engine. Please see Stirling.dk for more information.

Heh. I tried the recommended "stirling.dk" site, which is a honeypot blog for financial links. So I searched for "Mawera". Turns out they're a member of the Viesmann group, who make the thing I started this thread with. And so the worm turns...

http://www.mawera.co.uk/