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Kickstarter project for $100 - 1 kW - stirling engine

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Re: Kickstarter project for $100 - 1 kW - stirling engine

#11

Post by jws »

MichaelApproved wrote: post #4

"Well the average US household uses about 8,900KWH of electricity per year - that comes down to 24 KWH per day and so our goal is to have a minimum engine output of 1KW so that it can produce close to the average home use of electrical power per day (24 hours of 1 KW output give you 24KWH)." This math isn't taking into account that the power use isn't consistent, batteries will be needed to handle the variances in co…

You'll never get 100% efficiency from power storage so the amount needed per day is much higher.

Lead acid batteries are 85-95% efficient for getting power in and back out. It doesn't change your sizing much.

That said, until a significant percentage of the utility's customers are using these devices, it makes no sense to use batteries. Just sell surpluses to the grid and buy back to handle peaks.

If you have no grid, then about $1000 of batteries will cover you, and need replacing every 5-10 years. Either way, your inverter is probably around $2000.

I'd have already clicked to buy in, except there is a missing chunk of the efficiency. Assuming I don't have a small lava flow next to a stream in my basement, what is the total projected efficiency of these units from fuel to electrical energy? They don't seem to be addressing burner efficiency. How will it compare to a small gasoline powered generator? (You can't buy a diesel genset this small.)

Re: Kickstarter project for $100 - 1 kW - stirling engine

#12

Post by jgrahamc »

It's possible to buy something like this.

A WhisperGen which generates electricity (1kW) and makes hot water using a four-piston Stirling Engine: http://www.ehe.eu/ehe/dm/whispergen.asp?nombre=2401

They do both because they get cooling by transfering the heat to the domestic hot water supply getting hot water and electricity at the same time. They are powered by natural gas. The gas company E.ON in the UK did a study on them (they also provide them I believe): http://www.microchap.info/Carbon%20Trust%20field%20trial.pdf

To quote that report: "For typical family homes, carbon savings of up to 20% are realistically attainable with economic payback of around 3 years."

Re: Kickstarter project for $100 - 1 kW - stirling engine

#13

Post by colanderman »

jgrahamc wrote: post #12

It's possible to buy something like this. A WhisperGen which generates electricity (1kW) and makes hot water using a four-piston Stirling Engine: http://www.ehe.eu/ehe/dm/whispergen.asp?nombre=2401 They do both because they get cooling by transfering the heat to the domestic hot water supply getting hot water and electricity at the same time. They are powered by natural gas. The gas company E.ON in the UK did a study…

WhisperGen is also only available in Europe and costs two orders of magnitude more than this device would last time I checked.

Re: Kickstarter project for $100 - 1 kW - stirling engine

#14

Post by colanderman »

jerfelix wrote: post #3

Looks like a cool project. One note to entrepreneurs using Kickstarter, or creating any slide presentation for potential investors: Take the time to spell check your slides. Tim Sefton (creator of this project), if you happen to be reading this, here are some notes that may help you make your presentation more professional... "One thing.. The Sterling engine is about 10% more efficent then the gasoline engine, but st…

Not to mention it's "Stirling", and not "Sterling".

Re: Kickstarter project for $100 - 1 kW - stirling engine

#16

Post by colanderman »

TylerE wrote: post #8
MrEnigma wrote: post #5

Earlier quoted context omitted.

Also, there has to be some sort of mechanism for heat, and then something to actually generate it. All this is going to be is the engine to turn it I believe...

Sterlings are normally run on solar heat.

I don't know why you're being downvoted. One of the primary uses of Stirling engines, especially for off-grid homesteaders (at whom I'm sure this is aimed) is concentrated solar. All you need are a giant Fresnel lens (~$100), some black metal to act as a collector, and heat transfer compound to attach that to your Stirling engine and you're off to the races.

Re: Kickstarter project for $100 - 1 kW - stirling engine

#17

Post by JoeAltmaier »

colanderman wrote: post #13
jgrahamc wrote: post #12

It's possible to buy something like this. A WhisperGen which generates electricity (1kW) and makes hot water using a four-piston Stirling Engine: http://www.ehe.eu/ehe/dm/whispergen.asp?nombre=2401 They do both because they get cooling by transfering the heat to the domestic hot water supply getting hot water and electricity at the same time. They are powered by natural gas. The gas company E.ON in the UK did a study…

WhisperGen is also only available in Europe and costs two orders of magnitude more than this device would last time I checked.

But this device is vaporware, and its price is a pipe dream.

Re: Kickstarter project for $100 - 1 kW - stirling engine

#18

Post by TylerE »

colanderman wrote: post #16
TylerE wrote: post #8

Earlier quoted context omitted.

Sterlings are normally run on solar heat.

I don't know why you're being downvoted. One of the primary uses of Stirling engines, especially for off-grid homesteaders (at whom I'm sure this is aimed) is concentrated solar. All you need are a giant Fresnel lens (~$100), some black metal to act as a collector, and heat transfer compound to attach that to your Stirling engine and you're off to the races.

Yep, also somewhat common on boats, especially sailboats, for the same reasons.

Re: Kickstarter project for $100 - 1 kW - stirling engine

#19

Post by meow »

ck2 wrote: post #7

Yes gas is near $4 - what does that have to do with utility prices, since there aren't any gasoline powered plants in the USA since the 70s ? I would have to assume the way the utility company produces power is far more efficient than a town with thousands of mini-engines. Only stuff like solar cells work better in distribution. Not sure how this would work either - what fuel are you going to use to power it for 24 h…

Unlike other engines, a Stirling engine (like other external combustion engines) is more suited for using alternative power sources like solar energy. You can heat the end using a Fresnel lens or a solar concentrator (http://en.wikipedia.org/wiki/Solar_power_in_Spain). But more importantly, with a $100 price tag, it will be an affordable engine to experiment for hobbyists.

Re: Kickstarter project for $100 - 1 kW - stirling engine

#20

Post by meow »

ctdonath wrote: post #10

Variant idea: a small portable version for camping. Stick one end in a fire, USB plug for power connector at the other. 2.5W shouldn't be hard to get under conditions where "unreliable" is normal.

It will be kind of heavy though. For simple charging of appliances, other projects are very interesting:

http://www.kickstarter.com/projects/ryochijiiwa/bootstrapsol...

http://www.kickstarter.com/projects/davefoster/lilypad-using...

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