Although the goals are clearly different, Dean Kamen (inventor of Segway) has been working on optimizing Stirling engines for years with seemingly great results:
http://www.nextenergynews.com/news1/next-energy-news4.24.08d...
Kickstarter project for $100 - 1 kW - stirling engine
41–50 of 63 posts
Re: Kickstarter project for $100 - 1 kW - stirling engine
#42What sort of performance could you expect by just sticking this in the wall of your house? In the winter, you've got cold air outside and you're already heating the inside. In summer, you've got hot air outside and you're cooling the inside. Does it matter which side is hot/cold?
I like that idea - can anyone commment further?
Up here in the Yukon it's regularly -30C and below for long stretches and we all have our wood stoves burning 24x7 for 4+ months.... It would not be hard to have one end touching the wood stove (200-400C) and the other end outside (-30C - -40C). Will this work?
Re: Kickstarter project for $100 - 1 kW - stirling engine
#43An interesting side note: You can build one of these that will run off a candle and fit in the palm of your hand. I've got one in my office. It's a pretty neat technology.
Can you give us more details please - did you build it? buy it?
Re: Kickstarter project for $100 - 1 kW - stirling engine
#44Although the goals are clearly different, Dean Kamen (inventor of Segway) has been working on optimizing Stirling engines for years with seemingly great results: http://www.nextenergynews.com/news1/next-energy-news4.24.08d...
One particular design that I'm very interested in is a quasiturbine based stirling engine. It seem to have a lot better power/volume ratio than other stirling designs. Unfortunately, I haven't seen even a single running model yet :(
Re: Kickstarter project for $100 - 1 kW - stirling engine
#45What sort of performance could you expect by just sticking this in the wall of your house? In the winter, you've got cold air outside and you're already heating the inside. In summer, you've got hot air outside and you're cooling the inside. Does it matter which side is hot/cold?
I like that idea - can anyone commment further? Up here in the Yukon it's regularly -30C and below for long stretches and we all have our wood stoves burning 24x7 for 4+ months.... It would not be hard to have one end touching the wood stove (200-400C) and the other end outside (-30C - -40C). Will this work?
It depends on what your power requirement is. For a 200C difference, you should be able to get around 500W to 600W with a properly built stirling engine.
Re: Kickstarter project for $100 - 1 kW - stirling engine
#46>The second difference is the Stirling engine is more efficient then the gasoline driven engine.
Gotta proofread this stuff.
Anyway, I was thinking recently about how a stirling engine could be powered by solar energy, and discovered that this is actually done. From wikipedia:
>Placed at the focus of a parabolic mirror, a Stirling engine can convert solar energy to electricity with an efficiency better than non-concentrated photovoltaic cells, and comparable to Concentrated Photo Voltaics.
That's cool, and I'm startled that it isn't mentioned at all on this kickstarter page, especially considering the first paragraph of the pitch.
Re: Kickstarter project for $100 - 1 kW - stirling engine
#47An interesting side note: You can build one of these that will run off a candle and fit in the palm of your hand. I've got one in my office. It's a pretty neat technology.
Can you give us more details please - did you build it? buy it?
I suppose he is referring to this - http://www.thinkgeek.com/gadgets/9e84/
Re: Kickstarter project for $100 - 1 kW - stirling engine
#48>The second difference is the Stirling engine is more efficient then the gasoline driven engine. Gotta proofread this stuff. Anyway, I was thinking recently about how a stirling engine could be powered by solar energy, and discovered that this is actually done. From wikipedia: >Placed at the focus of a parabolic mirror, a Stirling engine can convert solar energy to electricity with an efficiency better than non-conce…
Problem is, CPV only works with clear sun. i.e. it's best for deserts. My hunch is this is targeted at off-grid homesteaders, who tend to live where there's vegetation (and thus clouds).
Re: Kickstarter project for $100 - 1 kW - stirling engine
#49"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…
If you have no grid, then about $1000 of batteries will cover you, and need replacing every 5-10 years.
This is wishful thinking, both on lifespan and cost of a household battery bank sufficient to run average household appliances like air conditioning and electric water heater and such. Even deep cycle batteries in this sort of working environment will need replacing every 3-5 years (and past 3 years, you'll probably be working with maybe half the capacity of what you started with). The workload of a household running off of batteries during periods when power usage far outstrips power generation is really hard on batteries. There are very expensive batteries that are rated for 5 years or more of use, but they cost two or three times what regular deep cycle lead acid batteries cost, making the total cost much higher. You'll also need more than $1000 worth of batteries for an average American household that uses air conditioning and electric heating devices.
I live in a motorhome with a $300 battery bank (a motorhome has far fewer energy users than a standard home, and I don't run AC, microwave, or electric heaters off of the batteries; I have to crank the generator to use those), and solar on the roof. I'm very familiar with the limitations of batteries, and lead acid battery technology is extremely unforgiving of discharging beyond 50% (even beyond 75% leads to degradation, but most people in RVs accept that because the weight of carrying more batteries to be able to run at 75+% charge at all times is more costly than replacing batteries more frequently).
But, I agree with you that selling back to the grid is the way to deal with this problem in a home on the grid. It's more cost-effective and more environmentally responsible.
Re: Kickstarter project for $100 - 1 kW - stirling engine
#50Earlier quoted context omitted.
I like that idea - can anyone commment further? Up here in the Yukon it's regularly -30C and below for long stretches and we all have our wood stoves burning 24x7 for 4+ months.... It would not be hard to have one end touching the wood stove (200-400C) and the other end outside (-30C - -40C). Will this work?
It depends on what your power requirement is. For a 200C difference, you should be able to get around 500W to 600W with a properly built stirling engine.
Sounds nice for all the people running off-grid up here who get so little precious sunshine in the winter.
Can you provide more information on where I might be able to buy such a Sterling engine? Are there any companies actively making them?