Stirling engine powered with wind turbine

Discussion on Stirling or "hot air" engines (all types)
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airpower
Posts: 91
Joined: Tue Oct 05, 2021 5:56 am

Stirling engine powered with wind turbine

Post by airpower »

Yes its a bit of a head-spinner, but
Been working away on my Eco-house design and one thing I also wanted is a wind turbine.
Everything available on the market is junk. So I came up with a design of utilizing the venturi effect inside a funnel. Funnel within a funnel to protect the tip of the blades from the push-back by “vacuum away” (have a lower pressure zone) and direct the direction of flow. One of the difficulties is the temperature drop and in winter time, it be icing up fast.
As I also intend to attach a scroll air compressor instead of electrical generator there is also significant more heat to deal with.
A logical way to deal with all of it is to attach a Stirling engine, at least in winter time and use the hot side on the working piston with a Alpha configuration.
More cold air at hand as hot and the cold side temperature can be ajusted.
The coastal region were I intend to use it has a yearly average of 3 m/s (10.8, 6.7 Mph, 5.8 knots) wind-speed, more in winter less in summer.
Original done with 1 m^2 catchment area and assumed 3 m/s wind speed, later changed to 1.5 m^2 and 2 m/s, same 3 m^3 volume.
Catchment on top of the house and channeled down to the “energy room” where the turbine will be with the batteries, compressed air tanks, garden tools…
Conventional wind turbines can handle about 50 m/s, I haven't the numbers yet but I say at 5 m/s or so the springs for the doors at back of catchment would need to start releasing some air.

If it works at all or how effective, will be discovered once the covid shenanigans is done with. As it stands it's theory only.
Taint yellow and blue is below atmosphere, darker blue increased speed, lower pressure once more.

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airpower
Posts: 91
Joined: Tue Oct 05, 2021 5:56 am

Re: Stirling engine powered with wind (turbine)

Post by airpower »

Using 40% for the blade side may be to much and not enough suction power.
So with 33% it gives:
1 m² catchment area and a light breeze from the ocean at 3 m/s is 3 m³ of air moving through.
Reducing in down 11 fold increases speed 11 times and pressure drops from atmosphere (1) to 0.993604737863 atm, velocity now 33 m/s
Using 33% for the "push" section is 0.03 m² (300 cm²). A diameter of 50 cm looks nice, 2 cm shaft gives a 24 cm long blade, and 300/24=12.5 high.
Pluging in the numbers
0.0006*0.4*33*33*33* 0.03*0.993604737863 = 0.257 Kw with 40% efficency or 0.0006*0.3*33*33*33* 0.03 *0.993604737863 = 192 Watt with 30%
1.7° C lower than ambient air temperature

So far so good, now the battle to fight the reaction. Ideally pressure is always reduced to just above freezing.
Velocity 33 m/s and remaining area is 600 cm², as blades are 12.5 lets say channel is 13 cm high (with spacing) gives 46 cm wide. (600/13)
2 m³ of air passing on the lower pressure side (66%)
Reducing it to half the width, speed doubles to 66 m/s and pressure drops to 0.974205776047, now the narrow part at zero with outside temp. of 7.2° C
With the pressure dropping from 1 to 0.97xx gives (1-0.974205776047)*101325/52 = 50 Vacuum watt (1 Vacuum watt per 52 pascal)
Reducing it to 200 cm² gives a speed of 100 m/s, pressure only 0.940784609841 atm and 115 Vaccum watt, 17° C below ambient air temperature.
Any type compressor will get to 100° C (210 degrees F), rotary scroll or vane, screw and piston type not so good for other reasons if enough work done.

With near freezing at one side and boiling below it is certainly possible to operate a Stirling engine with wind power, only a matter of time (if wind turbine works). Stirling can be made to run with just about anything, i dare say even with moonlight.

A thermal image camera should give a better view how it all works out, so many things happening at the end of it.
How much power in practice it will produce i will find out, not next week or month, it be some time.
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