wind generator for heat, no electric

Following the basic laws of thermodynamics, and efficiency, I think there is potential to design a much cheaper wind power for heat system.

My first thought is to have the shaft of the turbine enter into an insulated water tank, where blades are attached and will stir the water. The resulting friction of the moving blades in the water will heat the water. This hot water can then be piped into the house to provide heat.
I could build this from scrap materials for very little cost.

Why not?

Your idea is a head scratcher; I'm not sure why it wouldn't be more efficient to just generate electricity to run a heating coil. You have to MOVE the water, etc.

I think the benefit would be no efficiency loss in the generator. You are right, moving electrons is easier than water.

If one can get a motor for cheap, then ok. But the main goal is a system with very very low cost and simplicity.

Edit: well I can now imagine losing 20% of the heat in the water before getting it inside, maybe its not more efficient unless the turbine is on your roof with the shaft coming straight into the house. Good insulation would be essential for piping it of course.

I have heard this idea before, but without the part about pumping the water to separate radiators. I believe it may be quite old, from the days when small windmills were a common source of mechanical power for farms.

The conversion of shaft power from the windmill to heat will be extremely efficient. The only loss will be any noise generated, which will be a small fraction of total power. The only issue will be selecting the correct size impeller to properly load the windmill to make efficient use of the available wind power.

Sounds like a neat idea to me. I presume the blades on you wind generator would have to be pretty large if you want to generate that level of friction, but still sounds neat.

... not sure if converting mechanical energy to heat by a set of blades stirring the water is compact enought.
actually, you could make heat from the impeller mechanical energy using brake
or a mix of blades and brake if you plan to use a part of the impeller mechanical energy to circulate the water

If you gear up the impellar it will grealty increase the heat for the same size impellar (doubling speed will cube the heat generated). Gearing is lossy, but if it's contained in your heating liquid then any loss will be captured as useful heat (and the noise supressed). Oil would be better than water as the more viscous the liquid, the more heat you will generate. It would also eliminate any problems with corrosion.

generators are 90%+ efficient most of the time

electric heaters may as well be 100% efficient (all electric is turned into heat, just maybe some of the heat doesn't go where you want it)

cable losses will be very low

the controllers that go between wind turbines and heaters (so the turbine can get up to speed before a load is applied to it) are very efficnet



you won't be able to beat that efficiency


plus, you need to load the turbine right for the wind speed / turbine rpm.... zero load when it's stopped, very low/no load while it's getting up to speed, then add load to it progressively as the speed increases, until you hit the generators maximum power (in very strong winds) then you need to break the turbine so it's doesn't overspeed


generating heat via stirring will be very hard to make efficient, it'll need to be really big, then you'll have to keep it all sealed up and insulated, insulate pipe runs, and figure out a way for your feed/return pipes to connect to the turbine which needs to rotate to face the wind

If one's goal is heating an area, and one has electricity or a spinning shaft to do it, you can use a heat-pump and use that energy to run a compressor using a refrigerant phase change process to draw heat from the colder ambient temperature into your warmer indoor area and gain something like ~500% efficiency vs simply using that energy into a heating element (or fluid friction heating).

Flip a wind AC unit around, so it blows the cold air outside and the waste heat input going into your house, and you just improved the heating per watt by a substantial factor, something like 300-700% depending on the unit and the temperature differences (and if you can keep condensation from icing up your evaporator outside).

ES member Methods taught me that trick, and I didn't even believe it was possible until looking into it a bit.

That's a very good point...

Lfp, that is an interesting idea. I don't quite understand how it becomes more efficient, because I thought a heating element is already near 100% efficient when it comes to heating. But I'm open to trying it out.

Because you are only pumping refrigerant around the system and running a small fan. Efficiency is confusing, think performance for your kW.

In air sourced heat pumps the refrigerant picks up the exterior heat from the air and transfers it inside the house, not sure how well they perform in colder areas, but then you can look at ground source heat pumps.

veloman said:

Lfp, that is an interesting idea. I don't quite understand how it becomes more efficient, because I thought a heating element is already near 100% efficient when it comes to heating. But I'm open to trying it out.

Click to expand...

By leveraging the effects of pressure on phase change for the refrigerant, you can compress it into being a liquid, then absorb a ton of energy by expanding it at a carefully controlled rate as the pressure drop causes it to boil back into a gas.

You can draw even from freezing ground or freezing air and leave it colder than you found it because you absorbed energy from it by making it boil your liquid into a gas through cleverly constraining a pressure drop.

It's not a free energy machine, it's more like a thermal energy transformer. You take energy from the cold outside air, leaving it even colder, and transform that thermal energy you absorbed from the cool air into warmer air to heat your pad. The power you dump into it isn't for heating your place (though it also does that), it's for running the compressor to enable the thermal energy state transfer to continue. It just happens conveniently that all the device's inefficiency from friction and pumping losses etc also contribute to heating your place equally as well as any resistive element could have spent the heating energy towards, the difference is this would also drags in many times that amount in thermal energy from the outside air as well.

Nissan Leaf switched to a heat pump a few years ago. It is almost always more efficient to move something than to make it directly

http://www.nissan-global.com/EN/TECHNOLOGY/OVERVIEW/heat_pump_cabin_heater.html

Better yet - you could connect solar collectors with wind-powered heat pump. The ultimate free energy device!

Solar thermal is great during the day assuming good sun. But its nighttime when the heat is needed in the house.

I have ideas to store the heat from the sun in a large water tank inside, with a radiator to cycle at night.

I just like to diversify and know what is possible.

As far as energy storage goes water is good but I have been looking into phase change mediums. PCM for short. Here one is storing energy in the latent heat of melting. Storage vessel Size can be much reduced. The collector can be run at much lower temperature which would signifigantly increase efficiency.

Right now they are expensive. But since this is a DIY forum.......

Yeh, at work we test different pcm for use in the batteries we are building for customers. Its like a wax. Expensive of course

How about solid energy storage, like massive concrete block? You could build any kind of tubing inside of it and it's cheap.
I would use mineral oil as transfer fluid and insulated concrete block as storage.

It's easy
http://bloemfontein.olx.co.za/antrasiet-stoof-iid-802806479