A specific building to be heated by windpower under high latitudes

[Jean-Louis Papel]

Hello everybody,

I a new on this forum.
I am working, as a hobby, since a few years on a project based on a windmill and the associated devices to heat a building directly using windpower.
Reaching complete heating-autonomy all over the year using an american-farm-type multiblade windmill, a water-stirrer to heat large quantities of water by friction, and a large seasonal-storage
There are many forums dealing about this question. What is maybe new in my approach is that I have designed a complete system in the deepest details, and discussed the very specific conditions where it could be competitively implemented.

In my attached blog, you will find all the details of the design for the windmill, the stirrer, the specific building, as well as some simulations of autonomy based on a case-study in Dunkerque (France).
The system allows to dynamically and continuously get the highest efficiency of the windmill whatever the wind-speed, thanks to a servo-mechanism also described in my blog.
I also make some comparisons of my solution versus others like using electrical resistors for instance.

In reality the most suitable locations to implement such a project are in countries with high latitudes like Scotland or Denmark in the north, Patagonia or New-Zealand in the southern hemisphere. The reason is that under lower latitudes it would be much easier to use solar-heating-panels to heat such a building.

Although the implementation could be rather expensive, the manufacturing of all the components (windmill, stirrer servo-mechanism etc ...) is very simple and accessible to local workshops.
The main tower, backbone of the building, could be the first portion of the steel-mast of an industrial 2MW windturbine, transported and installed by a company active in the region for wind-farm projects.
Obviously such a design would mainly address to municipal or professional buildings.

I am looking forward your critics and comments.

Note: I am french: Please excuse my poor English! The reason why I made this thread in english is that I think my project addresses mostly english-speaking countries (as I explained above).

My blog: www.windmill-for-heating-buildings.blogspot.com

[Rob Beckers]

Jean-Louis, welcome to the forum!
I read your blog. Wow!! You clearly did a whole lot of research!

I've skimmed through the text; My interest is in one part in particular, the stirrer. As you know the power from the turbine increases with the cube of the wind speed (~ speed^3). Does the stirrer provide a load that follows the same power profile vs. RPM? Or will it only match at a specific wind speed?

In a more general sense, there are a very large number of mechanical parts involved in your design. Would it not be simpler, and likely cheaper, to use a regular electrical wind turbine and use resistors to heat water?

-RoB-

[Jean-Louis Papel]

Hello Rob,

Thank you for your interest in my project.

Each type of windmill is charaterized by its specific tip-speed ratio which is the ratio between the actual wind-speed and the actual tangential speed at the extremity of the blades (which of course is directly proportional to the RPM of the windmill shaft).
The tip-speed ratio is determined by such characteristics as the profile of the blades, the number of blades, the static pitch angle of the blades etc .... For the american-farm windmill of our project, the design-ratio is made equal to 1 (for a two-blades wind-turbine it is more in the range of 7).
The windmills theory states that the maximum recoverable power is effectively recovered at a given time only if the instant tip-speed ratio equals the design tip-speed ratio.

So the purpose of the servomechanism is to ensure that this ratio is respected at every moment. For this reason, the RPM is measured continuously by a tachometer on the windmill shaft, and the wind-speed is measured continuously by an anemometer. Then a signal is elaborated in an electronic-circuit and compared to a voltage reference, characteristic of the designed tip-speed ratio. The signal-difference actuates the step-motor of the exit valve of water one way or the other.
By controlling the level of water in the stirrer, the servo enforces that the ratio is respected whatever the actual wind-speed.
The physical size of the stirrer must then be sufficient (in terms of the maximum volume of stirred water), to create the brake-effect corresponding to the strongest acceptable windspeed. This maximum operable windspeed is only governed by the capacity of the tower to withstand the drag generated by the wind on the windmill.

The curves in chapter-2 of my blog show how the system continuously follows the optimum when the actual windspeed changes (dot-line). Once the wind becomes steady, the level of water remains constant in the stirrer.
https://drive.google.com/open?id=0B3j3fowf9D7YRGFaT0U5cnhIU2c

The point that has to be confirmed by further studies, is about the reactivity of the servo-mechanism loop, considering the inertia of the water-level-control versus the instantaneous variability of the windspeed. Arbitrarily I have considered a 80% efficiency of the servo.

As regards the comparison of our solution with the solution using a standard wind-turbine associated with a motorized rheostat or a set of switcheable resistors, the main problem is to invent a servo-mechanim able to control the RPM so that the actual tip-speed ratio is continuously equal to the design-tip-speed ratio. If it is not the case, the optimum recoverable power will not be effectively recovered, as in our case. It will be probably lost by overheating of the electrical generator.

A second point is that above the nominal rate of the electrical generator (in kW), the system must control the pitch angle of the blades to artificially impair the windmill efficiency. But anyhow there is a limit given by the generator's rate to the recovered power, whereas with our solution the recovered power continues to grow exponentially up to the security wind-limit. At the end, there is a 20% loss versus our solution (see the curves and discussion at the end of chapter 8.1 in my blog).
https://drive.google.com/open?id=0B3j3fowf9D7YZ0tEX1RRVHgyeXM

Another point is that due to the sophisticated profile of the blades required by the high-speed wind-turbine, the electrical solution is in nature more expensive than our solution using simple bended steel sheets for the blades of the american-farm windmill. The same occurs for the electrical generator complexity (bound to failures), compared to the simpler stirrer technology. Once a prototype has been fully designed and validated, our solution should be more competitive than the electrical one.

I hope this answers your questions.

[Jean-Louis Papel]

Jean-Louis, welcome to the forum!

In a more general sense, there are a very large number of mechanical parts involved in your design. Would it not be simpler, and likely cheaper, to use a regular electrical wind turbine and use resistors to heat water?

-RoB-

Hello Rob,

With your remarks in mind, I went back into my books and made a few Internet researchs, and in fact I found-out some alternative efficient solutions implementing standard windturbines and heating resistors plunged in the water-tanks.

Using for instance the Sirocco 5.6m/6kW windturbine with the power electronic units required to interface with the grid, the provided MPPT tracking allows to be at optimum efficiency whatever the wind-speed, which solves the first problem. The second is to control the resistors so that they are only active when the wind blows sufficiently and with a variable resistance to match the instant windpower production. This could be done rather easily with a motorized rheostat controlled by an anemometer (or a set of switcheable fix resistors). If this is not achieved, the resistors will be permanently fed by the grid (which is obviously not an economical situation).

Another more economical, but less efficient solution would be to use a standard windturbine with the resistors directly connected to the 3-phase output of the generator. By selecting carefully the value of the fix-resistors and taking into account the internal inherent impedances of the generator, one could more or less match the prevailing wind distributions. The choice of a generator equipped with an auto-excited rotor (instead of permanent magnets), would even enhance the matching, although I don't know if such machines are easily available on the market, for this range of power.

I have modified chapter 2 of my blog to include more documented explanations and comparisons of these two alternative solutions versus my proposed solution.
(www.windmill-for-heating-buildings.blogspot.com)

In fact my solution of heating a building by windpower, would have to be rather considered as a quite marginal extra-cost, in the frame of a whole project of construction of a building designed to promote the alternative energies by its spectacular appearance. It is in no way accessible to individuals for their private houses.

[Vullnet Miraka]

I am in pressed of your hobby work results. What you can do in your project, is to and one additional HP generation system to cover up the needs of the areas you are describing are not covered by your system.
I have worked and studied for over 26 years in Hydrodynamic, and finally I got some good results.
I have created very simple system restoring the the water, used to generate electricity.
This water is restored using new concept of water pump. The new designed pump is not similar to any of conventional water pumps we know in today's market.
I have fully tested the new designed water pump, in small existing HPP. The results have been establishing: the new water pump have pumped 210 liters of water for second, in to altitude of 22 meters, energy spending 14.3 kw/h. The power plant increased the production by 41 kw/h.
The test was going continues 28 days.
The demonstration test, have been followed and by governmental institutions, relising the experts official certificate.
I will be more than happy to join your project, and hopefully it can be applicable to cover more needs for your project.
During my experimental prototypes, I have participated in different international competitions awarded with different medals.
You can verify it by Google my name, where you can find variety of articles and published patent, Gornal articles, Web address and more. In my website you can see the application in large HPP.
I wish you success with your very interesting project.
I wish that I can joining you.
:idea:

[Jean-Louis Papel]

Sorry Mr Miraka, I cannot support your project. It does not seem very sound to me on a scientific point of view. Anyhow I am not at all a specialist in terms of hydro-power to analyze it in details. Moreover I do not see any connection with my thread.
Best regards

[Jean-Louis Papel]

I was trying to find alternative to replace the voluminous water-stirrer of my project by a more compact device.
I looked into the following solutions:

1) A water-brake absorber generally used as a dynamometer to measure the torque of car-engines on a test bench.
This device is interesting since it could be mounted directly on the horizontal shaft of the windmill on top of the tower. It is very compact and relatively low-weight. The resistive torque can be easily controlled by adjusting the rate of the flow of water injected in the device. This flow of water is also used to transfer the generated heat to the underground seasonal water-storage . An immersed water-pump is required to circulate the water in the cooling loop.
The range of absorbed-power matches the power of the windmill by selecting the right model.
An example of such a water-brake absorber is the DYNOmite 5":
http://www.dynomitedynamometer.com/absorber/dynamometer_water-brake_absorber.htm

The problem is that the normal operating RPM range is the one expected for a car-engine, that is between 2000 and 10,000 RPM. A gear-multiplier by about 70 times should then be inserted between the windmill and the water-brake.

2) A device named "retarder" is used on the trucks or buses to slow-them down on steady slopes, to save their normal brakes life-time.
The manufacturer VOITH (for instance) proposes two suitable models although oversized.
The Secundary Water Retarder SWR which works directly with the coolent water, and the R115E which uses oïl for the process and then an heat-exchanger for the transfer to water.
Aquatarder SWR (en) - YouTube

They are less compact than the DYNOmite, but still acceptable. Their range of operating RPM matches the windmill-shaft's speed without multiplying gear.

The problem is that the control of liquid admitted in the system to adjust the resistive torque, is pneumatical and requires a very specific interface.

3) I have not yet considered the Eddy-current brakes since they are generally air-cooled which is not directly compatible with the purpose.

For comparisons with the characteristics of the above-mentionned water-brakes, here are some figures relative to the 5m diameter, multiblades (30), low-speed windmill used in my project:

5m/s 19RPM 600W/0.8HP 285N.m
10m/s 38RPM 4.6kW/6.2HP 1140N.m
17m/s 65RPM 22.5kW/30HP 3300N.m (the SWR is limited to 3500N.m max.)
25m/s 95RPM 71kW/95HP 7150N.m

The interest of such devices is that they are standard and compact products, but they are rather sophisticated, expensive and bound to failure.. By comparison my proposed water stirrer needs a rear 4x4 axle, a very long power-transmission shaft and a voluminous water stirrer. But it is a low technology device, easy to manufacture in a local workshop.

Any comments or advices ?
Thanks in advance.