Would a windmill shaped like a waterwheel work?

Question

The culture I'm working on lives in a constant state of snow storms and tundra. In the snow lives a bioluminescent type of algae that thrives on the cold and only glows when its temperature goes above freezing. I would like to develop a way that they harvest this algae to encase in jars, and one of the ideas I've had is a waterwheel shaped device that catches the algae against its blades which doubles as a ventilation system for their forges beneath the ground.

I mostly chose this style because it could be lower to the ground, and they could use a bar of metal to lock the wheel in place while they scraped the algae off. Is this too complicated or could it work? It would also be made of metal instead of wood, due to the lack of trees and the abundance of mines they have developed deep underground.

Answer 1

When I had to take the finishing exam in high school, we had to make a project as part of the exam.

Mine was about making a little wind generator. How we did it was cutting 2 soda cans in half along the length, attaching the 4 halves to 2 arms and having the arms power a dynamo.

Crude as it can get, but it produced some power.

The problem is that, outside of school projects, one has to look at the profitability of what gets done, and such a design is not as effective as the propeller shape.

When I studied the subject at the university, I learned that, in the case of water, there are different designs which are optimal for different conditions: the waterwheel type, or better its evolved version the Pelton, works well with small moving masses with high specific kinetic energy, while the propeller shaped work better with large moving masses at low specific kinetic energy, such as tide induced flow.

Similar consideration holds also for air flow: wind is normally high mass of air with low specific kinetic energy, which make the propeller more efficient at extracting energy from it.

You can find vertical axes wind turbines, like the one in the picture

and they are mostly used for small domestic application, where saving space becomes as or more important than yield.

Answer 2

the efficiency would be horrendous compared to even a regular water wheel. Water wheels work by gravity pulling the water down, and turning the wheel as you do it. Wind is different as air is compressible, and the principle of operation is the same as the way an aircraft wing works, which is completely different to a water wheel. Water is not compressible so expect power to be much much less.

Answer 3

Such ventilation devices exist in the real world but are positioned horizontally because wind can blow from multiple directions. Look at more buildings roofs.

So with your idea, the first problem is that the wind can only blow from one direction.

The second problem is that a vertical wheel is a poor choice for ventilation in your scenario because any pipe directly leaving the wheel exits horizontally. That means that the wheel has to be hanging off a 90 degree elbow of a tall vertical pipe going into the ground, or sticking out of the side of a tall building which your underground dwellers do not have. And even if they did, a wheel that it reaches both high up enough for wind to blow but low enough so people on the ground can scrape it requires a structure so massive that it is structurally not the best option to have it cantilevering like that...unless you have want it hanging between two pipes or two buildings.

Isn't it also a bad thing to be close to the ground? You say snow is always blowing, which means there is always thick snow on the ground of varying levels.

Why can't they just take in air from the outside through conventional means and filter it while inside the ventilation system like buildings in the real world do? No need to lock the wheel, or go outside, and you could possibly remove the snow from the air it reaches the algae filters.

Answer 4

Waterwheels work because the water pushes one side but not the other. They do not work as windmills because the wind will try to push the wheel both ways at once and it will barely move. For example if the wind comes from the left, it hits the blades at top of the wheel and pushes it clockwise. It also hits the blades at bottom of the wheel and pushes it counterclockwise. Windmils solve this problem by facing into the wind, rather than sideways to the wind.