Beautiful, sometimes playful, but always practical. This is the way the multifunctional water tanks of František Pochylý from the Department of Fluid Engineering should be like. The technical solution of his invention is protected by a Czech patent and the first license has already been sold. While the principle of the device would always be the same, the specific looks of the reservoir are just a matter of fantasy. And the students of Design of the University of Zlín, created various proposals on how to sensitively integrate these water tanks into the urban and rural landscapes.
The idea for the development of a water tank builds on the previous work of Professor Pochylý and his colleagues, namely the issue of long-distance water transportation. "When there is a drought in some area, logically there is no water available at the place and often not even anywhere close. Water needs to be transported over a relatively long distance, which today means building not only the pipelines, but also a network of pumping stations. This all is expensive and impractical," says Pochylý, who has been interested in fluid mechanics all his life.
He was thinking of how to use an axial pump to transport water and, at the same time, he had an ambition to design it to be as simple as possible. This is how the idea for a hybrid pumping system emerged, for which František Pochylý and his colleagues won the Gold Medal of the International Engineering Fair in 2018. "We used the principle of an annular electric motor, whose rotor is formed by the rotor of the axial pump while the stator is part of the pipe. The system can be used to transport the irrigation water, but it could also help, for example, firefighters with pumping water needed for extinguishing," explains Pochylý.
However, when developing the pumping system, the question arose as to where to find the energy needed to drive the pump? "Whether it is pumping water from a lake or from the ground, for example, the problem is the same: outdoors, there is usually no electricity available. That's why I started thinking about how to design a water tank that would be energy self-sufficient," recalls Pochylý.
A multifunctional water tank uses solar and wind energy and should not only be self-sufficient, but even able to produce more energy than it consumes. The conversion of energy into mechanical energy is used to drive a special displacement pump, based on the principle of reciprocating motion screw with a cross guide. This was the challenge for the researchers. "Coincidence helped me here a little. A colleague brought a tiny ball screw from America. It differs from a conventional bolt with a nut in that it has two helical raceways and a small ball inside. You keep turning the screw in one direction and the screw moves up, let's say, but as soon as the ball reaches the center of the two helixes, the screw starts to move downwards. But all this time, you keep turning in one direction. I got an idea to use this principle to drive the axial pump," says Pochylý.
The researchers turned to the Kuřim-based company, the successor of the well-known TOS Kuřim, which used to be a world-class manufacturer of ball screws. They joined efforts with their engineers and within a year they managed to produce a ball screw of the necessary parameters. "You may know it from TV westerns – on the American prairies, there used to be the water tanks that were powered by the wind and that pumped water from the depths. However, these tanks used a crankshaft with a very small stroke. Our ball screw can feature any stroke you need and that's its big advantage," adds Pochylý.
Due to weather fluctuations and climate change, it is increasingly necessary to be prepared for prolonged droughts. Irrigation systems will then be crucial in both agriculture and in cities. And because there should be plenty of them everywhere, František Pochylý was also interested in how they would look. "We approached the Faculty of Multimedia Communications of Tomas Bata Universities in Zlín, their students of product design had our water tank as the topic of their coursework. They suggested a lot of beautiful ways how the reservoir could look like and perhaps fulfill another purpose: for example, a climbing wall, an observation tower, an amphitheater... The construction of the water tank is considered from the esthetic perspective, using pliable solar panels in combination with a wind motor. It would be not only functional, but also beautiful," Pochylý praises the students' proposals.
On a larger area, it would be sufficient to build only one water tank with a pump, other towers intended for irrigation would take water from the central water tank on the principle of connected vessels, and the solar and wind energy generated by them could be used for other purposes. "We could irrigate large areas and at the same time create large solar farms without abusing the land," says Pochylý.
The invention was licensed by Thein Innovations in March this year. The technology is still waiting for its first use in practice. "The question here is money. We have selected several locations where it would be possible to build a water tank as a pilot, one would be a location near Soběšice, where a borehole is available and its owner agrees to build a water tank. The agricultural school in Rajhrad is also dealing with the issue of Irrigation of the area and its principal was enthusiastic about the idea. But someone has to pay for the construction, which is still a matter of further negotiations," says Pochylý, who believes in his idea. "I have set myself the goal of irrigating the whole of South Moravia," he concludes.