Where engineers think outside the box


(Published in The Produktkulturmagazin issue 3 2017)

A changing world entails unknown challenges. Questions arising from this provide the fertile ground in which new ideas germinate. Expanding building sizes in metropolitan cities have inspired the creative heads at thyssenkrupp elevator technology to rethink the traditional elevator principles. Head of Product Development, Markus Jetter, tells us how it is possible for the new elevator system, Multi, to go sideways. 

Mr Jetter, metropolitan cities are growing rapidly worldwide. What does this mean for the transportation of people in large buildings? 

Whilst our cities are growing and buildings become bigger and higher, planners and architects are confronted with the challenge of transporting a rising number of people comfortably and quickly to their destinations. Multi helps solve this problem as it can increase transport capacities by 50 percent. This fact alone provides dramatic improvements for the mobility in high rise buildings. In contrast to the self -contained elevator, the new technology is not restricted regarding height. In addition, Multi enables you to go vertically as well as horizontally. All this offers hitherto unknown architectural possibilities and building designs. A student project at Columbia University demonstrated that office workers in New York City spend 16.6 years waiting for elevators and 5.9 years travelling in them. This indicates that increased availability of elevators will lead to significant improvements. Another study carried out in 2013 on two-dimensional elevator systems compared the deployment of one cabin per shaft with operating just one train on the same railway between two cities – a clear waste of resources. 

To what extent do current elevator systems meet their limits? 

The critical transport height is 500 to 600 metres. This is the limit of the commonly used cable technology. Moreover, it is a waste of building area to use just one cabin in a shaft of this height. 

Your new elevator system Multi is regarded as a groundbreaking revolution. What is so unique about the concept? 

Multi presents the first cableless sideways travelling elevator system. Instead of letting one cabin per shaft go up and down, this system offers the possibility to let many cabins circulate independent of each other, comparable to an underground train system within a building. Multi gets the linear motor technology from thyssenkrupp, which had been developed for the Transrapid maglev train. The cabins therefore move within the shafts like trains on rails, with several cabins per shaft as well as vertical and horizontal movements within the building. Safety is guaranteed through a multi-stage braking system in the cabin and by tried and tested security control systems, which thyssenkrupp had previously developed for the twin elevator system. 

Please tell us about the advantages this new technology provides. 

Amongst other things there are significantly shorter waiting times, reduced space requirements, notably higher capacity and much less weight and mass. Moreover, it makes new building sizes and designs possible. The linear motor technology of the Transrapid maglev train adopted by the Multi maximises the shaft efficiency in medium and high rise buildings and offers immense advantages for both the developer and passenger. Omitting the supporting cable and equipped with the multi-stage braking system as well as a wireless data and energy transfer from shaft to cabin, the Multi requires a smaller shaft compared to previous solutions. Thanks to multiple cabins in the same shaft, passengers never have to wait for more than 15 to 30 seconds for the next elevator. Another advantage is the steady energy use without significant cost increases. This makes it possible to manage energy efficiently and to consistently reduce the investment for the electricity provision. Regarding the development of cabins and doors we have used innovative carbon fibre materials, which at a weight of 50 kilograms are 250 kilograms lighter than the building parts of standard elevators. All in all, this makes it possible to reduce the weight by 50 percent compared to technologies used up until now. The linear system requires only one motor for both horizontal and vertical movements, while a transfer device moves the cabins from shaft to shaft. Multi combines groundbreaking technology with a simple operating system and high levels of comfort for its passengers. This elevator system with variable cabins per shaft is not just a vision for the future, but will soon become reality. 

From the original concept to the current state – which steps has the project taken so far? 

The linear motor technology has been previously deployed in the Transrapid maglev train as well as in our innovative transport system Accel, and is a tried and tested modern drive system. In the past five years, we managed to improve all necessary technologies at thyssenkrupp and to combine them into a system which is ready to be officially implemented. This includes the drive technology, the lightweight design, new materials, horizontal movements of the cabin and functional safety concepts. Today we can present a fully functioning and ready installed elevator system at our test tower in Rottweil. 

Which aspects regarding safety did you have to rethink compared to conventional systems? 

Globally, elevators are the safest means of transport, and Multi is no exception. The safety of the passenger is guaranteed by the multi-layered drive and brake system of the cabins and also by the safety control system adopted from our twin elevator. We consistently follow all Functional Safety Management procedures in compliance with all registered certification organisations and institutes. 

You are currently testing the Multi-system in your very modern test tower in Rottweil. What makes the building so special and what do you focus your attention on when carrying out these tests? 

The test tower with a height of 246 metres offers everything you need for the development and control of high quality elevator systems. Thyssenkrupp invested more than 40 million Euros into this and now has a highly modern test centre for new elevator concepts and technologies at its disposal, located in the oldest town of the state of Baden-Württemberg. The test tower houses 12 elevator shafts altogether, nine of which are used for tests. Our engineers can send high-speed solutions on a test journey at 18m/h (64km/h). In addition, there are test centres for the twin elevator system, in which two cabins travel independently of each other in the same shaft. Three test shafts have been reserved for the revolutionary Multi. Some of the shafts are 200 metres high and almost touch the top of the tower, others are only 120 metres high. The space above them is used for storing energy. The heat produced by motors and computers during test procedures is collected here and put through a heat exchanger and filtered back according to requirements. Not only is the tower an ambitious skyscraper, but it also serves to achieve sustainability. 

Which improvements are you hoping to provide for the life of city dwellers? 

Building constructions of medium and large heights are regarded as the most economic and environmentally efficient solution to absorb the rapidly growing population of cities. These buildings require less space. They enable centralised, intelligent energy management and preserve the green spaces of the cities. Although the means and methods for the building of high rises are available, the functionality of skyscrapers remains limited. As for now, the possibilities for the transport of people inside the buildings are restricted. Efficient and comfortable logistics are not a luxury however, but an absolute necessity. Through its significantly reduced waiting times, the Multi increases the mobility of people in urban regions. The Multi is therefore an important innovation and signifies the start of a new era in the elevator industry. 

Which new possibilities does the new transport system unlock for building and town planners? 

The cableless system releases the architects and developers from the constraints of the elevator shaft’s height and vertical alignment. Multi enables design in all directions. 

What are the next steps in your plan for Multi? 

The research and development phase of the Multi technology has reached its next milestone: The first fully-functioning test system is being assessed. Our new test tower in Rottweil offers perfect conditions for testing and certification. A prototype should be ready for the market in 2019/20. 

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Markus Jetter has a degree in electro-technology and has been working in the elevator industry since 1991. He has been active in a variety of roles for thyssenkrupp, including contract design, product development, research management, consulting and research. He has focused on the research and development of cableless elevator systems since 2013. 

Picture credit © thyssenkrupp

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