3 weeks ago



In time with the sun

In time with the sun Since July 2018, the sewage treatment plant at Chur (Switzerland) features a very special roof: The HORIZON foldable solar roof by dhp technology is a one of its kind worldwide and allows for an intelligent dual use of industrial sites. Decentralised drives from NORD DRIVESYSTEMS are used for autonomously expanding and collapsing the folding roof panels. Power producer, sun shade, sun worshipper, weather expert and master in space saving – the HORIZON foldable solar roof by dhp technology, a Swiss start-up, is a one of its kind worldwide. It is erected over already used areas and thus allows for intelligent dual use without needing to cover a single additional square metre with buildings or restricting the primary use of the area below. This saves resources such as space and ground in populated areas, makes large decentralised solar power plants possible where electrical power is needed, and provides shade for persons, goods and infrastructures. In this way, car parks turn into charging stations, logistics spaces into freshness zones, and sewage treatment plants into power plants. Solar technology redefined “The foldable solar roof is a unique solution for generating solar electricity on infrastructure areas because supporting columns can be set wide apart”, explains Andreas Hügli, co-founder and co- manager of dhp technology. “This is possible because we have chosen to opt for cableway technology, and the flexible and lightweight foldable roofs can be retracted to a protective position. Thanks to this protective position, the entire photovoltaic system need not be designed to withstand extreme weather; instead, we can make the modules lighter and then protect them against wind, snow, and hail in the garage.” dhp technology, founded in 2015, made energy history in the Swiss city of Chur where the world’s first foldable solar roof covering a sewage treatment plant was commissioned – covering the Chur sewage treatment plant. On board: intelligent, decentralised drive technology by NORD DRIVESYSTEMS. Intelligent drive technology from NORD With an area of 5,800 m 2 , the foldable solar roof of the Chur sewage treatment plant covers the pretreatment, secondary (biological) treatment, and tertiary treatment basins. The 2,120 modules produce 550,000 kWh of electrical power per year – equalling about 20 % of the auxiliary power required by the plant. The foldable solar roof operates completely autonomously and adapts to ambient MOTION AND DRIVES Safety 4.0 ROBA ® -topstop ® —the certified braking system for vertical axes with brake monitoring your reliable partner MAYR-eng.indd 1 19.08.2019 14:34:12 18 WORLD OF INDUSTRIES 5/2019

conditions automatically using weather data provided by a local weather station and external sources. The sun controls the intelligent drive units with integrated PLC automatically: Using robust cableway technology, the solar panels unfold automatically as soon as the first sun rays penetrate the clouds in the morning. They return to their protective garage position when the sun goes down in the evening. The foldable solar roof also returns to this position automatically in case of snow, hail or wind, and extreme situations – such as power or communication failures. Intelligent NORD DRIVESYSTEMS drives are used for retracting and extending the folding roof panels. The company, headquartered in North Germany, is one of the leading global full-service providers in the industry and supplies optimally matched drive systems consisting of gear unit, motor, and frequency inverter – an important asset for dhp technology. “We chose a solution provided by NORD because we wanted a provider that supplied drive technology from a single source” says Andreas Hügli. “And what’s more: NORD products perfectly meet our requirements. The fact that frequency inverters are directly mounted on the motors makes installation much easier. The PLC integrated in the drive unit also convinced us. With this intelligent control system, we can retract the foldable roof groups to the garage using an autonomous homerun function at any time if communication should fail. This maximizes the operational safety of the system and for us is a key factor of the drive solution.” The NORD drives – consisting of a UNIVERSAL worm geared motor with brake, magnetic encoder and motor-mounted NORDAC FLEX SK 205E frequency inverter – are mounted in a protected position on the supporting structure and can be addressed separately. This allows the maintenance personnel to retract individual folding roof groups into the garage and perform maintenance to specific basins. Each of the 53 folding roof groups has a drive of its own and can be extended and retracted, depending on the weather. Four drives each are electrically linked via the internal CAN bus, with one of the drives controlling the movement sequences as master. 01 The drives are worm geared motors with motor-mounted frequency inverters. The revision switch is easily accessible for maintenance personnel. 02 The drives are safely mounted on the supporting structure. Each of the 53 folding roof groups has a drive of its own. NORD.” No wonder that additional optimisations and joint projects have already been wrapped up. Detection of a communication failure, for example, is to be implemented in the PLC integrated in NORD frequency inverters. Another objective is to simplify installation by providing preassembled connectors. And the successful partnership between dhp technology and NORD DRIVESYSTEMS will also be continued for installations of foldable solar roofs to come. Automated extension and retraction But how do the drives know when to extend and when to retract? This is where the powerful PLC integrated in the NORD frequency inverters comes into play. “The PLC reads local and external weather data and processes this data using a generic meteo algorithm to issue the “Extend” and “Retract” commands,” explains Philip Racine, dhp technology system engineer. Rotary encoders ensure that the position of the panels is known at any time. “The ramp function is also very important for us as it ensures we can retract the panels in an adequate period of time,” Racine continues. The ramps start up slowly, accelerate in the middle, and slow down when the garage is reached. The drive unit PLC controls this as well. The ramps for extending and retracting the foldable roofs are always identical and for this reason always require the same amount of energy. Thanks to their high overload capacity, the compact and robust NORD worm geared motors are capable of handling any malfunction that requires more energy to return the panels into the garage. Talking about malfunctions: The control unit has been programmed to retract the solar panels into the secure garage position automatically in case of a power or communication failure. This means: Manual intervention via remote maintenance is possible but unnecessary for secure operation. Sunny outlook “Cooperation with NORD was very agreeable. Everything just fitted perfectly – the product range and also the personal contact,” reports Andreas Hügli enthusiastically. “They offer top quality, quick delivery times, and perfect consulting and servicing. The good support in case of problems, further development and program extensions must also be pointed out. To sum up: we felt we were in very good hands with


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