Making clever use of the sun

Dispensing system for precise bonding of the world’s first retractable solar roof

Parking spaces, logistics areas and waste water treatment plants require a lot of space. Why not make efficient use of this space? This is what the Swiss start-up dhp technology thought when it constructed the world’s first retractable solar roof. The individual modules are manufactured with dispensing technology from DOPAG.

At the car park for Kronberg cable car system in the Swiss canton of Appenzell Innerrhoden, visitors have a pleasant surprise in store. They can park in the shade and charge their electric vehicles at the same time. The 4,000 m² car park is covered by a retractable solar roof. This provides power to the Kronberg cable car system, which climbs from the valley to the mountain station situated at approximately 1,600 metres. During stormy weather, hail or snowfall, the solar modules fold up by themselves and are stored in long garages. The world’s first patented retractable solar roof was developed under the name Horizon by dhp technology AG. The car park roofing is one of the latest projects from the young Swiss company based in Zizers in the canton of Graubünden. This all began with the roofing of wastewater treatment plants. In 2018, the first model went into operation in the wastewater treatment plant for the town of Chur. It was the first installation of its kind in the world. With an area of 6,400 m², the retractable solar roof covers 20 per cent of the electricity demands of the energy-intensive wastewater treatment plant. The benefit of this is that the entire system remains fully accessible, and the retractable solar roof provides shade during necessary maintenance work in summer and reduces algae growth.

Focus on automation

The retractable solar roof has a system control function with an integrated meteo algorithm. In connection with data collected by a weather station mounted on the system, the modules are either unfolded or, during inclement weather, folded up and stored in a garage. Managing directors Andreas Hügli and Gian Andri Diem have found a niche in the market with this business idea. The pair turned to cable car technology for the flexible photovoltaic roof. The lightweight system consists of a galvanised support structure and the roof made of solar modules suspended from supporting cables. These are made from non-glare plastic and connected to one another by means of hinges.

"As far as production is concerned, we have focused on automation from the very beginning, as this allows us to grow."

Gian Andri Diem

For the production of the individual solar modules, the eldomix metering and mixing system from DOPAG was integrated into the production line. It meters and mixes a dual-component adhesive which is used to bond the thin plastic photovoltaic modules to a metal frame. Application of the material is fully automated. The individual modules are then assembled into a complete retractable roof group. The company has already used a rental system from DOPAG in the production of a prototype. "The solar modules are exposed to extreme weather conditions, from strong solar radiation, wind and rain to snow and sub-zero temperatures", says Andreas Huegli.

"Stable, durable bonding of the modules to the frame is therefore vital for us. We are impressed by the precise, reliable metering and mixing technology from DOPAG."

Andreas Hügli

Everything is fully automated in the production hall: the photovoltaic modules are bonded to the metal frame with the eldomix metering and mixing system. The material is supplied via gear pumps. They are then assembled into a complete retractable roof group. (Pictures: dhp technology)

Eldomix conveys the two components by means of two gear metering pumps. These are driven by three-phase asynchronous motors and offer high metering precision. The material is supplied directly from the original container by means of two drum pumps. In general, eldomix is suitable for processing low to medium-viscosity multi-component materials based on polyurethane, epoxy or silicone. The material is homogeneously mixed via a static mixing system. The mixing ratio and the discharge quantity are variable. The material can be discharged in shot form or continuously via a dispensing valve.

In this way, the photovoltaic modules can be safely and reliably bonded to the metal frame and then assembled into a high-quality retractable solar roof. Andreas Hügli and Gian Andri Diem have been successful with their idea. The production line is running at full capacity and more retractable solar roof systems will soon follow in Switzerland and Germany.

Please click here for more information about dhp technology:

Your partnership with DOPAG

  • One contact for the entire system solution
  • All applications from one provider
  • Implementation of specific requirements and automation
  • Competent support from DOPAG experts
  • A dedicated technical centre for testing and customer training
  • Close collaboration with material manufacturers
  • Decades of experience in metering and mixing technology
  • Global distribution and service in over 40 countries

Reference projects


Choose your applications:
All DOPAG articles at a glance:
  1. Metering mixing and applying thermally conductive silicone material

    The vectomix TC metering and mixing system from DOPAG processes thermally conductive materials precisely and cleanly. This application shows the processing of Wacker Semicosil 9672.

  2. Adhesive beading in the electronics industry

    Higher quantities in less time - For bonding housings for LED luminaires, DOPAG has configured an automated metering system that meets precisely these requirements.

  3. With automated production to the optimum PU foam gasket
    Technology, material and component - these three factors must be optimally coordinated for the automated production of PU foam gaskets. DOPAG and Stassen Industries GmbH advise customers together.
  4. FIPFG series production of PU foam gaskets for control cabinets

    SAE Schaltanlagenbau Erfurt relies on the dynamicLine from DOPAG for the individual production of control cabinets. We have visited them on site.

  5. Dispensing two different types of grease

    We configured an automated lubricant dispensing system that optimises production processes in the automotive industry.

  6. Dispensing systems for the production of hydrogen tanks

    The eldomix dispensing system fills an impregnation bath for the production of hydrogen tanks using the filament winding process.

  7. Dispensing of liquid silicone rubber (LSR) in medical technology, food industry and e-mobility

    Particularly strict conditions apply to production in the medical technology and food industries. A special configuration from DOPAG enables the use of the dispensing system in the clean room.

  8. How to switch from manual to machine application

    When is it beneficial to switch from manual dispensing to a metering and mixing machine? - We support you to identify all relevant influencing variables.

  9. High cost-effectiveness and a wide range of applications for PU foam gaskets

    Learn all about Form-In-Place-Foam Gasketing (FIPFG) and how it’s already begun revolutionizing engineering industries and applications around the world.

  10. Gaskets and electronics potting for wallbox production

    PU gaskets and potting compounds protect the sensitive electronics in a wallbox against dust, dirt and moisture. We offer solutions for both applications.

  11. Metering and mixing technology for the production of LNG tankers

    We offer dispensing systems for a reliable application of adhesives and sealants in the manufacturing of liquefied natural gas (LNG) transport tanks.

  12. Contactless application of grease and oil

    The contactless application of lubricants meets all conditions for complex, automated production processes and is now standard in many industries. We present the options.

  13. PU gaskets for recyclable HEPA filters

    With the dynamicLine, DOPAG provides an automated and clean application of PU foam gaskets on recyclable HEPA filters from the Swiss manufacturer Tecnofil.

  14. Precise bonding for the world’s first retractable solar roof

    The Swiss start-up dhp technology constructed the world’s first retractable solar roof. The individual modules are manufactured with dispensing technology from DOPAG.

  15. Gasketing and bonding of control cabinets

    With the dynamicLine, DOPAG offers a system for both applications and thus enables an efficient, automated series production.

  16. Manual application of lubricants

    DOPAG offers special dispensing stations for the manual application of lubricants. With the help of an adapter, components such as O-rings and other seals can be greased or oiled manually. 

  17. Coating self-adhesive labels with silicone

    Self-adhesive labels and stickers are produced with silicone coating via coating systems. We provide the metering system to ensure material feed.

  18. Potting electronics boards

    DOPAG provided a metering and mixing system for potting electronics boards for e-bike battery packs. 

  19. Serial production of PU foam gaskets in the automotive industry

    With the dynamicLine, DOPAG offers an efficient solution for series production of PU foam gaskets in all industries.

  20. Bonding and sealing in aircraft production

    The metering and mixing system volumix provides a smart solution for filling cartridges with adhesives and sealants in aircraft production.

  21. Automated bonding of filters

    For the production of plastic filter elements, DOPAG configured and automated metering and mixing system.

  22. Automated application of sealants

    DOPAG provides an individual solution for the application of one-component sealant in the production of cardan shafts for special vehicles.

  23. Series production of PU foam gaskets

    With the dynamicLine, DOPAG offers an efficient solution for series production of PU foam gaskets in all industries.

  24. Metering and mixing system for adhesive bonding of automotive components

    DOPAG develops a metering and mixing system for adhesive bonding of automotive components to ensure uniform standards worldwide.

  25. Valves for grease spraying in furniture production

    DOPAG offers furniture manufacturers flexible and reliable solutions for the automated application of lubricants.

  26. Efficient handling of components during dispensing sealing foam

    For the automated application of PU gaskets to control cabinet doors, DOPAG provides a dynamic mixing system in combination with a linear robot and shuttle sliding tables.

  27. Honeycomb potting of sandwich panels

    With the dispensing system coredis, the honeycomb core of sandwich panels, which are used for the interior of aircraft, could be filled homogeneously.

  28. Sealant dispensing for truck manufacturer

    DOPAG successfully supported a truck manufacturer with a dispensing system for the manual application of a single-component sealant.

  29. Valves for the contactless spray application of grease and oil
    Valves for the spray application of grease and oil. Contactless application of lubricants in areas difficult to access.
  30. Precise potting of filters and filter elements

    Precise potting of filters and filter elements is necessary for high safety and purity. DOPAG supported a global manufacturer with individually configured metering and mixing systems.

  31. Profitable production of components for control cabinets and enclosures
    With the dynamicLine from DOPAG, customers will be able to implement gasketing and bonding applications with just one system.
  32. Metering systems for optimal lubricant dispensing

    The requirements for the type of lubricant dispensing vary and always depend on the application being carried out. Learn here more about the four key factors for successful system design!

  33. Continuous dosing of lubricants, adhesives and sealants

    The membrane dispensing valve ensures a clean application and a high reliability in automated dosing processes.

  34. Dispensing thermal gap fillers

    Using thermal gap fillers leads to more advanced metering technology requirements - learn more about the solutions from DOPAG.

  35. Automated application of PU gaskets on components

    Compared to manually inserted seals, automatically applied PU gaskets offer many advantages.

  36. Shot valve for contactless greasing

    DOPAG presents the shot valve in a new video: It is perfectly suited for contactless material application in highly automated processes.

  37. Perfect FIPFG applications

    The control cabinet manufacturer Fandis applies foam gaskets on various components. DOPAG has designed a FIPFG system for this application.

  38. Individual grease dispensing

    DOPAG has developed two special lubricant application systems for the production of ball screws in automotive industry.

  39. Dosing systems for liquid 3D printing

    The eldomix dispensing system fills material reservoirs of 3D printers with liquid printing technology.

  40. Automated systems for electronic potting

    DOPAG provides automated potting solutions for variuos applications - two practical examples!

  41. Turnkey systems for automated metering and mixing

    CTO Daniel Geier talks in the interview about challenges in automated dispensing technology.

  42. Automated grease metering

    DOPAG presents a production cell, that could be used for greasing and oiling applications. Disocver also valves for contactless material application.

  43. Dosing technology in rotor blade production

    Metering and mixing systems are necessary in various applications in rotor blade production. DOPAG presents its solutions. 

  44. Individual systems for automated glue dispensing

    The household appliance manufacturer Amica uses an invidual glue dosing system from DOPAG for the production of oven doors.

  45. Automated production of foam gaskets

    With dynamicLine, the metering technology manufacturer DOPAG presents a new dynamic mixing system for a wide range of applications.

  46. Accurate dosing of grease and oil

    DOPAG developed a special dosing system for the automated lubrication of gas springs.

  47. Lubrication in the automotive industry

    Individual grease and adhesive dispensing systems from DOPAG guarantee highest quality electric parking brakes.

Show more