Bridges vol. 42, December 2014 / Feature
By energy innovation austria, BMVIT & the Climate and Energy Fund
By Stefanie Waldhör, projektfabrik.at
This quarterly publication presents current Austrian developments and results from research work in the field of forward-looking energy technologies. The content is based on research projects funded by the Austrian Federal Ministry for Transport, Innovation and Technology and by the Climate and Energy Fund.
Projects and perspectives
In the field of sustainable building, Austrian technological advances lead the way internationally. Pioneering products and Austrian know-how in this sector are well on their way to carving out a chunk of international markets. The Arab world, where interest in modern energy technologies and energy-saving measures is growing, holds great potential. The project “Sheikh Zayed Desert Learning Center” is an impressive example of a how a cutting-edge, comprehensive strategy from Austria is being implemented in the United Arab Emirates.
Around the world, buildings account for 40 percent of end-use energy consumption. Starting from the construction materials employed, their production and transportation, through the provision of space heating, cooling, and hot water, and finally lighting and operating a wide variety of electrical equipment, the building sector offers vast potential for saving energy and using energy-efficient technologies that can help to reduce Greenhouse gas emissions.
In the field of sustainable building construction, Austria has invested in research and technological development for years. Pioneering Austrian firms have a wealth of know-how and experience with cutting-edge building technologies, and have been able (frequently in close collaboration with research institutes) to implement pilot projects that attract international attention and to launch new products.
As part of their funding programs, the Federal Ministry for Transport, Innovation and Technology (BMVIT) and the Climate and Energy Fund initiate pioneering R&D activities and projects in this field. In the Arab world, interest in sustainable building technologies is currently growing apace. Even though the Arab countries still have large reserves of fossil fuels, there is increasing need for technologies that save energy, improve energy efficiency, and make use of renewable sources of energy. Because electricity is heavily subsidized in these countries, energy-saving measures have not yet been attractive for consumers. However, as the high cost of such subsidies has an increasing impact on government budgets, interest is growing in strategies and technologies to conserve the resources.
Austrian energy technologies and building innovations have excellent opportunities in these markets. The topics of insulating buildings, multifunctional façade systems, solar heating and cooling, supplying electricity locally by means of photovoltaics, storage technologies, ultraefficient lighting systems, demand-side management, Smart Home solutions, and technologies for conserving refuse and water are particularly relevant.
One cutting-edge flagship project is the Sheikh Zayed Desert Learning Center, implemented in the United Arab Emirates and completed in 2014; the Vienna partnership of architects Chalabi Architekten & Partner managed the project, which demonstrated impressively how a pioneering overall strategy for a sustainable building can be successfully implemented under extreme climatic conditions.
Many of the technologies and innovations employed there have been developed by Austrian companies, and some of these achieved commercial viability beforehand by means of research work and pilot projects funded within the programs Haus der Zukunft (BMVIT) and Neue Energien 2020 (Climate and Energy Fund).
The Sheikh Zayed Desert Learning Center
Al Ain (United Arab Emirates)
A gigantic sustainable tourism project, ordered by the government of Abu Dhabi, is taking shape in the city of Al Ain. The project includes a 400-hectare wildlife park and resort with hotels, themed safaris, residential areas, and the associated infrastructure.
The first building erected, as part of the master plan was the Sheikh Zayed Desert Learning Center, was planned as a museum and research center for desert environments and ecological issues. With pioneering state-of-the-art architecture and technology, this building (total investment cost €56 million) proves that sustainable building concepts can also be implemented in desert locations. The goal was to reduce environmental impact and life-cycle costs significantly through innovative designs and technologies.
The project was designed by the Vienna architects Chalabi Architekten & Partner, as lead consultant in the comprehensive process, and implemented largely with Austrian contractors (STRABAG AG, S.O.L.I.D. GmbH, ertex solar GmbH, Bartenbach GmbH, iC consulenten ZT GmbH, Bollinger, Grohmann & Schneider) and in collaboration with scientific partners (AIT Austrian Institute of Technology).
A walk-in sculpture
The starting-point for the architectural approach was the idea that the building should grow out of the landscape and adapt to its harsh, rugged surroundings in terms of design. The architects planned a walk-in sculpture in the shape of a three-dimensional spiral, whose highest point towers almost 20 meters above the desert landscape. Covering roughly 14,000 m2, the structure circles around an enclosed courtyard, and leads up to an elevated vantage zone that offers a fine view of the Wildlife Park and the rugged ridges of Jebel Hafeet, one of the highest mountains in the United Arab Emirates.
Construction utilized mainly local materials; for instance, the entire building shell is clad with natural sandstone from neighboring Oman. The lozenge-shaped structure of the façade reflects the differing surface treatments received by the stone to create smooth and rough surfaces.
Beacon of sustainability
A key issue in hot climates is how to cool buildings which, as a rule, consumes a great deal of energy. The Desert Learning Center reveals how the architectural design can help to minimize energy consumption for cooling.
The building lies partially submerged in the ground – one third of its cubic content lies below ground level. The entrance area faces north, and a low heat transfer coefficient, coupled with the considerable thermal mass of the outer shell (massive concrete walls with an insulated sandstone façade plus an air gap behind), greatly reduces the amount of energy required to cool the building. A roofed and enclosed courtyard and a shaded outside court also benefit the building‘s climate.
Deep window recesses and roof overhangs above the large glass façades minimize the amount of direct sunlight entering. But enough daylight is still admitted into the building to illuminate the interior efficiently, in conjunction with the building‘s pioneering approach to lighting.
Pioneering Technologies for maximum resource efficiency
For a highly efficient building strategy to be implemented successfully, an integrated planning process is essential that takes into account all aspects of energy and building services engineering. iC consulenten ZT GmbH were commissioned to plan the energy systems (based on renewable sources) and state-of-the-art building services, and also provided advice on building physics, energy-efficient operation, and certifying the Desert Learning Center. Austrian firms supplied the bulk of the systems and components employed.
The Desert Learning Center‘s overall energy consumption is 40 percent lower than that of comparable conventional buildings, and its water consumption is 80 percent lower.
Warm ambient air is first drawn through an underground system of nine ducts (overall length 1200 meters) lying 8 meters beneath the desert surface; this lowers the temperature of the incoming air by roughly 8o to 10o C. This method of cooling the air in advance reduces cooling energy consumption by about 20 percent.
Active solar cooling system
Solar cooling technology is of interest in hot climates where plenty of solar energy is available, since a building’s energy demand is more or less proportional to its insulation. Solar collector panels are used to heat large quantities of water to a temperature of 90° C. An absorption chiller is driven by this solar heat and produces cold water at 14° C, which is pumped into a distribution system.
The Desert Learning Center‘s cooling system utilizes ultramodern solar cooling technology from the Styrian firm S.O.L.I.D. The cooling system is coupled to thermally activated elements: cold water flows through pipes integrated into the building‘s floors, walls, and ceilings. The cooling load for the building is around 1 MW. The solar cooling system supplies the active elements in the concrete core, which has a set point of 16° C. Six closed-circuit cooling towers with adiabatic precooling are on hand to cool the compression and absorption chillers; this arrangement minimizes water consumption while achieving the required limited deviation of only 4° C above wet-bulb temperature.
Key technical data of the solar cooling system:
> Cooling capacity of lithium/bromide absorption chillers: 352 kW
> Collector: 1.134 m2 high temperature collectors
> Slope: 25°
> Capacity of hot-water storage tanks: 2x13 m3
> Capacity of cold-water storage tank: 5 m3
> Recooling: 6 closed circuit-cooling towers in conjunction with compression chiller
> Solar yield: 825 kWh/m2a
Power supply from renewable sources of energy
The bulk of the electrical base load for the Desert Learning Center is covered by the photovoltaic system. PV modules from ertex solar (a manufacturer from Lower Austria) were installed on the roof of the building on a large scale, supplying solar power to the entire complex via eight power inverters; total rated capacity is 149 kWp.
Extensive simulation was necessary to work out the most suitable dimensions and specifications for the PV modules. For this special-purpose application, a custom-made sandwich design was developed with two layers of glass each 2 mm thick, making the modules highly elastic. Because they can actually be walked on, maintenance work can be done on the module array without individual panels shattering. Installing the panels on the roof surface, which is curved in three dimensions, was also quite a challenge.
Key technical data of PV equipment:
> Rated capacity: 150 kWp
> 1030 panels measuring approx. 1x1 m
> Individual panel rating: 145 W
> Sandwich design with two glass layers 2 mm thick
> Framed modules bolted to customized supports
> Dummy panels employed: 95 Dummy panels 0.5x1.0 m; 26 Dummy panels 0.5x0.5 m
There is no fresh water in the desert, so drinking water for the Desert Learning Center must be brought to Al Ain from a desalination plant 150 km away.
As part of building services engineering, extensive water conservation measures were implemented: Vacuum toilets were installed throughout the complex – the first time they have been used in the United Arab Emirates; water from the sewage plant is purified in three stages and used for the cooling towers; rainwater is collected, and condensation from the ventilation system is also reused.
Thermal building simulation
If exact modeling is carried out while sustainable buildings are being planned, comfort and energy efficiency will be improved in actual operation. For the Desert Learning Center, extensive simulation of the entire complex was performed at AIT Austrian Institute of Technology in order to work out the most suitable configurations for the active solar cooling system and the pioneering ventilation approach. Planning the air precooling arrangements, for instance, involved calculating the drops in temperature to be expected with differing configurations of the underground air ducts.
Scientific supervision was a great help during the planning process, putting the project on firm foundations; the calculations also formed the basis needed for certification. As the building is so complex in engineering terms, the TRNSYS software normally used in energy simulation had to be extended and modified on a large scale.
Pioneering lighting design with energy-efficient lighting systems
The Tyrolean lighting specialists Bartenbach GmbH developed the lighting design for the Sheikh Zayed Desert Learning Center; it features integrated lighting fittings (largely concealed) that highlight the building‘s architecture and bring out the complex geometry of the rooms. The lighting strategy is intended to guide visitors through the building dynamically and intuitively. Much of the light is provided by means of energy-efficient LED lights on rails set into the floors, walls, and ceilings.
A glancing light is generated on the walls, creating the impression of light from the setting sun on sand. A variety of lighting elements are fitted into the ceiling honeycomb grid, with indirect and direct light sources illuminating the rooms harmoniously. The light follows the succession of rooms, and the turns in the spiral leading to the next platform are accentuated more brightly. To provide integrated lighting without visible light sources, every single lighting device, such as narrow-beam LED lights on rails set into the floors, LED wall washers, and other LED lights on rails, is fitted with Jordan reflectors to direct the light.
Although light levels in the museum are kept fairly low, care has been taken (as part of the overall conception) to provide enough openings for daylight to comply with the standard required for LEED certification. A relationship to the outdoors is established via the courtyards within, skylights facing north, and openings for light in deep recesses in the façade. Generous windows open onto the office space.
Austrian solar technology for 36,300-m2 facility in Saudi Arabia
In 2012 one of the largest solar facilities to supply hot water anywhere in the world started operation in Riyadh. Millennium Energy Industries (MEI), a plant supplier based in Jordan and specializing in renewables, implemented the facility. Austrian know-how was employed for the collectors and the hydraulic engineering: the solar collectors for this project came from the Carinthian manufacturer GREENoneTEC, and experts from the research institute AEE INTEC developed all the system hydraulics. Both organizations have been researching and developing pioneering energy strategies and technologies for years, partly within national and European funding programs.
The project partners succeeded in making the collectors significantly more efficient and easier to integrate into large collector arrays hydraulically, while adapting collector design to the climatic extremes in this region. The facility is located on the campus of the Princess Noura bint Abdulrahman University for women in Riyadh, where it supplies hot water and supports the heating system. The facility is implemented as a central array of collectors on the flat roof of a warehouse with an area of 60,000 m2. At the planning stage, it was essential to ensure uniform flow distribution throughout the array, while minimizing pressure drops and simplifying pipework (to keep both costs and heat losses down).
Another challenge: With sandstorms involving wind speeds up to 150 km/h, wind loads are a real structural issue. The heat from the collectors is fed directly into a district-heating grid; to cope with periods of intense insolation and modest consumption, a storage system with a capacity of 900 m3 has been provided. In conjunction with an oil-fired boiler unit, the facility supplies the entire university campus, including buildings and infrastructure for roughly 40,000 students.
Automated supervision of thermal solar facilities
The core units in the thermal solar facility at the Sheikh Zayed Desert Learning Center are remotely supervised by means of IP Solar, a monitoring system developed in Austria. The system evaluates instrument data, supervises operation, and monitors the energy yield of solar facilities automatically. It was developed by S.O.L.I.D. in collaboration with four research partners: Graz University of Technology/Institute of Thermal Engineering, Kassel University/Department of Solar and Systems Engineering, Cerebra Informationssysteme GmbH, and Schneid GmbH.
In practice, the energy yields from many large thermal facilities do not come up to expectations. High solar yields can be maintained long-term only if operation is monitored continuously. With IP Solar, an inexpensive method is now available for automatically supervising solar-based energy supply systems in a standardized way. Quality control and yield assessment are handled by an intelligent system of complex algorithms. Not just the solar circuit, but the entire energy supply facility (including storage circuit, downstream heating unit, and process water treatment) are monitored automatically. The current data are retrieved from the solar facility‘s controller and data logger. Any malfunction immediately triggers an SMS or e-mail message to the facility operator, making it possible to plan maintenance steps in advance and to remedy malfunctions in operation without delay. As a result, service and maintenance costs are kept low and energy yields are maximized throughout. IP Solar currently supervises thermal solar facilities in Europe, Asia, and North America with a total area of roughly 17,000 m2.
Building on experience so far, the project partners AEE INTEC, S.O.L.I.D, LandesEnergieVerein Steiermark, and Cerebra are now developing the monitoring system further in the follow-on project METHODIQA. The aim is to provide automated supervision and quality assurance for biomass heat plants, thermal solar facilities, and systems combining solar, biomass, and fossil sources of energy.
AIT Austrian Institute of Technology
Contact: Michaela Jungbauer
Contact: Robert Müller
Bollinger, Grohmann & Schneider/Structural Design
Contact: Arne Hofmann
Contact: Dieter Moor
iC consulenten ZT GmbH
Contact: Klaus Kogler
Contact: Bernhard Gerardts
Riyadh Solar Facility
Contact: Christian Fink
Sheikh Zayed Desert Learning Center
Chalabi Architekten & Partner
Contact: Talik Chalabi
Contact: Harald Blazek
energy innovation austria presents current Austrian developments and results from research work in the field of forward-looking energy technologies. The content is based on research projects funded by the Austrian Federal Ministry for Transport, Innovation and Technology and the Climate and Energy Fund.