Imtech HVAC System Design on HelWin Beta Platform
It is the largest offshore wind platform ever built in the Netherlands. On 14 June, the HelWin bèta platform left on a barge from the Heerema Fabrication Group's (HFG) yard in Zwijndrecht for Schiedam to complete outstanding work. Last week, HelWin bèta reached its final destination in the German North Sea, where the platform will supply more than half a million households with sustainable energy. That requires high-tech systems. Imtech Marine is responsible for the design, construction and commissioning of the HVAC system, being the heating, ventilation and especially the cooling of all high-quality equipment on the platform. For Imtech's maritime division this represents the largest contract that it has ever undertaken in the heating, ventilation and air conditioning system (HVAC) discipline in the Netherlands. Imtech Marine introduced an alternative design which resulted in significant energy and weight savings.
Up until the present time Imtech Marine has equipped over 130 oil, gas and wind platforms with HVAC systems. This motivated the Heerema Fabrication Group to involve Imtech Marine in the project's tendering phase. "That experience and knowledge is very welcome," confirms Heerema Zwijndrecht Yard Director Ronald Wiebes. "Most certainly in a relatively young discipline such as wind energy. In this project, Imtech realized significant energy and weight savings by developing an alternative to the original design." Imtech modified the pre-design. The benefits are evident. Greater efficiency, better budget fit and a more sustainable solution. Project Manager Evert van Veldhuizen "We opted for water-based cooling instead of air-based cooling in some areas. This enabled us to reduce the eight planned air conditioning systems to three. That makes a tremendous difference in terms of the required external air, cooling capacity, air ducts and weight."
The HelWin bèta is a steel structure measuring 98 by 42 meters and weighing 10,200 tonnes. The platform comprises 5 decks and is 28 meters high. It will be transported to Helgoland where it will be installed off the coast near the German town of Büsum. HelWin bèta is an important link in a cluster of wind farms in the German part of the North Sea. The grid connection with a capacity of 690 megawatt must be operational by the first quarter of 2015. Customer TenneT and main contractor Siemens will use the platform to convert the alternating current of approximately 150 wind turbines around the Helgoland island into high voltage direct current. One of the key tasks of the HVAC system is to cool the Siemens transformers and converters.
Dutch companies leaders in wind energy
Heerema Fabrication Group and Imtech Marine have established a track record and gained a head start in the field of wind energy. But because it is still a young market, projects are not without their challenges. For example, regulations often lag behind actual practice. Classifications, budgets and designs are often based on experience gained in the oil and gas industry. This can make things difficult during the tendering phase, for example, when the basic design is not yet final. Van Veldhuizen: "And after that it is still quite a job to complete the design and the system on time. Most certainly when you are working with so many subcontractors who all depend on each other and work within the same space. But we succeeded. In fact, we were the first contractor to complete everything mechanically one week prior to the deadline. The collaboration with HFG and all subcontractors is reason to have confidence for the future."
3 air conditioning systems (capacity approx. 55,000 m3/h, 100% redundant)
4 local cooling systems for the transformers and converters (capacity approx. 240,000 m3/h)
64 fan convectors for local cooling of various areas
4 cold water units, each 625 kW
214 fire and smoke dampers
5,500 m2 air ducts
2,000 metre of pipes
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