Gammon Construction’s Global Switch Data Centre (Phase 2) project in Tseung Kwan O includes the requirements to design and install a chilled-water thermal-energy storage system with a “Design for Manufacturing and Assembly (DfMA)” approach.
The chilled-water thermal-energy storage system provides resilience to ensure the chilled water remains available at all times, whether due to internal equipment or external power failure. The DfMA with full off-site fabrication could factor in the consideration of site safety, quality and duration of the construction for this vital equipment.
The final design consisted of four 175m3 thermal tanks, each weighing 50 tonnes and measuring 7m in diameter and 9m high. Every element of the tanks – including all steelworks, fencing, cat ladders, baffles, coating, thermal insulation and external cladding, and even maintenance provisions – was then manufactured, preassembled and tested off-site in a DfMA factory. By doing so, Gammon eliminated the need for extensive scaffolding associated with high-level works, as well as the tremendous amount of on-site welding and painting activities, heavy lifting with complicated vertical operations, and confined space work inside the tanks.
Before work began, building information modelling (BIM) was adopted to streamline and verify our design. BIM was applied to structural analysis to ensure integrity and use of correct steel members, while computational fluid dynamics made certain that the components inside the tank were appropriate for effective thermal transfer of temperature profiles.
Once completed in the factory, the tanks were shipped by barge, Kanson Cranes has provided a 750-tonne mobile crane, Liebherr LTM1750-9.1 to hoist the tanks from the barge with a square spreader onto the ground while Set Win’s 500-tonne mobile crane, Liebherr LTM1500-8.1 hoisted to the roof and slid into their final positions in one action – no hot works and no high-level assembly were required. Installation of the four tanks took four days. They are also the heaviest DfMA thermal tanks installed in Hong Kong.