Variable-speed drives make for successful refurbishment
Using inverter drives on most of the plant in the refurbished Unilever House in London has minimised the need for local distribution boards.
The latest methods of installing building-management systems by using local distribution boards serving inverter-driven plant and localised outstations has proved highly successful for the redevelopment of Unilever House in London. This approach eliminated the use of centralised motor-control panels. As part of the £94 million redevelopment of Unilever House near Blackfriars Bridge. Integrated Controls Systems developed, designed and installed a £1.3 million BMS to a specification from Ove Arup that called for the localised approach. Construction manager Bovis Lend Lease awarded the contract to ICS to build local power-distribution boards, undertake all power and BMS wiring and install two web-enabled supervisors with complete graphical interfaces to serve the initial base-build BMS to incorporate Cat A and Cat B requirements. ICS worked primarily to meet the requirements of the landlord’s M&E systems, but was also required to cater for the special requirements of Unilever, which has now moved back into the 32 500 m2 listed building. ICS has also carried out Cat B fit outs on the remaining three floors. ICS installed over 800 fan-coil units with 28 different control configurations to meet the many special requirements posed by the use of specific areas. The control packages included various sensor control options, including heating and cooling by LPHW and chilled water or combinations of chilled water and electrical heating and, in some instances, only heating or cooling. Control options also offer conventional return-air control, room control with high-quality user displays and interface with passive infra-red sensors to activate sensors only when rooms are occupied. An IP infrastructure throughout the building connects the control panels, which incorporate Trend controllers. There are 26 IQ3 controllers on the Ethernet network backbone serving central plant — including boilers, chillers, cooling towers, AHUs, pumps etc. The IP infrastructure also supports two EINC controllers on each floor, serving a Trend network that accommodates communication modems for fan-coil units and their IQ200 controllers. John Reid, managing director of ICS, says, ‘The Ove Arup concept for local distribution did away with the need for conventional motor-control panels. We were able to optimise the philosophy with distribution boards serving related pieces of mechanical plant. Electrical installation costs were minimised by the proximity of the plant to the distribution boards so that only short runs were required for most cable installations. Additionally, only a small amount of switchgear was needed, as most of the plant is served by variable-speed drives. The refurbishment left the façade unchanged, but the interior of the building has been totally transformed with an stunning atrium, mix of open-plan and cellular offices, computer suites, facilities for meetings conferences and video conferences and dedicated staff amenity areas.
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