ICS takes controlling role in largest speculative office development in the City of London
The Broadgate Tower and 201 Bishopsgate in London are provided with separate shell and core building management systems, but operating to a common energy philosophy, to ensure the development is energy efficient. One building is 178 m high and the third highest in the City of London. The other, built alongside, is a 12- storey development with similar floor areas. The total space is 74 000 m2.
Appointed by British Land, Integrated Control Systems has completed the £2.7 million contract to design and install the building management systems in what is the largest speculative office development ever undertaken in the City of London.
To achieve the stipulated energy efficiencies, ICS has installed a system that uses a variety of different integration methods and a Tridium integration platform to connect third-party systems and plant.
A BACnet MSTP system at high level connects the BMS to outstations, while a BACnet IP system integrates chillers, variable-speed drives and other various elements of the infrastructure. LON communications serve over a hundred fan-coil units and air flow control stations on each floor, while Modbus has been employed for transferring metering data.
Working with consulting engineers JBB, ICS rationalised some of the functionality initially called for in the points schedule, resulting in, among other benefits, integration of the variable speed drives with BACnet comms connections, making them an extension of the BMS.
In 201 Bishopsgate, 42 network controllers (JACEs) tied together with patch panels monitor and control the landlord’s plant and are also available for future connection of tenants’ systems through a separate communications channel as occupancy progresses. They serve AHUs, chillers, ancillary ventilation systems, constant air volume boxes that distribute the air to office floors and fan-coil units serving the lift lobby and toilet areas.
Fan coil units have DC motors that can be controlled according to demand.
There are two chilled-water connections to each floor, each with an isolation valve to allow the building-management system to isolate all or part of each floor, and also for connection to fan-coil units installed at fit-out stage.
ICS also built a series of form 4 LV distribution boards (there are no conventional switch gear panels in the project) and installed them next to the relevant plant items.
The overall controls philosophy in The Broadgate Tower was broadly similar, the major difference just one network controller on each of the 34 tenanted floors, with plant on levels 2 and 22 as well as roof and basement, to assist with the monitoring and control of plant that distributes conditioned air and chilled water throughout all levels of the building.
There is only one chilled-water connection per floor, with heat exchangers to bring additional temperature regulation and provide elevated chilled-water temperatures after fit out.
John Reid, managing director of ICS, says, ‘We have built in a flexible infrastructure that will support various communications mediums and can readily interface with different manufacturers and component types. Where possible we have used all the communication mediums to connect plant at high level, enabling maintenance staff in the buildings to view the operation of chillers, variable speed drives and the like through the BMS.’
There are no conventional status lamps or over-ride switches on the variable-speed-drive system; these actions will be undertaken through the virtual network via inverter key pads connected to the BMS interface panels by means of the BACnet link.
The philosophy adopted on the number of points physically connected through the high level interface has opened up a series of opportunities that enables ICS and the end user to utilise all the attributes of each device. Operators will have more information at their disposal, particularly diagnostic data, giving the potential to identify possible problems before they become a reality.”
The technology use makes it possible to create a platform that will enable almost anything to be added to the system as tenants wish. The network controllers are easily adapted to control critical fit-out equipment such as the sophisticated DALI lighting system.
As part fitting out one of the floors in 201 Bishopsgate, ICS is providing a BACnet network for fan-coil units and using LON heat meters to establish the cost of the chilled water to the floor and MODbus communications to electricity meters to show consumption in specific areas of the floor. Data on the air delivered to the floor will be obtained through intelligent devices on CAV boxes. All the information will then be used for the tenant billing package.
