Latest towers in City use Trox fan-coil units and diffusers
These linked towers in the City of London being built for Land Securities include fan-coil units from Trox with waterside control and electronically commutated motors.
Trox has supplied a complete package of fan-coil units and diffusers for two British Land projects in London. The buildings are the 165 m-tall Broadgate Tower and the neighbouring 63 m-high 201 Bishopsgate. They will be connected by a glass canopy. Trox has separate orders for the shell-and-core work at both speculative office developments, which are being built in tandem. The order for the grilles, diffusers and fan-coil units for Broadgate Tower came from FCS Ductwork. The order for 201 Bishopsgate was from Gardner & Co. (Kent) The consultant for both buildings is JB & B, and the construction manager is Bovis Lend Lease. The fan-coil units have EC motors with infinitely variable speed control, enabling significant energy savings to be made compared with constant-speed units by matching speed to air-volume requirements. These FCUs have waterside control, as well as EC motors, and are the first Trox has supplied on a significant site. Trox carried out energy-efficiency testing and a full control mock-up test for the job, with extensive test reports to the design team. The tests were carried out at Trox’s factory in Thetford and witnessed by British Land. Noise tests were carried out at Sound Research Laboratories, with further mock-up at Thetford attended by the commissioning company, controls company, consulting engineer, Bovis and the contractor. One challenge was to ensure the EC motors integrated with the BMS, ensuring that the 0 to 10 V control signals gave the correct voltages to achieve design duties and turndown. The use of variable-volume FCUs also required careful attention to the selection of grilles and diffusers to ensure satisfactory air distribution at reduced airflow. When airflow is reduced to about 60% of maximum, diffusers may dump. When the airflow is subsequently increased, it has to be raised to 80% to re-establish the coanda effect. The two buildings will contain more about 70 000 m2 of space.