Industrial control meets nature in green building

Faced with controlling one of the most innovative ecological buildings in the UK, GB Innomech decided that industrial-grade equipment would give a far better performance at much lower cost than a standard environmental control system. The building is near Ely in Cambridgeshire and has a host of green features. They include special triple-glazed and coated front feature windows on the south aspect with integral automatically controlled blinds to track the Sun. The underfloor heating system is served by a ground-source heat pump. A solar vacuum-tube water heater generates DHW. The ventilation system recovers heat, and the low-energy DC fans have inverter drives. There is also a host of passive measures. GB Innomech is an automation solutions company specialising in solving difficult manufacturing problems. The company has the ability to cross-fertilise technologies and techniques between the sectors of industry it serves. When building a new corporate headquarters, it felt natural not to assume that a standard control system would be the best solution. The system that GB Innomech designed is based on a Mitsubishi Electric programmable logic controller with an interactive graphic panel and distributed networked local control nodes. One of the decisions was to integrate as many functions as possible into aone central control system to constantly optimise the entire building for energy performance. Robert Colvin, the GB Innomech control-systems engineer now overseeing the project, explains, ‘We have a total of 150 digital and 50 analogue points monitoring the building’s environmental conditions. Actuators control heat, light and ventilation to 15 offices and meeting rooms, 10 communal rooms and 300 m2 of workshops.’ Central control is provided by a Mitsubishi Q01CPU PLC connected on a distributed network to reduce wiring. Mitsubishi’s CC-Link was chosen as an open system that can communicate with a wide range of field hardware. Touch screens allow users to set preferences for each room and display the current status and historical trends of monitored and controlled devices. The control system anticipates building heat demand using real-time clock triggers sent from the touch screen to the PLC. The system is linked into the IT network for archiving trend data and generating alarm and status reports. Both the building and the control system have been designed to treble in size without much difficulty.