All large and complex organisations have a massive impact on the environment, and the University of Cambridge is no exception. This can often make finding the appropriate environmental solutions extremely difficult, as it is rare that one approach alone can tackle a multitude of energy and carbon reduction problems. At the University of Cambridge one such problem to tackle is the approximate £1,825 spent every hour on energy whilst still providing the best learning environments and minimising disruptions. Consequently, the University of Cambridge have dedicated staff and engineers working around the clock to solve operational inefficiencies while maintaining the high operational standards expected by academics, researchers and students.
Following conversations with our customers and peers one concern that keeps resurfacing is the difficulty of knowing, in real-time, how many people are occupying a room. This is especially relevant for rooms such as lecture theatres, which have very variable occupancy levels, large volumes of air to condition and, usually, a sedentary audience. Controlling these rooms presents a challenge for setting time schedules and AHU speeds for ventilation controls and lighting.
Appropriate adjustments and close management in conditioning these spaces can reduce energy wastage, improve internal air quality conditions and fulfil thermal comfort requirements. All these features create a healthier working environment, which directly affects occupant’s wellbeing and productivity levels.
Together with the University of Cambridge Estate Management we began a pilot for demand based ventilation in the Biffen lecture theatre (with a capacity for 170 people). The goal was to uncover more opportunities for improvement and HVAC automation.
Upon investigation, we found that although there was a manual high/low ventilation switch in the lecture theatre, the standard BMS times schedules did not correlate to when the room was in full use. In addition, the manual switch could be left in high-speed position potentially consuming more energy than required for the size of the audience.
As this was a shared lecture theatre with frequent reoccurring bookings the BMS operatives did not know when the lecture theatre was being used and whilst the room booking system was accurate it did not include the level of occupancy nor was linked to the BMS in case of cancellations or postponed starts. As a result, ventilation was scheduled to run at the same rate each day between 8am and 6pm regardless of the room’s usage density.
The solution and results…
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