Control of carbon dioxide concentration in educational spaces using natural ventilation

This paper reports on research carried out to develop natural ventilation control strategies for densely occupied learning spaces with the intention of improving indoor air quality and heating energy consumption. Investigations were carried out for two test cases according to the characteristics given in CIBSE Guide A (2006) and Building Bulletin (BB) 101 (Department for Education, 2006). The performance of these test cases were assessed using dynamic thermal simulation with fixed CO2 set-points, based on which opening dampers are controlled. Improvements to the control strategy are then proposed. The results show that acceptable indoor air quality can be achieved in almost all cases by adopting typical, traditional control strategies. However, energy consumption can be reduced further by applying more advanced control strategies which use two CO2 set-points to regulate the opening sizes in a non-linear, but stepwise manner. Simulation results predict savings in heating energy consumption of at least 30%.