Control logics of natural ventilation for energy efficiency and thermal comfort

Building automation systems can improve energy and thermal performance of buildings, integrating or replacing the conventional efficiency strategies, if properly integrated with adequate control logics. In this paper, specific control logics of windows opening are investigated in order to value the effects of ventilative cooling on thermal discomfort reduction during the summer season. The control strategy is focused on existing residential buildings located in the Mediterranean climatic context of southern Europe (Italy). In particular, in relation to different critical assumptions (i.e. climate, orientation of building) an optimized control strategy of windows opening is developed to reduce energy consumption for cooling, ensuring adequate levels of indoor comfort. The operation algorithm of windows opening is calibrated on a variable set-point based on optimal temperatures (according to theory of adaptive comfort). A multi-objectives Particle Swarm Optimization (PSO) method is defined and implemented in MATLAB, with thresholds that are optimized to reduce the discomfort for overheating and undercooling The optimization logics are then coupled with energy performance simulation performed in TRNSYS. The air flows in the building have been calculated with a multi-zone airflow model, performed by TRNFLOW within the TRNSYS software. Varying the context conditions, thermal comfort analysis, according to the adaptive thermal comfort theory (EN 15251-2007), and energy simulations show the potentialities of natural ventilation strategies for thermal comfort in summer without mechanical cooling