Mixed-mode ventilative cooling opportunity for an existing shopping mall retrofit

Shopping centres currently design has included a small portion of automated windows sized for smoke ventilation. Their presence is mandatory for fire regulation and they are usually operated just in case of fire. Nevertheless, these buildings can potentially take advantage of those openable windows to exploit the potential of natural ventilation to guarantee the minimum air change rate required by IAQ standards and for ventilative cooling purpose reducing cooling and electrical consumption.
The work presented in this paper investigate the retrofit performance potential of a mixed-mode ventilative cooling strategy tailor-made for an existing shopping centre. At the present, natural ventilation in the case study common areas is provided just on the basis of the energy manager judgment, without taking into account a robust control strategy based on indoor-outdoor climatic condition, thermal comfort and building use. A building model was created within TRNSYS environment and calibrated based on the real monthly electrical energy consumption. Then, with the support of the TRNFLOW plug-in, that couple thermal and airflow simulations, we were able to simulate and test the effectiveness of the tailor-made mixed-mode strategy. The simulation results show that windows opening can be operated starting from March to November. Running common areas with mixed-mode strategy over a year can allow to save 265 MWh which means cutting the electrical consumption by 23%.The initial costs for control strategies implementation can be paid in the first year of operation.
The main contribution of this work is to demonstrate the feasibility of a mixed-mode ventilative cooling solution for an existing shopping mall common area retrofit highlighting how the exploitation of existing automated windows makes the solution cost-effective.