Analyzing the Impact of High Thermal Mass and Natural Ventilation Strategies on Indoor Temperatures in an Extreme Climate

The application of passive strategies in buildings has been gaining attention widely the past decade; however, it becomes more substantial in extreme environments. It can be difficult to keep a cool indoor environment in a hot summer while still having a warm indoor environment during an extremely cold winter in warm summer humid continental areas. In this paper, an emphasis will be done on applying passive strategies in extreme climates; the focus will be kept on the buildings’ envelope. A sample case study of a Minneapolis educational building was chosen. Because the majority of Minneapolis' school buildings were constructed before the implementation of energy rules, the majority of them will require extensive renovations to meet the current legal requirements. This study used extensive virtual studies on an energy modeling tool to uncover passive design characteristics. The measures targeted were aimed at reducing huge heating and cooling loads in the winter and summer, respectively. To achieve the reduction in heating loads, a study was done on the indoor temperatures applying high thermal mass on the envelope construction elements. Cooling loads were reduced by focusing on the effect of natural ventilation strategies on indoor temperatures. The total effect of applying high thermal mass instead of the medium thermal mass within the building envelope can be seen in the 4-hour delay of peak temperatures inside the classroom. Moreover, to tackle the cooling loads, an emphasis was held on the use of natural ventilation strategies in summer. Applying high thermal mass and night flushing resulted in a 3 oC decrease in peak temperatures in summer. A CFD analysis was done to make sure that human comfort is maintained in terms of air velocities inside the classroom. Finally, it can be concluded that performing a thorough climatic and case study analysis to determine the best combination of passive techniques can significantly reduce energy use.