Ventilative Cooling in Midrise Residential Buildings in the Netherlands

Abstract

This thesis investigates the potential for natural ventilative cooling strategies to improve the cooling and comfort of residential midrise buildings in the Netherlands. Ventilative Cooling is “the application of the cooling capacity of the outdoor air flow by ventilation to reduce or even eliminate the cooling loads and/or the energy use by mechanical cooling in buildings, while guaranteeing a comfortable thermal environment”. The effect of Day and Night ventilation strategies on the indoor environment of two common typologies of midrise apartments seen in the Netherlands was evaluated. The project investigated window and stack ventilation using dynamic energy simulations coupled with airflow network (AFN) modelling. EnergyPlus airflow network model was used for simulations with Grasshopper and Rhino as the user interface. Honeybee and Ladybug plug-in for Grasshopper translated the model into the EnergyPlus-readable input format. Various performance indicators were used to evaluate the apartments' comfort and cooling. These included temperature limit exceedance hours, GTO hours, Cooling requirements reduction ratio, Climate Potential for Natural Ventilation (CPNV), Natural Ventilative Cooling Effectiveness (NVCE) and Climate Potential Utilization Ratio (CPUR). Ventilative cooling simulations yielded favorable results. There was a significant reduction in the peak temperatures and GTO hours within the rooms when the windows were opened, compared to when they were closed. Out of the tested two typologies of apartments, the number of hours when the temperature exceeds 28°C reduced by 50-70% when the windows were fully opened in typology 1 apartments and was reduced by 36-70% in typology 2. GTO hours reduced by 70-80% when the windows were opened for ventilative cooling in typology 1 apartments and reduced by 55-60% for typology 2 apartments in comparison to when they were closed. Apartments with the capability of cross ventilation performed better than those with only single-sided ventilation. The cooling effectiveness of the existing building designs was also evaluated. The results showed that there is room for improvement of design to utilize the site’s potential for natural ventilation. When passive stack is used along with the opening of windows in an apartment, there was a slight reduction in temperature when compared to using only open windows for the same apartment. However, the reduction was not very significant. The findings are presented in a comparative and quantitative manner, providing valuable insight into the relevant field.