Assessing the efficacy of passive measures for the tropical context of Mauritius through parametric simulations and in-situ measurement

The transition from the traditional creole typology to the modern concrete vernacular structures has taken place progressively over the past few decades in Mauritius, motivated by the need for cyclone resistant buildings. However, the lack of consideration for thermal properties of the wall, glazing and roof construction has resulted in interior space conditions generally uncomfortable during summer conditions, evidenced by the increasing installation and use of air conditioning systems. With summers projected to become warmer due to climate change, passive design measures should be re-incorporated into existing and new constructions to decouple active cooling and urbanisation. This paper describes the parametric analyses carried out to generate cooling load (peak and coincident) for wall, glazing and roof components and temperature (operative, radiative and air) variations for a test building model made up of nine rooms, of which eight were peripheral and one central (with no external walls). The simulations were undertaken in Designbuilder® for a base case with no passive measures and for various low cost passive measures – overhang of various depths, external vertical shading and curtains, roof shading and planting tall trees around the building, incrementally rotated. The results allowed to assess the efficacy of each passive measure, validated against experimental data collected in actual buildings. The study also provided much needed quantitative data on surface and air temperatures prevailing inside buildings, which are key to bringing about the needed shift in mindset and the construction market.