From existing neighbourhoods to net-zero energy and nearly zero carbon neighbourhoods in the tropical regions

The main objective of this research is to evaluate, analyse and compare the thermal comfort, the energy consumption, and the carbon emission rate in two types of neighbourhoods (existing and suggested neighbourhoods), located in Madagascar island. The same neighbourhood was designed in 14 cities selected in six climate zones which 13 of these cities, were located in the coastal zone. The simulation was carried out under the basic of
Design Builder software which is one of the more recognized tools in energy and carbon optimization. The results showed that the comfort rate was estimated at 38% higher in suggested than existing neighbourhoods. The best solution allowing to reach simultaneously the objectives of “Net Zero Energy residential building”, and, “Nearly Zero Carbon emission”, required an annual expenditure of 1046$, with an emission concentration of 4783.2
kgCO2 (or 2.6kgCO2/m2), during the operational phase of neighbourhoods. This solution leads to 7.9% savings in the total costs together with a 99.4% reduction in the CO2 release. The best solution only allowing to reach “Net Zero Energy Costs “required an expenditure of 979$ per year, and accompanied by an emission of 51200 kg of CO2. This solution leads to 13.6% savings in the costs; together with a 5.1% reduction in the embodied carbon release. This point of Pareto Front showed an improvement of comfort hours of 13.1% in the case of suggested
neighbourhoods; of 33.8% in the case of existing neighbourhoods