Revisiting cooling energy requirements of residential buildings in Portugal in light of climate change

Since climate data for building energy simulation have recently been refreshed with 1971-2000 observational data and theoretically influenced by a conservative approach of climate change, benchmarks for cooling energy requirements for residential buildings are discussed for a set of 30 regions in Portugal, mainland and islands, as a contribution to the next revision of Portuguese building thermal code (DL 118/2013). The main conclusion is that gain utilization factor correlates with average external air temperature for summer season by a logarithmic function. The benchmark for gain utilization factor plays an important role in defining cooling energy requirements. A set of recommendations are suggested: (i) using the gain utilization factor as an index to evaluate the overheating risk, thus, for values above a defined threshold cooling energy needs could be neglected for primary energy demand quantification; this measure may encourage designers to integrate passive cooling systems; (ii) defining a national roadmap based on technological advances of shading solutions for benchmark parameterization of the west equivalent collecting area by unit of floor area starting from 0.065.