Climate change mitigation and adaptation in Spanish office stock through cool roofs

• Cool roofs can provide a 25 % reduction of cooling energy demand of office stock. • Cool roofs can provide a 6 % reduction of the current heating and cooling energy demand. • Cool roofs would reduce up to 12 % of future heating and cooling annual energy demand. • Cool roofs will help to reduce future offices’ energy demand in all climate zones. • Improvement in the thermal comfort ranges from 26 % to 78 % of discomfort degree days. In a context of climate change, the cooling period of buildings is increasing every year in Mediterranean countries. This will become a relevant issue when existing buildings are retrofitted. Cool roofs have a passive cooling effect on a building and can contribute to decreasing the annual cooling demand. In office buildings, thermal comfort has a considerable influence on workers’ performance. In these buildings cooling energy demands tend to be high due to the high internal thermal loads. This paper describes annual energy simulations of Spanish office stock to evaluate the potential energy savings of cool roofs within the context of building retrofitting. The energy demand and thermal comfort of representative office buildings is compared before and after the application of a cool roof coating, in the present time and in the year 2050, for all climate areas of Spain, under the most optimistic and most pessimistic future weather scenarios. Results showed that the cooling energy demand of Spanish office stock can be potentially reduced by 25 % when a cool roof is applied, and the annual energy demand for heating and cooling can be cut by 6 %, 11 % and 12 % in the present, the optimistic future scenario and the pessimistic future scenario, respectively.