Towards an optimized zero energy solar house: A critical analysis of passive and active design strategies used in Solar Decathlon Europe in Madrid

Solar Decathlon is an international multidisciplinary competition for designing, building and operating Zero Energy Solar House. Based on the existing evaluation framework, this research identifies 7 key decisions and 24 passive and active strategies that lead to an optimized Zero Energy Solar House with better architecture, comfort condition and electrical energy balance performance: selecting passive strategies regarding shape, function layout and microclimate organization, adopting solar systems and heating, ventilation and air-conditioning systems as active strategies, integrating the passive and active with prefabrication systems, and finally evaluating the project against sustainability (energy payback period). Focused on 2010 and 2012 Solar Decathlon Europe in Madrid, this research critically reviewed 33 involved projects using this framework. Furthermore, the research correlated the 24 strategies with their performance results in the competition through multi-criteria analysis. The review generated passive-active integrated empirical models for an optimized Zero Energy Solar House in Mediterranean climate conditions. Beyond the particular competition and climate, the research found five important lessons for integrating passive and active technologies for a solar house. The framework proposed by this research, and the strategies and lessons learnt from reviewing the Solar Decathlon Europe competitions can help to transfer the technologies and related knowledge gained from experiments into practice. (C) 2019 Elsevier Ltd. All rights reserved.