Retrofit planning and execution of a Mediterranean villa using on-site measurements and simulations

Abstract In this research, a full rehabilitation study (retrofit) of an isolated villa in a Mediterranean climate was carried out in order to show how a retrofit of a building with a combination of simple passive and active strategies can improve the sustainability, energy efficiency and the thermal comfort. This is performed thanks to the design of a methodology of using a thermal simulation tool with experimental measurements based on a low-cost open source hardware platform in order to evaluate the energy saving measures and analyse the thermal comfort and energy savings. To accomplish this, a study of the housing needs is performed a priori to later design the different actions in the rehabilitation, using if possible, ecological materials in its development. Basically, walls and ceilings are insulated, three solar air collectors are included to heat the air ventilation and decrease the heating demand, and two pellet stoves are installed. Finally, the refurbished house is modeled and simulated in EnergyPlus and compared with the indoor air temperature and relative humidity measurements, made using an Open-Source Monitoring System (OSMS) developed for this research in Arduino, obtaining results with no significant differences without the need to calibrate the system. The results of thermal comfort, heating and cooling demand and heating energy consumption of the house before and after the renovation are compared providing a decrease in thermal demand of 66% and a decrease in heating energy consumption of 50% in the winter season, where 60% of the energy consumed is contributed from renewable sources. In terms of thermal comfort, the comparison of the PPD and PMV values shows an improvement in the house in heating and cooling season.