Energy assessment of the implementation of renewable energies in a Portuguese household

This paper presents a detailed energy analysis of a 37-year-old house, located in Gondomar (Porto, Portugal). The current situation leads to overheating in the summer and low temperatures during the winter, causing high levels of discomfort to the occupants. With the aim to improve the overall comfort, several passive/active solar systems were proposed, and a complete energetic analysis was made. The household is located 100 m above the sea level and 13 km from the seashore. The place has a latitude and longitude of 41.2ºN and 8.5ºW, with a maritime temperate climate. The only air conditioning system used in the house is a wood-burning fireplace that distributes warm air through the rooms. During the Summer, no air conditioning is used. Throughout the year, comfortable conditions are not achieved for the occupants. Building energy requirements for the household in the cooling and heating seasons were quantified, under climatic conditions of Porto. The study was extended throughout a whole year: for the heating season, from November to April and for the cooling season, from May to October. Also, indoor temperatures were calculated through numerical simulations. The household and its components were modelled with the TRNSYS 17 simulation program. The climatic data were obtained through METEONORM, provided by TRNSYS and distributed under license from Meteotest. The results show that the integration of passive and active solar systems, guarantee an improvement in comfort and energy savings. The amount of energy required by the household is covered, to a very significant extent (approximately 71%), by energy from renewable sources. The renewable sources considered were solar energy and biomass. As passive measures, a change of the windows and the increase in wall insulation were considered. For the solar active systems, the application of thermal solar collectors for DHW and photovoltaic collectors for electricity generation at the household were analysed. The consumption of biomass in the burning fireplace was also assessed.