A methodological approach for energy demand assessment: theoretical analysis on solar thermal collector energy contribution

Solar thermal collector system is a widely used solution involving renewable energy source to cover the energy demand for domestic hot water production. At Italian level, the UNI TS 11300 provides a calculation methodology based on two approaches: the asset rating, which is easy to be applied but provides approximated results, and the tailored rating, which is more reliable but requires several detailed information. In this context, the present work proposes a new methodological approach to develop a simplified calculation method in order to obtain accurate energy performance results with no-additional cost for assessors and final users. Different case studies were analysed carrying out parametric simulations. The obtained results have led to the definition of the new simplified calculation methodology to predict the thermal energy supplied by solar thermal collectors; it allows also calculating the domestic hot water volume to be covered by other technical building systems, becoming a useful tool for their pre-dimensioning. Besides, the results open to new scenarios of interest, such as the application of the same approach to other energy services in order to integrate the outcomes of the asset rating provided by the UNI TS 11300