Energy needs calculation of italian residential buildings using a national standard and a dynamic simulation software

The energy consumption of the residential sector accounts for about 40% of the overall energy consumption in all industrialized countries. It is mainly due to the heating demand and is expected to grow significantly in the future. The depletion of natural resources, along with the increase in the global energy-related CO2 emissions, will require making a greater effort in this sector through the improvement of envelope insulation as well as the use of more efficient and less polluting energy supply systems. A number of options are currently available for building designers to answer the complex challenges of sustainability, with the selection of the more suitable solution requiring the careful evaluation of energy needs. Italian Standards UNI/TS 11300 define a simplified methodology for calculation of energy need for space heating based on a number of reference performance; the same calculation can be performed by following a more accurate approach based on a dynamic whole-building simulation software. In this paper, the energy need for space heating associated to a number of Italian buildings representing different periods of construction and sizes was calculated by means of the dynamic software TRNSYS 17 and then compared with that obtained by using the Italian Standards UNI/TS 11300 in order to estimate the relative difference as well as to assess the suitability of each method