Energetic Assessment of a Local District Heating Network With a Small-Scale Trigeneration Plant: Comparison of Different Performance Indices

Combined Heat and Power (CHP) is a technology that has been proven to be very effective in the industrial sector, when both thermal and electrical energy are required, as it allows a more rational use of the input primary energy. However, CHP technology is not limited to industrial uses, as it can also be effectively exploited in the civil sector, such as in District Heating (DH) applications. Moreover, in recent years the opportunity to develop hybrid systems, in which traditional and renewable energy sources are integrated, is gaining more and more consideration. For these reasons, the most recent European Standards propose a set of newly conceived indices whose aim is easily assessing the energetic performances of DH networks, but the effectiveness of these indices in the study of DH networks coupled with CHP and renewable energy systems has not yet been thoroughly investigated. This paper presents a comparative study, based on these indices, of different electrical and thermal generation technologies, with the aim of assessing their effectiveness when hybrid systems are analyzed. A CHP-DH application, actually installed and in operation in Turin, Italy, has also been considered in the analysis, in order to have a comparison with a real case. The results of the study are presented and discussed in detail in the following sections.