In the last decades the concept of distributed generation - i.e. The installation of (electrical and/or thermal) energy production systems at the final users - was born and found gradually increasing diffusion. For what concerns the electrical production, the distributed generation systems are directly connected to the National Electricity Transmission Grid, allowing a bidirectional energy flux at the utilities and giving rise to the so-called smart grid. In this scenario and considering that, even thanks to the direction taken by European regulations, in the European territory there is already a large number of thermal power generation's distributed systems (e.g. solar thermal panels), in the near future the concept of smart grid could be extended to the heat sector, especially in relation to District Heating Networks (DHNs). As a consequence, with the aim of analyzing the penetration of this type of networks, several possible layouts for the exchange utilities' substation have been developed and will be presented in this study. Such layouts allow to optimize thermal exchange, as a function of network design temperatures (for both the supply and the return), of utilities' thermal power requirement and depending on the characteristics of the production system. © 2015 The Authors. Published by Elsevier Ltd.