Dario Prando

Analysis of the energy and economic impact of cost-optimal buildings refurbishment on district heating systems

This article aims to define the energy and economic performance of district heating considering the impact of cost-optimal refurbishment solutions of the connected buildings. The possibility to shift to low-temperature district heating is considered as a feasible solution to compensate for the loss of performance of the network in combination with a systematic approach to the refurbishment of the connected buildings. For this purpose, an integrated model for both buildings and network has been developed. Several refurbishment measures for the existing buildings have been investigated, and a multi-objective (energy and economic) optimization has been conducted, by means of a genetic algorithm to reduce the computational time. The results highlight that building refurbishment strongly influences both the energy and economic performance of the district heating system. The distribution efficiency is considerably low during summer—only domestic hot water need—and when a high number of refurbished buildings is considered in the district heating network. Nevertheless, the implementation of the minimum network temperature allows partial compensation for both the energy and economic losses deriving from the refurbishment. Although an incentive to promote the use of heat at lower temperature has been considered, the economic loss deriving from the incentive could not be paid back.