Abstract:

The revamping of existing high temperature district heating systems with low temperature solutions will ensure a better usage of primary energy thanks to the reduction of thermal losses through the networks and to the possibility of use low grade enthalpy heat for the scope, including renewables and waste heat. However, several criticalities are present that make the evolution from the 3rd to the 4th generation of district heating not immediate. The paper aims to identify general technological and non-technological barriers in the revamping of traditional district heating networks into low temperature ones, with a particular focus on the Italian framework. Possible solutions are suggested, including also relevant advices for decision makers. Furthermore, the paper analyses how the possible solutions required for the up-grade of the existing district heating network can be classified through the Analytic Hierarchy Process (AHP) to prioritize the best resulting ones for more advanced evaluations.

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