Message from the Guest Editors

The global transition toward low-carbon and decentralized energy systems has accelerated the development of Renewable Energy Communities (RECs) as an innovative model for sustainable regional energy management. By promoting local renewable energy generation, collective self-consumption, and stakeholder participation, RECs are becoming an important component of the energy transition.

Within this framework, the integration of renewable energy, energy reduction, and energy recovery provides a comprehensive pathway toward a future free from fossil fuels, summarized by the “3R for 4F” paradigm. This approach highlights the complementary role of renewable energy deployment, energy efficiency improvement, and energy recovery technologies in supporting sustainable territorial development.

At the same time, the increasing complexity of modern energy infrastructures emphasizes the importance of thermophysical systems and engineering thermophysics in enhancing the performance of distributed energy solutions. Thermal energy storage, thermal management, transport phenomena, and integrated energy processes play a key role in improving efficiency, flexibility, and reliability.

This Special Issue focuses on the interaction between Renewable Energy Communities and thermophysical systems as key enablers of sustainable regional energy transition. It includes selected contributions from the “Study Day on Energy Communities for Territorial Development”, held in Milis (Oristano, Italy) on 16 February 2026, together with additional studies addressing renewable energy integration, energy efficiency, energy recovery, thermal storage, and advanced energy system modeling in support of the 3R for 4F vision.

Guest Editors

Oronzio Manca

Dipartimento di Ingegneria, Università degli Studi della Campania "Luigi Vanvitelli", Italy.

Research interests: Heat Transfer and Convection; Thermal Sciences and Applied Thermodynamics; Buoyancy-Driven Flows; Heat Transfer in Engineering Systems; Energy and Thermal Management; Numerical and Experimental Thermal Analysis, Heat Transfer in Porous Media.

Bernardo Buonomo

Dipartimento di Ingegneria, Università degli Studi della Campania "Luigi Vanvitelli", Italy.

Research interests: Analysis of Active and Passive Solar Systems; Thermodynamics Analysis of Natural Convection in Open-Ended Cavities; Analysis of Heat Transfer in Porous Media; Microchannels; Nanofluids.

Alessandro Franco

Dipartimento di Ingegneria dell’Energia, dei Sistemi, del Territorio e delle Costruzioni (DESTEC), Università di Pisa, Italy.

Research interests: Applied thermodynamics, heat transfer and two-phase flow phenomena in thermal devices, energy efficiency and sustainability, renewable energy systems, geothermal and solar energy applications, hydrogen technologies, thermal energy use in hard-to-abate sectors, energy transition and decarbonization of industrial energy systems, smart sector integration.

Sergio Nardini

Dipartimento di Ingegneria, Università degli Studi della Campania "Luigi Vanvitelli", Italy.

Research interests: Thermal conduction, natural and mixed convection in partially open cavities, analysis of active and passive solar systems, enhancement in heat transfer, characterization and use of nanofluids in heat transfer, thermal energy storage systems, forecast of national electricity consumption, heat transfer in transport, life cycle assessment for thermal components and systems.