Title: Energy, exergy and environment analyses of a hybrid PV-system district heating system for a new household settlement in Germany

Authors: Khaoula Daghsen; Dorra Lounissi; Nahla Bouaziz; Anna Kallert; Young Jae Yu

Addresses: Ecole Nationale d'Ingénieurs de Tunis, Unité de Recherche Energétique et Environnement, Université Tunis El Manar, BP, 37, Le Belvedere, 1002 Tunis, Tunisia; École Nationale d'Ingénieurs de Monastir, Université de Monastir, Avenue Ibn El Jazzar 5019 Monastir, Tunisia ' Ecole Nationale d'Ingénieurs de Tunis, Unité de Recherche Energétique et Environnement, Université Tunis El Manar, BP, 37, Le Belvedere, 1002 Tunis, Tunisia ' Ecole Nationale d'Ingénieurs de Tunis, Unité de Recherche Energétique et Environnement, Université Tunis El Manar, BP, 37, Le Belvedere, 1002 Tunis, Tunisia ' Fraunhofer Institute for Energy Economics and Energy System Technology IEE, Gottschalkstr. 28a, 34127 Kassel, Germany ' Fraunhofer Institute for Energy Economics and Energy System Technology IEE, Gottschalkstr. 28a, 34127 Kassel, Germany

Abstract: This work presents an exergetic and environmental assessment of a hybrid district heating system (HDHS) and normal district heating system (NDHS) analysed within two supply temperature levels. Energetic, exergetic and environmental performances are investigated. Results indicate that different scenarios have a lower degree of exergy efficiency in comparison to energy efficiency. The HDHS has a higher exergy efficiency (around 2%) and lower primary exergy demand (around 3%) compared to NDHS. Moreover, the combination of photovoltaic (PV) modules and low supply temperature reduces around 90% of the exergy losses. Results of the environmental study confirm that the lower supply temperature added to the PV modules reduce CO₂ emissions. In general, exergy analyses of the district heating systems should be conducted to make the exergo-environmental model, the matching of the quality level of demand and supply and the environmental impact, more known to the public and decision makers in the context of multi-grid energy systems.

Keywords: CO₂ emission; district heating; exergy; hybrid energetic systems; PV-modules; multi-grid energy supply; exergo-environmental impact; exergy efficiency; exergy loss.

DOI: 10.1504/IJEX.2022.124171

International Journal of Exergy, 2022 Vol.38 No.3, pp.267 - 292

Received: 04 Mar 2021
Accepted: 18 Aug 2021
Published online: 15 Jul 2022 *

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