Retrofitting of the District Heating System Based on the Application of Heat Pumps Operating with Natural Refrigerants

Damir Požgaj, Branimir Pavković (), Boris Delač and Vladimir Glažar
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Damir Požgaj: Faculty of Engineering, University of Rijeka, 51000 Rijeka, Croatia
Branimir Pavković: Faculty of Engineering, University of Rijeka, 51000 Rijeka, Croatia
Boris Delač: Faculty of Engineering, University of Rijeka, 51000 Rijeka, Croatia
Vladimir Glažar: Faculty of Engineering, University of Rijeka, 51000 Rijeka, Croatia

Energies, 2023, vol. 16, issue 4, 1-28

Abstract: The implementation of renewable energy sources and heat pumps with natural refrigerants in the existing 3rd-generation district heating (DH) systems is a promising technology for the conversion to a 4th-generation DH system. This paper aims to investigate this transition through a case study for the existing DH system in Croatia. The district of Rijeka, which is considered in the case study, has an existing 3rd-generation DH system with a capacity of 9.2 MW, which was originally designed for a temperature regime of 130/70 °C and produces thermal energy from natural gas. In order to use heat pumps efficiently in such a system, the temperature of the distribution system and the energy consumption should be reduced. Trnsys software was used to perform complete dynamic simulations of the DH system. Used baseline models were validated according to the actual energy consumption reported by the heat supplier. The application of heat pumps with natural refrigerants in combination with on-site electricity production (PV system) can almost eliminate system CO 2 emissions, reduce primary energy consumption and lower operation costs. Simulations were performed for 18 different scenarios that included 2 different building envelope variants. The results were compared, then discussed and conclusions were drawn.

Keywords: district heating; heat pumps; natural refrigerants; CO 2 emissions; simulation (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2023
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

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