Integration of booster heat pumps in ultra-low temperature district heating network: Prototype demonstration and refrigerant charge investigation

Tingting Zhu; Yanjun Du; Jierong Liang; Wilko Rohlfs; Jan Eric Thorsen; Brian Elmegaard

doi:10.1016/j.enbuild.2023.113516

Integration of booster heat pumps in ultra-low temperature district heating network: Prototype demonstration and refrigerant charge investigation

Tingting Zhu, Yanjun Du, Jierong Liang^*, Wilko Rohlfs, Jan Eric Thorsen, Brian Elmegaard

^*Corresponding author for this work

Heat Transfer and Thermodynamics

Research output: Contribution to journal › Article › Academic › peer-review

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Abstract

Decentral booster heat pumps (BHPs) integrated in ultra-low temperature district heating (ULTDH) systems are deemed a sustainable solution for low-carbon building systems. The performance of BHPs is critical for the implementation of ULTDH systems. In this study, we experimentally investigate the effect of refrigerant charge on temperature, pressure, system coefficient of performance (COP), and heating capacity to evaluate the operability and sensitivity of ULTDH. A performance-guaranteed range of refrigerant charge is proposed to ensure the feasibility of the system. We also analyse the component-level exergy destruction and the system-level exergetic efficiency of a BHP prototype. The exergetic efficiencies range from 24.9 % to 33.4 % under operational conditions for ULTDH. The condenser and evaporator's exergy destruction is influenced by the temperature profiles on both sides, suggesting the potential to improve BHP performance by tailoring operating parameters. Additionally, the return water temperature significantly affects the system COP when the domestic hot water supply temperature is fixed. Within the allowable range of return water temperature, BHP operation with high evaporator outlet water temperature can improve the overall efficiency of the ULTDH system.

Original language	English
Article number	113516
Number of pages	14
Journal	Energy and buildings
Volume	298
Early online date	4 Sept 2023
DOIs	https://doi.org/10.1016/j.enbuild.2023.113516
Publication status	Published - 1 Nov 2023

Keywords

Booster heat pump
COP
District heating
Domestic hot water
Exergy analysis

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1016/j.enbuild.2023.113516Licence: CC BY

S0378778823007466Final published version, 158 KBLicence: CC BY

Cite this

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title = "Integration of booster heat pumps in ultra-low temperature district heating network: Prototype demonstration and refrigerant charge investigation",

abstract = "Decentral booster heat pumps (BHPs) integrated in ultra-low temperature district heating (ULTDH) systems are deemed a sustainable solution for low-carbon building systems. The performance of BHPs is critical for the implementation of ULTDH systems. In this study, we experimentally investigate the effect of refrigerant charge on temperature, pressure, system coefficient of performance (COP), and heating capacity to evaluate the operability and sensitivity of ULTDH. A performance-guaranteed range of refrigerant charge is proposed to ensure the feasibility of the system. We also analyse the component-level exergy destruction and the system-level exergetic efficiency of a BHP prototype. The exergetic efficiencies range from 24.9 % to 33.4 % under operational conditions for ULTDH. The condenser and evaporator's exergy destruction is influenced by the temperature profiles on both sides, suggesting the potential to improve BHP performance by tailoring operating parameters. Additionally, the return water temperature significantly affects the system COP when the domestic hot water supply temperature is fixed. Within the allowable range of return water temperature, BHP operation with high evaporator outlet water temperature can improve the overall efficiency of the ULTDH system.",

keywords = "Booster heat pump, COP, District heating, Domestic hot water, Exergy analysis",

author = "Tingting Zhu and Yanjun Du and Jierong Liang and Wilko Rohlfs and {Eric Thorsen}, Jan and Brian Elmegaard",

note = "Funding Information: The research leading to these results has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement no. 713683 (H. C. {\O}rsted Postdoc project HPMixPerform: Performance optimization of heat pumps using zeotropic mixtures as working fluid). The authors gratefully acknowledge the financial support provided by EUDP (Energy Technology Development and Demonstration) under the project “EnergyLab Nordhavn-NewUrban Energy Infrastructures” (Project number: 64014-0555). The authors would also like to express our heartfelt gratitude to Jan Horne Hansen and Benny Edelsten for their help with the experiment setup. Publisher Copyright: {\textcopyright} 2023 The Authors",

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doi = "10.1016/j.enbuild.2023.113516",

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AU - Zhu, Tingting

AU - Du, Yanjun

AU - Liang, Jierong

AU - Rohlfs, Wilko

AU - Eric Thorsen, Jan

AU - Elmegaard, Brian

N1 - Funding Information: The research leading to these results has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement no. 713683 (H. C. Ørsted Postdoc project HPMixPerform: Performance optimization of heat pumps using zeotropic mixtures as working fluid). The authors gratefully acknowledge the financial support provided by EUDP (Energy Technology Development and Demonstration) under the project “EnergyLab Nordhavn-NewUrban Energy Infrastructures” (Project number: 64014-0555). The authors would also like to express our heartfelt gratitude to Jan Horne Hansen and Benny Edelsten for their help with the experiment setup. Publisher Copyright: © 2023 The Authors

PY - 2023/11/1

Y1 - 2023/11/1

N2 - Decentral booster heat pumps (BHPs) integrated in ultra-low temperature district heating (ULTDH) systems are deemed a sustainable solution for low-carbon building systems. The performance of BHPs is critical for the implementation of ULTDH systems. In this study, we experimentally investigate the effect of refrigerant charge on temperature, pressure, system coefficient of performance (COP), and heating capacity to evaluate the operability and sensitivity of ULTDH. A performance-guaranteed range of refrigerant charge is proposed to ensure the feasibility of the system. We also analyse the component-level exergy destruction and the system-level exergetic efficiency of a BHP prototype. The exergetic efficiencies range from 24.9 % to 33.4 % under operational conditions for ULTDH. The condenser and evaporator's exergy destruction is influenced by the temperature profiles on both sides, suggesting the potential to improve BHP performance by tailoring operating parameters. Additionally, the return water temperature significantly affects the system COP when the domestic hot water supply temperature is fixed. Within the allowable range of return water temperature, BHP operation with high evaporator outlet water temperature can improve the overall efficiency of the ULTDH system.

AB - Decentral booster heat pumps (BHPs) integrated in ultra-low temperature district heating (ULTDH) systems are deemed a sustainable solution for low-carbon building systems. The performance of BHPs is critical for the implementation of ULTDH systems. In this study, we experimentally investigate the effect of refrigerant charge on temperature, pressure, system coefficient of performance (COP), and heating capacity to evaluate the operability and sensitivity of ULTDH. A performance-guaranteed range of refrigerant charge is proposed to ensure the feasibility of the system. We also analyse the component-level exergy destruction and the system-level exergetic efficiency of a BHP prototype. The exergetic efficiencies range from 24.9 % to 33.4 % under operational conditions for ULTDH. The condenser and evaporator's exergy destruction is influenced by the temperature profiles on both sides, suggesting the potential to improve BHP performance by tailoring operating parameters. Additionally, the return water temperature significantly affects the system COP when the domestic hot water supply temperature is fixed. Within the allowable range of return water temperature, BHP operation with high evaporator outlet water temperature can improve the overall efficiency of the ULTDH system.

KW - Booster heat pump

KW - COP

KW - District heating

KW - Domestic hot water

KW - Exergy analysis

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DO - 10.1016/j.enbuild.2023.113516

M3 - Article

AN - SCOPUS:85170423195

SN - 0378-7788

VL - 298

JO - Energy and buildings

JF - Energy and buildings

M1 - 113516

ER -

Integration of booster heat pumps in ultra-low temperature district heating network: Prototype demonstration and refrigerant charge investigation

Abstract

Keywords

UN SDGs

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