Session: 30-07 Heat Pumps

Submission Number: 177857

Steady-State Modeling and Experimental Validation of an Industrial Large-Scale Transcritical CO2 Heat Pump: Insights From a 70 MWth Installation in Esbjerg 

The imperative necessity to mitigate climate change has never been more pressing. With the heating sector accounting for a substantial portion of global greenhouse gas emissions, a rapid transition toward sustainable energy systems in this sector is essential. Among the most promising solutions are large-scale heat pumps, which offer the potential to decarbonize heating by leveraging renewable energy sources and relying on state of the art power-to-heat technologies. In particular, transcritical CO₂ heat pump systems have emerged as highly suitable for medium to high temperature lift applications.

A landmark development in this field is the commissioning of two first-of-a-kind 35 MWₜₕ seawater-to-water heat pump plants by Everllence in Esbjerg, Denmark. These installations represent a significant step forward in the deployment of industrial-scale transcritical CO₂ heat pump technology. Fully instrumented, they provide a rare opportunity to validate and refine numerical models aimed at predicting system performance, with a focus on steady-state operation across a wide range of boundary conditions.

This paper begins with an overview of the heat pump plant architecture, including its main components and typical boundary conditions encountered throughout the year. The modeling approach is then described for each major subsystems in particular the compressor as well as heat exchangers with its gas cooler and evaporator.

Model predictions are compared to on-site measurements collected during various operational scenarios, ranging from peak winter demand to reduced summer loads. For this purpose, key performance indicators are compared at components level (efficiency, pressure drop, UA) as well as at cycle level (COP). Discrepancies between predicted and measured values are discussed, with insights into model limitations and potential improvements.

Findings are then synthesize to identify the most accurate modeling approaches for large-scale transcritical CO₂ heat pump systems. These insights are intended to support future design optimization and broader deployment of this technology in industrial and district heating applications.

Keywords: Transcritical CO2 Heat Pump, sCO2, Validation, Steady-state modeling, Esbjerg

Presenting Author: Maxime Podeur Everllence Schweiz AG

Presenting Author Biography: Maxime Podeur graduated from EPFL (Switzerland) with a degree in Mechanical Engineering, specializing in fluid dynamics and turbomachinery. He then joined the ITSM Institute (Stuttgart, Germany) as a PhD candidate, where he conducted research on diabatic compression of light gases. In 2023, Maxime joined Everllence as a Research and Development Engineer, where he is now responsible for the steady-state modeling of industrial-scale heat pump systems.

Authors:

Maxime Podeur Everllence Schweiz AG
Philipp Jenny Everllence Schweiz AG