@ARTICLE{10.21494/ISTE.OP.2024.1104, 

TITLE={Optimization of a highly-efficient hydro-CO<sub>2</sub> piston for commercial refrigeration}, 
  
AUTHOR={François FARALDO
, Philippe LOISEAU
, Paul BYRNE, }, 
	
JOURNAL={Entropy: Thermodynamics – Energy – Environment – Economy }, 
	
VOLUME={5}, 

NUMBER={Special issue IREEC 2}, 
	
YEAR={2024}, 

URL={https://openscience.fr/Optimization-of-a-highly-efficient-hydro-CO2-piston-for-commercial}, 
	
DOI={10.21494/ISTE.OP.2024.1104}, 
	
ISSN={2634-1476}, 
	
ABSTRACT={This paper presents a novel thermodynamic system developed to generate heat and cold for industrial processes. The efficiency is improved compared to commercialized ones and current state-of-the-art systems. The proposed hydro-CO2 piston combines three counter-intuitive innovations with the operation of discontinuous and slowed thermodynamic cycles where mechanical work is transferred to the refrigeration through a hydraulic circuit based on modified transcritical Carnot and Rankine cycles. This allows to operate unusual thermodynamic transformations such as isothermal compression and two-phase isentropic expansion. The cycles are tailored to the demand and irreversibilities are minimized to make cold/heat generation valorisation highly efficient and cost-effective. This study focuses on the technology energetic efficiency for commercial refrigeration producing negative (-20°C) and positive (0°C) cold. Based on numerical analysis and validated models using numerical tools (EES, Python) and thermodynamic data bases (REFPRP), simulations results compare standard CO2 transcritical cycles (STC) to the hydro-CO2 piston in two different case studies. The results show an increase in COP between 38 and 112% showing the energy efficiency and environmental impact decrease potential of the technology.}}