Titre : Optimization of a highly-efficient hydro-CO2 piston for commercial refrigeration Auteurs : François FARALDO , Philippe LOISEAU , Paul BYRNE, Revue : Entropy: Thermodynamics – Energy – Environment – Economy Numéro : Special issue IREEC 2 Volume : 5 Date : 2024/02/28 DOI : 10.21494/ISTE.OP.2024.1104 ISSN : 2634-1476 Résumé : 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. Éditeur : ISTE OpenScience