Prototyping a novel lab-scaled High Temperature Heat Pump for usage in Thermally Integrated Carnot Batteries

Prototyping a novel lab‑scaled high temperature heat pump (HTHP) for thermally integrated Carnot batteries enables efficient recovery of industrial waste heat at high temperature levels relevant for latent thermal energy storage (TES). Within the EU‑funded SEHRENE project, a 10 kW laboratory test bench is being developed that couples an HTHP located at the University of Liège to a phase change material (PCM) TES, targeting a condensing temperature of 125–130 °C in a pressurised water loop to ensure complete PCM melting. A first-cycle design using the low‑GWP working fluid R1233zd(E) was implemented and simulated in EES, combining simplified heat exchanger pinch point constraints with a semi‑empirical reciprocating compressor model calibrated against manufacturer data to estimate mass flow rate, isentropic efficiency, and electrical power consumption, yielding a predicted COP of about 3.1 at the design point. The study highlights key integration options for the TES—indirect coupling via hot water, flash‑assisted two‑phase operation, and direct circulation of working fluid through the PCM—as well as the need for dedicated compressor thermal management strategies, such as oil cooling, shell air‑cooling, or controlled refrigerant injection, to cope with discharge temperatures above 120 °C. These preliminary results define the operating envelope and critical design trade‑offs for the upcoming lab prototype, guiding the next steps in compressor modelling refinement, TES–HTHP hydraulic integration, and control strategy development for thermally integrated Carnot batteries.