<b>Modeling and Test Stand Development for a High Temperature Heat Pump up to 200 °C</b>

<p dir="ltr">High-temperature heat pumps (HTHP) are essential for improving the efficiency of industrial heating processes. Increasing the HTHP supply temperatures up to 200 °C can enable a broader impact of the technology on different industrial sectors, but bring challenges associated with cycle efficiency, compression technologies and their discharge temperatures, and material compatibilities. This study presents a refrigerant screening and compressor isentropic efficiency sensitivity study for the application of steam-generating heat pumps (SGHP) at a variety of operating conditions to determine the ideal refrigerant combinations the effect of isentropic efficiency at different steam supply conditions. Additionally, the modeling efforts are presented for the design and development of a state-of-the-art test facility for a novel HTHP architecture, aiming to produce heat at 200 °C in a subcritical cycle. Specifically, the cycle features refrigerant economization coupled with internal refrigerant cooling of the twin-screw compressor rotors to reduce discharge temperature and improve overall efficiency. Potential refrigerant candidates were filtered based on a previous refrigerant screening and the refrigerant that yielded the most fitting results was pure cyclopentane. Integrating compressor maps and moving boundary heat exchanger models provided increased system model fidelity, resulting in a predicted coefficient of performance (COP) of 2.85, second law efficiency of 48.7%, and a heat sink outlet temperature of 201 °C. The test setup will confirm the ability to provide heat at 200 °C, assess refrigerant and lubricant compatibility, and explore compressor behavior and material compatibility. This integrated work demonstrates the feasibility of this cycle architecture in maximizing HTHP efficiency for industrial applications.</p>