Proposal of a transcritical R-1234ze(E) high-temperature heat pump for industrial heating.

This study explores the performance of a transcritical high-temperature heat pump (HTHP) using R-1234ze(E) as a low-global warming potential (GWP) refrigerant for industrial heating applications. A thermodynamic model was developed to optimize the cycle, mainly focusing on compressor discharge pressure regulation and the impact of temperature gradients on system efficiency. The transcritical system offers greater operational flexibility. The results indicate that heat production in the 100-160 °C range is feasible, achieving a coefficient of performance (COP) between 2.52 and 3.99 depending on operating conditions. Integrating an internal heat exchanger (IHX) improves system performance by reducing the required discharge pressure and improving overall efficiency. Furthermore, the findings reveal that larger temperature glides in the heat sink contribute to an improved Lorenz efficiency, reaching a peak value of 0.54. These findings indicate that transcritical HTHPs may be a viable alternative to traditional systems for industrial applications like drying and preheating.