Experimental investigations of upscaling effects of high-temperature heat pumps with R1233zd(E)

Titelangaben

Jeßberger, Jaromir ; Arpagaus, Cordin ; Heberle, Florian ; Brendel, Leon ; Bertsch, Stefan ; Brüggemann, Dieter:
Experimental investigations of upscaling effects of high-temperature heat pumps with R1233zd(E).
In: International Journal of Refrigeration. Bd. 164 (2024) . - S. 243-256.
ISSN 1879-2081
DOI: https://doi.org/10.1016/j.ijrefrig.2024.04.023

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Abstract

High-temperature heat pumps (HTHP) are crucial for decarbonizing district heating and industry. Hence, a reliable performance estimation considering effects of scaling is of interest for cost-efficient system integration. This study compares two laboratory HTHPs with the same refrigerant R1233zd(E). These systems have a similar plant design but a capacity scale factor of 3.2. The aim is to evaluate scale effects and make general valid statements about the challenges of upscaling laboratory test results. The analyses show that it is essential to distinguish between design effects like temperature differences at the pinch point or different heat exchanger surfaces and scale effects like relative heat losses and efficiencies of components and the system. At the component level, large surface reserves in the heat exchangers lead to 3–5 K smaller approach temperature differences in the lower capacity HTHP. At the system level, the relative heat losses are about 15 % higher than in the system with a larger capacity. The coefficient of performance of both HTHPs shows a similar trend as a function of the temperature lift from the heat source to the sink. Cross-referencing these performance results with over 200 data points from the literature, validated the possibility of upscaling.