Industrial waste heat, ORC, PEORC, Energy efficiency, Financial performance.

Abstract: In this paper, the Organic Rankine Cycle (ORC) and the Partially Evaporated Organic Rankine Cycle (PEORC) are techno-economically compared for low-temperature waste heat recovery, with a particular focus on industrial applications. Numerical models of the two power cycles were developed, while a dedicated two-phase expansion model simulating the performance of an industrial expander in the two-phase region was applied to estimate more precisely the efficiency of the PEORC. Different WFs, temperatures of the heat source, and waste heat transfer rates were considered for a complete mapping of the power cycles’ efficiency. The PEORC power cycle simulations indicate that its heat-to-power efficiency is highly dependent on the performance of the two-phase expander, with vapor quality at the evaporator outlet identified as the most crucial operating parameter. The efficiency comparison between the two alternative power cycle architectures reveals that the PEORC performs consistently better, achieving thermal efficiencies between 2.28% and 7.75%, whereas the respective values for the ORC are in the range of 1.25% to 7.13%. Both the ORC and the PEORC demonstrate favorable financial performance for the studied operating conditions. By applying the PEORC, the Levelized Cost Of Electricity (LCOE) for the industry is expected to fluctuate between 0.015 and 0.119 €/kWh, 16-17% lower than the values estimated with the ORC. Favorable PayBack Periods (PBP) (4-5 years) and Net Present Values (NPV) (260-480k€) are expected when the PEORC is applied, always higher than the respective values for the ORC because of its increased energy efficiency.

Keywords: Industrial waste heat, ORC, PEORC, Energy efficiency, Financial performance.

Date Published:
DOI: 10.11159/jffhmt.2024.012

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