Design and optimization of a novel organic Rankine cycle with improved boiling process
Artikel i vetenskaplig tidskrift, 2015

In this paper we present a novel organic Rankine cycle layout, named the organic split-cycle, designed for utilization of low grade heat. The cycle is developed by implementing a simplified version of the split evaporation concept from the Kalina split-cycle in the organic Rankine cycle in order to improve the boiling process. Optimizations are carried out for eight hydrocarbon mixtures for hot fluid inlet temperatures at 120 °C and 90 °C, using a genetic algorithm to determine the cycle conditions for which the net power output is maximized. The most promising mixture is an isobutane/pentane mixture which, for the 90 °C hot fluid inlet temperature case, achieves a 14.5% higher net power output than an optimized organic Rankine cycle using the same mixture. Two parameter studies suggest that optimum conditions for the organic split-cycle are when the temperature profile allows the minimum pinch point temperature difference to be reached at two locations in the boiler. Compared to the transcritical organic Rankine cycle, the organic split-cycle improves the boiling process without an entailing increase in the boiler pressure, thus enabling an efficient low grade heat to power conversion at low boiler pressures.

Genetic algorithm

Organic split-cycle

Zeotropic mixtures

Low grade heat

Novel power cycle

Författare

J. G. Andreasen

Danmarks Tekniske Universitet (DTU)

Ulrik Larsen

Chalmers, Sjöfart och marin teknik, Maritim miljövetenskap

T. Knudsen

Danmarks Tekniske Universitet (DTU)

F. Haglind

Danmarks Tekniske Universitet (DTU)

Energy

0360-5442 (ISSN)

Vol. 91 48-59

Styrkeområden

Transport

Energi

Ämneskategorier

Energiteknik

Drivkrafter

Innovation och entreprenörskap

DOI

10.1016/j.energy.2015.06.122