Thermodynamic and Exergy-based Lifecycle Analysis of an Ejector Organic Rankine Cycle for Cooling and Power Generation

Authors: *Onwuzurike, I.G., Ntunde, D.I. And Ugwu, H.U.

DOI Info: http://doi.org/10.5281/zenodo.21047819

ABSTRACT

The study considered the investigation of a modified organic Rankine power-cooling cycle (ORPCC) integrated with an ejector system. The system comprises a vapour generator, turbine, an ejector, a pump, a throttling valve, an evaporator and a condenser and is driven by solar heat energy. Three organic refrigerants - R245fa, R1234yf and R1234ze were used for the analysis that covered exergy-based life cycle concept. The simulation of the system was done using a developed source code in Engineering Equations Solver (EES). The thermodynamic results show that the organic Rankine cycle (ORC) system configuration has a better energy and exergy efficiencies (up to 34.43, 28.87 and 32.38% energy efficiencies while 25.7, 31.27 and 31.68% exergy efficiencies for R245fa, R1234yf, and R1234ze, respectively). This enhancement was due to the additional cooling provided by the ejector refrigeration system (ERS), generating 151.9, 120.8, and 153 kW for R245fa, R1234yf, and R1234ze, respectively. The results further demonstrate that R1234ze and R245fa are thermodynamically better options for running the developed system. The system components using R245fa has the least environmental effect with a value of 518,830 mpts while the components using R1234yf has the highest environmental effect of 540,340 mpts. The environmental effect due to refrigerant leakage was highest when using R1234ze with a value of 933325.3 mpts while the least impact was 78,123.46 mpts for R1234yf respectively. The study recommends a multi-objective optimization of the plant in order to find the refrigerant that satisfies both the thermodynamic efficiency and environmental impact.

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