3E investigation on novel ORC-ERC system suitable for low temperature applications

Abstract

Combined cooling and power generation have gained significant attention due to their improved input energy utilization compared to standalone power cycles. The novel system combines an ejector refrigeration cycle (ERC) with the Organic Rankine cycle (ORC). The ORC-ERC system uses three heater configurations to heat the working fluid, utilizing waste heat from the ORC turbine exhaust, the ejector, and engine waste heat. The parameters to be evaluated are the hot source temperature and the turbine inlet pressure (TIP). As the temperature of the heat source and the pressure of the turbine inlet increase, the energy efficiency of the power production system also increases, but the net output and energy efficiency decrease. At 145 °C heat source temperature and 19 bar pressure at the turbine inlet, maximum output is reported. The ERC system has resulted in net work and energy efficiency of 254.6 kW and 12.38% at 24 bar TIP. Whereas the exergy efficiency is reported as maximum with 56.37% at a TIP of 19 bar, The exergy destruction in the components HE2 and turbine results in 48.1 kW and 50.47 kW, respectively, at higher input conditions for the turbine. At a TIP of 24 bar, the component turbine and heat exchanger HE1 have a combined exergy destruction and capital investment cost rate of 96,111.77 and 7861 $/Yr., respectively. Among the other components, the endogenous and exogenous exergy for the turbine results were high, with 38.23 kW and 7.67 kW, respectively. The exergy destruction for the HE2, turbine, and ejector, with respective values of 45.9, 38.2, and 18.28 kW, influences the exergoenvironmental effect rate. The present study reports a total exergoenvironmental impact rate of 3241.62 mPts/hr at a TIP of 24 bar.