Transient simulation of hybridized system: Waste heat recovery system integrated to ORC and Linear Fresnel collectors from energy and exergy viewpoint

Abstract

Industrial waste heat often has a discontinuous flow with considerable fluctuations in both mass flow rates and temperature. Besides, there are challenges associated with the reliability of solar power due to its intermittent nature. The present study has prepared a continuous and steady heat load for the Organic Rankine Cycle (ORC) in two sectors. The first sector, waste heat recovery system (WHRS) of low-temperature gases in an electric arc furnace (EAF) integrated to ORC, secondly the hybrid of WHRS and ORC along with linear Fresnel collectors (LFC). Steam accumulators as thermal energy storage (TES) stabilize the thermal power fluctuations in both WHRS and LFC. The steam accumulator thermodynamic model was simulated in terms of the non-equilibrium thermal model for the liquid and vapor phases. The behavior of the hybridized WHRS was presented with three solar multiples of 1.8, 2.1, 2.8. Constant and continuous thermal power for the ORC was provided with a solar multiple of 2.8 in a full day (20th August) with an average net power of 1252 kW. It should be noted that the transient state of the system was examined from the energy and exergy viewpoint. The thermal and exergy efficiencies of the WHRS integrated with the ORC were 16.4% and 27.1%, respectively. However, the hybridized WHRS concerning thermal and exergy efficiencies were 12.3% and 16.35%, respectively. Moreover, the exergy destruction rate for all system components was calculated, and the maximum value was found to occur in the LFCs.