Optimization of Waste Heat Recovery Systems in Energy-Intensive Industries

Abstract

Energy-intensive industries discharge thermal energy through exhaust gases, cooling systems, hot products, wastewater, and equipment surfaces. Recovering part of this energy can reduce purchased utilities and improve industrial resource efficiency. However, the quantity of available heat alone does not determine the suitability of a recovery project. Temperature, contamination, operating schedules, heat demand, equipment constraints, and economic conditions influence its practical value. This narrative review examines the optimization of industrial waste heat recovery through source characterization, thermodynamic analysis, process integration, technology selection, equipment design, operational control, and economic assessment. Particular attention is given to heat exchanger networks, organic Rankine cycles, industrial heat pumps, thermal storage, and the effects of fouling and pressure losses. An integrated optimization framework is proposed in which useful energy delivery and lifecycle performance are evaluated under realistic operating conditions. A theoretical graph illustrates how source temperature affects the maximum reversible work obtainable from heat supplied by an isothermal reservoir; it does not represent actual recovery-system efficiency. The review argues that effective optimization should prioritize avoidable heat-loss reduction, suitable source–sink matching, and reliable operation before pursuing maximum equipment output. Application-specific measurements, uncertainty analysis, and verification of realized savings are essential for translating theoretical potential into durable industrial benefits.