Design and Performance Analysis of a Counter flow Heat Exchanger Using Industrial Waste Hot Water

Abstract

Industrial processes discharge a large amount of waste hot water that is commonly released without energy recovery, leading to avoidable thermal losses. This study focuses on utilizing this low-grade thermal energy through a counter flow heat exchanger system. The primary objective is to recover heat from industrial waste hot water and transfer it to normal inlet water, thereby reducing fuel consumption, heating time, and overall energy demand in industrial applications. A counter flow heat exchanger was designed using a GI pipe for hot waste water and a copper tube for normal water flow inside a cylindrical shell. Waste hot water entered the system at 60°C and exited at 32°C, while normal water entered at 23°C and exited at 28°C under steady-state conditions. The system demonstrated effective heat recovery, increasing the normal water temperature by 5°C using only waste thermal energy. For counter flow operation, the temperature differences were 32°C and 9°C, resulting in a Log Mean Temperature Difference (LMTD) of approximately 18°C, indicating acceptable heat transfer performance. The proposed heat exchanger successfully converts industrial waste hot water into a useful energy source, reducing energy loss and operating costs. This approach offers a practical and sustainable solution for improving thermal efficiency in industrial water heating systems.