Thermal Enhancement of Plate Heat Exchangers and Nanofluids for Sustainable Waste Heat Recovery

Abstract

Abstract. The thermal enhancement of plate heat exchangers using nanofluids presents a promising solution for sustainable waste heat recovery. Conventional heat exchangers often have limited thermal efficiency, particularly in industrial applications. Nanofluids, with their superior thermal conductivity, can significantly improve heat transfer rates and energy efficiency. The focus is on optimizing nanoparticle concentration to maximize thermal performance and long-term stability. Nanofluids are prepared by dispersing nanoparticles in base fluids such as water or ethylene glycol, using ultrasonication and surfactants to ensure uniformity and stability. Key parameters like flowrate, temperature differences, and pressure drop are measured during testing. Nanoparticle concentrations between 0.5% and 2% by volume are chosen to enhance heat transfer without compromising fluid stability. The beetle swarm optimization algorithm (BSOA) is used to optimize the nanoparticle concentration, balancing thermal conductivity with viscosity for improved efficiency. Experimental results show that nanofluids significantly enhance heat recovery; for instance,, a 1.0% nanofluid concentration achieves 1.53 kW heat recovery with 82% efficiency, compared to 1.20 kW and 68% efficiency for the base fluid. CuO/ethylene glycol (EG) nanofluid exhibits the highest thermal conductivity (0.85 W/m·K) among those tested. However, increasing nanoparticle concentration raises pressure drop, affecting system performance. Future research should focus on optimizing nanoparticle concentration for a balance between heat transfer and pressure drop, exploring long-term stability, and improving heat exchanger designs for industrial applications.