Application of nanofluids for performance improvement of plate heat exchangers: A comprehensive review

The demand for efficient thermal management in industries has driven research into nanofluids (NFs) as potential replacements for conventional heat transfer fluids (HTFs) in plate heat exchangers (PHEs). A key challenge is achieving higher heat transfer rates (HTRs) while minimizing pressure drop, which is crucial for improving energy efficiency in industrial processes. NFs are categorized into two types: simple (mono) NFs, such as single-walled (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) dispersed in base fluids, and hybrid NFs, which combine multiple nanoparticles to enhance performance. Studies show that mono NFs improve thermal conductivity, increasing heat transfer coefficients by 6.18%–16.79%. However, their high viscosity and pressure drop remain challenges. In contrast, hybrid NFs demonstrate superior thermal performance, with heat transfer coefficient improvements of up to 39.16% and only a slight increase in pumping power. This suggests they offer an optimal balance between heat transfer enhancement and operational cost efficiency. Critical factors influencing performance include operating parameters, particle concentration, inlet temperature, and flow rate. Future research should explore nanoparticle shape and size through experimental and numerical studies, along with long-term stability and cost-effectiveness in industrial applications. Addressing these areas could unlock NFs' potential to revolutionize heat exchanger technology, leading to more efficient and sustainable thermal systems.