Title:Improvement in Energy Performance of Tubular Heat Exchangers Using Nanofluids: A Review
VOLUME: 16 ISSUE: 2
Author(s):Sumit Kr. Singh and Jahar Sarkar*
Affiliation:Department of Mechanical Engineering, Indian Institute of Technology (B.H.U.), Varanasi, UP 221005, Department of Mechanical Engineering, Indian Institute of Technology (B.H.U.), Varanasi, UP 221005
Keywords:Nanofluids, double-tube heat exchanger, shell-tube heat exchanger, thermal performance, pressure drop, energy
application.
Abstract:Both mono and hybrid nanofluids, the engineered colloidal mixture made of the base fluid
and nanoparticles, have shown many interesting properties and become a high potential nextgeneration
heat transfer fluids in various heat exchangers for engineering applications. The present
review focuses on improving the performance of tubular heat exchangers by using nanofluids. For
this, the present review briefly summarizes the preparation, characterization and thermophysical
properties (thermal conductivity, viscosity, specific heat capacity and density) of mono and hybrid
nanofluids. Research works on heat transfer and pressure drop characteristics of nanofluids in the
double tube and shell-tube heat exchangers with both straight and coiled tubes, and various engineering
applications (power generation, refrigeration and air-conditioning, renewable energy, domestic
cooling or heating, etc.) are well-grouped and thoroughly discussed. Physical mechanisms for the
heat transfer enhancement using nanofluids are explored as well. Most of the studies reveal that there
are significant enhancements in the heat transfer process and in the effectiveness of both straight and
coiled tube heat exchangers with a slight increase in pressure drop using nanofluids. Hence, there is
an excellent opportunity to use nanofluids in tubular heat exchangers; however, high cost (high payback
period) and stability are the main challenges for practical implementation. Finally, some useful
recommendations are also provided.