Thermal performance analysis of a 1–5 TEMA E shell and coil heat exchanger operating with SWCNT–water nanofluid with varied nanoparticle concentration

Abstract

Single-walled carbon nanotube-water nanofluids were tested in a 1-5 TEMA E shell and coil heat exchanger. Cold nanofluid, flowing inside the coil, was heated by hot water flowing in the shell side. Volumetric fraction of nanoparticles, inlet temperature of nanofluid, and mass flow rate of nanofluids ranged from 0 to 0.21%, 2.3 to 23.4 °C, and 40 to 90 g/s, respectively. For a given Reynolds number, at the coil side, pure base fluid (φ = 0%) performed better than low-concentration nanofluid samples (φ = 0.035% and 0.053%) and was nearly equivalent to the nanofluid of highest concentration, φ = 0.21%. The thermal conductivity enhancement factor of the nanofluid ranged from 0 to 0.2 and to 0.45, at inlet temperatures of 30 °C and 50 °C, respectively. It is believed to work in favor of a better performance of the nanofluid samples. On the other hand, the unusual (literature-wise) low temperature of the nanofluid further amplified the enhancement of the nanofluid viscosity, with a reduction effect on the Reynolds number. Besides, other thermal resistances of the heat exchanger work toward an attenuation of the enhancement effect that nanoparticles may have in the heat exchanger performance. KeywordsSWCNT-water nanofluids • 1-5 TEMA E • Shell and coil heat exchanger • Helically coiled tube heat exchanger • Thermal performance • Volumetric concentration effects This article has been selected for a Topical Issue of this journal on Nanoparticles and Passive-Enhancement Methods in Energy.

Experimental data of heat transfer nanofluids for trigeneration systems: viscosity at below-ambient temperatures

“…Therefore, the data here presented allow for a valuable and original information on the viscosity of graphene and MWCNT nanofluids, particularly at below-ambient temperatures, inherent to refrigeration, and trigeneration systems, as well. Due to their observed enhancement in thermophysical properties, heat transfer nanofluids, engineered colloidal suspensions of solid nanoparticles in a heat transfer base fluid, for example, [ 5 , 6 ], can potentially improve the performance of several thermal systems, including trigeneration plants (below-ambient temperature fluid flowing between refrigeration plant and cold demand point). Given the scarcity of thermophysical properties related to these nanofluids, notably at below-ambient temperatures, the data presented here will be useful and important to thermal engineers, as more accurate results for the calculation of thermal systems, will be available.…”

“…Due to their observed enhancement in thermophysical properties, heat transfer nanofluids, engineered colloidal suspensions of solid nanoparticles in a heat transfer base fluid, for example, [ 5 , 6 ], can potentially improve the performance of several thermal systems, including trigeneration plants (below-ambient temperature fluid flowing between refrigeration plant and cold demand point).…”