Thermosyphon Flat Plate Collector with Nanodiamond‑Water Nanofluids: Properties, Friction Factor, Heat Transfer, Thermal Efficiency, and Cost Analysis

摘要

Thermal efficiency, friction factor, heat transfer, and cost analysis of a flat plate collector operates with water-based nanodiamondnanofluids under thermosyphon (natural circulation) conditions are investigated experimentally at 0.2%, 0.4%,0.6%, 0.8%, and 1.0% particle volume concentrations. The thermophysical properties of the working fluids are analyzedas well. Results show that the maximum thermal conductivity and viscosity enhancements are obtained by using 1.0 vol%concentration of nanofluid and found to be 22.86% and 79.16%, respectively, compared to water at a temperature of 60 °C.The maximum increases in Nusselt number are 19.53% and 36.17% using 1.0 vol% concentration of nanofluid compared towater at Reynolds number of 140 and 345, respectively. The maximum increases of friction factor are attained by using 1.0vol% concentration of nanofluid and found to be 1.14 times and 1.25 times of water friction factor at Reynolds number of143 and 345, respectively. The collector thermal efficiency increases from 57.15% using water to 69.85% using nanofluidwith a concentration of 1.0%. The collector cost decreases approximately by 18.18% for 1.0 vol% nanofluid compared towater. The relative deviations of the equations developed to evaluate Nusselt number and friction factor are within ± 2.5%.