Theoretical investigation of the efficiency of a U-tube solar collector using various nanofluids

Hyeongmin Kim, Jeonggyun Ham, Chasik Park and Honghyun Cho

Energy, 2016, vol. 94, issue C, 497-507

Abstract: Using thermal energy balance, this paper analyzes and investigates the thermal performance of a U-tube solar collector whose temperature thermal energy is high due to solar radiation. A working fluid of 20% PG (propylene glycol)–water is used. Solar collector efficiency was calculated and energy savings predicted for various nanofluids, such as MWCNT, Al2O3, CuO, SiO2, and TiO2. As a result, thermal conductivity increased as the concentration of nanofluid increased. Solar collector efficiency increased in the following order from greatest to least: MWCNT, CuO, Al2O3, TiO2, and SiO2 nanofluids. When the thermal loss value ((Ti−Ta)/G) was equal to 0, the solar collector using 0.2vol% MWCNT nanofluid showed the greatest efficiency (62.8%, a 10.5% improvement compared to 20% PG–water). By dispersing nanoparticles in the working fluid, the coal usage could be further reduced by approximately 39.5–131.3 kg per year when 50 solar collectors are used. Therefore, CO2 generation could be reduced by 103.8–345.3 kg and SO2 generation by 0.4–1.1 kg per year, compared to solar collectors using a base working fluid of 20% PG–water. These findings contribute to knowledge of solar energy technology, which has the potential to reduce electricity and energy consumption world-wide.

Keywords: U-tube solar collector; Nanofluids; Thermal efficiency; Energy saving (search for similar items in EconPapers)
Date: 2016
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (22)

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Persistent link: https://EconPapers.repec.org/RePEc:eee:energy:v:94:y:2016:i:c:p:497-507

DOI: 10.1016/j.energy.2015.11.021

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