Optimizing MWCNT-Based Nanofluids for Photovoltaic/Thermal Cooling through Preparation Parameters

Area of Science:

• Materials Science
• Renewable Energy Engineering

Background:

• Photovoltaic thermal (PVT) systems require efficient cooling, especially in extreme environments like Baghdad's summer.
• Nanofluids offer enhanced thermal properties compared to traditional coolants.
• Multiwalled carbon nanotubes (MWCNTs) are promising nanoparticles for improving heat transfer in nanofluids.

Purpose of the Study:

• To determine the optimal nanofluid composition for cooling PVT systems in Baghdad's hot climate.
• To evaluate the impact of base fluid, surfactant, and sonication time on nanofluid performance.
• To assess the thermal conductivity, stability, and overall efficiency of MWCNT-based nanofluids in PVT systems.

Main Methods:

• Investigated water as the base fluid, comparing it with ethylene glycol (EG), propylene glycol (PG), and heat transfer oil (HTO).
• Examined the role of surfactant (CTAB) and sonication time in preparing the MWCNT nanofluid.
• Tested the optimized nanofluid in a PVT system under Baghdad's environmental conditions.

Main Results:

• The optimal nanofluid (0.5% MWCNTs, water, CTAB, 3.25 hours sonication) showed significant thermal conductivity enhancements: 119.5% over EG, 308% over PG, and 210% over HTO.
• The nanofluid-cooled PVT system achieved 88.85% higher electrical efficiency than standalone PV and 44% higher than water-cooled PVT.
• Thermal efficiency increased by 20% compared to water-cooled PVT systems, with maintained performance at peak temperatures.

Conclusions:

• MWCNT-based nanofluids, particularly with water and CTAB, are highly effective for PVT cooling in extreme heat.
• Optimized nanofluids significantly enhance both electrical and thermal efficiencies of PVT systems.
• This approach offers a viable solution for improving PVT performance in challenging climates.