UK researchers have demonstrated a photovoltaic thermal panel that uses an MXene/water nanofluid for heat transfer. They said that the nanofluid can not only improve the thermal and electrical performance of the panel, but also reduce its size by 14.5%.
Scientists at Ulster University in the United Kingdom have demonstrated a photovoltaic thermal panel (PVT) that relies on a heat transfer fluid (HTF) based on water. and two-dimensional transition metal carbides and nitrides known as MXenes. Rich land MXenes The compounds take their name from their graphene-like morphology and are made by selectively carving out a few atomic layers from a bulk crystal known as MAX.
According to the researchers, the MNenes particles can significantly improve the thermal conductivity of the base fluid and the improvement of the heat transfer of the panel. Their numerical simulation was performed on a module with dimensions of 1,640 mm × 200 mm × 5 mm and a sheet-and-tube absorber geometry consisting of a glass cover, a ethylene vinyl acetate (EVA) sheet, a photovoltaic panel, another EVA sheet, a Tedlar sheet, an absorber sheet, and an absorber tube.
The UK group considered different concentrations of MXene nanofluid at 0.01, 0.1, and 0.2 wt%. “The upper limit of MXene nanofluid concentration was chosen from the literature based on the highest concentration that creates better thermophysical property improvement with minimum viscosity enhancement,” it explained.
The academics compared the performance of the panel module with heat transfer fluid based on water and module with fluid using ethylene glycol (Eg). They performed the simulation through different mass flow rates while maintaining constant inlet temperature, and solar radiation. Thermal efficiency, electrical efficiency, heat transfer coefficient (HTC), and pressure drop are the key parameters in their analysis.
Image: Ulster University, Clean Energy Systems, Creative Commons License CC BY 4.0
The panel based on MXenes showed the highest percentage improvement in thermal efficiency of 17% over the water-based system. “The highest thermal efficiency of 67.49% was reported with 0.2 wt% MXene nanofluids,” the scientists said. “About 63% and 60.4% thermal efficiency was shown by MXene nanofluids of 0.1 and 0.01 wt%, respectively. Increasing the mass flow rate of 0.2 wt% nanofluid at 60 kgh-1 producing about a 21% increase in the thermal efficiency of the system.”
The MXenes fluid also contributed to the highest increase in photovoltaic efficiency, which was 15.94% and was achieved at 0.2 wt% nanofluid concentration. “However, the corresponding increase in electrical efficiency of N-PV/T is only about 0.65%,” said the research team. “The highest overall energy efficiency achieved by N-PV/T with 0.01, 0.1, and 0.2 wt% MXene nanofluid was calculated to be around 76, 78, and 83% at 90 kgh-1. Also, the outlet temperature was found to decrease with the flow rate. “
Their analysis also showed that the new nanofluid could help reduce the module size by 14.5%. “The highest size reduction (14.5%) was found to be possible with 0.2 wt% MXene nanofluid,” they highlighted. “The corresponding system size reduction achieved with 0.1 wt% and 0.01 wt% was calculated to be 7.8% and 4.45%, respectively.”
They presented the paper module “Numerical investigation and feasibility study of MXene/water nanofluid based photovoltaic/thermal system,” published in Cleaner Energy System. “For the practical implementation of N-PV/T additional costs will be incurred in the installation of a secondary heat exchanger, long-term sustainability measures, and safe disposal,” the academics said. “Therefore, the proposed improved PVT efficiency based on MXenes should compensate for the additional costs compared to conventional PVT.”
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