Evaluation of the potential of nanofluids containing different Ag nanoparticle size distributions for enhanced solar energy conversion in hybrid photovoltaic-thermal (PVT) applications

Abstract

Hybridising photovoltaic and photothermal technologies into a single system that can simultaneously deliver heat and power represents one of the leading strategies for generating clean energy at more affordable prices. In a hybrid photovoltaic-thermal (PVT) system, the capability to modulate the thermal and electrical power output is significantly influenced by the spectral properties of the heat transfer fluid utilised. In this study, we report on one of the first experimental evaluations of the capability of a multimodal silver nanofluid containing various particle shapes and particle sizes to selectively modulate the solar energy for PVT applications. The diverse set of particle properties led up to a 50.4% enhancement in the solar energy absorbed by the nanofluid over the 300 nm – 550 nm spectral region, where silicon is known to exhibit poor photovoltaic conversion performances. This improved substantially the absorption of solar energy, with an additional 18 – 129 W m-2 of thermal power being generated by the PVT system. Along with the advancements made in the thermal power output of the PVT system, a decrease of 4.7 – 36.6 W m-2 in the electrical power generated by the photovoltaic element was noted. Thus, for every ~11 W m-2 increase of thermal power achieved through the addition of the nanoparticles, a reduction of ~3 W m-2 in the ability to generate clean electricity was sustained by the PVT. Despite the energy trade-offs involved under the conditions of the nanofluid, the PVT system cumulatively harvested 405 W m-2 of solar energy, which amounts to a total conversion efficiency of 45%. Furthermore, the economics of the additional energy harvested through merging of the two systems was found to reach an enhancement of 77% under certain European conditions.

Experimental and Theoretical Evaluation of a Commercial Luminescent Dye for PVT Systems

“…The vulnerability of the worth factor to geographic and economic changes in the interaction between the abundant availability of electrical and thermal energy could enable a strategic choice of locations suitable for implementing a full-scale PVT system. To close the gap between theoretical and isolated laboratory-based research and suggest possible solutions suitable for practical implementation, a merit function study [32,51,59,66,67] was performed. By applying this simulation to real-world scenarios, the study aims to offer valuable insights into selecting optimal sites for PVT installation based primarily on the location's energy market and the country's merit function for electrical and thermal energy generation.…”

The Role of Solar Spectral Beam Splitters in Enhancing the Solar-Energy Conversion of Existing PV and PVT Technologies

“…A recent approach involves the placement of the working fluid in front of a solar cell, as with LSC/LDS layers. In this case, the entire structure can operate as a spectral beam splitter PVT (SBS-PVT) [75,160,[166][167][168][169][170][171][172][173]. Coupling in this manner (Figure 6) allows the working liquid to act as a spectral modulator and a heat-transfer fluid.…”

“…Popular investigations into these systems are primarily focused on nanofluids, with silver nanoparticles introduced in the working fluid receiving more attention due to the plasmonic effects that such nanoparticles can introduce [157,160,166,[178][179][180][181]. A noticeable omission from the literature relates to the use of low-cost commercial-grade luminophore materials in SBS-PVT systems.…”

“…Analyses involving the merit function consider various factors that relate to the operational effectiveness of the SBS-PVT system [75,160,167,177]. To evaluate whether a working fluid can convert solar energy into electrical and thermal energy more efficiently within a PVT system, a merit function is implemented following equation 6 [75,160,166,167].…”

“…where P PV and P PV(un f iltered) are the filtered and unfiltered electrical power output of the silicon cell, respectively, P Pt is the thermal power output of the PVT system when a working fluid is employed, and, w is the factor of the worth of the electricity to the thermal energy [75,166,167]. Classically, heat-transfer fluids are evaluated using a 3:1 worth factor of electricity to thermal energy [157,157,160,161,178,180].…”