Periodic Reporting for period 1 - NANOSPLIT (Nanofluid Spectral Beam Splitter Assisted Hybrid CPV/T System)
Période du rapport: 2021-11-01 au 2023-10-31
The light-to-power conversion efficiencies of PV systems need to be further enhanced (conversion efficiencies of commercial silicon solar cells lie between 14% to 20%). In experiments, it has been discovered that using PV cells in conjunction with a solar radiation concentrator can increase the PV cell conversion efficiency. However, a major disadvantage of concentrating photovoltaic (CPV) systems is the cell efficiency decrease brought on by the noticeably higher temperatures, which can also cause damage to the cells. These increased PV cell temperatures arise due to the non-utilisation of the entire solar irradiation spectrum for power conversion.
The PV module's efficiency improves in conventional PV/T (pre-absorption method) systems because of the heat that is eliminated through direct contact with the working fluid (coolant). However, the temperature of the harvested heat in this system is very low, typically 40–50°C at most which is too low to be useful for secondary applications. To exploit the entire spectrum and create a highly efficient PV-T (CPV-T) system, a liquid-based spectral splitter (absorption and transmission method) based on the 'pre-absorption' approach is suggested. In this method, the incoming radiation with energy beyond the band-gap energy of the PV cells can be efficiently converted into solar heat. The visible spectrum of solar radiation often contains the desirable band for photovoltaic cells. This band is well-suited to most PV materials and allows for higher solar-to-electricity efficiency. The thermal band frequently encompasses both the high-frequency UV spectrum and the low-frequency infrared spectrum. This thermal band's solar energy is inappropriate for producing PV power. In addition, a desirable separation of sunlight into electricity and heat can be achieved by varying the nanoparticle concentration in the splitter according to specific application needs.
Implementing advanced loss suppression techniques and spectral splitting concepts into hybrid PV/T collector designs have emerged as key routes towards next-generation PVT collectors, which promise higher performance at a lower cost than traditional solutions. The overall aim of NANOSPLIT is to design and test a novel CPV/T system using nanofluids as the solar spectral splitter (NSS) that can co-produce electricity and heat for domestic or industrial applications. In this novel approach, the concentrator increases the electrical efficiency of the PV cells by concentrating solar radiation, while the nanofluids (nanoparticles) spectrally filter off wavelengths that are inefficiently utilised by the PV cells in the form of heat. NANOSPLIT will offer “significantly higher heat transfer fluid (HTF) outlet temperatures without significant reduction in electrical efficiency”, and this would noticeably widen the spectrum of CPVT system-integration options.
Objectives:
1. To develop a plasmonic-material-based nanofluid spectral splitter that will have capabilities for visible light harvesting (which supports electrical conversion) and heat absorption (by filtering UV and infrared rays).
2. To develop a novel nanofluid spectral splitter (NSS)-assisted hybrid CPV/T collector, which will improve electrical efficiency by spectrally filtering off wavelengths in the form of heat that are inefficiently utilised by the PV cells, enabling the delivery of high-temperature (>100 °C) heat and enhancing the life of the PV cells.
3. To achieve an energy distribution ratio between electrical and thermal energy by adjusting nanoparticle concentration, hence overcoming the problem of delivering fluctuating power and heat in response to various home and industrial applications.
The PV module's efficiency improves in conventional PV/T (pre-absorption method) systems because of the heat that is eliminated through direct contact with the working fluid (coolant). However, the temperature of the harvested heat in this system is very low, typically 40–50°C at most which is too low to be useful for secondary applications. To exploit the entire spectrum and create a highly efficient PV-T (CPV-T) system, a liquid-based spectral splitter (absorption and transmission method) based on the 'pre-absorption' approach is suggested. In this method, the incoming radiation with energy beyond the band-gap energy of the PV cells can be efficiently converted into solar heat. The visible spectrum of solar radiation often contains the desirable band for photovoltaic cells. This band is well-suited to most PV materials and allows for higher solar-to-electricity efficiency. The thermal band frequently encompasses both the high-frequency UV spectrum and the low-frequency infrared spectrum. This thermal band's solar energy is inappropriate for producing PV power. In addition, a desirable separation of sunlight into electricity and heat can be achieved by varying the nanoparticle concentration in the splitter according to specific application needs.
Implementing advanced loss suppression techniques and spectral splitting concepts into hybrid PV/T collector designs have emerged as key routes towards next-generation PVT collectors, which promise higher performance at a lower cost than traditional solutions. The overall aim of NANOSPLIT is to design and test a novel CPV/T system using nanofluids as the solar spectral splitter (NSS) that can co-produce electricity and heat for domestic or industrial applications. In this novel approach, the concentrator increases the electrical efficiency of the PV cells by concentrating solar radiation, while the nanofluids (nanoparticles) spectrally filter off wavelengths that are inefficiently utilised by the PV cells in the form of heat. NANOSPLIT will offer “significantly higher heat transfer fluid (HTF) outlet temperatures without significant reduction in electrical efficiency”, and this would noticeably widen the spectrum of CPVT system-integration options.
Objectives:
1. To develop a plasmonic-material-based nanofluid spectral splitter that will have capabilities for visible light harvesting (which supports electrical conversion) and heat absorption (by filtering UV and infrared rays).
2. To develop a novel nanofluid spectral splitter (NSS)-assisted hybrid CPV/T collector, which will improve electrical efficiency by spectrally filtering off wavelengths in the form of heat that are inefficiently utilised by the PV cells, enabling the delivery of high-temperature (>100 °C) heat and enhancing the life of the PV cells.
3. To achieve an energy distribution ratio between electrical and thermal energy by adjusting nanoparticle concentration, hence overcoming the problem of delivering fluctuating power and heat in response to various home and industrial applications.
NANOSPLIT reports on the synthesis of plasmonic silver metal with ZnO nanoparticles utilising simple wet chemical techniques. The hybrid material has good spectral splitting capabilities, which are employed in photovoltaic cells to gather visible light and convert it into electricity. Through the filtering of UV and infrared radiation, the limited transparency bandwidth (400-1000 nm) also contributes to heat absorption. The water-based Ag-ZnO nanofluids were evaluated using optical transmission measurements, whilst Ag-ZnO hybrid nanomaterials were investigated in terms of structure, morphology, and chemical composition, which contributed to confirming the reported optical properties with those of the material. The published preliminary results may help shed additional insight on the optical and thermal mechanisms that give rise to spectral beam splitting (SBS). Ag nanostructures exhibit localised surface plasmons in the visible range (400 nm), ZnO band edge absorption above 375 nm, and infrared absorption (IR absorption, especially for low-energy photons). The selection of the nanofluid filter parameters, such as the type, size, mass fraction, and base fluid type of the nanoparticles, requires further work. However, the results are promising in terms of demonstrating a spectral beam-splitting composition that is environmentally friendly, benign, and inexpensive. The nanofluids showed remarkable spectrum selectivity in the UV and IR bands, which were absorbed or reflected, respectively. A high transmittance was found in the visible area, promoting higher PV cell efficiencies.
The outcomes of this initiative are being prepared for publication in key scientific journals. The results were also presented to the scientific community at recognised conferences such as ECOS2023 and ASME-ES-2023. The fellow participated in events like the Great Exhibition Road Festival, European Researchers' Night, and British Science Week. The fellow gave four speeches that were invited. In addition, the fellow has been actively promoting initiatives on social media (ResearchGate, Twitter) to both the public and other scientists. The impact of publishing the fellowship findings will be increased by utilising this internet presence even further.
The outcomes of this initiative are being prepared for publication in key scientific journals. The results were also presented to the scientific community at recognised conferences such as ECOS2023 and ASME-ES-2023. The fellow participated in events like the Great Exhibition Road Festival, European Researchers' Night, and British Science Week. The fellow gave four speeches that were invited. In addition, the fellow has been actively promoting initiatives on social media (ResearchGate, Twitter) to both the public and other scientists. The impact of publishing the fellowship findings will be increased by utilising this internet presence even further.
The plasmonic nanofluids were evaluated for their electrical and thermal performance as spectral splitters in PV-T and CPV-T systems. The fellow is currently investigating ways to develop next-generation PV-T systems that are extremely efficient for use in both industry and domestic environments. The project's primary outcomes support renewable power generation (e.g. solar, wind) to be as inexpensive or cheaper than fossil fuels in most places of the world (aligned with the UN Global Sustainable Development Goal 7). The proposed technology, along with road mapping workshops and community-led activities, has the potential to significantly reduce greenhouse gas emissions (in line with the 13th and 17th UN Global Sustainable Development Goals). This future direction of energy research has the potential to help the EU meet its net-zero emission targets by 2050 as part of the European Green Deal. It also aligns with the goals of the EU's European Solar Rooftops Initiative.
The scientific community in Europe will become more knowledgeable about next-generation PV-T systems as a result of further investigation and use of this unique mechanism, which will have a significant impact on society in Europe.
The scientific community in Europe will become more knowledgeable about next-generation PV-T systems as a result of further investigation and use of this unique mechanism, which will have a significant impact on society in Europe.