Pathways for mitigating thermal losses in solar photovoltaics

Vaillon, Rodolphe; Dupré, Olivier; Cal, Raúl Bayoán; Calaf, Marc

doi:10.1038/s41598-018-31257-0

Cited by 77 publications

(42 citation statements)

References 25 publications

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“…6b shows the theoretical and empirical improvements to the panel operating temperature resulting from improvements to the panel average convective heat transfer coefficient. A simplified energy balance model developed by Vallion et al to investigate the pathways for enhancing solar PV efficiency, with some of the results are shown as solid lines 7 . Data points represent mean temperatures for cases measured in this www.nature.com/scientificreports www.nature.com/scientificreports/ experiment.…”

Section: Theoretical Enhancement Due To Convectionmentioning

confidence: 99%

Utility-scale solar PV performance enhancements through system-level modifications

Glick

Ali

Bossuyt

et al. 2020

Sci Rep

Self Cite

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performance of solar pV diminishes with the increase in temperature of the solar modules. therefore, to further facilitate the reduction in cost of photovoltaic energy, new approaches to limit module temperature increase in natural ambient conditions should be explored. thus far only approaches based at the individual panel level have been investigated, while the more complex, systems approach remains unexplored. Here, we perform the first wind tunnel scaled solar farm experiments to investigate the potential for temperature reduction through system-level flow enhancement. The percentage of solar irradiance converted into electric power depends upon module efficiency, typically less than 20%. The remaining 80% of solar irradiance is converted into heat, and thus improved heat removal becomes an important factor in increasing performance. Here, We investigate the impact of module inclination on system-level flow and the convective heat transfer coefficient. Results indicate that significant changes in the convective heat transfer coefficient are possible, based on wind direction, wind speed, and module inclination. We show that 30-45% increases in convection are possible through an array-flow informed approach to layout design, leading to a potential overall power increase of ~5% and decrease of solar panel degradation by +0.3%/year. The proposed method promises to augment performance without abandoning current pV panel designs, allowing for practical adoption into the existing industry. previous models demonstrating the sensitivity to convection are validated through the wind tunnel results, and a new conceptual framework is provided that can lead to new means of solar pV array optimization. The operating temperature has a significant effect on the cost of photovoltaic (PV) solar energy. PV panels in the field often operate 20-40 °C above their rated temperatures, and each rising degree decreases both panel efficiency and lifetime 1-3. For example, in a typical utility scale PV installation in Colorado, summer ambient temperatures average 28.6 °C and the panel nominal cell operating temperature (NOCT) averages 48.2 °C with summer maximum module temperatures reaching 59 °C. This increase becomes important as a 5 °C increase in temperature with respect to the standard test condition (STC) has the effect of decreasing the panel efficiency 1-3% 4,5. Therefore, these sizeable effects make temperature reduction a key strategy on the roadmap to lowering solar energy costs 6. Two general strategies exist to try to achieve this goal. The first is to maximize cooling through enhanced convection/conduction and radiative cooling, and the second minimizes the thermal load through increased efficiency or advanced reflectance 7. A variety of techniques have been proposed to lower panel temperature for individual panels including phasechange materials, heat sinks, and active methods such as air and water cooling 8. For example, Krauter 9 used spray water (4.4 L/min m 2) to increase the performance of the M55 module by 1.5%. Abdo...

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Section: Theoretical Enhancement Due To Convectionmentioning

confidence: 99%

Utility-scale solar PV performance enhancements through system-level modifications

Glick

Ali

Bossuyt

et al. 2020

Sci Rep

Self Cite

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“…In our approach, we considered that PV cleaning maintenance is selected to avoid energy losses from dirt and dust and PV arrays are not affected by shading losses through trees, houses, or other bodies in proximity to PV modules. To reduce losses by temperature (8-15% in the module [85]), we will install spacers to allow 15-20 mm of space between PV modules to allow air circulation and cooling down the PV plant. Many investigations have proved the yearly average daily solar to increase over the years [86,87].…”

Section: Monthly and Yearly Variation In Energy Produced In Pv Arraysmentioning

confidence: 99%

Converting a Water Pressurized Network in a Small Town into a Solar Power Water System

Pardo

Fernández²,

Jódar-Abellán

2020

Energies

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The efficient management of water and energy is one challenge for managers of water pressurized systems. In a scheme with high pressure on the environment, solar power appears as an opportunity for nonrenewable energy expenditure reduction and emissions elimination. In Spain, new legislation that eliminates old taxes associated with solar energy production, a drop in the cost of solar photovoltaic modules, and higher values of irradiance has converted solar powered water systems into one of the trendiest topics in the water industry. One alternative to store energy (compulsory in standalone photovoltaic systems) when managing pressurized urban water networks is the use of head tanks (tanks accumulate water during the day and release it at night). This work intends to compare the pressurized network running as a standalone system and a hybrid solution that incorporates solar energy supply and electricity grids. The indicator used for finding the best choice is the net present value for the solar power water system lifespan. This study analyzed the possibility of transferring the energy surplus obtained at midday to the electricity grid, a circumstance introduced in the Spanish legislation since April 2019. We developed a real case study in a small town in the Alicante Province, whose findings provide planning policymakers with very useful information in this case and similar case studies

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“…Variations in the temperature of solar cells have been theoretically investigated by solving the heat balance equation (El-Adaw, Shalaby, Abdl El-Ghany, & Attallah, 2015) and through finite element (Lee & Tay, 2012). It is revealed that besides maximum value of the daily incident global solar radiation, as well as optical, physical, and geometrical parameters, another leading factor that determines the tempera- Variations in the temperature of solar cells have been theoretically investigated by solving the heat balance equation Vaillon, Dupré, Cal, and Calaf (2018) present the possible strategies that can be deployed to mitigate thermal losses in PV systems and quantified the approaches. Three strategies are stated to be available: maximizing cooling by conduction/convection with a colder medium and by radiation toward the surroundings; minimizing the thermal load (internal heat source) in the panels; and minimizing thermal sensitivity (temperature coefficient) of the electrical power output.…”

Section: Effect Of Temperature On Pv Systemsmentioning

confidence: 99%

Small‐scale electricity generation through thermal harvesting in rooftop photovoltaic picogrid using passively cooled heat conversion devices

Ajewole

Olabode

Alawode

et al. 2020

Environmental Quality Mgmt

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Investigated in this study is harnessing the heat energy absorbed by photovoltaic (PV) solar cells for electricity generation, in order to boost the electric power output of rooftop PV power system, without expending on cooling the energy conversion devices. An experiment was carried out in which a metallic plate was attached to the back of a low rate rooftop PV installation to capture the waste heat of the PV array and evenly distribute the heat to the conversion devices. Four commercial thermoelectric generator (TEG) modules were attached to the plate for the conversion of the heat to electricity. The modules were passively cooled and connected in parallel. Outputs of the PV array and the TEG bundle were obtained on a data logger while the experiment lasted for 11 weeks during a sunny season in Nigeria. Voltage and current up to 2.5 V and 4 A, respectively, were obtained from the harvested heat, while the PV-TEG combination operated at higher efficiency than that of the PV alone. Potential of rooftop PV system in hot climates is thus maximized by the passive cooling. The approach could be improved further using metal plate with higher conductivity.

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Pathways for mitigating thermal losses in solar photovoltaics

Cited by 77 publications

References 25 publications

Utility-scale solar PV performance enhancements through system-level modifications

Utility-scale solar PV performance enhancements through system-level modifications

Converting a Water Pressurized Network in a Small Town into a Solar Power Water System

Small‐scale electricity generation through thermal harvesting in rooftop photovoltaic picogrid using passively cooled heat conversion devices

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