| 1. |
- Cabral, Diogo, PhD, 1990-, et al.
(författare)
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Parametric comparison of a CPVT performance evaluation under standard testing procedures - ISO 9806:2017 and IEC 62108:2016 - for an automated and manual 2-axis tracking solar system stand
- 2024
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Ingår i: Energy Reports. - : Elsevier. - 2352-4847. ; 11, s. 1242-1255
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Tidskriftsartikel (refereegranskat)abstract
- Currently, a noticeable lack of literature with respect to a wide-ranging comparison of the precision exhibited by automated and manual two-axis tracking solar systems, particularly within the context of adhering to the standard testing protocols delineated by ISO and IEC. To address this research gap, a symmetrical concentrating Photovoltaic-Thermal solar collector underwent a detailed evaluation encompassing two standard testing procedures such as ISO 9806:2017 and IEC 62108:2016. This comprehensive assessment covered thermal and electrical performance parameters, unfolding across two distinct geographical locations: Athens (Greece) and Gävle (Sweden). Within this experimental framework, an automated two-axis tracking solar system stand was employed at the Greek testing site, while in Sweden it was characterized by the employment of a manual two-axis tracking solar system. The collective peak power performance presented marginal divergence within a narrow range of ± 1% across both testing sites. This culminated in an overall peak power output of 1550 Wpeak, which included an electrical peak capacity of 218 Wpeak and a thermal peak power of approximately 1332 Wpeak. Notably, the most pronounced deviation has been materialized in the transversal and longitudinal Incidence Angle Modifier coefficients, with disparities remaining limited to a threshold of < 5%. These findings underscore the commendable precision hallmarking. In summary, the outcomes presented in this study not only contribute to the extant body of knowledge by bridging the existing gap in literature, but also emphasize the precision inherent to manual two-axis tracking solar systems when compared with automated equivalents.
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| 2. |
- Lança, Miguel, et al.
(författare)
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Thermal performance of three concentrating collectors with bifacial photovoltaic cells part I – Experimental and computational fluid dynamics study
- 2024
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Ingår i: Proceedings of the Institution of mechanical engineers. Part A, journal of power and energy. - : Sage. - 0957-6509 .- 2041-2967. ; 238:1, s. 140-156
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Tidskriftsartikel (refereegranskat)abstract
- Bifacial photovoltaic cells can produce electricity from incoming solar radiation on both sides. These cells have a strong potential to reduce electricity generation costs and may play an important role in the energy system of the future. However, today, these cells are mostly deployed with one side receiving only ground reflection, which leads to a profound sub-optimal utilization of one of the sides of the bifacial cells. Concentration allows a better usage of the potential of bifacial cells, which can lead to a lower cost per kWh. However, concentration also adds complexity due to the higher temperatures reached which add the requirement of cooling in order to achieve higher outputs. This way, this paper focuses on the effectiveness of forced air circulation methods by comparing the thermal performance of three specific concentrating bi-facial collector designs. This paper developed a computational model, using ANSYS Fluent intending to assess the thermal performance of a covered concentrating collector with bifacial Photovoltaic (PV) cells. These results have then been validated by outdoor measurements. Results show that even a simple natural ventilation mechanism such as removing the side gable can effectively reduce the receiver temperature, thus resulting in favourable cell operation conditions when compared to the case of an airtight collector. Therefore, compared with a standard model, a decrease of 13.5% on the cell operating temperature was reported when the side gables are removed. However, when forced ventilation is apllied a 22.8% reduction on temperature is found compared to the standard air-tight model. The validated CFD model has proven to be a useful and robust tool for the thermal analysis of solar concentrating systems.
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| 3. |
- Lança, Miguel, et al.
(författare)
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Thermal performance of three concentrating collectors with bifacial PV cells. Part II – parametrical study
- 2024
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Ingår i: Proceedings of the Institution of mechanical engineers. Part A, journal of power and energy. - : SAGE. - 0957-6509 .- 2041-2967.
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Tidskriftsartikel (refereegranskat)abstract
- One of the problems in using PV cells to extract energy from sunlight is the temperature effect on PV cells. As the solar panel is heated, the conversion efficiency of light to electrical energy is diminished. Moreover, successive temperature elevations can cause dilatations in the array of cells which may also contribute to the degradation of the receiver. Some of the operating temperature mitigation approaches may include air-flow ventilation. In this study, data obtained by experimental and numerical simulations of a collector with bifacial PV cells is compared to the expressions found in the literature for the estimation of the heat transfer coefficient. Forced ventilation was applied to the studied collector as it accounts for much better heat dissipation. A new correlation for the estimation of the heat transfer coefficient is developed for such a geometry, for inlet velocities ranging between 3 and 8 m/s. Values of heat transfer coefficient estimated in the present work have been compared with studies of other researchers.
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