- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Passive cooling of building-integrated photovolatics in desert conditions: Experiment and modeling
摘要： The ef?ciency of photovoltaic modules depends mainly on the cell operating temperatures. Performance enhancement of building-integrated photovoltaic (BIPV) panels by passive cooling has been investigated both experimentally and with computational modeling. It has been shown that mounting the BIPV with a narrow channel can reduce the operating temperature of the photovoltaic panel. This enhancement in the heat transfer from the PV panel results in decreasing the average temperature of the PV panel from 5 to 10 (cid:1)C. Results show that having a 30 cm channel beneath the panel can increase the electrical output by 3e4%. This increase in PV output can translate into a signi?cant amount over the life cycle of a given PV module. Various channel aspect ratios have been tested in order to correlate the enhancement in performance to the cooling channel geometry. There is signi?cant consistency between the experimentally measured PV panel surface temperatures and those obtained from the computational model.
关键词： Building-integrated,Thermal performance,Passive cooling,Photovoltaic array
更新于2025-09-23 15:23:52
-
Estimation of the performance limits of a concentrator solar cell coupled with a micro heat sink based on a finite element simulation
摘要： Concentrated photovoltaic (CPV) technology makes use of cheap optical elements to amplify the irradiance and focus it on small-sized solar cells enabling the extraction of higher amounts of electricity. However, increasing the solar concentration raises the temperature of the PV cell which can deter its performance and can also cause its failure. To combat this issue both active and passive cooling mechanisms are utilized for different types of CPV systems. In this study, we determine the limits of passive cooling systems and establish when an active cooling system is needed based on the recommended operating temperature of the solar cell. We investigate the temperature characteristics of the solar cells bonded to three different substrate materials under different solar concentrations. Results showed that cell temperature is linearly dependent on the concentration ratio and ambient temperature independent of the substrate material. Further, the integration of a micro-finned heatsink results in higher heat dissipation by 25.32%, 23.13%, and 22.24% in comparison with a flat plate heatsink for Direct Bonded Copper (DBC), Insulated Metal Substrate (IMS), and Silicon Wafer (Si wafer) substrates respectively. The low thermal resistance of the IMS substrate compared to the DBC and the Si wafer substrates result in the best thermal performance in terms of maintaining the cell temperature < 80 °C and allowing a wider range of high concentration ratio.
关键词： Concentration Ratio,Passive cooling,micro fin heat-sink,finite element,Concentrating Photovoltaic,flat-plate heat-sink
更新于2025-09-23 15:19:57
-
Analysis of novel passive cooling strategies for free-standing silicon photovoltaic panels
摘要： Silicon-based photovoltaic (PV) panels are sensitive to operating temperatures, especially during exposure to high solar irradiation levels. The sensitivity of PV panels is reflected through the reductions in photovoltaic energy conversion efficiency (electrical efficiency) and in PV panel lifetime due to thermal fatigue. In this study, different and novel passive cooling strategies were proposed and numerically investigated for the case of 50-W market-available free-standing silicon PV panels. The focus of the research was to examine the effect of the proposed modifications on the temperatures of the specific PV panel layers as well as on the velocity contours. The used numerical model was upgraded based on a previously developed numerical model that was validated through an experimental manner. Three different passive cooling scenarios were numerically investigated, and the most promising one was the case where the PV panel was provided with slits through the front PV panel surface resulting in a reduction of about 4 °C for the PV panel operating temperature. The other examined cases proved to be less effective with the detected temperature reduction being less than 1.0 °C. The consideration of novel PV panel frame materials was found to be a viable possibility. It was also found that all the proposed modifications can generally lead to the performance improvement in the PV panels and reduce the materials spent on the production of commercial PV panels.
关键词： Photovoltaics,Numerical analysis,Passive cooling,Renewable energy,Energy efficiency
更新于2025-09-23 15:19:57
-
Solar gain mitigation in ventilated tiled roofs by using phase change materials
摘要： Several passive cooling design techniques are known for reducing solar heat gain through building envelope in summer season. These include the use of phase change materials (PCM), which has received an increased attention over the last years, and the strategy of increasing the above-sheathing ventilation (ASV) in ventilated roofs. However, few studies combine both technologies to maximise the building resilience in hot season. The effect of including a PCM layer into a ventilated roof is numerically analysed here in two different configurations: firstly, laid on the roof deck (PCM1 case) and, secondly, suspended in the middle of the ASV channel (PCM2 case). A computational fluid dynamics model was implemented to simulate airflow and heat transfer around and through the building envelope, under 3 days of extreme hot conditions in summer with high temperatures and low wind speed. Results showed slight differences in terms of mean temperatures at the different roof layers, although temperature fluctuations at deck in the PCM1 case were smaller than half of those estimated for the benchmark case. However, PCM2 configuration achieved a daily reduction of about 10 Wh/m2 (18%) in building energy load with respect to the benchmark case, whilst PCM1 got only 4% due to the lower ventilation at night time. Therefore, a suspended PCM layer in the ASV channel would be a better measure in terms of energy performance than laid on the deck surface, although this last option significantly decreases thermal stress of the insulation layer.
关键词： passive cooling technique,ventilated pitched roof,computational fluid dynamics,phase change material
更新于2025-09-23 15:19:57
-
A Photovoltaic Greenhouse with Passive Variation in Shading by Fixed Horizontal PV Panels
摘要： The traditional shading systems that greenhouses use cause some of the solar radiation that is re?ected or absorbed to be lost and, therefore, not used by the plants under cultivation. An interesting solution to these problems is to position photovoltaic (PV) panels on the roofs of greenhouses. All of the photovoltaic greenhouses that have been realized in Mediterranean areas are characterized by a ?xed position of the PV panels and excessive shading, especially in autumn and winter. The purpose of this study is to describe a prototype of a photovoltaic greenhouse with both ?xed and horizontal PV panels that exploit the natural variation in the elevation angle of the sun’s rays during the year to allow for “passive” variation in shading. The considerable variation in the elevation angle of the sun’s rays (from 24.4° to 71.1°) results in a high variation in shading (from 39.4% to 72.6%), with the highest values in the summer months and the lowest values in the winter months. This trend is favorable for meeting the photosynthetically active radiation (PAR) needs of greenhouse plants. If the plants under cultivation require more solar energy, it is necessary to increase the distance between the panels. We implement a speci?c mathematical relationship to de?ne the precise distance to be assigned to the photovoltaic panels on the roof pitch.
关键词： ?xed horizontal PV panels,passive variation of shading,passive cooling system,PAR,renewable source
更新于2025-09-19 17:13:59
-
Spectrally selective approaches for passive cooling of solar cells: A review
摘要： Waste heat is generated in solar cells during the daytime because they operate with a limited electrical efficiency. Moreover, the generated heat increases the solar cells’ operating temperature, and this has an adverse effect on their electrical efficiency. Therefore, numerous cooling methods have been developed to cool solar cells, such as forced air/water flow, hybrid photovoltaic/thermal system, and phase change material based photovoltaic application. Recently, a novel concept of changing the solar cells’ spectral response to both sunlight and thermal radiation has been proposed and developed to provide a passive cooling method for solar cells, which has drawn much attention from materials science to engineering fields. In this paper, the recent advancements of such a spectrally selective approach to passively cool solar cells, including radiative cooling of solar cells and full-spectrum thermal management of solar cells are reviewed, analyzed, and discussed from fundamental principles to detailed demonstration. Furthermore, the technical challenges involved in developing this new cooling technology are discussed. This paper is devoted to give a systematic introduction to a new passive cooling technology for solar cells by controlling the spectral property of solar cells, aiming to open a new opportunity for solar cells’ cooling.
关键词： Radiative cooling,Thermal management,Spectrally selective filter,Solar cells,Passive cooling,Thermal radiation
更新于2025-09-19 17:13:59
-
Performance, Limits, and Thermal Stress Analysis of High Concentrator Multijunction Solar Cell under Passive Cooling Conditions
摘要： Concentration of solar radiation onto the surface of triple-junction solar cells causes high cell temperature and system failure. Recently, several cooling methods were proposed for these systems. However, quantitative evaluation of the essential heat transfer coefficients to maintain stable operation of these systems at different meteorological and operating conditions is not found in the literature. Therefore, in this study, a comprehensive three-dimensional coupled thermal and structural model is proposed for the latest triple-junction AZUR SPACE solar cell. The model is used to investigate the performance of an HCPV system under different solar concentration ratios (CRs), ambient temperature, direct solar irradiance, wind speed, backside heat transfer coefficient, and copper-II substrate area ratios. In addition, a new structure of the solar cell is proposed by modifying the typical solar cell assembly by changing the area of the rear copper layer. The results indicate that by increasing the ambient temperature, CR and direct solar irradiance significantly increase the predicted cell temperature at the same backside heat transfer coefficient. In addition, increasing copper-II substrate area ratios significantly reduces the average cell temperature at the same backside heat transfer coefficient and CR. At the highest backside heat transfer coefficient, when the copper-II substrate area increased, the cell temperature decreased to a certain limit and subsequently remained constant. Critical values of the highest backside heat transfer coefficient were about 200, 600, 1000, and 1600 W/m2 K at CRs of 50, 500, 1000, and 1500 Suns, respectively. In addition, at the highest backside heat transfer coefficient of 1600 W/m2 K, the critical area ratio values were about 2, 3, 4, and 6 at CRs of 50, 500, 1000, and 1500 Suns, respectively.
关键词： Passive cooling,Concentrator photovoltaic,Thermal stress,Triple-junction solar cell
更新于2025-09-16 10:30:52
-
Annual Energy Harvesting of Passively Cooled Hybrid Thermoelectric Generator-Concentrator Photovoltaic Modules
摘要： Approximately 60% of the incident energy is dissipated as heat in conventional concentrator photovoltaic modules. The hybridization with thermoelectric generators (TEGs) aims to recover part of the waste heat and transform it to electricity. Recently, the feasibility of passively cooled designs has been assessed for small sized solar cells (3 mm × 3 mm). It is expected that novel prototypes will be developed according to this concept. However, the existing feasibility studies are based on reference operating conditions, while the behavior of the hybrid modules under changing atmospheric conditions remains unknown. In this article, real atmospheric data of Jaén, Southern Spain, including irradiance, temperature, and spectral data, are used to analyze the behavior of four designs of TEG-concentrator photovoltaic modules: low ZT-low temperature (A), low ZT-high temperature (B), high ZT-low temperature (C), and high ZT-high temperature (D). This behavior is compared with that of a typical concentrator photovoltaic-only module. Results show that, while the global ef?ciency at reference conditions can be enhanced up to 4.75%, the annual averaged global ef?ciency can only be increased up to 4.30%. The results of this article will help to understand the impact of the atmospheric conditions on the real behavior of these structures.
关键词： concentrator photovoltaics (CPV),efficiency improvement,Annual energy,thermoelectric generator (TEG),hybrid system,passive cooling
更新于2025-09-16 10:30:52
-
Performance analysis of a photovoltaic panel integrated with phase change material
摘要： The conversion efficiency of photovoltaic (PV) panels is reduced while the PV temperature rises. It is revealed that that every Celsius degree rise in PV temperature can result in as large as a 0.65% drop in the efficiency. This phenomenon attracts substantial scholar attentions in mitigating and controlling the PV temperature. Among those applied techniques, phase change material (PCM) is considered as a potential candidate to hold the PV temperature at a low degree because of its latent heat storage. The integrated system is therefore named PV-PCM system. In this study, the daily performance and viability of this system was evaluated through simulation, illustrating that the temperature of PV can be reduced by 24.9°C through adding PCM, and hence the electricity output increased by up to 11.02%. This study also demonstrates that the latent heat capacity of PCM and natural convection of melted PCM can control PV temperature and enhance the heat dissipation rate from PV to PCM rate by 4 to 5 times.
关键词： Photovoltaic,Phase change material,PV-PCM,Passive cooling,Thermal management
更新于2025-09-12 10:27:22
-
AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Finite element analysis of cooling mechanism by flat heat-sinks in ultra-high CPV systems
摘要： The potential cost reduction of Concentrator photovoltaic (CPV) systems is closely related to the concentration factor because higher light concentrations imply lower amount of semiconductor material required for the solar cells. However, the thermal management at such ultra-high light fluxes is difficult. The use of small-sized solar cells is beneficial for improving the thermal management. Among the possible cooling strategies, the use of flat-plate heat-sinks for passive cooling, if feasible, would be the simplest way to dissipate heat and would accelerate the development of ultra-high CPV prototypes. In this work, a thermal 3D finite-element model is used to investigate the possibilities of flat-plate heat-sinks for passive cooling at concentration ratios within 2,000-10,000 suns. Results show that a micro solar cells of 1mm x 1mm area can be thermally handled with conventional Aluminium flat plate heat-sinks up to 10,000 suns.
关键词： ultra-high concentration,passive cooling,Concentrator photovoltaic (CPV),thermal management,flat-plate heat-sinks
更新于2025-09-11 14:15:04