Experimental Study of Using Passive Cooling of the Photovoltaic Module Under Hot Climate Conditions

2021 ◽  
Author(s):  
Mohammed Alktranee ◽  
Peter Bensc
2021 ◽  
Vol 31 (4) ◽  
pp. 243-248
Author(s):  
Nassima Bakir

Most developing countries have hot climate, ordinary jobsites characterized by reduced of human resources, equipment and infrastructures. The objective of this article is to make an experimental study of the influence of the hot climate such as that of Algeria, on the different properties of concrete in the fresh state, such as excessive water evaporation from the concrete surface, increased demand for water, increased slump loss corresponding to additional water on job-site, higher plastic shrinkage cracking and difficulty in controlling air content. At the hardened state, we could mention a reduction of strength at 28 days, decreased durability resulting from cracking at long-term period. To show the problems linked to concreting under these conditions and to present the appropriate solutions concrete or mortar can withstand the conditions in which it is implemented. Thus, negative effects caused principally by hot weather concreting motivated the choice of the such study. The research experimental work conditions in which the cementitious matrix was kept concerned two different environments, namely hot and dry climate conditions (t = 40°, h = 0%) alike the climate of the region of M'sila., and that of a medium with a hot and humid environment (t = 40°, h = 100%). The output of the investigation demonstrated the crucial role of the cure method in hot regions. The comparison of results for a reference concrete kept in air without any curing measures with two curing types simulating hot weather environment of the region M’sila was undertaken. These obtained outcome results were discussed based on the influence of climatic conditions to conclude procedures for hot weather concreting and suitable cure methods.


2021 ◽  
Author(s):  
Mohamed Sharaf ◽  
Mohamed S. Yousef ◽  
Ahmed Huzayyin

Abstract In the present work, a passive cooling strategy combining an aluminium foam matrix (AFM) with PCM was employed to regulate the temperature of a photovoltaic (PV) system The comparison between three PV modules was established ,the first one was conventional without any changes ,the second one was PV combined with PCM (PV-PCM) and the last one was PV combined with modified PCM which contain an aluminum foam matrix embedded in it (PV-PCM/AFM).Outdoor experiments were carried out in the hot weather of Benha, Egypt, which is situated at latitude 30.466° North and longitude 31.185° East. A comparison of the three PV designs was given and analysed, based on PV surface temperature, PCM temperature, open-circuit voltage, output power generated, and electrical efficiency. It was observed that using composite PCM resulted in better heat absorption from the PV module and better temperature distribution inside the PCM enclosure. Furthermore, the results indicated that against the unmodified PV system, the average cell’s temperature in the PV-PCM system was dropped by 13.3% and its electrical power was enhanced by 9%. Meanwhile, the average cell temperature in the PV-PCM/AFM configuration was reduced by 21.6% while the enhancement of the electrical power was at 14%. Furthermore, the findings demonstrated that, as compared to unmodified PCM, AFM impregnation accelerated the melting of modified PCM by roughly 37%.


2018 ◽  
Author(s):  
Sophie Szopa ◽  
Rémi Thiéblemont ◽  
Slimane Bekki ◽  
Svetlana Botsyun ◽  
Pierre Sepulchre

Abstract. The stratospheric ozone layer plays a key role in atmospheric thermal structure and circulation. Although stratospheric ozone distribution is sensitive to changes in composition and climate, the modifications of stratospheric ozone are not usually considered in climate studies at geological time scales. Here, we evaluate with a chemical-climate model the potential role of stratospheric ozone chemistry in the case of the Eocene hot conditions. We show that the structure of the ozone layer is significantly different under these conditions (4×CO2 climate and high concentrations of tropospheric N2O and CH4). While at mid and high latitudes, the total column ozone is found to be enhanced, the tropical ozone column remains more or less unchanged. These ozone changes are related to the stratospheric cooling and an acceleration of stratospheric Brewer-Dobson circulation simulated under Eocene climate. The meridional distribution of the total ozone column appears also to be strongly modified, showing particularly pronounced mid-latitudes maxima and steeper negative poleward gradient from these maxima. These anomalies are consistent with changes in the seasonal evolution of the polar vortex during the winter, especially in the Northern Hemisphere. Compared to a pre-industrial atmospheric composition, the changes in local ozone concentration reach up to 40 % for zonal annual mean and affect temperature by a few Kelvins in the middle stratosphere. As inter-model differences in simulating the deep past temperatures are quite high, the consideration of atmospheric chemistry, which is computationally demanding in Earth system models, may seem superfluous. However, our results suggest that using stratospheric ozone calculated by the model (and hence more physically consistent with Eocene conditions) instead of the commonly specified preindustrial ozone distribution can change the simulated global surface air temperature by 14 %. This error is of the same order as the effect of non-CO2 boundary conditions (topography, bathymetry, solar constant & vegetation). Moreover, the results highlight the sensitivity of stratospheric ozone to hot climate conditions. Since the climate sensitivity to stratospheric ozone feedback largely differs between models, it must be better constrained not only for deep past conditions but also for future climates.


2000 ◽  
Vol 41 (9) ◽  
pp. 883-890 ◽  
Author(s):  
Bilal A Akash ◽  
Mousa S Mohsen ◽  
Waleed Nayfeh

2021 ◽  
pp. 1-50
Author(s):  
Xiaoquan Chen ◽  
Fengcun Xing ◽  
Shu Jiang ◽  
Yongchao Lu ◽  
Zhongrong Liu ◽  
...  

Using fresh cores samples, we determined the origin and formation process of Eocene lacustrine dolomites in the Tibetan Plateau through petrological, mineralogical, and geochemical analyses. Dolomitic rocks were collected from the upper member of Eocene Niubao Formation in the Lunpola Basin, and consist of dolomitic mudstone, argillaceous dolomite, dolomite-bearing mudstone and mud-bearing dolomite. These dolomites are dominated by aphanotopic and micro-crystalline dolomites, with minor amounts of euhedral or subhedral powder- and fine-crystalline dolomites. Carbon and oxygen stable isotopes, combined with ubiquitous gypsum in study area, indicates a semi-saline continental lake under strong evaporative conditions. The revealed relatively high temperature of dolomitization(33.8°C–119.1°C), combined with hydrothermal minerals such as cerous phosphate and barite, reflect the participation of dolomite from hot fluids. Moreover, the inferred dolomitization temperatures decrease gradually toward the centre of the lake basin, suggesting the resurgence of hydrothermal fluids along a fault zone on the lake margin. This proves that frequent thermal events occurred at the boundary fault of the Lunpola Basin margin during early Himalayan orogenesis. In addition, Jurassic carbonates interacting with hydrothermal fluids, as well as strong evaporation conditions, likely provided favourable conditions for the formation of primary lime sediments. A rich source of Mg2+ brought by volcanic ash, hydrothermal fluids, and the Jurassic carbonates then created conditions for dolomitization during the depositional period. Strong evaporation under a relatively hot climate enhanced penecontemporaneous dolomitization, thus forming dolomite. Tibetan Plateau was under arid to semi-arid climate conditions, and there was a widespread distribution of dolostones in western, central, and northern China during the Eocene period. The hydrothermal dolomites of the upper Niubao Formation testify for active hot springs, while lacustrine dolomite imply arid or semi-arid climates during the Eocene, in the early stages of Himalayan orogenesis.


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