This paper provides an overview of the cleaning aspects of solar panels through a literature review. We first discuss the drawbacks of unwanted deposits on solar panels in terms of energy production and efficiency. Existing cleaning practices and technologies are then presented with an emphasis on factors such as the size of the facility, location, cost, and available resources. Finally, a comparative cost–benefit analysis is carried out using decision support tools and taking into account different relevant criteria to support users choose the right cleaning maintenance for their specific solar installation.

Photovoltaic-thermal (PV/T) collectors have gained a lot of attention in recent years due to their substantial advantages as compared to ST or PV systems alone and even to other non-solar technologies. However, PV/Ts are still not as popular in industry or construction and they are not even known to major players implementing solar energy installations. In this article, a general presentation of PV/Ts and a review of their applications are given. First, different heat extraction media (e.g., air, water, bi-fluid, etc.) and hybrid design configurations of hybrid PV/T collectors are addressed. Next, the main applications of PV/T collectors are discussed in order to highlight their feasibility and usefulness and to raise awareness for adoption in the industry and buildings sector. Applications include desalination, air-conditioning, drying, trigeneration, etc. This paper should be considered as a reference form of PV/Ts to extract key points for future research and development as well as for other applications.

Today, climate change combined with the energy crisis is accelerating the worldwide adoption of renewable energies through incentive policies. However, due to their intermittent and unpredictable behavior, renewable energy sources need EMS (energy management systems) as well as storage infrastructure. In addition, their complexity requires the implementation of software and hardware means for data acquisition and optimization. The technologies used in these systems are constantly evolving but their current maturity level already makes it possible to design innovative approaches and tools for the operation of renewable energy systems. This work focuses on the use of Internet of Things (IoT) and Digital Twin (DT) technologies for standalone photovoltaic systems. Based on Energetic Macroscopic Representation (EMR) formalism and the Digital Twin (DT) paradigm, we propose a framework to improve energy management in real time. In this article, the digital twin is defined as the combination of the physical system and its digital model, communicating data bi-directionally. Additionally, the digital replica and IoT devices are coupled via MATLAB Simulink as a unified software environment. Experimental tests are carried out to validate the efficiency of the digital twin developed for an autonomous photovoltaic system demonstrator.

Urbanization, anthropogenic activities, and social determinants such as poverty and literacy rate greatly contribute to heat-related mortalities. The 2003 strong heat wave (Lucifer) in France resulted in catastrophic health consequences in the region that may be attributed to urbanization and other anthropogenic activities. Amiens is a medium-sized French city, where the average temperature has increased since the year 2000. In this study, we evaluated the Heat Vulnerability Index (HVI) in Amiens for extreme heat days recorded during three years (2018–2020). We used the principal component analysis (PCA) technique for fine-scale vulnerability mapping. The main types of considered data included (a) socioeconomic and demographic data, (b) air pollution, (c) land use and cover, (d) elderly heat illness, (e) social vulnerability, and (f) remote sensing data (land surface temperature (LST), mean elevation, normalized difference vegetation index (NDVI), and normalized difference water index (NDWI)). The output maps identified the hot zones through comprehensive GIS analysis. The resultant maps showed that high HVI exists in three typical areas: (1) areas with dense population and low vegetation, (2) areas with artificial surfaces (built-up areas), and (3) industrial zones. Low-HVI areas are in natural landscapes such as rivers and grasslands. Our analysis can be implemented in other cities to highlight areas at high risk of extreme heat and air pollution.

More than 40 heat indices are being used across the world to quantify outdoor thermal comfort. The selection of an Outdoor Heat Stress Index (OHSI) depends on several parameters, including clothing, age, awareness, local environment, food consumption, human activities, and resources. This study investigates various indicators of heat stress, including (i) OHSIs officially used to quantify heat stress worldwide, (ii) the estimation methods of these indices, and (iii) the sensitivity analysis of indices, namely, Corrected Effective Temperature (CET), Heat Index (HI), Wet Bulb Globe Temperature (WBGT), Universal Thermal Climate Index (UTCI), Discomfort Index (DI), Summer Simmer Index (SSI), and Predicted Mean Vote (PMV). The results indicate the degree of sensitivity of indices, with the HI being the most sensitive for estimating heat stress. Additionally, the WBGT, HI, and CET are recommended indices that can be directly measured using sensors instead of relying on calculated indices that are based on estimation techniques and some ideal physical assumptions.

Worldwide need for renewable energy sources increases significantly with the drastic negative greenhouse effects of climate change. This study considers a water-cooled hybrid thermo-electric panel (PV/T) which contributes to better harvesting of solar energy. A numerical CFD model was developed for power generation of a standard PV panel as well as for a water-based PV/T system laminated with polymer matrix composite (PMC) materials, and user-defined functions (UDFs) were developed and integrated with the CFD model to implement exact boundary conditions. Experimentation under daily weather conditions was carried out in order to validate the numerical CFD model by measuring the surface temperatures of PV and PV/T systems as well as the temperatures of the water inlet and outlet of the cooling system. The results show that the maximum and minimum deviations of the surface temperature between numerical and experimental studies matched well compared with the studies performed in the literature. Moreover, the numerical model had a rapid response to temperature changes of PV and PV/T modules under sudden weather changes (cloudy/sunny). It was shown that the electrical efficiency of the cooled PV/T module can achieve 20.8% in addition to a thermal efficiency of 53.5%. The current study is a validation of the performance of polymer composite laminated water-cooled PV/T systems under daily weather conditions.