Purpose -The purpose of this paper is to investigate the dark properties as a function of reverse current induced defects. Dark characteristics of solar modules are very essential in the understanding the functioning of these devices. Design/methodology/approach -Reverse currents were applied on the photovoltaic (PV) modules to create defects. At several time intervals, dark characteristics along with surface temperature were measured. Findings -Current-voltage (I-V) and capacitance-voltage (C-V) characteristics furnished valuable data and threshold values for reverse currents. Maximum module surface temperatures were directly related to each of the induced reverse currents and to the amount of leakage current. Microstructural damages, in the form of hot spots and overheating, are linked to reverse current effects. Experimental evidence showed that different levels of reverse currents are a major degrading factor of the performance of solar cells and modules. Originality/value -These results give a reliable method to predict most of the essential characteristics of a silicon solar cell or a module. Similar test could help predict the amount of degradation or even the failure of PV modules.

Internet of things (IoT) technology is based on connecting each real object to the internet. Every single object is uniquely recognized and reachable over the network. IoT last mile connectivity is based on different communication technologies and protocols, where the majority is categorized as short-range networks that operate in ISM band like Zigbee, Wifi and Bluetooth. Short-range technologies were successfully tested and deployed in different industrial sectors. However, in the energy sectors its deployment is challenging in certain hard to reach areas where a reliable last mile connectivity is required between the home area network (HAN) smart meters and the meter data management system (MDMS). Therefore recently, Low Power Wide Area Network (LPWAN) technology, which offers a long range connectivity, has emerged as a promising technology for IoT. Within LPWAN, variety of platforms exist and operate in licensed and unlicensed spectrum respectively like NB-IoT, and LoRaWAN, Sigfox. In this paper we discuss both the performance of LoRaWAN in a real-world environment and its deployment as a low cost, long range and reliable last mile solution for energy smart metering in urban area scenario where short range solution may not work the best. Furthermore, a prototype that is adapted to the existing Lebanese traditional energy sector was developed to test LoRaWAN usefulness in Lebanon.

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