Direct cloud-enabled sensor nodes offers certain advantages over low-power wireless communication technologies but require high-power. Conventional wireless sensor nodes, which are battery-powered, have relatively low lifespan. In a battery powered direct cloud-enabled sensor nodes, the peak current needed during the data transmission process will add extra burden on the already strained battery resources and may accelerate the capacity degradation, further reducing battery life. The condition deteriorates where applications require frequent data transmission. This paper proposes a novel power management device architecture tailored to direct cloud-enabled sensor nodes’ requirements for indoor applications with extended lifespan. This research also recommends using Photovoltaic energy harvesting with a hybrid storage technique consisting of a battery and supercapacitor to power the node. The work’s novelty lies in the use of a supercapacitor-battery hybrid storage scheme, which provides the required peak current during the data transmission, sufficient enough to fulfill the load requirement during the data transmission process. A novel drip charge controller synchronized with the sleep period, and the active period of the sensor node is introduced. The power management unit was designed simulated and validated experimentally to verify performance with the indoor application.
This study aims to investigate the impact of the PJS on the performance of multi-jet stratum ventilation. A validated Computational Fluid Dynamics (CFD) model was used to conduct the year-round multivariate analysis. A total of eight PJSs, four inlet locations and five climate zones were discussed synthetically. Air distribution performance index (ADPI), ventilation effectiveness (Et) and economic comfort coefficient were employed as the evaluation indicators to assess the thermal comfort and energy efficiency in various scenarios. Research results indicated that the PJS showed different influences on the indoor thermal comfort and energy utilization efficiency as a result of cooperative effect including energy dissipation, air short-circuit probability, air distribution uniformity and airflow path. Combining with building energy simulation method, the optimum PJSs of stratum ventilation with different air inlet positions in five climate zones were obtained, which can help provide a comfortable indoor thermal environment and improve energy efficiency in a low-cost way.
Energy consumption is one of the main sources of GHG emissions in China with the development of rapid urbanization. To tackle climate change and energy conservation, China has processed a series practices that gain co-benefits towards meeting sustainable development goals along with climate change mitigation since 2007.This paper evaluates the impact factors of population, urbanization level, GDP per capita, industrialization level on the environmental energy saving impact using the Stochastic Impacts by Regression on Population, Affluence and Technology (STIRPAT) model based on China provincial panel data from 2005 to 2017. The results show that industrialization has the largest potential effect on environmental impact, followed by urbanization level, GDP per capita and population. Industrialization and GDP per capita can cause an increase in energy consumption per capita. Whereas, urbanization level and population can lead to a decrease in energy consumption per capita. An in-depth analysis on energy consumption of China’s recent urbanization is carried out and policy recommendations are put forward.
International energetic agreements define future targets to push the decarbonization process by renewables increasing. Their deep penetration in AC grids will determine limited and alternating operative modes of traditional Synchronous Generators. In such scenarios, instabilities will not intrinsically be balanced causing inertia critical conditions. In this paper a dual approach is proposed to mitigate the problem. The strategy constituted by preventive and solving actions employ DC microgrids to locally include and manage suitable Variable Energy Resources amount and to assure prompt virtual inertia provision to the AC grid. 2030 case studies for an Italian city are analyzed.