The article illustrates the fluid-dynamic and mechanical analysis of some forms of small-power vertical axis wind turbines, resistant type, whose blades are made of wood and easily workable in a joinery. In particular, a classical-shaped Savonius, a modified two blades Savonius, a three-bladed Savonius and, again, a rotor with three straight blades having a crescentmoon section, were studied. A result of the study, worthy of note, concerns the possibility of greatly reducing the mechanical stresses on the support relatively to the rotor having the last shape. This is very important for its installation near inhabited buildings or even integrated into roofs. Furthermore, the crescent-moon section prototype is able to provide 1 kW power at the nominal wind condition of 12.5 m/s and an annual energy production of 1200-1500 kWh/year, considering a typical urbane site having an average wind speed between 4.5 and 5 m/s.
Experiments are conducted under typical humid ambient conditions of Singapore on an advanced airconditioning system wherein desiccant coated fin-tube heat exchangers (DCFTHX) are retro-fitted within the ducting of a conventional HVAC system with a watercooled condenser. The desiccant is regenerated using room-return air (specific humidity of 0.0109 kg/kg d.a.) and the low-grade heat (warm water at 35.5oC) from the condenser unit. During dehumidification, water from the cooling tower helps in maintaining low air temperature, thereby improving the adsorption performance of the DCFTHX. It is found that DCFTHX managed 39% of the cooling load thereby reducing the compressor load by the same percentage. The experiments prove the efficacy of such internally cooled/heated desiccant systems for practical applications.
Power industry is the most important basic energy industry of national economy development, and it is also a big carbon emitter. With the continuous and rapid growth of renewable energy (RE) capacity, the contradiction between the scale development of renewable energy and the lack of market capacity is becoming more and more obvious. To achieve lowcarbon development and build a low-carbon society, we must develop low-carbon electricity and construct a feasible low carbon electricity price mechanism. In this paper, based on the efficient RE consumption, we introduce carbon cost to construct dynamic and variable low carbon real time electricity price mechanism, including the spot market pricing, grid fees and RE surcharge. Then the paper gives the electricity price strategy and its realization algorithm and verifies the beneficial effect of the proposed pricing mechanism by the example analysis. The proposed low carbon price mechanism is of great practical significance for the development and consumption of large-scale renewable energy.
In addressing the challenge of climate change, smart cities are expected to play an important role in introducing renewable energy sources and improving energy efficiency while maintaining resilience against natural disasters as well as socio-economic disruptions. In this paper, we examine the innovation system of smart cities in the Greater Bay Area, with a particular attention to knowledge and technological domains, actors and their networks, and institutions surrounding the actors. The innovation system of smart cities in GBA in China mainly concerns health and medical care, transportation, logistics, agriculture, surveillance, and public safety and shows a disintegrated structure of functions provided by companies in the electric and electronic industry.
The simple and cost-effective method was adopted to prepare hollow 1D porous structure of g-C3N4 to generate hydrogen by photocatalysis. It plays a substantial role in efficient photocatalysis of water splitting. In general, the protonated melamine was calcined at high temperature to get 1D structure. It exhibits improvement in hydrogen evolution (2.54 mmol. g -1 .h-1 ) in contrast to bulk g-C3N4 (0.10 mmol. g-1 .h-1 ). Due to porous in nature, it has a high surface area (51.369 m2 g -1 ) in contrast to bulk sample (7.73 m2 g -1 ). Furthermore, 1D structure display low resistance against the charge transfer and have low recombination rate. These observations claiming that the hollow 1D porous structure play a crucial role to enhance photocatalytic activity.
Technologies are changing in both the mobility sector, with electric, autonomous, and demandresponsive service mobility vehicles, and the energy sector, with increasing usage of alternative energy sources, battery efficiency, and microgrids. In such a crucial time to achieve sustainable practices to ward off major climate change impacts, these changes across different systems need to be integrated globally. The objective of the study of mobility services and microgrids in the Sumida Ward of Tokyo, Japan is to find the optimal placement for an integrated space, referred to as Smart Hubs, for both vehicular charging and energy storage using MATSim simulation and EnergyPlus modeling methods. The findings could enlighten planners and public officials of the optimal placement of these new community spaces for both time and energy optimization of new mobility services and to change the way urban energy systems are managed and utilized.
IPCC special report on Global Warming of 1.5°C presents the assessment based on available scientific literature that accelerated deep decarbonization is at the core of global mitigation strategy consistent with 1.5°C warming compared to pre-industrial level. The same report also presents the high agreement and robust evidence of risks evaluated by the scientific community in faster and deeper mitigation strategies through possible threats to multiple social and economic dimensions of sustainable development for countries with high dependency on fossil fuels for revenue, economic development and employment generation. The same concerns are coming from literature on just transition which are representing voices around possible job loss, loss of investment flow despite new resource identification, high risks of stranded assets, lower revenue earning with fluctuating oil and gas prices, dwindling resources. Another set of literature on policy instruments talk of need for diversification of economy and energy sector to ease these adverse consequences of transition and need for creating enabling conditions. The diversification discourse is mostly dominated by focus on new investment opportunities limited to wind and solar energy sectors. Also, the countries at risk discussion get dominated by GCC (Gulf Countries Council) countries. All these discourses ignore multiple challenges and realities in many small but fast emerging developing country perspectives. So, the research question for this paper is how can accelerated global transition address the ‘trio’: ‘just, sustainable and peaceful transition’ through cooperation for oil and gas dependent developing countries and what is the potential for leapfrog. We refer this ‘trio’ with reference to oil and gas based fossil fuel energy systems which is caught up in a complex combination of problems due to likely uncertainty and redundancy of human resource currently engaged in the sector, stranded asset due to prospective early retirement of infrastructure and projected reduction in investment and need for finding substitute of fossil based energy carrier to cleaner, renewable energy carrier. Our hypothesis is that for Bangladesh endowed with gas resources and drilling infrastructure one of the transition path can be through geothermal energy system. The policy can encompass objectives of scaling up contributions of renewable energy to electricity production, promoting appropriate, efficient and environment friendly use of renewable energy and promoting clean energy as the country is facing risk of natural gas depletion. However, currently policies make no reference to geothermal potential as a part of the solution. So this study will make a novel and unique contribution in the subject and discourse.
Soft Open Points (SOPs) have the ability to regulate the power flow among their terminals in a continuous manner, which can solve the problems brought by the synergy of distribution networks and PV, and improve the system reliability and power supply capability. To address the current lack of quantitative measurement on the effects of SOPs, the power supply capability evaluation method for active distribution networks with four-terminal SOPs considering reliability is proposed. Firstly, the topology and configuration modes of fourterminal SOPs are studied, and the control modes of them are investigated in normal operation and supply restoration conditions. Then, using the feeder partition method, the effects of four-terminal SOPs on the states of different load areas after a fault are studied, and the reliability evaluation process for active distribution networks with four-terminal SOPs is developed based on the quasi Monte Carlo method. Later, with reliability as the main constraint, the power supply capability evaluation model for active distribution networks with four-terminal SOPs is established, and the solution algorithm is proposed. Finally, the effectiveness and applicability of the method proposed are verified through case study.
The physico-chemical structure of co-pyrolysis char significantly affects its gasification reactivity. Pore distribution and microcrystal structure of co-pyrolysis char from polyvinyl chloride (PVC) and bituminous coal were investigated by specific surface area analyzer and X-ray diffraction. Based on fractal theory and deconvolution method, the influence of PVC on copyrolysis char structure was analyzed quantitatively. The results showed that the specific surface area of copyrolysis char increased slightly compared with PVC char. Similar to the PVC char, the pore size distribution of copyrolysis char was wide and uniform. The ordering of carbon microcrystal structure of co-pyrolysis char was promoted by the addition of PVC. This study can provide basic data for exploring the relationship between gasification characteristics and structure parameters of co-pyrolysis char.
Biomass CO2 gasification has attracted much attention as part of the CO2 utilization and mitigation. In this study, biomass CO2 gasification is investigated based on an equilibrium model. Parameter sensitive analysis is conducted to investigate the influence of CO2/C ratio and gasification temperature on the gasification process. The results show that the syngas production can be enhanced by increasing the CO2/C ratio of the biomass CO2 gasification. Higher gasification efficiencies are also obtained under higher gasification temperatures.