Storage is going to be a crucial part of the electrical grid of the future, with the penetration of renewables. It is necessary to have a long-term storage method to take care of seasonal variations of Solar Energy. The system must be environmentally friendly and must not have hazardous materials. A thermoelectric storage system is proposed in this work to take care of these challenges. Cooling of a Phase Change Material can be done via Peltier modules and the energy to supply latent heat of fusion can be considered as the charging process. By operating the Peltier modules as a thermoelectric generator (i.e. Seeback Effect) the discharging of the cell can be done. The system must be suitably insulated to prevent heat loss. Coefficient of performance and efficiencies of the thermoelectric modules may be a deterrent but by modulating power judiciously via Power Electronics the technology can be scaled up.
In this paper, the quantitative investigation of the free-surface effect on tidal turbine performance by using a multi-phase flow formulation is presented. The computational formulation is briefly introduced. The free-surface effect is rigorously studied by the simulations performed for a single turbine and two back-to-back turbines using different inflow conditions and immersion depths. The thrust and power coefficients of the tidal turbines in free-surface flows are quantified. It is found that the presence of free-surface has a significantly negative effect on tidal turbine performance by decreasing the thrust and power coefficients in idealized inflow conditions, such as uniform inflow and Airy wave inflow conditions. The comparison with pure hydrodynamics simulation results shows that pure hydrodynamics simulations are unable to provide accurate predictions and the free-surface effect must be taken into account in the modeling and simulations of tidal turbines, especially for shallow immersion depth.
With huge reserves, marine natural gas hydrate is one of the most potential unconventional alternative energy sources after shale gas, coalbed methane and tight gas. The research and pilot engineering of natural gas hydrate exploitation technology mainly adopts the depressurization method at home and abroad, all of which refer to the exploitation technology of conventional oil and gas. However, if the depressurization method is used to exploit the weak cementing and unstable non-diagenetic marine natural gas hydrate, the hydrate will be decomposed disorderly and uncontrollably, and 6 great risks will be faced. Therefore, the project team led by Academician Zhou of the Chinese Academy of Engineering divided the hydrate into the kind of diagenetic and non-diagenetic, proposed the technological strategy of 6 “utilize”, firstly created the technological principle of solid fluidization exploitation of non-diagenetic natural gas hydrate and the technological process of hydrate mining, crushing, ejection and fluidization of seawater, separation and backfill of sand, slurry lift and deep separation and re-backfill in the platform, and achieved the safe and green exploitation which let nature take its course, turned the harm into a benefit, and turned the uncontrollable into controllable. Based on this principle, Southwest Petroleum University invented the experimental simulation method and technology, cooperating with China National Offshore Oil Corporation and Sichuan Honghua Petroleum Equipment Co. Ltd. The overall process simulation of solid fluidization exploitation with water depth of 1500 m and pipeline length of 4500 m is achieved. The world’s first large physical experimental simulation system of solid fluidization exploitation of marine natural gas hydrate is researched and developed, which has full independent intellectual property rights and includes 3 modules and 12 subsystems of sample preparation of hydrate, crushing and slurry modulation, high-efficient pipeline transportation and separation of slurry, image capture in real-time, data collection and automation of security control and so on. Moreover, the experiment of solid fluidization exploitation is carried out systematically for the first time, which provided an important basis for the formulation of the test scheme, the optimization design of the process and the research and development of downhole tools, supported the world’s first successful test exploitation of solid fluidization method, and proved the scientific feasibility of the principle and the technology of solid fluidization exploitation. The experimental simulation technology and system, as well as the first testing results, were reported in the Journal Science. The successful research and development and the further upgrading of the system are expected to promote the technology of solid fluidization exploitation of marine nondiagenetic natural gas hydrate to become a disruptive technology leading the world’s frontiers, and are expected to accelerate the commercial development of natural gas hydrate in China and even the whole world.
Geothermal heating technology is critical in urban sustainable development and climate change mitigation. This research paper conducts a numerical simulation and multi-objective optimisation for geothermal heating systems based on factors such as ground demand, profitability regulation modes, and region areas. It’s indicated that well spacing and production rate are the two main factors affecting production performance as well as emission reduction efficiency of geothermal heating systems. The heating mode also plays a vital role in the utilization of geothermal reservoirs. There is a delay in the formation time of thermal breakthroughs of the regulated geothermal heating system. The radius of the cold front shrinks, while production performance and emission reduction efficiency also decrease. Comparing the regulated geothermal heating system to the unregulated geothermal heating system, the construction investment of geothermal wells and the annual water consumption both decrease by up to 30% and 60%, respectively. Additionally, electricity costs increase by 5% to 25%. The regulated geothermal heating system with well spacing of 300m and production rate of 100m3/h generates the highest efficiencies in terms of heat production, emission reduction, and economic performance, all of which are most suitable for this project in Qingfeng. The simulation method and optimisation model of this research paper can be extended to other regions.
To promote the development of solar photovoltaics, dozens of countries implemented Feed-in-Tariff (FiT) Scheme in succession. However, accompanied with the increasing installed solar capacity, the issue of unequal distribution of the subsidies also arises due to its implementation. In China, a large number of solar PV stations concentrate in the more developed areas, which means that these areas could get more subsidies from the central government, whilst the burden is borne by all the electricity consumers. In 2014, China launched the Photovoltaic Poverty Alleviation Project (PPAP) to construct solar PV stations for the poor, indicating that the poor can also enjoy the subsidies derived from FiT Scheme. This paper is intended to illustrate the distributional justice of FiT subsidies in mainland China, so as to fulfill the gap of empirical studies in this field. What’s more, whether the implementation of the PPAP could enhance energy justice and become a reference for other countries is also discussed. The results suggest that the distribution of per capita subsidy was increasingly even during the past five years. However, the per area subsidy is significantly correlated with the local economic development, which is inseparable from the provincial preferential policies. As for the PPAP, it can improve the distributional justice to some extent but the impact is slender at current stage.
Overview of hydrocarbon and other energy sources and their impact on global warming is given. It is shown that the developed countries, which represent 15% of the world’s population, should provide business plans and clean technologies for the developing countries which constitute 85% of the world’s population. Thus, greenhouse gas (GHG) emissions and global warming can be globally reduced. Furthermore, cleaner transportation, such as electric and hybrid vehicles need much more adaptation in order to be universally applicable, this as well as other green technologies that are environment-friendly.
The relative permeability curves are the key parameters of mechanics of fluid flowing through porous media multiphase flow, which was influenced by many factors. However, only few study on the correlativity between relative permeability curves and porous media parameters were conducted, which is unfavorable for actual application. The capillary pressure and the relative permeability curve testing experiments were measured simultaneously for the same core samples, which could be used for theoretical and mathematical statistics analysis. The fractal theoretical model was used to analyze the capillary pressure curve and the fractal dimensions could be obtained through regression. Theoretical analysis and mathematical statistics were used for analyze the correlation between the relative permeability parameters and the physical property parameters of the porous media. The most significant finding is that the better the physical property parameters are, the lower the irreducible water saturation and the residual oil saturation are, and the higher the wetting phase endpoint values are. But the correlation between the oil phase index and water phase index were not good enough with the physical property parameters, however satisfied with the fractal dimension. The parametric variation trend of the relative permeability curve could be not only used for the development effect improvement, but also the porous media parameters control for other engineering fields application.
Solar collectors (SCs) and Photovoltaics (PVs) can intervene with tri-generation systems to form a poly-generation system. Many studies have accessed this intervention, however, these studies depended on the performance of these components as individual components not on a system basis. They haven’t dealt with the environmental and exergetic aspects of the whole system. Moreover, they haven’t dealt with optimal planning and scheduling of these systems. A methodology of real system level comparison is presented in contrary to component-level comparisons that are available in the open literature. This methodology depends on comparing an optimized Solar CCHP poly-generation system with side-by-side PVs and SCs, against an optimized CCHP (Combined heating, cooling and power) system. The comparison is under the constraints of maximizing a formulated combined efficiency that combines energy, economy, environment and exergy aspects. Results showed that the Solar-CCHP system has higher combined efficiency but with lower Net Present Value (NPV). Another novel contribution for determining the actual selling price of both sold CCHP-electricity and Solar electricity is presented. These results assured the importance of reducing the capital costs of solar energy systems to facilitate its deployment in future energy systems as they already prove their ability to increase overall combined efficiency of energy systems by decreasing the fuel used and emission produced.
Effective messaging and evidence-based demonstration of implicit economic opportunities in transitioning to leaner 1.5℃ pathways can go a long way in creating consensus for massive social mobilization and committed government actions towards deeper decarbonization. In this study we assess the direct and indirect economic impacts of India’s Nationally Determined Commitments (NDCs) and beyond at the subnational level using an integrated macro-econometric dynamic simulation model: E3-India. An array of distinct economic trajectories associated with energy decarbonization and energy efficiency targets at national level and state level were simulated using the model. Results reveal that selective investments in ambitious climate mitigation policies will lead to overall economic growth for Indian economy. However, distributional impacts across states, especially those already identified as climate hotspots, will be heterogenous. These regions will therefore need effective policy interventions to manage the transition and ensure resilience in the face of climate change.
It is difficult to effectively control the vertical grinding process of raw materials due to its characteristics of strong coupling, non-linearity and large hysteresis. This paper proposes a vertical mill intelligent control system based on data mining to predict the operating conditions of the slag grinding system. Taken into consideration corresponding shortcomings of each algorithm, we combine several algorithms to propose a feature extraction method for analyzing operating conditions and determining the indicators that affect the operation. Next, we clustered the healthy operating conditions to get the distribution of health conditions, and based on this, established a healthy operating condition library. The operational data are compared with the reference conditions, and the prediction model is trained using the ARIMA algorithm to predict the trend of the corresponding indicators. To verify the effectiveness and practicability of the method, we developed a software system and applied it to the actual case analysis. It is concluded that the vibration of the control group is decreased by an average of 10%, and the average power consumption per ton is decreased by 6.05%. According to the total number of vertical mills of 350,000 tons, the average power consumption per ton is 43.5 degrees. Therefore, the total annual power consumption will be 1.5225 million kilowatt hours, which can save 921,100 kilowatt hours. According to the average industrial price of 1.5 yuan / kWh, the annual saving will be 1,381,700 yuan.