Abstract

This paper reviews the conditions for ensuring the space consolidation and time reconciliation of all scales involved in power system energy planning. At the upper space scale, a simplified description of the grid based on the Kuramoto model is adopted to assess the stability of the synchronism state of the power system. The consequences of a massive dissemination of renewables for the future of the power system is addressed in the case of France in a long-term planning exercise up to 2050. Attention is paid to how the new capacities are dispatched among the administrative regions. While a favorable impact of sparse generation on the synchronism is obtained, the constraint on the inertia provided by the kinetic energy has to be endogenized to enforce an operable power mix under admissible disturbances.

Abstract

Energy is vital in modern society and almost in every production process for sustainable economic growth. China is developing country and poverty is always higher especially in rural areas. The study examines the relationship between renewable energy (RE), as whole & by sources solar, wind, geothermal, foreign direct investment (FDI) and poverty alleviation (PA) for sustainable economic development in China. Ordinary Leas Square OLS and Fully Modified OLS methods are use in this study. The results found that there is long run relationship between variables and increase in investment and renewable energy sources production to reduce the poverty. Poverty causes lack of income and production resources, poor infrastructure, inequality and social discrimination. China first needed to overcome these issues for poverty alleviation for sustainable economic development.

Abstract

This work proposes a novel design incorporating a passive heat recovery device into a windcatcher and investigates its performance using numerical and experimental analysis. Numerical modelling and experimental testing were used to characterise the radial blade design of the heat recovery rotary wheel in terms of performance. Two configurations of the radial blades provide data that can be used to assess how air velocity is affected by the design, the pressure drop across the device and the heat transfer capabilities of the radial blades. To further assess the potential of the proposed devices, it was incorporated into a multi-directional windcatcher ventilating a small room. Despite the blockage of the rotary heat recovery wheel, it was able able to provide adequate ventilation. In addition to sufficient ventilation, the heat in the exhaust airstreams was captured and transferred to the incoming airstream, raising the temperature between 0.5-4K depending on the indoor/outdoor conditions, this passive recovery has the potential to reduce demand on space heating systems.

Abstract

Electric vehicles (EVs) have been widely developed for their advantages of energy saving and environmental protection. However, the disorderly charging of largescale EVs will bring challenges to the security and stability of the power grid due to the randomness and uncertainty of charging behavior. In this paper, the charging and discharging management system of Electric vehicle (EV) is added between the two-way interactive service system of smart grid and EV to realize the information interaction between EV and grid. Further, the charging and discharging operation of EV is optimized and controlled according to the needs of its both sides. To maximize the revenue of the grid company, the EV charging price is optimized and the EV charging load is transferred through the behavior characteristics prediction of EV users. Then, the EV is charged and discharged in an orderly manner. Besides, the grid load characteristics, voltage quality and frequency quality are improved on the grid side.

Abstract

Omnipresent charging infrastructure is a requisite for ensuring smooth transition to e-mobility. Reliable, sustainable, cost-effective and photovoltaic (PV) panel based charging of EV batteries could be befitting solution. This paper presents a PV module-integrated converter for EV charging station which can track maximum power point besides providing requisite high gain boost in voltage to a usable value even under intermittent conditions, i.e. insolation variation and partial shading conditions. The current control scheme evacuates the maximum available power amidst intermittent conditions. The performance of the system is evaluated under Matlab/Simulink environment. Presented simulation results show close conformity with design and validates the effectiveness of the system proposed.

Abstract

This paper is built on a study performed to investigate the possibilities to take care of fiber sludge from a former pulp mill in the city Tampere, Finland. A pilot plant biorefinery process has been developed by Finnoflag and tested during 2018-2019 for the conversion of the cellulosic material into useful chemical products by the help of a microbial process. The results from this are used as input to a study on downstream processing performed through lab and pilot plant tests of different technologies, as well as system simulations. An economic analysis is also performed with respect to installation costs for the different alternatives of downstream processing – ion exchange, distillation and membrane filtration. It was found that all three processes would successfully concentrate the main product (lactic acid), however distillation would likely be energy intensive, and ion-exchange costly for materials. Therefore, the recommendation from this study is to focus on reverse osmosis after ultrafiltration, with the addition of evaporation if necessary. Besides the resulting chemicals fraction the biorefinery produced hydrogen, and the residues could be converted effectively into methane. These gases provided energy for the industrial unit and could be converted into energy, too. On the other hand, the feasible production of the chemicals gave an economic justification for the energy producing units.

Abstract

Solid oxide fuel cell (SOFC) has attracted more and more attention due to its power generation characteristics of high efficiency, low emission, and strong fuel adaptability. In order to ensure the stable and efficient operation of the system, it is urgent to study the thermoelectric characteristics and control laws of SOFC systems under different fuels for different fuel types can result in different thermoelectric characteristics. Therefore, based on the 200-hour experimental data obtained from an external steam-reforming SOFC independent power generation system, the temperature distribution and electrical characteristics of the system at different power stages are studied. Moreover, the thermoelectric characteristics of the independent SOFC systems under pure hydrogen and methane fuel types with the same output power are further compared. The results show that, the stack voltage and the fuel utilization rate of the methane fed SOFC system is lower than that of the hydrogen fueled SOFC system. And the temperature gradient on the fuel side of the methane fed SOFC system is relatively large, while the temperature gradient on the air side of the hydrogen fueled SOFC is relatively large. The analysis process plays a significant role in system control strategy design, which improves the fuel adaptability of the system.

Abstract

This paper presents a cooperative estimation approach for SOC and SOH with the consideration of temperature and aging. The co-estimation is realized by using a co-estimator which is a combination of a modelbased algorithm and a data-driven technique for joint SOC and SOH estimation, and by a developed thermoelectro-aging coupling model which can reflect the dynamic and static characteristics of the parameters related to the SOC and SOH. In this co-estimator, unscented Kalman filter (UKF) and long short-term memory recurrent neural network (LSTM RNN) are designed to estimate SOC and SOH respectively and update mutually as temperature and current input; an optimized dual-time scale strategy based on slowvarying SOH and fast-varying SOC characteristics is implemented. Simulation results indicate that compared with the popular dual EKF and the UKF, the proposed algorithm gains higher accuracy and faster error convergence speed, and its estimate error for SOC and SOH are statistically less than 0.4% and 0.21% respectively under a wide range of condition.

Abstract

The operation of power plants must meet a series of requirements in order to enable the increasing penetration of intermittent renewable energy and the consequent intensifying demand for flexible generation. It is proposed here that during off-peak demand, steam can be extracted from Rankine-cycle power stations for the charging of thermal storage tanks that contain suitable phase-change materials (PCMs); during peak demand time, these thermal energy storage (TES) tanks can act as the heat sources of secondary thermal power plants in order to generate power, for example as evaporators of organic Rankine cycle (ORC) plants that are suitable for power generation at reduced temperatures and smaller scales. This type of solution offers greater flexibility than TES-only solutions that store thermal energy and then release this back to the base power station, in that it allows both derating and over-generation compared to the base power-station. The approach is here applied to a case study of a 670- MW rated nuclear power station, since nuclear power stations are generally suitable for baseload generation and the proposed system configuration could increase the operational flexibility of such plants.

Abstract

With the rapid development of high temperature superconducting technologies in the application areas of power transmission, communication and so on, the demand for high reliable and efficient cryocoolers is growing dramatically. Due to the flexibilities of cooling temperature and capacity, the pulse-tube cryocoolers driven by linear compressors are very suitable solutions for these applications. In the pulse-tube cryocoolers, phase shifters are indispensable to construct a suitable acoustic condition for the cryocooler and achieve a high cooling performance. In the traditional pulse-tube cryocoolers, the orifice-reservoir or inertance-reservoir phase shifters are often used, in which the expansion work out of the cryocooler is dissipated into heat. Thus, additional cooling method must be required for the phase shifter especially in a high cooling capacity situation. In this paper, the pulse-tube cryocooler with linear motor phase shifter is proposed. The linear motor can not only provide a suitable acoustic impedance, but also convert the expansion work into electricity, which can possibly reduce the input power of the compressor. In the experiments, a maximum cooling power of 154 W at 80 K and a maximum relative Carnot efficiency of 28.5% were obtained with the charging pressure of 3 MPa, the pressure ratio of 1.2 and the working frequency of 60 Hz, respectively.