In this paper an electromagnetic vibration type energy harvester based on diamagnetic levitation system is designed, fabricated and tested. The structure and principle of the energy harvester are expounded and the output induced voltage analyses are performed by COMSOL Multiphysics 5.2 under vertical excitation. The output induced voltage of the coils under different excitation frequency is tested. The peak voltage is up to 268mV and the average output power can reach 62µW at 2.8Hz under horizontal excitation. Seven capacitors are charged respectively by the energy harvester, which sever as a temporary power source can light up an LED.
Smart Grid Network (SGN) has recently received a great deal of attention and attracted a considerable amount of research. In fact, (SGN) becomes an alternative source of power since it provides efficiency and reliability power consumption. Thus, SG architecture includes several communication schemes to ensure the best transmission of power and satisfy the consumer’s requirement. To reach these ambitions, the transmission must be established at time and without error. In the traditional transmission, every consumer transmits the power demand using a TDMA mechanism which prolongs the delay. In this paper, the purpose is to suggest a model that can quickly transmit the power demand and achieve a good performance in terms of delay. The scheme is called Cooperative Wireless Transmission for Smart Neighbor Area Network (CWT). The cooperative means that all consumers can participate and coordinate between them to transmit the total power. So, the first purpose is to gather the total power of all consumers simultaneously and rapidly by employing QPSK modulation so that to improve the throughput, the second one is to evaluate the performance of CWT in terms of Cooperative Symbol Error Rate (CSER) and Estimated Power (EP). All results are presented using numerical simulations
For environmental protection, solvent-based post-combustion carbon capture (PCC) process has been applied to the coal-fired power plant as an end-of-pipe approach. Power plant needs to provide steam for PCC process and this will significantly influence the net power output. In this regard, this paper aims to: 1) provide an integrated model of small-scale PCC process with small-scale coal-fired power plant; 2) propose feed-back control structures for the integrated system and 3) develop a feed-forward controller to manipulate the steam draw-off flowrate in order to satisfy the rapid response to grid demand. Case studies were presented to investigate the system performance in the face of setpoints tracking and response to load change. The simulations were carried out in gCCS toolkit. Results demonstrate that the feed-forward controller can satisfactorily lower the time needed for power output target tracking.
Double skin facades (DSFs) are widely recognised as sustainable design elements for reducing energy consumption in buildings. However overheating problems in DSFs in warm seasons have been reported in various studies which may cause additional increase in cooling loads in buildings. Although various thermal management strategies and devices are available, they do have some limitations and cannot be readily used for enhancing the performance of DSFs. This paper focuses on both experimental and numerical evaluations on the thermal performance of an integrated phase change material (PCM) blind system for DSF buildings. The numerical models were validated with experimental data in a DSF test facility integrated with the developed prototype. Temperature and heat flux profiles in the DSF integrated with the proposed PCM blind system and aluminium blind were simulated and compared by using computational fluid dynamics (CFD) method. The experimental results indicated that the system was able to stabilise the average temperature in the DSF to about 36 °C in summer days with no significant increase as compared with ambient temperature. Further theoretical evaluations also showed that in comparison with basic aluminium blind, the PCM blind can reduce the air temperature as well as absorbing more heat gain in DSF. Even though the developed system has demonstrated some level of capacity to mitigate the overheating phenomenon in DSF, there is need for further research in optimising the geometry of the system and improving the energy storage efficiency of the PCM.
This research work aims at investigating the effect of carbon dioxide feed in biomass gasification as a possible way to directly exploit the exhaust gas from the engine of combined heat and power systems to convert carbon dioxide to carbon monoxide via Boudouard reaction and consequently increase the carbon conversion and reduce char yield. The effects on biomass gasification using air, and air diluted with carbon dioxide were assessed in a reverse downdraft lab-scale gasifier utilizing 2 kg of pelletized biomass. This reactor is mounted on a digital weighing balance which enables the recording of mass loss during the gasification process. Furthermore, the mixture of air and CO2 is obtained from two mass flow controllers which enable constant and desired flux of gasifying agents across the gasifier. At the same time, an in-house developed thermodynamic equilibrium model was applied to predict the gas composition and char output. Unlike the classical equilibrium strategy that calculates the gasification products using the Gibbs energy minimization method at fixed temperature and pressure, the current approach is based on the enthalpy of the reactants, analogous to the adiabatic combustion temperature. Also, a correction factor accounting for the heat losses, was implemented. The model outcome shows a good agreement with the experimental results, especially in terms of predicted char yields and trends of the dominant producer gas species. The same strategy was used to describe the behavior of the gasification system and estimate the quality of producer gas and the cold gas efficiency of the system. (C) 2019 The Authors. Published by Elsevier Ltd.
