Abstract

The inhomogeneity of gas concentration is a key factor which can influence the fuel cell performance. This paper proposed a multi-point gas sampling system which can sample gases in different locations of fuel cell and analyze the concentration distribution. Results prove that the gas concentration of large format fuel cell gradually varies along the channel, and the distribution between channels is also different.

Abstract

Considering the vital role of electricity in the energy consumption and electricity transportation being a bottleneck of high proportion renewable energy development in China, this paper assessed the current and future flow from a provincial perspective. According to the electricity flow in 2015, we found that most provinces mainly relied on local electricity power supply, while there was massive curtailment of the utilization of wind and solar power in some provinces due to the lack of electricity transportation capacity. From the perspective of provincial China-TIMES model in reference scenario, the southern and eastern provinces with large population or GDP will need to import electricity from northern and western provinces with high proportion integration of renewable energy. In the case study of Inner Mongolia and Henan in low carbon scenarios, the demand for electricity output capacity of Inner Mongolia is increasing and further optimization of the national electricity transportation capacity is needed as the increase in electricity flow.

Abstract

As the power sector decarbonizes, transport becomes the main driver of CO2 emissions growth. However, sustainable road transportation is nowadays achievable throughout the electrification of propulsion systems as it represents a promissory to achieve the climate goals. In this paper, a library developed using the object-oriented mathematical modelling language Modelica was used to simulate the impact of different driving behaviors, more specifically top-speed and acceleration rate, on the operational range of an electric vehicle. Results found differences over 50% on the operational range of the vehicle with different acceleration rates and cruise speeds selected. Furthermore, this paper analyzed the impact of external environmental conditions on the battery range. It was found that sub-zero temperatures could reduce driving range by over 17%. These results offer great insights for successful implementations of eco-driving modes on electric vehicles, as well as designing efficient driving strategies for autonomous cars.

Abstract

Renewable energy resources have been integrated to the electricity generation industry. Those systems usually require the addition of energy storage units, so microgrids have been proposed to simplify analysis of such complex energy systems. Hybrid AC-DC microgrids use both AC and DC buses in order to reduce power conversion losses due to the AC and DC nature of house loads, so residential buildings became an interesting application field. A hybrid AC-DC microgrid composed of a PV generator, two storage units, AC and DC loads is proposed, which also can connect with the main grid. Power and control subsystems for the converters of the microgrid are described, then load and PV profiles are employed to size generating and storage units of the microgrid. Besides that, simulations under maximum generation and demand events are analyzed, as well as improvement in power efficiency when compared to a traditional AC microgrid.

Abstract

Steam power plants have a huge potential to meet the growing energy demand but its viability has been hampered by its dependence on conventional fossil fuels. One of the ways to minimize fuel consumption and improve effectiveness of thermal power plant is by introducing feed water heaters (FWHs). In this study, thermodynamics performance analysis of a reheatregenerative steam power plant was carried out using CyclePad version 2 software. The impact of the available feed water heaters on the functionality indices of the selected power was examined. Results of the study show that as the number of feed water heater increases from one to ten, the thermal efficiency and boiler efficiency improve from 42.17% to 45.97% and 79% to 96.4 %, respectively. While the fuel consumption, heat rejected to condenser, heat rate and heat input to the power cycle decreases from 9.697 kg/s to 4.686 kg/s, 209.32 kJ/kg to 129.68 kJ/kg, 8536.87 kJ/kWh to 8318.48 kJ/kWh and 361.11 kJ/kg to 237.98 kJ/kg, respectively. This implies decrease in operation cost of the plant and environmental impacts can be achieved by increasing the number of FWHs. Hence, the importance of FWH revamp performance of steam turbine power plant is established.

Abstract

Nowadays, the electrical needs in Indonesia become a very important sector, but the electrification is still at the 6th position in the Southeast Asia region, therefore in 2019, the government aims to increase the electrification to be 99.99 percent. However, it must also be balanced by the increase in the use of New and Renewable Energy (NRE). This is in accordance with the target of the Ministry of Energy and Mineral Resources to achieve 23 percent of the use of NRE in 2025. One of the areas in Indonesia that has the potential for the utilization of applied renewable energy is Diwak Village, Semarang, Central Java. The New and Renewable Energy is the micro-hydro power (MHP). Therefore, this research aims to determine the potential of the microhydropower in Diwak Village, Semarang. Basically, the micro-hydro power (MHP) could be used for an area that has stable water flow discharge and the amount of slope. The methods are calculating float method for flow discharge data, Rock Mass Rating (RMR), and calculating the capacity power. As a result, lithologies at the location are the volcanic and autoclastic breccia. The flow discharge in Diwak River is 0.29 m3 / sec, and the minimum power that will be generated with its discharge is 40.29 KW. These results sum up that the flow has good potential in utilizing MHP in Diwak Village.

Abstract

This paper describes the study and research taken under Project oBEMS (Office Building Energy Management System). This is an intelligent hardware and software overlay for office building automation systems based on the advance methods for measuring thermal room conditions. This method allows for managing thermal comfort in certain space by controlling installed Heating, Ventilation and Air Condition system (HVAC) in real time with the use of multisensory map of comfort.

Abstract

The paper presents a study of arc flash protection in a PV power plant connected to distribution network. It first put forward an approach applying relay protection and coordination to reduce arc flash hazard. An example of micro-grid with PV power plant connected is then proposed to verify the effectiveness of the approach. In recent years, the growing concern for environment preservation has caused the sustainable power and energy system gets more attention. The renewable energy integrated with traditional power system, such as the PV power plants connected to micro-grids, turns out to be lack of stability and more vulnerable to typical faults. Among many kinds of faults, the arc fault could result in serious arc flash accident, even terrible fire and explosion, leading to casualties and huge economic losses. In order to study the hazard of an arc flash accident and the way to protect the equipment from it, the paper uses a power system analysis software, named EasyPower, to simulate an arc flash accident happens in a PV power plant inside a micro-grid and makes an assessment of the hazard. After that, the time-current curves are plotted for the purpose of protection coordination among all the protective devices. The original relay settings are adjusted to satisfy the selectivity and backup protection.

Abstract

This paper presents a phosphate flash dryer integrated with a parabolic trough collector (PTC) at bench scale. Due to the discontinuity of the solar radiation, the dynamic response of the system is analyzed for the performance prediction and the control strategy design. For this purpose, a solar flash dryer model is developed and simulated using the Engineering Equation Solver software. Then, the impact of the environmental parameters on the drying temperature is examined. Regarding the dynamic behavior of the solar flash dryer versus the months of year, it was shown that the oil temperature is more affected by the solar radiation and the solar incidence angle, conducting then to a maximum drying air temperature and a maximum product mass flow rate of 140°C and 60 kg/h respectively. Also, in order to keep drying conditions stable during tests, the oil temperature regulation is covered by the electrical heater. Finally, the global performance of the process is evaluated and compared to other solar industrial processes. According to the obtained results, the gained output ratio of the solar flash dryer is limited to 0.11 compared to 0.34 by the solar distillation. This value will be optimized in the future work based on the process model and exergy analysis.

Abstract

Thermal management of large-format Li-ion cells is crucial due to their spatial- and temperature-dependent electrochemical reaction kinetics and heat generation. However, existing battery modeling mostly employs a pseudo-2D model which is not able to capture the local current density and temperature across the entire cell geometry. Therefore, in this paper, we propose a simplified 3D electrochemical/thermal model to investigate the temperature and voltage responses of a Li-ion pouch cell. Concurrently, a lock-in thermography experiment is conducted. The model can achieve good accuracy in predicting the surface temperature and cell voltage of the battery during cycling. A scaling analysis is subsequently carried out to determine the dimensionless numbers that affect the battery performance. The proposed approach helps to facilitate a fundamental understanding of the dominant mechanisms related to voltage polarization, heat generation and temperature non-uniformity.