Abstract

The application of integrated energy system can effectively realize the complementary advantages of various energy sources, better meet the various load demands of users, and improve the energy utilization rate. With the aim of carbon neutralization and the development of hydrogen gas turbine technology, considering the low carbon characteristics of hydrogen fuel and renewable energy hydrogen production technology’s advantage, it is significant for the integrated energy system develops towards using low carbon emission fuel like hydrogen to achieve the goal of carbon neutralization. In this paper, we construct an integrated energy system considering multiple types of energy sources, and build the system performance analysis model to analyze the impact of different combinations of renewable energy input directly to the power grid and conversion to hydrogen on system operating costs and carbon emissions. The result shows that determining an appropriate ratio of renewable energy input directly to the system internal power grid and conversion to hydrogen by the system operating conditions will help the system to achieve carbon neutrality with maximum emission reduction capability, while paying a small cost.

Abstract

The dual-temperature display cabinet stores hot and cold products in the same unit and requires a heat source in addition to the refrigeration system. The heat is provided by an electric heater in a baseline system and can be replaced by leveraging condensing-heat. Two natural fluids were numerically investigated in this study, R290, and R744. Experimental data from a baseline dual- temperature display cabinet validated the numerical model in this study. Among the geometric and operating parameters of the two heat exchangers, it was found that the most important parameter is the air volumetric flow rate of the condenser. In the medium and high temperature environment, the R290 has a better energy-saving effect, while the R744 is more suitable for low temperature conditions. When the ambient temperature is 25°C, the power consumption of the heat pump system using the R290 and R744 has 49% and 43% energy saving benefits over the baseline, respectively.

Abstract

In a battery application, overcharging may occur due to possible inconsistency among the batteries, or failure of the battery management system, thereby accelerating the degradation of the batteries. At low temperatures, the overcharging is more likely to occur, because the charging cut-off voltage is more easily exceeded due to the stronger polarization effect. In this paper, the characteristics and mechanisms of Li(Ni0.5Co0.2Mn0.3)O2/graphite battery degradation caused by overcharging to 4.4-4.8 V at 0.2-1C currents at -10℃ were experimentally investigated. The results show that there are two modes of battery degradation, linear fading at 0.2C charging, and two-stage linear fading with turning points at 0.5C and 1C charging. According to the incremental capacity analysis curve, the loss of active material is the main mechanism leading to battery degradation, followed by the loss of lithium ions, and the conductivity loss is the least.

Abstract

Noise is defined as a sensation of unwanted intensity of a wave. It is perception of a pollutant and a type of environmental stressor. The unwanted intensity of a wave is a propagation of noise due to transmission of energy source waves (viz. physical agents) such as sun, light, sound, heat, electricity, fluid and fire. Human Noise Behavior is checked by identifying a source and a sink of noise i.e., a person making noise and a person affected by such noise. The Monarchy of Concordia is a globalized society with the objective of maintaining peace and harmony in the world by controlling human noise behavior. Sustainable Eco-Cities in the monarchy of Concordia follow rules of low carbon economy. The eco-city concept involves sustainability goals. Minimal noise is generated in energy and noise systems and noise behavior is checked by proper noise monitoring and instrumentation which results in noise reduction in cities. The monarchy of Concordia has proposed business models in which various international governments and people are charged subscription fees, taxes and fines on noise behavior and creating noise pollution in similar lines with climate change with applicability of energy perspective on a per capita basis. Examples of energy intensities and noise calculations based on newly devised noise scales are also elaborated.

Abstract

In order to deal with the chloride ions enriched in FGD wastewater which arises from the control of SO2 emissions, ZLD technology is widely applied in coal-fired power plants. One of the technologies to achieve ZLD is spraying atomized FGD wastewater into the duct between the air preheater and ESP, and the purpose of this study is to figure out the evaporation characteristics of FGD wastewater for greater efficiency. According to the calculating results with variable parameters of atomized droplet particles, it could be concluded that increasing the original temperature, reducing the injection velocity, or reducing the original diameter of the FGD wastewater droplet particles is beneficial to improve evaporation efficiency. Of these three measures, the last one is the most effective due to the quickly-finished preheating process which accelerates the evaporation.

Abstract

Regional integrated energy system (RIES) has received extensive attentions, because of its excellent energy coupling and utilization capability. However, how to effectively and reasonably develop the expansion planning of RIES remains unsolved. Therefore, in this paper, a cooperative game based expansion planning model for community-scale RIES is proposed, considering both network structure and gridsource coordination. Firstly, the mathematical models of energy hub (EH) and system constraints, based on grid-source coordination, are established. A cooperative game based expansion planning model is then established and an iterative particle swarm optimization (IPSO) algorithm is introduced to solve the mixed-integer game model. Numerical case analysis shows that the cooperative game based expansion planning will not only increase the capacity of clean energy generation (e.g. CHP units), but also effectively reduce the alliance cost and system carbon emission.

Abstract

With the improvement of energy consumption level in China, environmental pollution and energy shortage are becoming more and more prominent. Hydrogen energy as a clean and efficient new energy has gradually entered the public’s field of vision, H2 was developed rapidly. Hydrogen fuel cell vehicles (HFCVs) is an important development direction of H2 energy application as a net zero carbon emission transportation form. However, the development of H2 energy has been hindered by H2 storage, transportation and other problems in practical applications. H2 is lighter than air and will dissipate rapidly while existing leakage in open environment. But H2 will accumulate and cause incalculable damage while existing accidental leakage in semi-enclosed or enclosed space (i.e., garage or tunnel). The study to leakage of high pressure H2 is the necessary prerequisite for the promotion of hydrogen fuel cell vehicles. In this paper, the effects of atmospheric stability conditions and source term variations on confined space dispersion scenarios were systematically evaluated by using the coupled integral model and computational fluid dynamics (CFD) method.An integral model was used to simulate the process of source term formation after 3.5kg high pressure hydrogen was released. This paper also studied the influence of the existence of obstacles and the arrangement of vents on H2 concentration distribution in the leakage process emphatically. Combined with the simulation results at the initial stage of leakage, a feasible method was provided for the risk assessment of hydrogen fuel cell vehicle garages.

Abstract

This paper presents a study on 33 kV polymeric outdoor insulator’s performance with non-linear resistive field grading composites based on Zinc Oxide microvaristors. The effect of non-linear field grading composites with optimized design and characteristics in stress control of 33 kV polymeric outdoor insulators using 2D models is evaluated. Also, a 3D model of the 33 kV polymeric insulator is developed to obtain more accurate and realistic results. The field computation and simulations are conducted using the (FEM) Finite Element Method and COMSOL Multiphysics. The proposed insulator with resistive field grading composite shows improved electric field distribution under various conditions. In addition, the heat generated along the insulator surface has been computed and compared. The simulation results demonstrate that the field grading of polymeric insulators using non-linear grading composites can improve the insulator performance under different surface conditions and increase the flashover voltage by reducing the potential of dry bands formation.

Abstract

To investigate the release and transformation of fuel potassium during oxygen-steam gasification of biomass, wheat straw is gasified in a fixed-bed reactor system from 400 to 1000 °C. Weight measurement, elemental composition analysis and chemical fractionation analysis are performed. The influence of temperature on the release and transformation of inherent potassium is discussed. The results show that with the increase of gasification temperature, the water-soluble and NH4Ac-soluble K transform into other occurrence modes and the former plays a more important role. During the experiment, slagging is observed at 800 and 1000 °C. Further analysis conforms that the slagging at 1000 °C comprises of potassium silicate. The char obtained from 800 °C gasification is porous and the original fibrous structure of raw sample could be observed.

Abstract

The concept of “more and all electric plane” has been running high in the last two decades, which will boost the extensive utilization of air-borne electrical actuators such as permanent magnet synchronous machines (PMSMs). Thus, considerable waste heat will be generated inevitably during their operation due to the incomplete energy conversion, which would be a great challenge for the conventional onboard thermal control system. It would lead to a sharp temperature rise in thermal-sensitive components of the onboard devices if the huge generated heat cannot be removed efficiently. This overheating will cause operational failures which are intolerable in aerospace applications. For the purpose of improving the current thermal protection measures and gain a higher compatibility of the current PMSM system aboard, a phase change material based (PCM-based) thermal protection strategy using commercial wax is proposed in this paper. Comparative investigation was organized to show that the temperature did drop down, demonstrating the advantages of deploying the proposed PCM-based cooling scheme. Further data processing using partial derivative to attain a relative optimal operating condition. Such method can be promoted to wider applications using PCM as a cooling medium as dimensionless study was conducted in this paper.