• Energy Research
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• 7. Clean energy close

AbstractTo estimate the life cycle cost of thermal power equipments in engineering, this paper established a comprehensive evaluation model of life cycle cost with the life cycle breakdown and cost breakdown structure. Based on the model, this paper defined the cost elements of the thermal power equipment, analyzed influences of the thermal power equipment. Finally, the model is applied to an instance to estimate various cost categories in each life phase, which were summed up to the life cycle cost of the thermal power equipment.

The rapid development of advanced metering infrastructure provides a new data source—building electrical load profiles with high temporal resolution. Electric load profile characterization can generate useful information to enhance building energy modeling and provide metrics to represent patterns and variability of load profiles. Such characterizations can be used to identify changes to building electricity demand due to operations or faulty equipment and controls. In this study, we proposed a two-path approach to analyze high temporal resolution building electrical load profiles: (1) time-domain analysis and (2) frequency-domain analysis. The commonly adopted time-domain analysis can extract and quantify the distribution of key parameters characterizing load shape such as peak-base load ratio and morning rise time, while a frequency-domain analysis can identify major periodic fluctuations and quantify load variability. We implemented and evaluated both paths using whole-year 15-minute interval smart meter data of 188 commercial office building in Northern California. The results from these two paths are consistent with each other and complementary to represent full dynamics of load profiles. The time- and frequency-domain analyses can be used to enhance building energy modeling by: (1) providing more realistic assumptions about building operation schedules, and (2) validating the simulated electric load profiles using the developed variability metrics against the real building load data.

AbstractThis report illustrates the experimental data associated with solar overheating. The experimental data has validated an analytical model which allows for the study of the influences a primary circuit's design has on the overheating of the solar tank.Secondly, the report includes a study of the stagnation in a solar facility. The evolution of the temperature in the hydraulic circuit by means of its measurement at 30 different points, together with the data of the pressure and flow, allow for the real behavior of the solar installation in stagnation conditions to be investigated.Finally, the study shows the measurements obtained on a solar thermal installation located in Alicante (southern Spain). Every installation has been monitored for several months and the main temperatures and pressures around the solar circuit have been noted. The measurements and their processing have allowed for the detection of overheating and stagnation problems in real operating conditions.

Abstract The prime purpose of this work is to prepare a novel kind of Pickering interfacial solid catalysts for biodiesel production to meet the requirements of highly efficiency and environmental benign. To achieve this goal, the core–shell P[xSPA-yDABCO]@SiO2@Fe3O4 composite materials with a shell of photo-responsive and base catalytic sites were manufactured by means of layer-by-layer fabrication method. The modified materials, entirely characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), Fourier transform infrared (FT-IR) spectra, X-ray powder diffraction (XRD) and magnetization versus magnetic (VSM) techniques, demonstrated sufficient catalytic active sites and photo-responsive sites. Among all the so-prepared catalysts, P[3SPA-2DABCO]@SiO2@Fe3O4 performs extremely well and can stabilize soybean oil-in-methanol Pickering emulsion for 24 h, achieving a biodiesel yield up to 98.2% at a catalyst dosage of 5 wt% after the reaction time of 5 h at 60 °C. Furthermore, the double responsive solid catalyst can be readily separated from the mixture of reaction by an external magnet and UV irradiation, and still presented superior catalytic activity after 6 cycles.

To cope with global warming and environmental protection in recent years, the requirements for clean energy are enhancing, and the installation of wind power, as one of such energy, is increasing in various countries. Nevertheless, the connection of wind blades and support blades often break when wind turbine are running. To avoid such a problem in the design stage or the successive reinforcement through proper methods has become an urgent problem in engineering. Commercial software, Solidworks Simulation, is used for simulating stress distribution and the patch reinforcement design in this paper. The analyses show that the maximum stress of the original design not being reinforced with patches has exceeded the tensile strength of the material and result in the breaks and damage of the entire structure. Using composite patches to reinforce the interface of wind blades and the supportive structure could effectively reduce the maximum stress and the displacement of deformation. Moreover, patches could effectively reduce the maximum stress that the optimal reinforcement should take a larger fillet into account.

The distribution feeders often gets overload under peak power demands. This situation is generally countered by load shading, which leads to financial losses to utilities and individual users. This paper presents the new methodology to support the real and reactive power demand through energy storage (ES) to avoid the load shading situation. The compensation of real / reactive power not only provides the voltage profile improvement but also ensures the sustain power to the consumers. A control scheme incorporated also maintains the unity power factor on source side. This relieves the existing distribution network from the extra reactive loading hence the line is having extra capacity for real power transfer to its maximum thermal limit. This additional capacity availability adds more customer base to justify the energy storage investment. The operational features are presented through a simulation of a realistic urban feeder data. The financial analysis is also presented to justify the energy storages with the distribution networks.

This paper deals with a mitigation of a three-phase cable line magnetic field by a new type of passive shield. We consider a cable line with a flat arrangement of cables. The developed single-loop shield has an asymmetric magnetic coupling with the cable line, due to the use of two different ferromagnetic cores. Its high shielding efficiency is experimentally confirmed. As the developed shield is 0.2÷0.3 m away from the cable line, its thermal effect on the cable line is negligible. As the result, we obtain expressions for the shielding efficiency, parameters of the shield and the cores.

The electro-hydraulic servo pump control system (EHSPCS) is a volume control system that uses a permanent magnet synchronous motor (PMSM) with a fixed displacement pump to directly drive and control the hydraulic cylinder. The energy transmission law of the system is very complicated due to the transformation of electrical, mechanical and hydraulic energy as well as other energy fields, and qualitative analysis of the energy transfer efficiency is difficult. Energy transfer analysis of the EHSPCS under different working conditions and loads is proposed in this paper. First, the energy flow transfer mechanism was analyzed, and the mathematical and energy transfer models of the key components of the system were established to explore the energy characteristic state transition rule. Second, a power bond diagram model was built, its state equation and state matrix were deduced, and a system simulation model was built. Finally, combined with the EHSPCS experimental platform, simulation experiments were carried out on the dynamic position following and steady-state position holding conditions of the system, and the variation rules of the power of each energy characteristic state and the system energy transfer efficiency under different loads were obtained. The research results provide a foundation for the study of power matching and energy-saving mechanism of the EHSPCS.