Advanced Materials Research Vols. 171-172

Abstract: Computer implementation of the models in solar energy engineering is very important. This paper summarized the models and realized them by ArcGIS/MATLAB/ SQL Server/ VC++ mixed programming. The experimental results show that it is feasible to apply mixed programming in solar energy engineering. The storage and management of solar energy data are of good performance. The implementation brings convenience for the solar energy reasonably utilization. Further, it puts forward a new direction for solar energy data analysis and calculation.

Abstract: This paper carries the study on the optimization of the heat medium transportation velocity. Based on the analysis to the factor influencing the cost of heat medium transportation system, the mathematical model to optimize the heat medium transportation velocity is constructed. An example of application proves that the optimization mathematical model is practical.

Abstract: Carbon nanotube (CNT) nanofluids, with three sizes of CNTs (L-MWNT-1030, L-MWNT-4060, L-MWNT-60100) and different mass concentration (MC) of surfactant, were prepared to investigate the effects of CNTs and surfactant on the solidification behavior of deionized water (DI water). The thermal responses of the samples were tested in a constant temperature trough. It’s found that the MC of the surfactant and the size of the CNTs influence the supercooling degree (SCD) and freezing time (FT). For the L-MWNT-1030, the CNT nanofluids had lower SCD and shorter beginning FT than the DI water. But when the MC of surfactant was 0.10 %, the finishing FT was equal to that of the DI water. For the L-MWNT-4060 and L-MWNT-60100 CNT nanofluids, the SCD and FT were comparable with those of the DI water. The unusual results imply that the mechanism of nucleation and stability of the CNT nanofluids also influence the solidification behavior.

Abstract: This paper presents a level measurement system of the frequency modulation continuous wave (FMCW) radar. The procedure is designed by LabVIEW7.0. The system adopts FMCW radar sensor and high-quality data acquisition card. The marine tank level can be measured. For improving the precision of the level measurement, this paper presents an improved algorithm. By using this algorithm, we first adjust the sampling number based on current frequency for meeting the request of the integral period sampling, afterwards, the spectrum is corrected accurately. The experiment is completed by applying the algorithm in LabVIEW. The result shows that the improved algorithm can increase the frequency measure precision for 100 times and more than ordinary algorithms, the measurement error of the level is smaller then 5mm.

Abstract: Voltage regulation can be control after distributed generation (DG) into the distribution network. This paper deals with a voltage regulation algorithm for a grid-connected DG, based on active and reactive power control. It also proposes the algorithm of the simplified voltage—superposition theorem. The proposed method is applied to the power distribution system model, and its effectiveness is verified through simulation results. At in the end of the paper, we make a conclusion.

Abstract: In order to ensure the privacy of user profile from disclosure when the users quit using the mobile social network service (MSNS) at temporary scenarios, the paper proposes the privacy insurance module (PIM) based on distributed mobile social network service (DMSNS), which supports triggering the user profile complete deletion on several conditions. One of the conditions the paper proposes is the customized time setting for user profile deletion and the paper also designs the mechanism and algorithms for proper complete deletion by classification, which enriches the user experience and meanwhile protects user profile from being misused and disclosed.

Abstract: The exergy utilization efficiency is the better reasonable to measure quantity and quality of thermal system then energy utilization efficiency .This text analyzed the exergy utilization efficiency of gas engine-driven heat pump(GEHP) at different combined supply energy modes. . Simulation computes gives that the heat recover plays the important action for increases exergy utilization efficiency of GHP system, especially at combined heating and electricity operational models, and the rules of heat recollection ratio and heat recollection temperature to exergy utilization efficiency of CHCP system were provided.

Abstract: The tubular electro-thermal component will produce thermal stress when water in the tube is heated by electricity, which is one of important factors to cause the fracture. In this paper, the finite element simulation and theoretical analyzing methods are used to analyze the thermal stress field of the electro-thermal component tube with different substrates, i.e., quartz glass and borosilicate glass. The result shows that under the same condition, the highest temperature of electro-thermal component using borosilicate glass substrate is higher than that using quartz substrate. When in service, the inner surface of electro-thermal component endures tensile stress and the outer surface endures compressive stress. The inner surface produces greater thermal stress and therefore fracture is more likely to emerge on the inner surface. Therefore, in order to prevent forming of the fracture and reduce the thermal stress, compared with borosilicate glass, priority should be given to quartz glass as the material for manufacturing electro-thermal component.

Abstract: Streaming media is an important research direction in internet applications. In this paper, A Smallest Cache Utility algorithm based on Popularity in future (SCU-PK) is proposed. It comprehensively considered the merit of media time popularity and the smallest cache utility algorithm, using the entire file byte usefulness instead of the file segment bytes usefulness, so that a more effective byte usefulness calculation method and a more rational file segment popularity calculation method was designed and implement. The experiments show that the SCU-PK algorithm has better performance in increasing cache space utilization rate and byte hit ratio than LRU, LFU and SCU-PFUT in stream media proxy cache.

Abstract: This paper introduces the application of the TAS simulation support software to determine the energy performance in between a full mechanical ventilated building than that of a hybrid ventilated-- combined mechanical and naturally ventilated (atrium area to be naturally ventilated) building. A modeled three-storey commercial office building will be used as the main subject of this analysis. To determine the thermal comfort level of the central atrium, Parameters will be set in such a way that the full height windows will be 100% open. Results will be then tabularized to determine and analysis the output of the simulation. Recommendations will be then given based on the output performance of the building. In Tropics, it’s very difficult to achieve better thermal comfort in a naturally ventilated building. With the help of these simulation tools we can find whether natural ventilation is possible in this tropical climate in terms of thermal comfort, ventilation system and energy demand.