Applied Mechanics and Materials Vols. 284-287

Abstract: This paper presents a novel photovoltaic (PV) model for a commercial PV module, which is augmented with an energy balance equation to simultaneously describe cell temperature and PV electricity output characteristics. Having the thermal and electrical characteristics of commercial PV module available from the manufacturer datasheet, the proposed PV model is implemented on the Simulink environment and verified under the standard test condition (STC) and nominal operating cell temperature (NOCT) condition. The NOCT verification with a commercial PV module datasheet is first addressed. Through experimental measurement of a commercial PV module in real operation from June 1 to August 31, 2011, the proposed model demonstrates the good estimation performance of both cell temperatures and output electricity characteristics. Comparing with ones of the other methods, the predicted output characteristics of the proposed model have a better agreement with the measured ones of an operating PV module.

Abstract: We present a study of electric field effect on the efficiency of GaN/In_0.1Ga_0.9N p-i-n solar cells by using the advanced physical models of semiconductor devices (APSYS) simulation program. In this study, the electric field strength and other parameters such as optimum thickness of p-type layer and efficiency of GaN/In_0.1Ga_0.9N p-i-n solar cells with different i-layer thicknesses have been performed. On the basis of simulating results, for a high efficiency solar cell, it is found that the optimum p-type layer concentration is above 4×10¹⁶ cm^-3 and the suitable thickness is between 0.1 to 0.2 μm. For different i-layer thickness and p-doping concentrations, a critical electric field (Fc) has been found at 100 kV/cm. It is worth to note that when the electric field strength of i-layer below Fc value, the solar cell efficiency will dramatically decrease. Thus Fc can be seen as an index for acquiring the quality of solar device.

Abstract: This paper aims to study the solar energy produce hydrogen combine fuel cell generation system. Utilization digital signal processor of power conversion for solar charging system for the overall system control center to achieve all stability of power system The system consists of a solar module to DC 14V 37W, PEMFC power generation 30W, digital signal processor( TMS320LF2407), assembly of bipolar electrolyzer and power converter The self –made hydroxide ion film of this experiment is excellent performance in separating hydrogen from Oxygen, so the hydrogen purity can be as high as 99.2%,and the generating efficiency of the fuel cell can be maintained at 29%.

Abstract: There are in total about 1.9 million air conditioners (ACs) in Taiwan, and during the summer time the energy consumption of these ACs is about 30% of total country energy consumption. Therefore, effective energy management of these ACs is an essential task to energy saving and carbon reduction. The purpose of this paper is thus to design and to develop an energy billing and demand control system for buildings with aggregated ACs, such as schools, company offices, factories, apartments, etc. The system presented in this paper consists of a power meter, an RFID billing reader, and a demand control module with infrared remote control and relay control. Computer GUI for supervisory control and data acquisition (SCADA) and energy management is also developed. Based on the experimental results, the demand variations of ACs indeed follow the commands sent from the presented system, and the fluctuation of the room temperature is not large during the demand control period.

Abstract: This study proposes an islanding detection method for use of grid-connected inverter of renewable generation system. The proposed method is based on an index: the change of power factor (COPF). When an inverter is grid-connected, the COPF is lower than the threshold values. In contrast, as an islanding occurs, the COPF becomes much higher than the threshold value. Detection systems monitor the terminal voltage and load current at the grid-connected point to calculate COPF, and issue an operating signal when the value of COPF exceeds a given threshold. In this study, experiments are conducted to illustrate the principles of the proposed technique for a prototype grid-connected inverter. The test results show that the proposed method is reliable, economical, and easy to implement for islanding detection of grid-connected inverter.

Abstract: In response to international concern about climate change and environmental degradation, the Korean government recently began developing the new concept of the Green Building Index (GBI), which represents the overall quality of green buildings. As the initial stage of the developmental process, this research contrastively analyzed two green building comprehensive assessment methods: the Weighted Total Comprehensive Method (GBCC method) and Relative Efficiency Comprehensive Method (CASBEE method), by reconstituting GBCC with the concept of CASBEE and performing calculations in order to understand the characteristics of these methods. The analysis results demonstrated that there were big differences between the two methods. Even though the two buildings received the same total, they are not the same with respect to environmental efficiency, because the ratios of environmental quality (Q) and environmental load (L) in the total gain score were different. Therefore, when setting the grading standard, the characteristics of different comprehensive methods should be considered in order to make GBI a more rational and agreeable representative index.

Abstract: Sustainable development is often spoken of by the public over the past few years. In the third world countries such as Malaysia, the development of sustainable highways is something new to be explored. Within this context, this paper aims to highlight the basic elements needed towards the development of an assessment framework for green highways in Malaysia. An extensive literature review was undertaken which shows about twenty five elements were identified as having roles in green highways. Questionnaire survey was distributed to highway construction experts in order to gain their response in validating the identified elements. The results show that elements will serve as a basis for the development of an assessment model for Malaysia green highway

Abstract: In order to decrease the impacts of climate changes and global warming on the environment, many countries have started the zero carbon or low carbon researches to decrease the production of CO2. The government of Taiwan also follows the trend in conserving energy and decreasing carbon production and develops a “low carbon island” demonstration plan. The energy consumption of a building is closely linked to the climates of its location. Therefore, studying the local climates is the foundation of low carbon building design. However, the meteorological data collected for general purposes do not provide detailed sorting and time selection for building design. Therefore, it is important to create an architectural meteorological database specially for building design. In this research, we created an architectural meteorological database for Liuqiu island, an off-shore island in the “low carbon island” plan of Taiwan. Using this database, the building designer can improve the natural ventilation design of the building to decrease the usage of air conditioning and the goal of low carbon building can be achieved easily.

Abstract: Hub and Spoke (H&S) network reflecting the scale economies through consolidation and a large amount of freight transportation is widely used to reduce total transportation costs. H&S network has transportation routes that go to the final delivery point pass through hub linking destination from hub linking origin. In this paper we present a 0-1 integer programming model and a solution method for the capacitated asymmetric allocation hub location problem (CAAHLP). We determine the number of hubs, the locations of hubs, and asymmetric allocation of non-hub nodes to hub with the objective of minimum total transportation costs satisfying the required service level. As the CAAHLP has impractically demanding for the large sized problem, we develop a solution method based on ant colony optimization algorithm. We investigate performance of the proposed solution method through the comparative study. The experimental results show that the newly proposed asymmetrically allocated network can provide better solution than the singly allocated network in terms of cost and service level.

Abstract: The design strength of concrete-filled tubes (CFT) is being calculated based on two approaches including the AISC and ACI methods. The AISC applies the steel column formulas with the use of coefficients for transforming the concrete into steel to determine the CFT design strength. The design strength of AISC is being evaluated through the use of two approaches including the plastic stress distribution and strain compatibility methods. This study used both the plastic stress distribution and strain compatibility methods to calculate the design strength of CFT, and compare the design strengths using these two methods. This study presents a more accurate numerical approach to evaluate the CFT columns including rectangular and square sections. The illustrated example is presented to demonstrate the step-by-step procedure to obtain the CFT design strength based on the AISC Specification. The provided design procedure for the strength evaluation of CFT columns enables those who need a better estimation on the CFT axial strengths based on the AISC Specification.