Abstract: The infrared image of solar cell's electroluminescence (EL) is one of the important means of hidden defects detection. In order to improve the automatic recognition rate of defect images, this paper adopts improved invariant moments for feature extraction. The scale factor of the improved invariant moments is eliminated by transformation. Therefore they have the properties of translation, rotation and scale invariance simultaneously in discrete state. At the same time, Support Vector Machine (SVM) is used to distinguish the defect image. The system which combined invariant moments with SVM is applied to classify the debris, crack, off-grid, open weld and black pieces. The recognition rate of 5 kinds of defects has reached more than 90%.
Abstract: Taking household heating for an example, this paper has introduced the composition and characteristics of combined heating system with condensing wall-mounted boiler and solar water heater; and through the simple contrastive analysis of the economy and environmental protection with the solar heating system assisted by electric heating and wall-mounted gas heater, it is believed that the heating system combined with condensing gas heater and solar heating is the better choice of household heating considering its energy saving, economy and environmental protection.
Abstract: Photovoltaic (PV) industry in China shows more growth potential because of the favorable political support, deep market penetration will be expected to follow. A detailed and comprehensive assessment for photovoltaic (PV) power plant is extremely necessary. This paper study the feasibility and profitability of the grid connect PV power plant by analyzing a case using RETScreen photovoltaic project model. It was concluded from this study that finding the optimal tilt angle is extremely necessary for the fixed installation. All kinds of financial indicators show that the project has good profitability, whether considering greenhouse gasses reduction credits or not. In addition, the results from sensitivity and risk analysis showed that avoided cost of energy、renewable energy production and initial cost have great effects on net present value (NPV). The effects of annual cost, debt rate and debt term on NPV are so small that we can ignore their impact. This study is of high value when attempting to analyze PV power plants comprehensively.
Abstract: A seasonal solar soil heat storage (SSSHS) system applied in greenhouse heating has been designed and introduced. The system consists of solar collector subsystem, soil heat storage subsystem, greenhouse heating subsystem, hydronic subsystem and control subsystem. By applying soil heat storage, solar energy stored in the soil under the greenhouse can be transferred and utilized in winter to realize the utilization of cross-seasonal energy. TRNSYS is used to simulate the process and effect in the system of the solar energy collection and soil heat storage in Shanghai, and the simulation is calibrated to improve the precision of the TRNSYS model. When the indoor air temperature of the greenhouse is kept at 12°C throughout the year, the energy saving by using the SSSHS system in Shanghai can be 46.2kWh/(m2∙year).
Abstract: Intelligent LED plant light supplement system can improve and enhance plant photosynthesis, increase crop yields, especially for anti-season greenhouse cultivation in the facility agriculture.For the application of greenhouse crop cultivation, design and development of intelligent LED plant lights system based on solar-powered, the system uses solar photovoltaic power supply to save the cost and environmental protection. And using the digital control technology to achieve intelligent LED plant light supplement system control. The hardware and software design of system were described in detail in the paper, the experimental tested prototype was completed.The designed system has the advantages of energy saving, digital smart, green and efficient, etc., which suitable for promote the application of modern facilities agriculture.
Abstract: This research has recognized the problems of temperature rise in most solar cell (PV: photovoltaic) modules currently utilized. First, if the temperature rises to 70~80°C, it damages the white-pipe tempered glasses used on the module surface and reduces the module lifespan to a significant extent. Also, if the temperature is risen by 1°C, the modules excluding a thin film module would show efficiency degradation by approx. 0.45~0.55%. To address such problems, if a cooling system is used to lower the average temperature of the PV module, its lifespan and power generation amount increase. In order to maximize the power generation efficiency and cooling device usage by establishing a control system, this research seeks to explore the following goals.
Abstract: Currently most researches on photovoltaic are for a single field such as market, policy and technology. This paper with scenario analysis method, considers the impact of various factors to build a variety of possible development scenarios. It forecasts the development trend of Chinese photovoltaic industry with situational analysis. And it raises suggestions of resolution for the different scenarios.
Abstract: This paper mainly analyses a BAPV system of 3kWp and a BIPV system of 10 kWp in Shanghai, China. Net present value (NPV) and the payback time (Pd) as the parameters to determine the profitability of the system based on some actual measured data. As there are two subsidy policies in China, including the initial investment subsidy and PV electricity tariff subsidy. The variations of NPV and Pd with the initial investment subsidy and PV electricity tariff subsidy are researched. Analysis results indicate both the systems have a good economic benefit. Since the manufacturing, utilization and recycling periods of PV systems can lead to negative impacts on the environment. Environmental impacts by both the systems are also evaluated in this paper by the energy payback time (EPBT) and greenhouse-gas payback time (GPBT). Results show both the systems have a good environmental benefit, PV technology and PV system are sustainable.
Abstract: The goal of I-V characteristic measurement of photovoltaic (PV) module is to reduce uncertainty not only for PV laboratories but also for manufacturers. This paper presents the results comparison and data analysis between two PV laboratories. Even though both laboratories have obtained the ISO 17025 certificate, the I-V results show inevitable deviation. The cause of deviation depends on photovoltaic scale traceability of laboratory, system bias, internal quality control measures and other uncertainty sources. The analysis also shows that the PV scale traceability is the most important factor to reduce result deviation among laboratories and measurement uncertainty. The various contributions to the result deviation are critically illustrated for different traceability chains. Besides, the calibration method of reference photovoltaic devices (reference cell or module), spatial uniformity of irradiance and I-V data acquisition unit should be paid more attention as well.