Performance evaluation of a 10 kWp PV power system prototype for isolated building in Thailand

This paper describes the design and testing of a 10 kW_p photovoltaic (PV) system and summarizes its performance results after the first 6 months of operation. This system functions as a stand-alone power system that is used to supply electricity for isolated buildings and is designed for integration with a micro-grid system (MGS), which is the future concept for a renewable energy-based power network system for Thailand. The system is comprised of the following components. An array with three different types of PV modules consisting amorphous thin film of 3672 W, polycrystalline solar cell of 3600 W and hybrid solar cell of 2880 W, making up a total peak power of 10.152 kW. In addition, there are three grid-connected inverters of 3.5 kW each, three bi-directional inverters of 3.5 kW each and an energy storage system of 100 kWh. After the first 6 months of system operation, it was found that all the components and the overall system had worked effectively. In total, the system had generated about 7852 kWh and the average electricity production per day was 43.6 kWh. The average efficiency of amorphous thin film panel, polycrystalline panel, hybrid solar cell panel and entire PV panel system was 6.26%, 10.48%, 13.78% and 8.82%, respectively. From the analysis of the daily energy production, daily energy consumption and energy storage, the results seem to indicate that there was some mismatching between energy supply and demand in the system. However, this can be overcome by integrating the system to a micro-grid network whereby the energy from the system can be diverted to other loads when there is a surplus and additional energy can be drawn from external sources and fed to the system when the internal supply is insufficient.     

科学发展生物能源能若干问题探讨

目前我国生物能源发展迅速，问题和挑战并存，为了节约资源，高效循环利用，发展有中国特色的生物质能源，本文提出首先发展沼气，二是纤维乙醇，三是生物柴油，四是淀粉乙醇，五是秸秆发电的发展思路。     

Influence of the management strategy and operating conditions on the performance of an adsorption chiller

The aim of this experimental work was to study the influence of the operation mode (i.e. cycle time and relative duration of ads-/desorption phases, R) as well as of the operating conditions on the performance of an adsorption chiller. The testing campaign demonstrated that the management optimization strongly improves the performance of such kind of machines. The Coefficient of Performance (COP) and the Specific/Volumetric Cooling Power (SCP, VCP) vary, respectively, in a range of ±133% and ±43% when the cycle time (τ_cycle) increases from 5 to 20 min at fixed boundary conditions (T_e = 15 °C, T_c = 35 °C, T_h = 90 °C) while a further increasing in performance (up to 15%) is reached, at fixed cycle time, by protracting the duration of the adsorption phase at the expense of the desorption one. The complete set of results allowed to draw a map of performance suitable for the optimization of the management mode taking into account the specific application. At T_e = 15 °C, T_c = 35 °C, T_h = 90 °C, if high SCP is required (e.g. automotive air conditioning), the optimal choice is τ_cycle = 7 min and R = 2.5 (SCP = 394 W/kg, COP = 0.60, VCP = 223 W/m³) while to assure a good efficiency (e.g. solar cooling) the proper management is τ_cycle = 20 min and R = 1 (SCP = 204 W/kg, COP = 0.69, VCP = 116 W/m³).     

天然气分布式能源热力系统性能评价测试方法

为科学客观地评价天然气分布式能源系统,提出了一种天然气分布式能源热力系统的性能评价测试方法。通过界定测试边界,确定了热力系统的一类特征测试参数,并给出了各特征参数的测量不确定度、测量原理及测试方法,推导出机组的热效率、热耗率,系统的输出热/冷量、一次能源利用率、相对节能率和热电比等各性能指标的计算方法。通过对某示范工程项目的现场测试,验证了该方法的科学性、可行性和测试结果的可信度。     

世界主要国家生物质能战略及对我国的启示

本文总结了世界主要国家生物质能发展战略的特点,分析了生物质能战略制定的要点,为我国生物质能战略的确立提出政策建议。     

科学发展生物能源的若干问题探讨

目前我国生物能源发展迅速,问题和挑战并存,为了节约资源,高效循环利用,发展有中国特色的生物质能源,本文提出首先发展沼气,二是纤维乙醇,三是生物柴油,四是淀粉乙醇,五是秸秆发电的发展思路。     

Online performance evaluation of alternative control strategies for building cooling water systems prior to in situ implementation

This paper presents the online test and evaluation of the performance of five practical control strategies (fixed set-point control method, fixed approach control method, two near optimal strategies and one optimal strategy) for building cooling water systems to identify the best strategy for future field validation. All of these strategies were tested and evaluated in a simulated virtual environment similar to the situation when they are actually implemented in practice. A virtual building system representing the real building and its central chilling system was developed and used to test the operational performance of the system controlled by different strategies. The packages of each control strategy are separately computed by the application program of Matlab, as the control optimizers to identify the necessary control settings for the given condition based on the collected operation data. The data exchanger between the virtual building system and the control optimizer was managed by a software platform through a communication interface. The results showed that the optimal control strategy is more energy efficient and cost effective than the other strategies, and its computational cost is manageable and can satisfy the requirements of practical applications. This strategy is being implemented in a super high-rise building for field validation.     

海带发酵生产乙醇及其影响因素的控制研究

以海带为原料,在实验室条件下,通过微生物发酵过程,建立了海带生产乙醇的工艺流程,并对影响因素及其控制进行了研究。实验结果表明,海带通过发酵过程能使部分碳水化合物转变为乙醇,控制温度30-35℃、pH值为6-7和发酵时间6-7 d,可以获得最大的乙醇产率;酵母培养液磷酸盐和镁离子的最适营养浓度分别为3 g/L和1.5 g/L。这不仅为利用海带发酵生产乙醇提供了重要的技术参数,而且对开辟新的海藻生物能源具有一定的实践意义。     

Performance evaluation of an alkaline fuel cell/thermoelectric generator hybrid system

A hybrid system consisting of an AFC (Alkaline Fuel Cell), a TEG (Thermoelectric Generator) and a regenerator is put forward, where the AFC converts the chemical energy in the hydrogen into electrical energy and thermal energy, and the released thermal energy is subsequently converted into electrical energy through the bottoming TEG. The main irreversible losses in each element of the hybrid system are characterized, and numerical expressions for the efficiency and power output of the AFC, TEG and hybrid system are respectively derived. The fundamental relation between the operating current density of the AFC and the dimensionless current of the TEG is obtained, from which the region of the operating current density of the AFC that the TEG exerts its function is determined. By employing such a hybrid system, the equivalent maximum power density of the AFC can be increased by up to 23%. The effects of the operating current density, operating temperature, heat conductivity, and integrated parameter on the performance of the hybrid system are revealed. The results obtained in the present paper will provide some theoretical guidance for the performance improvement of the AFC.     

我国发展林木生物质能源的制约因素与对策

制约我国发展林木生物质能源的因素有原料短缺,原始投资成本偏高,缺少能源树种选育栽培技术支撑,产业化基础薄弱,成本与价格较高,缺少有效的产业政策扶持等。为此提出分类指导,定向培育,规模发展,强化机构能力建设和人员培训,筛选和定向改良能源植物,加大产业扶持力度,结合生态工程构建生物能源产业链的对策建议。     

利用延迟焦化方法处理生物质的技术可行性分析

延迟焦化是加工重质油的主要工艺之一.通过分析生物质能利用所存在的问题,提出了利用延迟焦化工艺和装置处理生物质的设想,通过对比延迟焦化和生物质热裂解的工艺条件以及模拟延迟焦化工艺过程的生物质热解试验,分析了利用延迟焦化方法处理生物质的技术可行性,展望和构思了该方法工业化应用的实现方式.     

中国微藻生物质能源专利技术分析

大力发展微藻生物质能源是解决能源危机和环境问题的有效途径。文章从微藻资源、微藻培养系统、培养物采收技术、微藻生物柴油炼制、含油微藻综合利用等方面出发,综述了中国微藻生物质能源专利的发展现状,旨在使科研工作者更加全面地了解这一领域发展趋势,并且促进科研工作者对自主知识产权的保护意识。     

Bio-energy in Europe: changing technology choices

Bio-energy is seen as one of the key options to mitigate greenhouse gas emissions and substitute fossil fuels. This is certainly evident in Europe, where a kaleidoscope of activities and programs was and is executed for developing and stimulating bio-energy.     

Performance testing of a linear fresnel reflector

Results of optical and thermal performance evaluation tests conducted on a prototype linear Fresnel reflector system fabricated using locally available material are presented in this paper.     

Demographics,energy and our homes

The projected growth in households in the UK is a key factor in future domestic energy consumption, particularly electricity consumption. While every household needs a home and its heating, lighting and appliances, increasing incomes have historically led to significantly higher appliance ownership, higher expectations of levels of energy service and greater usage. In the past this trend was combined with increasing household numbers to drive growth in domestic electricity demand. Official projections for population growth and household composition indicate significant drivers for future growth in energy demand. Curbing this will require policies to reverse the tendency for energy–efficiency improvements to be overwhelmed by growing numbers of households, more widespread appliance ownership and increased service expectations.     

Performance evaluation of combined solid oxide fuel cells with different electrolytes

The performance of a hybrid system of solid oxide fuel cells with different electrolytes, i.e., an oxygen-ion conducting electrolyte (SOFC-O²⁻) and a proton-conducting electrolyte (SOFC-H⁺) is evaluated in this study. Due to an internal reforming operation, SOFC-O²⁻ can produce electrical power as well as high-temperature exhaust gas containing remaining fuel, i.e., H₂ and CO that can be used for SOFC-H⁺ operation. The remaining CO can further react with H₂O via water gas-shift reaction to produce more H₂ within SOFC-H⁺ and thus, the possibility of carbon formation in SOFC-H⁺ can be eliminated and overall system efficiency can be improved. The simulation results show that the performance of the SOFC-O²⁻–SOFC-H⁺ system provides a higher efficiency (54.11%) compared with the use of a single SOFC. Further, the SOFC hybrid system performance is investigated with respect to important operating conditions, such as temperature, pressure, degree of pre-reforming, inlet fuel velocity, and cell voltage.     

黄泛平原农村合理利用与开发生物质能的探讨——以山东省鄄城县糖牛楼村为例

对位于黄泛平原的山东省鄄城县糖牛楼村能源资源量与消费现状进行了调查，分析了该村能源的构成和消费特征，并进行了节能和开发新能源的实验，提高了生物质能利用率。