Applied Mechanics and Materials Vols. 672-674

Abstract: The vertical panels of solar chimney have internal dimensions of 2000mm height、1000mm length. Under the condition of heat flux and chimney gap variety, we research chimney interior velocity field. Experimental Results show that airflow increased with chimney gap augmentation, the airflow and air velocity augment with the increase of solar radiant intensity, and air velocity decreases with the increase of solar chimney gap. Air velocity is higher near the heated surfaces than it in the middle chimney. Meanwhile velocity boundary layers form near the heated surface.

Abstract: This paper proposes a solar-air compound source heat pump system, for the rural residential area of Hebei and independent villas. The system can realize heating in winter and refrigerating in summer, and demand of heat water. This paper simulates and analyzes the winter heating situation of this system. The entire heating season, heat collecting efficiency of the solar collector is 0.45 in average, and solar guarantee rate is 46%. Solar-air compound source heat pump system average COP is 4.5 in the heating season, increased by 26% than the air source heat pump system run separately , and the fluctuation range is small. Throughout the heating season, the contribution of solar collectors is 59%, the contribution of air source heat pump is 41%.

Abstract: The response, control and fault characteristics of the typical distributed grid-connected photovoltaic generation are described in this paper.And the whole experimental testing platform containing type testing platform, dynamic simulation testing platform and moving experimental process is structured, which describes composition and function of each testing platform. Finally the performance index test of distributed photovoltaic power generation system relying on Shanghai Electric Power Research Institute is carried out. And the experiment results reflect the performance of distributed grid-connected photovoltaic power generation comprehensively.

Abstract: This article is about designing and building a small scale prototype tower system to gather solar energy and store it in a molten salt tank. The system consists of several heliostats directing incident solar rays to a receiver at the top of a tower. It is intended to establish highly reputable research and development facility in solar thermal energy systems. A thorough investigation in the field of building and utilizing solar tower system was conducted. The authors studied and presented the current state of art of the technological developments concerning the solar tower systems and an assessment of their advantages and disadvantages. The adaptability of CSP (Concentrating Solar Power) power systems to Saudi Arabia climate was closely investigated. A scheme for a pilot solar power plant that it most suited to the conditions of Saudi Arabia was proposed. The next stage will be building, fabrication, and constructing the various subsystems; heliostats, tower, receiver, and storage tank.

Abstract: Aiming at the water quality monitoring needs,a novel solar-powered digital water quality detecting instrument was designed in this paper. The water water quality detecting instrument using digital control and solar power technologies, which has the advantages of energy saving and environmental protection.The system components,hardware and sof tware of detecting instrument is introduced,and a prototype of designed water quality detecting instrument was developed and experimental test. Compared to the existing water quality detecting instruments,the designed has the advantage of energy saving and environmental protection, portable and efficient, accurate and reliable,which can be used for industrial and civil water quality monitoring.

Abstract: The application of solar photovoltaic poer genernation usually has stand-alone and grid-connected modes,but most of the existing solar photovoltaic inverter has only a single function of off-grid or grid-connected,the suitability of system is relatively poor, difficult to meet the needs of the particular application. A medium and low-power stand-alone/grid-connected dual-mode inverter for solar photovoltaic system was designed,the composition, working principle and implementation of the inverter were introduced and developed.The designed inverter with a variety of functions,which can meet stand-alone or grid-connected and other solar photovoltaic applications, and can be used in different solar occasions.

Abstract: Based on the mathematical model of the three-phase two-stage PV grid inverter, the fuzzy-PID control strategy is applied in the grid connected control of PV system in this paper. The purpose of the intelligent control of photovoltaic grid connected inverter has been achieved. The digital simulation and physical simulation show that the fuzzy-PID control strategy can improve the PV system grid control dynamic process and get the smooth connection of the PV system with the power grid. At the same time, the harmonic pollution on the grid has been significantly reduced.

Abstract: Fast pyrolysis of corn stalk was performed at temperatures in the range of 450 - 600 °C in a fluidized bed. The chemical composition of bio-oil was analyzed by GC–MS, and its main properties were determined. The results showed that the bio-oil yield increased with increasing pyrolysis temperature from 450 °C to 500 °C and then declined with a further increase in pyrolysis temperature. The highest bio-oil yield of 43.3wt% was obtained at 500 °C with the dolomite as bed material. The char yield always decreased with the rise of temperature. The major chemical compounds of bio-oil included hydroxyacetone, butanone, acetic acid, propionic acid, ethylene glycol, phenol, etc.

Abstract: Production of 2,3-Butanediol (2,3-BD) from renewable resources can be sustainable and inexpensive. Many studies have been done on the fermentation using Klebsiella pneumoniae, Klebsiella oxytoca and Paenibacillus polymyxa. Although significant quantities of 2,3-BD have been accumulated by these bacteria, which one is the best strain of great fermentation capacity still be insensible. In this paper, Klebsiella pneumonia and Klebsiella oxytoca HD79 were opt to ferment concentrated and non-detoxified corn cob hemicelluose hydrolysate and concentrated detoxified hydrolysate. Then glucose was utilized as carbon source to verify the quality of the hydrolysate. At last, we compared the fermentation capacity between them. The results showed that K. pneumoniae has more resistance with inhibitors than K. oxytoca HD79, which has showed better ability of producing 2,3-BD. K. pneumoniae might be a promising strain for 2,3-BD production using renewable resources.

Abstract: A systematic hydrothermal pretreatment of corncob has been conducted with an aim to trace the content and property of lignin during the pretreatment process. The result showed that the lowest content of lignin was obtained under the following condition: water-solid ratio is 3:1,180 °C for 90min with 0.4g auxiliary medium. TG and FTIR analysis has been conducted to investigate the thermal stability and structure of lignin, and the result indicated that hydrothermal pretreatment influenced the thermal stability and structure of lignin extracted from corncob.