SNOW AND ICE ALBEDO MEASURED WITH TWO TYPES OF PYRANOMETERS1

ABSTRACT: In order to obtain total short-wave albedos of snow and ice, both incident and reflected solar radiation were measured over a frozen lake surface using two different types of radiation measurement devices: a Kipp and Zonen thermopile pyranometer with a spectral sensitivity of 300 to 2800 nm and a LI-COR photovoltaic pyranometer with a spectral sensitivity of 400 to 1100 am. The spectral response of the LI-COR pyranometers limits its use as a short-wave radiation measurement device. Therefore, two equations were developed to adjust both the daily incident radiation data and the daily reflected radiation data measured by the LI-COR instrument to total short-wave radiation values, i.e., to the waveband of 300 to 2800 nm (visible to near-infrared spectrum). The LI-COR data were then adjusted, and a total short-wave adjusted albedo was calculated with a modeling efficiency of 0.97.     

Water-saving Technologies,Solar Green House and Ecological Rehabilitation in Minqin Oasis of Gansu Province,China

Land degradation and desertification have become severe environmental problems in arid areas due to excessive use of water resources. It is urgent to reduce agricultural water use for ecological rehabilitation, which may result in a decrease in agricultural production and farmer＇s welfare. This paper focused on the impacts of some main measures including extensions of watersaving irrigation, expanding solar green house and increasing off-farm employment, which are generally recognized to be important to alleviate water shortage and poverty. A bioconomic model is applied taking Minqin Oasis in Gansu Province as a case study site. Simulation results showed that the effect of expanding solar greenhouse was more positive than other ones so it drew more attention. On the view of the different effects between each irrigation zone, mixed policy patterns suitable for them are suggested. In Baqu, expanding solar greenhouse should be the most important, auxiliary with encouraging pipe irrigation. Inversely, with regard to Quanshan, the major attention should be paid to subsidy for pipe irrigation and it would be better to supply the off-farm employment opportunities to the households in Huqu, where the expanding of solar greenhouse should also be summoned. Finally, it should be noted that farmer＇s income would only resume to 90% of the current level in the short run by putting more effort into local policies. Thus, the ecological compensation is needed to ensure farmer＇s welfare.     

Impact of utilizing reflector,single-axis and two-axis sun trackers on the performance of an evacuated tube solar collector

ABSTRACT

In this paper, a novel evacuated tube solar collector (ETSC) is first designed and built. Then, the impact of adding reflector, reflector plus single-axis sun tracker and reflector plus two-axis sun tracker to the built ETSC on the thermal efficiency of the ETSC is evaluated both theoretically and experimentally. In this regard, four identical versions of the proposed ETSC have been built and utilized in four collectors built and presented in this research work. The first collector is the same proposed built ETSC, the second collector is a parabolic trough solar collector comprising one built ETSC and a reflector (ETSC+R), the third collector is composed of one built ETSC, a reflector and a single-axis sun tracker all built in this study (ETSC+R+ ST), and the fourth collector consists of one built ETSC, a reflector and a two-axis sun tracker all built in this study (ETSC+R+ DT). Theoretical basis and concepts of the four collectors are formulated and analyzed in separate subsections. Theoretical results are outlined and highlighted at the end of each subsection. Experimental measurements and data obtained from the operation of the four collectors in the four seasons are presented that point by point verify theoretical results obtained in this study. To provide a comprehensive view, a techno-economic numerical comparison is performed between the four collectors. The following points, which are also the novelty and contributions of this work, are deduced from theoretical concepts, experimental data, and comparison provided in this study:

?There is no technical and economic justification for adding a reflector to an ETSC that results in forming a parabolic trough solar collector (ETSC+R) without any sun tracker.

?There is no economic justification for adding a single-axis sun tracker to a parabolic trough solar collector (ETSC+R).

?There is no economic justification for adding a two-axis sun tracker to a parabolic trough solar collector (ETSC+R).

?Comparing between a two-axis sun tracker and a single-axis sun tracker, adding the single-axis type to a parabolic trough solar collector (ETSC+R) is more advantageous.     

AN INSULATED EVAPORIMETER1

Evaporation was measured from a circular evaporation pan, 18 inches in diameter and 8 inches deep. The pan was insulated on the sides and bottom using 2 inches of freon-blown polyurethane foam. A U.S. Weather Bureau Class A evaporation pan was used to obtain reference evaporation measurements. Water evaporation from the Class A pan and the insulated pan were highly correlated. Using a water-methanol mixture, the insulated pan may be operated at temperatures below 32 F; the equivalent liquid water evaporation may be determined using a regression equation.     

用三性法对巴楚伽师6.8级地震的跨越式预测

介绍了用三性法对2003年2月24日新疆巴楚伽师6．8级地震的早期跨越式预测，并讨论了某些相关问题。所谓三性法就是大震时序上的周期性、倍周期性和黄金分割性的排列。     

太阳活动对地球表面温度影响的研究进展

论述了近年来对地球表面温度变化特征、原因研究的意义及研究进展。许多研究表明，20世纪全球地表气温的变化是自然因素和人为因素共同作用的结果。根据多种反映太阳活动的代用指标拟合的气候模型指出，太阳活动可以解释1850年以前气温变化的大部分情况。工业革命以来，温室气体成为不可忽视的影响因素，太阳活动对气候影响所占的比重及其相互作用的物理机制仍然是有待深入研究和解决的问题。     

炼油企业挥发性有机物无组织排放通量监测现状与发展

炼油企业是重要的挥发性有机物(VOCs)人为排放源,排放的VOCs主要来自无组织源,监控及排放核算困难。笔者总结了国内外炼油企业VOCs排放通量监控及核算技术体系,综述了各类VOCs无组织排放通量监测技术的原理及适用范围,着重评述了工业场地VOCs无组织排放通量监测最佳实用技术——红外掩日通量监测(SOF)和差分吸收激光雷达(DIAL)及其在炼油企业的应用进展。总体上,SOF仪器及监测费用适中,但易受阳光等天气条件限制; DIAL几乎可全天候监测,但仪器及监测费用较高。SOF和DIAL监测的欧美炼油企业VOCs排放系数一般为0. 02%～0. 10%,约为排放清单值的3～10倍。国内炼油厂VOCs排放核算采用的排放系数约为美国排放清单值(0. 01%～0. 02%)的10倍,尚待实测校验和修订。VOCs无组织排放通量监测技术也可用于检查或评估炼油企业泄漏检测与修复(LDAR)等VOCs无组织排放控制效果。     

Identifying the roots of Green Civil War over utility-scale solar energy projects on public lands across the American Southwest

Utility-scale solar energy (USSE) development is an emerging cause of land use change across the American Southwest. Many proposed projects in the region have encountered resistance from environmental groups because of concern about endangered, threatened, and special status species. Projects have also faced resistance from impacted local communities and Native American tribes. This research documents land use conflicts that surfaced during the initial wave of USSE development from 2009 to 2015. The goal is to identify potential roots of land use conflict over renewable energy development, to help explain why there is consistent support for renewables in general, but widespread opposition to projects during the proposal and development stages. The primary data presented include public comments to formal rule-making processes, semi-structured interviews conducted from 2009 to 2013, and various media sources. The paper concludes describing emerging planning frameworks that identify sites for USSE with fewer land use conflicts.     

CFD analysis on the performance of a solar chimney power plant system: Case study in Algeria

The solar chimney power plant (SCPP) is a power generator which uses solar radiation to increase the internal energy of the air circulating in the system, thereby transforming the useful gain of the solar collector into kinetic energy. The produced kinetic energy then can be converted into electrical energy by means of an appropriate turbine. In this paper, four locations in Algeria

(Constantine, Ouargla, Adrar, and Tamanrasset) were considered as case studies to describe the SCPP mechanism in detail. Numerical simulation of an SCPP which has the same geometrical dimensions was performed to estimate the power output of SCPP in these regions. Using the CFD software FLUENT we simulated a two-dimensional axisymmetric model of a SCPP with the standard k-ε turbulence model. The simulation results show that the highest power output produced monthly average value 68–73 KW over the year and the highest hourly power produced in June is around 109–113 KW.     

Moisture transfer modeling during solar drying of potato cylinders considering shrinkage

In the present work, the thin layer drying kinetics of potato during natural convection solar drying was investigated experimentally. Cylindrical potato samples with length 50 mm and varying diameter of 8, 10 and 13 mm were dried in an in-house designed and fabricated laboratory scale mixed-mode solar dryer. Thirteen different thin-layer mathematical models were fitted to the experimental moisture ratio (MR) data. The obtained results indicated that the Modified Page model could satisfactorily describe the drying curve of potato cylinders with higher value of R² and lower values of RMSE and χ². The shrinkage parameter is incorporated in the analytical diffusion model to study the moisture transfer mechanism of potato cylinders. It was observed that the values of effective diffusion coefficient (D_eff) and convective mass transfer coefficient (h_m) are overestimated in the range of 85.02–90.27% and 39.11–45.11% for the range of sample diameter examined, without considering the shrinkage effect in the mass transfer analysis. A Multiphysics approach was adopted in this study to get insight into the drying behavior of potato cylinders in terms of food-moisture interactions during the solar drying process. The predicted results of MR are in close agreement with the experimental data. Moreover, the anisotropic behavior of shrinkage as well as the moisture distribution inside the potato cylinder was very well described by Multiphysics model.