日本打开“宇宙帆”实验获得成功

日本宇宙研究开发机构报道曾于近日在鹿儿岛发射一枚#310小型火箭，火箭在太空中旋转飞行时，成功地打开了直径为10m的两个树脂薄膜“宇宙帆”。宇宙研究开发机构说，这次实验的目的是研制接受阳光的“太阳帆”，使宇宙探测器能以太阳能为动力，向遥远的木星     

空间太阳能漫谈

据推测，在 2050年以前地球上的人口总数可能超过 80亿，要想既不破坏地球环境又能为人类提供所需的能量确实是对人类社会提出的一个挑战。为此，人类研究了多种方案，如火力发电站、核电站、水电站、风力发电站和建立在地面上的太阳能电站，或许还有在将来才能实现的核聚变发电站。然而，对 21世纪而言，可能还有另外一种可选择的能源，即空间太阳能。　　从全球角度考虑，与对其它种类能源的需求相比，对电能的需求量增长最快。美国能源部按保守值估计，到 2015年，在所谓的占世界人口 80％的发展中国家，电能消耗量将和工业化国家持平…     

Evolution of space solar cells

The solar cells used in space for over 40 years are reviewed by discussing the semiconductor materials which have provided the best cells. Most emphasis was on high efficiency, combined with good tolerance to charged particle bombardment, and the steady increase in efficiency is discussed. The most important requirement is that the cells must be highly reliable, consistent in performance, and stable while operating in space. The need for highest reliability makes the costs less important. The progress to date has provided a good foundation for future applications for space cells.     

High-efficiency silicon space solar cells

SHARP's activities on Si solar cells developments and features of Si solar cells for space use in comparison with GaAs solar cells are presented. Two types of high-efficiency silicon solar cells and the same kinds of high-efficiency solar cells with integrated bypass function (IBF cells) were developed and qualified for space applications. The NRS/LBSF cells and NRS/BSF cells showed an average of 18% and 17% efficiencies, respectively, at AMO and 28°C conditions. The IBF cells have P⁺N⁺ diodes on the front surface to protect itself from reverse voltage due to shadowing. The designs and features of these solar cells are presented. The radiation tests results of these solar cells are also presented. The NRS/BSF cells showed lower degradation rate compared to conventional BSFR cells with the same thickness (100 μm). But the NRS/LBSF cells showed a higher degradation rate than the BSFR cells. The IBF cells showed almost the same radiation characteristics as the same kinds of cells without IBF. The results of radiation tests on these high-efficiency solar cells and the discussions about the radiation characteristics of them are presented. In the last section, the future silicon solar cell development plan is discussed.     

Radiation-resistant solar cells for space use

This paper reviews the present status of radiation-resistant solar cells made with Si, GaAs, InP and InGaP/GaAs for space use. At first, properties of radiation-induced defects in semiconductor materials and solar cells are described based on an anomalous degradation of Si space solar cells under high-energy, high-fluence electron and proton irradiations. Advantages of direct bandgap materials as radiation-resistant space cells are presented. Unique properties of InP as radiation-resistant cells have also been found. A world-record efficiency of 26.9% (AM0) has been obtained for an InGaP/GaAs tandem solar cell. Radiation-resistance of the InGaP/GaAs tandem cells is described.     

乘风破浪走远洋

远古以来,人类就把风当作能源使用。早在公元前3000多年,埃及和巴比伦等文明古国就已发明了风帆船。帆的发明,使风力代替了部分人力。帆船(如图所示)的应用是古代人民把风当作能源的最初形式。早在秦汉时期,我国利用风力驱动的帆船就已经在江河上航行,到了明朝,我国风帆助航技术达到鼎盛时期。     

Performance analysis of solar space heating system

The paper deals with solar space heating for a school during winter. The system, which is an extension of Solar Vapour Absorption Cooling Project, consists of coupling the solar collector field, the air handling units and the thermal energy reservoir in a single circuit with one pump. The analysis of the system has been done to describe the temperature history of the hot water reservoir as a function of two non-dimensional parameters. These parameters, which are functions of environmental and air handling unit characteristics, dictate the net thermal energy inflow or outflow from the reservoir. The problem solution has been obtained in a generalized form and predicted results are shown in dimensional form for the basic data chosen from an actual on-going project.     

Load optimization in solar space heating systems

When load variables, such as window and insulation types, are included in the economic optimization of a solar space heating system, the over-all cost is lower than that resulting from optimization of collection area for a fixed load (as by FCHART [1] and SOLCOST [2]). In this paper an algorithm is derived for choosing insulation levels, as well as solar collection area, so as to minimize the over-all cost of constructing and heating a building. The general algorithm is applicable with any solar performance prediction method, and with any economic criterion where the “cost” is a linear function of collection area and of auxiliary energy consumption. A specific algorithm is also derived for active solar systems using the Relative Areas method of performance prediction [3] and a conventional present worth life cycle cost analysis. The degree-day model is used for the load calculations.     

Optimum glazing combination for solar space heating

A study is made for comparing the maximum seasonal energy yield obtainable by solar collectors for space heating application. Different glazing combinations with glass and plastic as glazing materials are considered. The study is made for four different locations. The performance of eight glazing combinations with covers ranging in number from one to three is compared to obtain the optimum combination for each location. The results show that selecting the optimum glazing combination improves the performance significantly. In general, plastic covers give higher yield. The study confirmed that the use of two covers is justified in cold, cloudy climates while a single cover is suitable for temperate climates. In most cases three covers lead to a significant reduction in the yield. Replacing plastic by glass as a top cover for longer life results in a small yield reduction. Some of the other conclusions are that the ratio of average to normal transmittance-absorptance product changes significantly with location and month of the year. However, the seasonal average value of this ratio is almost constant for any number of covers but changes with location.     

Thermic diode solar panels for space heating

Thermic diode solar panels are a new method of heating buildings using solar energy. Each panel combines all the necessary elements of a complete solar energy system (collector, controls, storage heat exchangers and ducting) into a single module. They have no moving parts and they need no external power. Panal operation is discussed and thermic panels are compared to other typical solar heating systems: air heating, water heating, active and passive. Residential and commercial applications are also discussed.

The performance of thermic panels are compared to conventional solar systems. A computer simulation of thermic panels in a residential space-heating application resulted in predictions of the percentage of solar heat provided by the panels. The predictions are compared to similar analyses of conventional solar systems. Thermic panels did as well or better than conventional systems in the six climate types investigated. However, since their installed cost is less, they are expected to be more economic than conventional solar systems.

Thermic panels improve the economics of flat-plate collectors by their modularity and simplicity. Modularity reduces installation costs and raw materials cost; simplicity reduces maintenance costs. Furthermore, the panels can be integrated into the buildings structure, saving the cost of the wall or roof elements they replace.