Experimental study of natural brine solar ponds in Tibet

A salinity gradient solar pond (SGSP) is a simple and effective way of capturing and storing solar energy. The Qinghai-Tibet Plateau has very good solar energy resources and very rich salt lake brine resources. It lacks energy for its mineral processes and is therefore an ideal location for the development and operation of solar ponds. In China, solar ponds have been widely applied for aquaculture, in the production of Glauber’s salt and in the production of lithium carbonate from salt lake. As part of an experimental study, a SGSP using the natural brine of Zabuye salt lake in the Tibet plateau has been constructed. The pond has an area of 2500 m² and is 1.9 m deep. The solar pond started operation in spring when the ambient temperature was very low and has operated steadily for 105 days, with the LCZ temperature varying between 20 and 40 °C. During the experimental study, the lower convective zone (LCZ) of the pond reached a maximum temperature of 39.1 °C. The results show that solar ponds can be operated successfully at the Qinghai-Tibet plateau and can be applied to the production of minerals.     

The thermal characteristics and economic analysis of a solar pond coupled low temperature multi stage desalination plant

The paper discusses optimisation of the size of the pond and the number of stages for three different storage zone temperatures taking into account the large variation in quantity of energy supplied by the pond between summer and winter. One result is that over-sizing the pond, leading to some rejection of the heat collected during the summer (which is referred to as peak clipping), will result in a higher utilisation factor of the desalination plant and a reduction in the summer/winter yield ratio. Optimum peak clipping days, leading to the minimum product water cost, for each storage zone temperature and performance ratio is presented.The sensitivity analysis of the various factors affecting the overall water costs show that the capital costs comprise about two thirds (2/3) of the total desalinated water costs. This demonstrates and re-emphasises the inherent and basic fact that solar desalination is a capital intensive enterprise. Each 1% increase in interest rate increases solar pond thermal energy costs by about 13-15% and desalinated water costs from SP/MSF combination by about 10-13%.     

An integrated technique using solar and evaporation ponds for effective brine disposal management

Desalination is a process that involves the removal of salts and non-ionic minerals from seawater to produce freshwater that is fit for human consumption. This process produces brine, which is typically redisposed into the sea. The relatively high salt concentration in the disposed brine increases the salinity of water and soil, which adversely affects the environment. However, brine is found to be rich in economically valuable minerals. In order to effectively manage the disposed brine, this study proposes an integrated technique using solar and evaporation ponds to filter valuable minerals from concentrated brine. The results of this study demonstrate that the proposed technique can be effectively employed for this purpose. Furthermore, this helps reduce desalination costs and complies with the notion of renewable energy production and eco-friendliness.     

The process of loss of internal stability in salt gradient solar ponds

Loss of the bulk stability in salt gradient solar ponds is a rather rare, short duration phenomenon, which can lead to complete mixing of the gradient zone. Laboratory investigations have allowed close observation of this phenomenon and comparison of the derived data with theory. It is shown that there is little or no probability of such instability occurring with the maximum salt concentration normally used (about 20% at the bottom). Boundary erosion of the gradient zone is an entirely unrelated matter.     

西藏地区盐湖太阳池技术开发应用的研究

盐湖太阳池是一种具有广阔应用前景的太阳能热利用技术，同时也为开发盐湖资源提供了能源支持。西藏地区常规能源缺乏，而太阳能和盐湖资源都非常丰富，是开发盐湖太阳池最适宜的地区之一。     

太阳池的研究与应用

自从1902年Kalecsinsky首次发现了天然太阳池现象以后，经过长期的研究和发展，太阳池技术已被广泛应用于发电、取暖、海水淡化．矿物加工等领域，太阳池成为近期内进行大规模太阳能热利用的最有前景的低温热源装置。主要综述了太阳池的集热原理及建造方法、太阳池中热量的贮存及提取方式、太阳池的应用以及研究动向等，并指出目前我国太阳池技术还处于实验研究的阶段，而我国具有丰富的太阳能和盐资源，大力开发太阳池技术将为发展地方经济起到重要的作用。     

Nonlinear dynamic behavior of non-convective zone in salt gradient solar pond

Non-Convective Zone (NCZ) of salt gradient solar pond is a typical double diffusive system of salinity and temperature, and it is subjected to instable effects of adverse temperature gradient. The onset of instability may occur as an oscillatory motion because of the stabilizing effect of the salinity. In this paper, the marginal state between the steady state and the convection of the NCZ is studied. The stability of the Boussinesq approximation of the Navier-Stokes equations is analyzed by a perturbation approach. The marginal states for the onset of convection are obtained by analytical method, which is based on the linearization of the ordinary differential equations, and then numerical method is used to solve the nonlinear ordinary differential equations. Numerical results provide the trajectories of the temperature and velocity coefficients in the three-dimensional phase space, as well as the two-dimensional temperature, salinity and velocity fields in NCZ. The results demonstrate that the numerical study is in agreement with the marginal stability and the critical Rayleigh number derived from linear stability analysis. Both the linear and nonlinear studies indicate that oscillation is a narrow region above the stable region; however, the nonlinear numerical results indicate that the linear stability analysis leans to a larger upper boundary in the oscillatory regions.     

Solar Technological Progress and Use of Solar Energy in the World

Solar energy can potentially play a very important role in providing most of the heating, cooling and electricity needs of the world The sun has produced energy for billions of years. Solar energy is the solar radiation that reaches the earth. There are a variety of different technologies used in order to take advantage of solar energy. The primary solar energy technologies include photovoltaics, concentrating solar power, and solar heating and cooling systems. Today solar sources provide around 10% of the energy used worldwide, but in the developing countries their share is still of the order of 40%. In 1999, installed photovoltaic (PV) capacity was 594 MWp in the world. Japan has the highest PV capacity as a result of an important program to support the development of PV markets. Japan had a PV capacity of 205 MWp in 1999.     

Study of breakage of main covalent bonds during co-pyrolysis of oil shale and alkaline lignin by TG-FTIR integrated analysis

Pyrolytic vapor generated over different temperature ranges can be correlated with breaking of different groups of covalent bonds. In the present study, pyrolysis of oil shale and alkaline lignin was studied by thermogravimetry coupled with fourier transform infrared spectroscopy (TG-FTIR) analysis. As the dominant fraction of pyrolytic gaseous products, methane (CH₄) was selected as an entry point to track the breakage of main covalent bonds during pyrolysis of oil shale and alkaline lignin. Through applying the deconvolution method, overall CH₄ evolution and differential thermogravimetric (DTG) curves of pyrolysis of oil shale and alkaline lignin could be fitted by a series of sub-curves assigned to different groups of covalent bonds. This indicated that the mass loss of oil shale was mainly caused by the fracture of three groups of covalent bonds. In contrast, mass loss of alkaline lignin was mainly caused by the fracture of two groups of covalent bonds. Furthermore, detailed influence of co-pyrolysis on the cleavage of covalent bonds was also analyzed for different blending ratios of oil shale and alkaline lignin. The results revealed that co-pyrolysis of alkaline lignin and oil shale led to the enhancement in CH₄ yield by promoting the breakage of linkages. It was also found that among three groups of covalent bonds, the third was most significantly influenced due to reduction in its bond energy.     

Examining potential benefits of combining a chimney with a salinity gradient solar pond for production of power in salt affected areas

The concept of combining a salinity gradient solar pond with a chimney to produce power in salt affected areas is examined. Firstly the causes of salinity in salt affected areas of northern Victoria, Australia are discussed. Existing salinity mitigation schemes are introduced and the integration of solar ponds with those schemes is discussed. Later it is shown how a solar pond can be combined with a chimney incorporating an air turbine for the production of power. Following the introduction of this concept the preliminary design is presented for a demonstration power plant incorporating a solar pond of area 6 hectares and depth 3 m with a 200 m tall chimney of 10 m diameter. The performance, including output power and efficiency of the proposed plant operating in northern Victoria is analysed and the results are discussed. The paper also discusses the overall advantages of using a solar pond with a chimney for production of power including the use of the large thermal mass of a solar pond as a practical and efficient method of storing collected solar energy.     

风光互补发电技术在油田边远单井上应用的可行性分析

介绍风光互补供电系统的基本原理及特点,根据用电负荷情况设计成独立的供电系统,并通过工程实例介绍了风光互补的设计步骤,将采用风光互补发电与传统供配电方式进行了比较。     

上海太阳能技术发展现状及其应用前景

简要介绍了上海的太阳能资源条件,分析了太阳能转换利用的主要技术途径,对上海太阳能技术发展现状和应用前景做了总结。     

中国太阳能热发电产业的发展现状及前景

主要阐述了太阳能热发电技术、国内外太阳能热发电产业的发展现状、国内热发电产业存在的问题,并提出了几点建议。最后,展望了国内热发电产业的发展前景。     

Valorization of the waste heat given off in a system alkaline electrolyzer-photovoltaic array to improve hydrogen production performance: Case study Antofagasta,Chile

The efficiency of an electrolyzer can be improved by preheating the water consumed, which is generally done by means of solar energy in PVT panels. In this research, the first objective is to determine whether it is possible to preheat the consumed water by using the residual heat given off by the electrolyzer itself fed by a PV array, and if the above is met, the second objective consists of quantify the benefits obtained in the performance of the system. The simulation is carried out over a period of one year, considering the meteorological conditions of the city of Antofagasta, Chile. The results indicate that it is possible to constantly maintain the water temperature consumed by the electrolyzer at its nominal value of 80 °C, since the energy contained in the waste heat is about 30 times higher than this hot water demand. Continuous operation at 80 °C compared to operation at variable temperature achieves an annual increase of 0.22% in hydrogen production and an average of 0.33% in electrolyzer efficiency. Moreover, by considering the thermal energy given off by the electrolyzer as useful output of the system, the overall energy efficiency increases by a relative percentage of 13%.     

Correlations of minimum miscibility pressure for pure and impure CO2 in low permeability oil reservoir

Minimum miscible pressure (MMP) is an important indicator to evaluate the miscibility of CO₂ with oil, and it is of paramount importance to the implementation of CO₂ flooding. In this study, the sensitivities of MMP to its influencing factors were analyzed quantitatively. And the MMP correlations applying for pure and impure CO₂–oil in low permeability reservoir were presented. These correlations are conducive to predicting MMP quickly and precisely when limited experimental data are available. In low permeability reservoirs, the main sensitive factors of MMP are reservoir temperature, oil components (C₅₊ molecular weight, volatiles and intermediates) and the components of injected gas (characterized with pseudo-critical temperature). MMP increases with the volatile/intermediate ratio, especially in the neighborhood of unity and decreases with the pseudo-critical temperature of impure CO₂. MMP shows strong sensibility to the pseudo-critical temperature of impure CO₂ when the critical temperature is less than that of pure CO₂.     

Solar and wind opportunities for water desalination in the Arab regions

Despite the abundance of renewable energy resources in the Arab region, the use of solar thermal, solar photovoltaics, and wind is still in its technological and economic infancy. Great potential exists, but economic constraints have impeded more rapid growth for many applications. These technologies have certainly advanced technically over the last quarter century to the point where they should now be considered clean-energy alternatives to fossil fuels. For the Arab countries and many other regions of the world, potable water is becoming as critical a commodity as electricity. As renewable energy technologies advance and environmental concerns rise, these technologies are becoming more interesting partners for powering water desalination projects. We evaluate the current potential and viability of solar and wind, emphasizing the strict mandate for accurate, reliable site-specific resource data. Water desalination can be achieved through either thermal energy (using phase-change processes) or electricity (driving membrane processes), and these sources are best matched to the particular desalination technology. Desalination using solar thermal can be accomplished by multistage flash distillation, multi-effect distillation, vapor compression, freeze separation, and solar still methods. Concentrating solar power offers the best match to large-scale plants that require both high-temperature fluids and electricity. Solar and wind electricity can be effective energy sources for reverse osmosis, electrodialysis, and ultra- and nano-filtration. All these water desalination processes have special operational and high energy requirements that put additional requisites on the use of solar and wind to power these applications. We summarize the characteristics of the various desalination technologies. The effective match of solar thermal, solar photovoltaics, and wind to each of these is discussed in detail. An economic analysis is provided that incorporates energy consumption, water production levels, and environmental benefits in its model. Finally, the expected evolution of the renewable technologies over the near- to mid-term is discussed with the implications for desalination applications over these timeframes.     

别墅建筑暖通节能及太阳能应用设计研究

本文以北京某别墅太阳能供暖及空调设计为例,通过太阳能的得热计算、建筑冷热负荷计算及供暖空调方案的分析选择,提出了一种节能舒适的应用天然能源的设计思路。     

太阳能在冀东油田勘探开发中应用

充分利用绿色替代能源是石油企业降低油田开采能耗的有效途径。本文结合冀东油田的气候特点，根据人工岛采油规划基本理念，从太阳能直接利用、光伏发电以及太阳能光热利用三个方面详细分析了太阳能在冀东油田人工岛上的应用，为冀东油田建设成节能降耗、绿色环保大油田提供理论依据。     

太阳能蓄热技术及其在木材干燥系统中的应用

介绍了太阳能蓄热技术及其在木材干燥系统中的应用以及存在的问题与建议。     

湖南省太阳能资源分布特征与开发策略

分析了湖南省太阳能资源的时空分布特征,结合湖南省能源产业和经济社会发展实际,提出湖南省的太阳能资源开发利用应重点考虑热利用和风光互补发电。