The potential of concentrating solar power in South Africa

In this paper all provinces of South Africa with a good potential for the implementation of large-scale concentrating solar power plants are identified using geographic information systems. The areas are assumed suitable if they get sufficient sunshine, are close enough to transmission lines, are flat enough, their respective vegetation is not under threat and they have a suitable land use profile. Various maps are created showing the solar resource, the slope, areas with “least threatened” vegetation, proximity to transmission lines and areas suitable for the installation of large concentrating solar power plants. Assuming the installation of parabolic trough plants, it is found that the identified suitable areas could accommodate plants with a nominal capacity of 510.3 GW in the Northern Cape, 25.3 GW in the Free State, 10.5 GW in the Western Cape and 1.6 GW in the Eastern Cape, which gives a total potential nominal capacity of 547.6 GW for the whole country.     

Dish Stirling technology: A 100 MW solar power plant using hydrogen for Algeria

In Algeria, the electricity demand is rapidly increasing. At the same time, Algeria is very rich in solar energy resources and possesses large wasteland areas in the Sahara that represent 80% of the total area and the market of solar energy is very promising. All these indicators make Algeria an ideal country for the implementation of the Concentrating Solar Thermal Power Plant technologies (CSTPP). In order to study whether the implementation of CSTPP under Algerian climate is economically feasible, we present in this article a techno economic assessment of 100 MW of CSTPP based on Dish Stirling technology using hydrogen as working fluid for centralized electricity production located in three typical sites of each geographical regions of Algeria (Algiers, In Salah and Tamanrasset). The National Renewable Energy Laboratory’s SAM software (Solar Advisor Model) is used to evaluate the monthly energy production, annual energy output and the Levelized cost of energy (LCOE) for this study. The results indicate that Tamanrasset is the suitable site yielding the lower LCOE (11.5 c$/kWh) and the higher annual net electric energy output (221 GWh/y).     

Assessment of different configurations for combined parabolic-trough (PT) solar power and desalination plants in arid regions

The combination of desalination technology into concentrating solar power (CSP) plants needs to be considered for the planned installation of CSP plants in arid regions. There are interesting synergies between the two technologies, like the possibility of substituting the condenser of the power cycle for a thermal desalination unit. This paper presents a thermodynamic evaluation of different configurations for coupling parabolic-trough (PT) solar power plants and desalination facilities in a dry location representing the Middle East and North Africa (MENA) region. The integration of a low-temperature multi-effect distillation (LT-MED) plant fed by the steam at the outlet of the turbine replacing the condenser of the power cycle has been simulated and compared with the combination of CSP with a reverse osmosis (RO) plant. Furthermore, an additional novel concept of concentrating solar power and desalination (CSP+D) has been evaluated: a LT-MED powered by the steam obtained from a thermal vapour compressor (TVC) using the exhaust steam of the CSP plant as entrained vapour and steam extracted from the turbine as the motive vapour of the ejector. This new concept (LT-MED-TVC) has been analyzed and compared with the others, evaluating its optimization for the integration into a CSP plant by considering different extractions of the turbine.     

Thermodynamic development and design of a concentrating solar thermochemical water-splitting process for co-production of hydrogen and electricity

A concentrating solar plant is proposed for a thermochemical water-splitting process with excess heat used for electricity generation in an organic Rankine cycle. The quasi-steady state thermodynamic model consisting of 23 components and 45 states uses adjustable design parameters to optimize hydrogen production and system efficiency. The plant design and associated thermodynamic model demonstrate that cerium oxide is suitable for thermochemical water-splitting cycles involving the co-production of hydrogen and electricity. Design point analyses at 900 W/m² DNI indicate that a single tower with solar radiation input of 27.74 MW and an aperture area of 9.424 m² yields 10.96 MW total output comprised of 5.55 MW hydrogen (Gibbs free energy) and 5.41 MW net electricity after subtracting off 22.0% of total power generation for auxiliary loads. Pure hydrogen output amounts to 522 tonne/year at 20.73 GWh/year (HHV) or 17.20 GWh/year (Gibbs free energy) with net electricity generation at 14.52 GWh/year using TMY3 data from Daggett, California, USA. Annual average system efficiency is 38.2% with the constituent hydrogen fraction and electrical fraction being 54.2% and 45.8%, respectively. Sensitivity analyses illustrate that increases in particle loop recuperator effectiveness create an increase in hydrogen production and a decrease in electricity generation. Further, recuperator effectiveness has a measurable effect on hydrogen production, but has limited impact on total system efficiency given that 81.1% of excess heat is recuperated within the system for electricity generation.     

Solar steam reforming for enriched methane production: Reactor configurations modeling and comparison

A solar low-temperature steam reforming process for the production of an Enriched Methane (EM) mixture composed by CH₄ and H₂ (20%vol) exploiting the solar energy stored in a Molten Salt stream heated up by a Concentrating Solar Plant (MS-CSP) is presented and simulated through a two-dimensional steam reforming reactor model.     

太阳能热水系统的实验研究

性能良好的太阳能集热器是太阳能热水系统关键设备之一。该文简单介绍了强制循环太阳能热水系统原理 ,着重考察了一种低温平板太阳能集热器在青岛气候条件下的工作性能 ,测定了瞬时效率曲线 ,其热损系数为 5 .76W /(m2 ·℃ )。     

太阳能热水系统流量分布的一种分析计算方法

分析了在求解太阳能集热器的流量分布时,能量守恒模型和现行的动量守恒模型存在的一些不足。在前人研究的基础上,综合考虑计算的可行性、准确性和简便性后,建立了新的数学模型,提出了一种改进算法,并对计算结果进行了误差分析。     

太阳能烟囱综合利用海水系统的初步研究

针对目前太阳能海水淡化技术和太阳能烟囱发电技术在经济或技术上存在的问题,提出了太阳能烟囱综合利用海水系统,在利用太阳能烟囱进行海水淡化的同时,以制取的淡水进行水力发电。首先以天津汉沽地区的气象数据对综合系统的性能进行了初步估算;其次建立并优化小型实验系统,获取不同冷凝方式的实验结果。通过实验与理论估算结果的对比来分析该综合系统的理论和经济可行性。理论和实验研究结果表明:采用间壁冷凝换热方式,所提出的综合设计方案具有可行性,并同时推动太阳能烟囱技术和海水淡化技术的发展。