Solar thermal heat engines for water pumping: An update
ABSTRACT Solar thermal-driven heat engines for water pumping have been previously reviewed for some authors in the past century. However, some devices have not been treated as metal hydride-based systems or the pumping subsystems of solar thermal-driven reverse osmosis desalination systems. Following the typical classification given in the previous literature, in this work an update of the solar heat engines for water pumping based in thermodynamic methods (conventional and unconventional) is presented. Besides small remarks about systems previously quoted by other authors, new designs found in the literature are described. In general, the main characteristics of these systems is their low efficiency, low power output and, in the case of unconventional designs, its simplicity. This work in conjunction with previous review papers make up reference point for the knowledge of the use of solar thermal energy for liquid pumping purpose.
- SourceAvailable from: Saidur Rahman
Conference Paper: Solar energy policy: Malaysia vs developed countries[Show abstract] [Hide abstract]
ABSTRACT: Countries all over the world is enquiring and taking efforts to implement the environment friendly renewable energy to mitigate the negative impacts of fossil fuels on the environment and their fast depletion. To reduce the reliance on fossil fuels and environmental degradation, many countries have focused and formulated solar energy related policies to increase its share into energy mix. In this paper a review of the solar energy policies, implemented in the developed countries and Malaysia, are discussed as well as the discussion of successful existing solar energy policies in the developed countries. According to the 2010 BP Statistical Energy Survey, the world cumulative installed solar energy capacity was 22928.9 MW in 2009, a change of 46.9 % compared to 2008. After the review of literature, FiT, RPS and Incentives are found to be the most beneficial energy policies implemented by the developed countries. These policies create the paths to promote the development and implementation of renewable energy technologies. Also, the current policies related to solar energy in Malaysia are investigated and compared with developed countries.2011 IEEE 1st Conference on Clean Energy and Technology, CET 2011; 01/2011
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ABSTRACT: The world economy heavily relies on fossil fuels. Their use leads to carbon dioxide emissions responsible of global warming and fuels international tensions. Renewable energy sources and energy efficiency are alternatives. An Organic Rankine Cycle is similar to a steam cycle but uses an organic fluid instead of water. It is suitable for conversion of solar radiation, geothermal energy, biomass energy, ocean thermal gradient, and waste heat into power. Although investigated in the 1970s, it was soon abandoned after the oil crisis. With the growing concern on the environment, the interest for this technology for electricity generation was renewed. The technology for medium and large scale systems is already mature but solutions are still sought for small systems. This book presents results of investigation on micro organic Rankine cycles of less than 2 kW power output. Overview of different organic Rankine cycle applications, working fluid selection, cycle performance analysis, and economic evaluation constitute the content of the book and will be useful to energy professionals, researchers working on thermodynamics and those interested in next generation power systems.10/2012; LAMBERT ACDEMIC PUBLISHING., ISBN: 3659128821
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ABSTRACT: The aim of this paper is to identify and evaluate potential areas of technical improvement to solar-powered desalination systems that use reverse osmosis (RO). We compare ideal with real specific energy consumption (SEC) to pinpoint the causes of inefficiency. The ideal SEC is compared among different configurations including a batch system driven by a piston, and continuous systems with single or multiple stages with or without energy recovery in each case. For example, to desalinate 1 m of freshwater from normal seawater (osmotic pressure 27 bar) will require at least 0.94 kWh of solar energy; thus in a sunny coastal location, up to 1850 m of water per year per m (m/m) of land covered by solar collectors could theoretically be desalinated. For brackish water (osmotic pressure 3 bar), 11570 m/m of fresh water could theoretically be obtained under the same conditions. These ideal values are compared with practically achieved values reported in the literature. The practical energy consumption is found to be typically 40−200 times higher depending on feed water composition, system configuration and energy recovery. For state-of-the-art systems, energy losses at the various steps in the conversion process are quantified and presented with the help of Sankey diagrams. Improvements that could reduce the losses are discussed. Consequently, recommendations for areas of R&D are highlighted with particular reference to emerging technologies. It is concluded that there is considerable scope to improve the efficiency of solar-powered RO system.Desalination and Water Treatment - DESALIN WATER TREAT. 01/2011; 35:14-32.