PDF Publication Title:
Text from PDF Page: 003
Author's personal copy 1796 international journal of hydrogen energy 38 (2013) 1795e1805 which boils a working fluid such as ammonia to generate a vapour which turns the turbine to generate electricity, and then is condensed back into a liquid in a continuous process. Eighty percent of the energy the Earth receives from the sun is stored in the Earth’s oceans [1,2], and many regions of the world have access to this OTEC resource. OTEC can produce fuels by using its product electricity to create hydrogen, which can be used in hydrogen fueled cars as well as in the devel- opment of synthetic fuels. For a small city, millions of tons of CO2 are generated annually through fossil fuel use while with OTEC the value is zero, during the operation of devices. OTEC has a potential to replace some fossil fuel use, perhaps via OTEC ships travelling the seas of the world. An OTEC system utilizes low-grade energy and has low energy efficiency (about 3e5%). Therefore, achieving a high electricity generating capacity with OTEC requires the use of large quantities of seawater and a correspondingly large amount of pumping energy. These factors impact negatively on the cost-effectiveness of this technology and OTEC is not commercially viable today. To improve the effectiveness and economics of OTEC cycles, it is proposed that they being integrated with industrial operations so that, apart from generating electricity, they could be used for fresh water production, air conditioning and refrigeration, cold water agriculture, aquaculture and mariculture, and hydrogen production [1]. Potential markets for OTEC have been identi- fied, most of which are in Pacific Ocean, and about 50 coun- tries are examining its implementation as a sustainable source of energy and fresh water, including India, Korea, Palau, Philippines, the U.S. and Papua New Guinea [3]. In 2001, as a result of cooperation between Japan and India a 1-MW OTEC plant was built in India [3], and others are planned to be constructed in the near future [4]. Considerable research has been directed to the develop- ment of OTEC recently. Uehara [5e8] conducted numerous theoretical and experimental studies on the major compo- nents of an OTEC plant, and showed that ammonia is a suit- able working fluid for an OTEC plant employing a closed organic Rankine cycle (ORC). The energy efficiency of the Rankine cycle in an OTEC plant is usually limited to around 5% due to the small temperature difference between surface water and deep water of the ocean. So, to improve the effi- ciency of OTEC, other thermodynamic cycles like the Kalina cycle and the Uehara cycle that use an ammoniaewater mixture as the working fluid are being considered [9]; they are reported to have better energy efficiencies rather than a Rankine cycle at the same temperature difference [9]. Increasing in the temperature difference between the hot heat source and the cold heat sink can improve the efficiency of OTEC plants, as can the integration of OTEC with other energy technologies. Saitoh and Yamada [10] proposed a conceptual design of a multiple Rankine cycle system using both solar thermal energy and ocean thermal energy in order to improve the cycle efficiency. In addition, Owens [11] opti- mized OTEC plants using ammonia as the working fluid in closed cycles. Uehara and Ikegamia [6] performed an optimi- zation study using the power method for a closed-cycle OTEC plant. Later, Uehara and Ikegamia [12] studied the perfor- mance of OTEC using the Kalina cycle and proposed a new OTEC cycle with an absorption and extraction process [13]. Rabas et al. [14] studied a non-condensable gas removal system for a particular 10-MW hybrid power plant. More recently, Kazim [15] proposed a hydrogen production cycle using ocean thermal energy, and Ikegamia et al. [7,16] proposed desalination using an integrated hybrid cycle and an open OTEC cycle. Energy analysis, which is based on the first law of ther- modynamics, often does not provide a clear picture of ther- modynamic efficiency and losses. Exergy is not subject to a conservation law, but is destroyed due to irreversibilities during any process [17]. Exergy analysis overcomes such deficiencies and can help improve efficiency and sustain- ability [18]. Exergy is a useful tool for determining the location, type and true magnitude of exergy losses, which appear in the form of either exergy destruction or waste exergy emission [19]. Therefore, exergy methods can assist in developing strategies and guidelines for more effective use of energy resources and technologies. Sun et al. [20] report an optimi- zation design and exergy analysis of an organic Rankine cycle in ocean thermal energy conversion, and show that ammonia is a good working fluid for an ORC cycle in OTEC from a net power output point of view. Also, from an exergy viewpoint, it has been shown that a larger scale ORC in OTEC can justify the use of a heat exchanger with a higher effectiveness to decrease the exhaust loss, which accounts for a large proportion of the exergy loss of an ORC in an OTEC system [20]. In this paper, a novel OTEC system equipped with a solar collector and PEM electrolysis to produce hydrogen is ther- modynamically modelled and assessed with energy and exergy analyses. The primary objective is to improve under- standing of this system. The following specific tasks are performed: Model and simulate (using Matlab software) the integrated system. Validate each part of the model and simulation. Perform energy and exergy analyses of the integrated system to determine the exergy destruction rate and energy and exergy efficiencies of each component and the entire system. Determine the sustainability index for the system and quantify its variation with exergy destruction, and examine the relation between exergy efficiency, exergy destruction and sustainability index. Conduct a comprehensive parametric study to determine the effect of major design parameters on system performance. 2. Modelling and energy analysis For thermodynamic modelling purposes, the integrated OTEC system for hydrogen production considered here (Fig. 1) is divided into three parts: flat plate solar collector, ocean thermal energy conversion (OTEC) unit and PEM electrolyzer. Fig. 1 shows a schematic diagram of an integrated OTEC system equipped with a flat plate solar collector and PEM electrolyzer. This integrated system uses the warm surface seawater to evaporate a working fluid like ammonia or a FreonPDF Image | H2 Energy
PDF Search Title:
H2 EnergyOriginal File Name Searched:
7ca1a819b900cabfed4ddb4705157053.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
| CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com | RSS | AMP |