PDF Publication Title:
Text from PDF Page: 024
4. Conclusions A set of natural refrigerants and their binary mixtures were thermodynamically evaluated as working mediums for a WHR-ORC for three different heat source temperatures (150, 225 and 300oC), under subcritical and supercritical operating conditions. It was determined that especially for the lowest heat source temperature, the critical temperature of the working fluids (either pure or binary mixtures) has a major influence on the heat source utilization and the overall system exergetic efficiency. Moreover, it also affects the dependence of the latter on the maximum operation pressure of the cycle. In general, the performance of high critical temperature working fluids increases for high heat source temperatures (225 and mainly 300 oC). On the contrary, working fluids with low critical temperatures are preferable when the temperature of the heat source stream is lower (150 oC), since their exergetic efficiency is better (although usually at significantly higher operation pressures). In almost all cases, the supercritical ORC can lead to the improvement of the system efficiency and smaller turbine size parameter values, at the expense of higher volume flow rates at the expander outlet, higher pressure and volume flow ratios in the turbine and increased rotational speeds. The use of binary mixtures can further improve the cycle performance for all the cases that were examined, although it is often accompanied by increased UA values in the condenser. The exergetic efficiency of the zeotropic fluids is influenced by their component ratio. More specifically, the critical temperature (especially for lower heat source temperatures) of the working fluid and the temperature glide during its condensation are key parameters in determining the optimal composition. As a general rule, the second law efficiency tends to be maximized when the temperature glide closely matches the temperature increase of the cooling stream in the condenser and when the concentration of the most efficient pure component is higher. It should be also noted that the mixtures consisting of the most efficient pure components also tend to have the highest efficiency. The supercritical ORC combined with the use of binary mixtures can result in substantial improvement of the exergetic efficiency. According to the cases investigated, the WHR-ORC exhibits the highest exergetic efficiency when the working fluid is a binary mixture and the maximum operation pressure is in the supercritical pressure range. For heat source temperatures of 150 and 225 oC the natural refrigerants and their binary mixtures can be considered as appealing alternatives to R245fa since they do not only have a better thermodynamic performance, but they also generally exhibit favourable size parameter, volume flow ratio and turbine volume flow rate values, although they are associated with increased turbine rotational speeds. When the heat source is at 300 oC, despite their superior exergetic efficiency, their technical evaluation parameters are substantially inferior compared to R245fa. Consequently, further techno-economic investigations are required to determine if the benefits in the second law efficiency outweigh the apparent economic drawbacks that are associated with the use of these fluids. References [1] Bao J, Zhao L. A review of working fluid and expander selections for organic Rankine cycle. Renewable and Sustainable Energy Reviews. 2013;24(0):325-42. [2] Campana F, Bianchi M, Branchini L, De Pascale A, Peretto A, Baresi M, et al. ORC waste heat recovery in European energy intensive industries: Energy and GHG savings. Energy Conversion and Management. 2013;76(0):244-52. [3] Vélez F, Segovia JJ, Martín MC, Antolín G, Chejne F, Quijano A. A technical, economical and market review of organic Rankine cycles for the conversion of low-grade heat for power generation. Renewable and Sustainable Energy Reviews. 2012;16(6):4175-89. [4] Wang EH, Zhang HG, Fan BY, Ouyang MG, Zhao Y, Mu QH. Study of working fluid selection of organic Rankine cycle (ORC) for engine waste heat recovery. Energy. 2011;36(5):3406-18. 24PDF Image | Thermodynamic investigation of waste heat recovery
PDF Search Title:
Thermodynamic investigation of waste heat recoveryOriginal File Name Searched:
Braimakis_et_al._final_332_1063_1_DRaccT4fromT23.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 (Standard Web Page)