PDF Publication Title:
Text from PDF Page: 005
The temperature changes of the fluids over the heat exchan- gers are not fixed. Rather, the pinch point analysis determines the maximum temperature drop and, thus, the amount of heat transfer possible for the specified pinch point temperature dif- ferences. 3.2 ORC cycle The ORC model uses standard thermodynamic relations to cal- culate the fluid conditions at each point in the cycle indicated in Figure 1b. The isentropic efficiency of the turbine and the pump was fixed at 0.8 and 0.75, respectively, for the calculations described in this paper. Feed pump work ðWpÞ is calculated from the pressure rise across the pump, DP, where P is the pressure, and is related to the specific enthalpy increase of the working fluid passing through the pump, by the following equation: is therefore one of the parameters that defines the design space within which meaningful cycle simulations can be carried out using the model. 3.3 Fluids modelled The fluids modelled are dry or isentropic, as recommended by Tchanche et al. [6]. Dry fluids have a positive vapour saturation curve, whereas isentropic fluids have a vertical saturation curve. This results in the fluid remaining in a superheated vapour state as it expands through the turbine in an ORC. Therefore, ORCs do not need high levels of superheating in order to avoid exces- sive wetness at turbine exit, unlike water/steam cycles. The fluids selected for the current ORC calculations are R245fa, n-pentane, n-octane, toluene, cyclohexane and R134a (isentropic). As the three heat sources considered have a wide range of temperatures, working fluids with a range of critical temperatures were selected to ensure ORCs for each source were possible within the defined operating limits and operating conditions of the fluids. Saturation curves for all fluids used are shown, a TS diagram, together with water, in Figure 4. 3.4 Model validation Aneke et al. [3] compare the performance of a model built with IPSEpro, using REFPROP 7.0 to calculate fluid properties, with real data from the Chena binary geothermal power plant. The cycle parameters used in the simulations run in Aneke et al.’s study have been input into the model used in this study. The resultsofboththesimulationsareshowninTable2. The results from both models agree closely. The net power output and overall cycle thermal efficiency calculated by the two Table 2. Comparison of results from the model by Aneke et al. [3] and the present model W 1⁄4 m_ DP 1⁄4 m_ ðh h Þ: P OhPr O 2 1 ð3Þ The work output from the turbine ðWTÞ is related to the isen- tropic (I) enthalpy rise across the turbine according to WT1⁄4hTm_Oðh3h4;IÞ; ð4Þ where h is the efficiency. Turbine outlet specific enthalpy, h4, is calculated from WT WT 1⁄4m_Oðh3 h4Þ)h4 1⁄4h3 m_ : O ð5Þ This is limited in the model to a minimum saturated vapour state corresponding to a dryness fraction of 0.75. At lower vapour qualities, the vapour is considered too wet to ensure the mechanical integrity of the turbine. Turbine exit vapour quality Figure 4. T S plots for water and the selected organic working fluids. Parameter error (%) Geothermal fluid mass flow rate (kg/s) Geothermal fluid temperature ðW CÞ Cooling water mass flowrate (kg/s) Aneke et al. model 33.39a 73.33a 101.68a 4.44a R134aa 0.8a 16.95a 4.39a 250a 40a 0:305ainferred 54.94 9.91 11.99 210 0.08 2570.38 2327.1 – Present Relative model 33.39a – 73.33a – 101.68a – 4.44a – R134aa – 0.8a – 16.95a – 4.41 0.39 254.81 1.69 39.97 20.08 0.305a – 54.76 20.32 9.92 0.10 11.99a – 214.25 2.03 0.083 3.22 2594.63 0.94 2342.01 0.64 1a– Organic Rankine cycles in waste heat recovery Cooling water source temperature Working fluid Turbine efficiency Turbine inlet pressure (bar) Turbine outlet pressure (bar) Gross generator power (kW) Pump power (kW) ðW CÞ Pump efficiency Geothermal exit temperature ðW CÞ Cooling water exit temperature ðW CÞ Working fluid mass flow rate (kg/s) Net plant power (kW) Thermal efficiency Evaporator heat transfer rate (kWth) Condenser heat transfer rate (kWth) Pinch point temperature difference ðW CÞ aIndicates input variable International Journal of Low-Carbon Technologies 2013, 8, i9–i18 i13 Downloaded from https://academic.oup.com/ijlct/article/8/suppl_1/i9/771990 by guest on 13 January 2021PDF Image | Organic Rankine cycles in waste heat recovery
PDF Search Title:
Organic Rankine cycles in waste heat recoveryOriginal File Name Searched:
ctt033.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)