Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                
SlideShare a Scribd company logo

Thermo-Economic Optimization of Subcritical and Transcritical ORC Systems

•
•
Thomas Tartière
Thomas Tartière

This document summarizes a thermo-economic optimization of subcritical and transcritical organic Rankine cycle (ORC) systems for low-temperature heat sources between 100-150°C. The authors developed models for ORC components like heat exchangers and turbines to evaluate seven working fluids. Genetic algorithms optimized cycle parameters to minimize specific investment costs. Results showed transcritical cycles with R1234ze(e) and R1233zd(e) had the lowest costs, around 2000€/kWe for a 150°C heat source. A breakdown of costs for R1234ze(e) at 150°C showed a total investment of 941k€ and net power of 604kW.

1 of 18
Download to read offline
THERMO-ECONOMIC OPTIMIZATION OF SUBCRITICAL AND TRANSCRITICAL ORC SYSTEMS THOMAS TARTIÈRE, BENOIT OBERT, LAURENT SANCHEZ ASME ORC 2013 – 2ND INTERNATIONAL SEMINAR ON ORC POWER SYSTEMS
ASME ORC 2013 2 WHO ? Startup company, created in 2008 Headquarters in Paris, France.15 employees Profile Design and construction of turnkey ORC systems and axial turbines Engineering and consulting in renewable energy References ORCHID©, Chateaubriand, France WHR 1 MWe November 2012 ORCHID© Cogen, Montpellier, France CHP 600 kWe + 4 MWth 90°C Summer 2014
ASME ORC 2013 3 PROBLEM STATEMENT Application : Low-temperature heat source (100°C – 150°C ), medium power (200-1000 kWe) Question : Do transcritical cycles result in a better profitability? Based on the SURORC Project (2012), funded by the French Energy Agency (ADEME), realized with partners:
ASME ORC 2013 4 METHODOLOGY Heat source : Water, inlet 100°C < T < 150°C, 15 kg/s Cold sink : Water, inlet 15°C, outlet 25°C Fluid selection : focus on non flammable/mildly flammable fluids Modeling • ORC cycle calculation EES® + REFPROP® 9.1 • Heat exchanger and axial turbine preliminary design • Realistic cost functions based on offers from suppliers Fluid R134a R227ea R125 R245fa R1234yf R1234ze(e) R1233zd(e) Tc [°C] 101,1 101,75 66,023 154,01 94,7 109,36 165,6 Pc [bar] 40,6 29,25 36,17 36,51 33,82 36,34 35,7 GWP 1430 3220 3500 1030 4 6 7 ASHRAE 34 A1 A1 A1 B1 A2 A2L A1 (?) HFC HFO
ASME ORC 2013 5 HEAT EXCHANGERS Plate heat exchangers Evaporator Welded plate heat exchanger (suitable for pressure up to 200 bar) Condenser Semi-welded plate heat exchanger (suitable for pressure<40 bars, temperature<150°C) Cost Linear with respect to heat transfer area • High heat transfer efficiency •Low refrigerant charge • Small temperature approach • Lower cost • Compact size
ASME ORC 2013 6 HEAT EXCHANGERS Model (inspired from Quoilin 2011) Enthalpy discretization of the heat exchanger. Iterate on geometry until total ∆P=30 kPa. Outputs: total heat transfer area A + refrigerant charge Condensation heat transfer correlation from Yan (1998) Evaporation heat transfer correlation from Hsieh (2002) Supercritical heat transfer correlation from Jackson (1979) Limits • Few experimental results on heat transfer and pressure drops with refrigerants at supercritical pressures • High uncertainty of subcritical heat transfer and pressure drop correlations at high pressures
ASME ORC 2013 7 AXIAL TURBINE PRELIMINARY DESIGN Hypothesis • Fixed rotation speed : 3000 rpm • Half reaction turbine • Repeated velocity triangles • Subsonic flow for higher efficiency • Simple geometry and manufacturing Goal
ASME ORC 2013 8 AXIAL TURBINE PRELIMINARY DESIGN Inputs: ,fluid, ω, Tin, Pin Nstage = i+1 Compute: • Velocity triangles • Thermo properties • Turbine geometry • Blade heights bk … Flow Mach < 1 and bk’s adequate END and cost calculation NO YES Outputs • Number of stages • Geometry of the turbine wheels • Height and number of the turbine blades
ASME ORC 2013 9 AXIAL TURBINE PRELIMINARY DESIGN
ASME ORC 2013 AXIAL TURBINE COST Fixed cost (valid only in a limited range of power and rotation speed) • Bearings • Mechanical seals • Lubrication system • Other… Variable cost Manufacturing time for the weel and casing Stator Rotor V1 V2
ASME ORC 2013 11 OTHER COST FUNCTIONS Refrigerant : from 6.5€/kg to 27€/kg Generator : Pump : Mechanical parts: • Piping (purchase + welding): • Other (skid, insulation, installation…) : fixed cost Electrical equipments, instrumentation and controls : fixed cost Other fixed cost : Engineering, transportation, installation, insurance…
ASME ORC 2013 12 GENETIC ALGORITHM OPTIMIZATION Heat source : 15 kg/s of water at T=100…150°C Optimization parameters • Relative evaporation pressure P_evap/P_crit : 0,1 … 1,3 • Superheating : 3 … 30°C • Evaporator pinch temperature difference : 3 … 15°C Objective function Minimize SIC (Specific Investment Cost) = Total Investment Cost/Net output Power Other parameters Condensation temperature : 30°C Condenser subcooling : 3°C Water cooling inlet : 15°C Water cooling outlet : 25°C Turbine efficiency : 85 % Generator efficiency : 95% Pump efficiency : 70%
ASME ORC 2013 13 OPTIMIZATION 0 0,2 0,4 0,6 0,8 1 1,2 100 105 110 115 120 125 130 135 140 145 150 P_evap/P_crit Heat source temperature [°C] Optimum evaporator pressure R134a R227ea R1234ze R1234yf R125 R1233zd R245fa
ASME ORC 2013 14 OPTIMIZATION 1000 1500 2000 2500 3000 3500 4000 4500 100 105 110 115 120 125 130 135 140 145 150 SIC[€/KWe] Heat source temperature [°C] Specific Investment Cost R134a R227ea R1234ze R1234yf R125 R1233zd R245fa
ASME ORC 2013 15 OPTIMIZATION 1000 1500 2000 2500 3000 3500 4000 4500 100 105 110 115 120 125 130 135 140 145 150 SIC[€/KWe] Heat source temperature [°C] Specific Investment Cost R134a R227ea R1234ze R1234yf R125 R1233zd R245fa
ASME ORC 2013 16 OPTIMIZATION 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 140 141 142 143 144 145 146 147 148 149 150 SIC[€/KWe] Heat source temperature [°C] Specific Investment Cost R134a R227ea R1234ze R1234yf R125 R1233zd R245fa
ASME ORC 2013 17 SPECIFIC INVESTEMENT COST BREAKDOWN – 150°C Net power 706 kW 659 kW 604 kW 601 kW 654 kW 687 kW 523 kW Total Investment 1072 k€ 1042 k€ 941 k€ 991 k€ 1003 k€ 968 k€ 1024 k€
THANK YOU THOMAS TARTIÈRE, BENOIT OBERT, LAURENT SANCHEZ ENERTIME 62,64 RUE JEAN JAURÈS, 92800 PUTEAUX, FRANCE WWW.ENERTIME.COM thomas.tartiere@enertime.com

More Related Content

Thermo-Economic Optimization of Subcritical and Transcritical ORC Systems

  • 1. THERMO-ECONOMIC OPTIMIZATION OF SUBCRITICAL AND TRANSCRITICAL ORC SYSTEMS THOMAS TARTIÈRE, BENOIT OBERT, LAURENT SANCHEZ ASME ORC 2013 – 2ND INTERNATIONAL SEMINAR ON ORC POWER SYSTEMS
  • 2. ASME ORC 2013 2 WHO ? Startup company, created in 2008 Headquarters in Paris, France.15 employees Profile Design and construction of turnkey ORC systems and axial turbines Engineering and consulting in renewable energy References ORCHID©, Chateaubriand, France WHR 1 MWe November 2012 ORCHID© Cogen, Montpellier, France CHP 600 kWe + 4 MWth 90°C Summer 2014
  • 3. ASME ORC 2013 3 PROBLEM STATEMENT Application : Low-temperature heat source (100°C – 150°C ), medium power (200-1000 kWe) Question : Do transcritical cycles result in a better profitability? Based on the SURORC Project (2012), funded by the French Energy Agency (ADEME), realized with partners:
  • 4. ASME ORC 2013 4 METHODOLOGY Heat source : Water, inlet 100°C < T < 150°C, 15 kg/s Cold sink : Water, inlet 15°C, outlet 25°C Fluid selection : focus on non flammable/mildly flammable fluids Modeling • ORC cycle calculation EES® + REFPROP® 9.1 • Heat exchanger and axial turbine preliminary design • Realistic cost functions based on offers from suppliers Fluid R134a R227ea R125 R245fa R1234yf R1234ze(e) R1233zd(e) Tc [°C] 101,1 101,75 66,023 154,01 94,7 109,36 165,6 Pc [bar] 40,6 29,25 36,17 36,51 33,82 36,34 35,7 GWP 1430 3220 3500 1030 4 6 7 ASHRAE 34 A1 A1 A1 B1 A2 A2L A1 (?) HFC HFO
  • 5. ASME ORC 2013 5 HEAT EXCHANGERS Plate heat exchangers Evaporator Welded plate heat exchanger (suitable for pressure up to 200 bar) Condenser Semi-welded plate heat exchanger (suitable for pressure<40 bars, temperature<150°C) Cost Linear with respect to heat transfer area • High heat transfer efficiency •Low refrigerant charge • Small temperature approach • Lower cost • Compact size
  • 6. ASME ORC 2013 6 HEAT EXCHANGERS Model (inspired from Quoilin 2011) Enthalpy discretization of the heat exchanger. Iterate on geometry until total ∆P=30 kPa. Outputs: total heat transfer area A + refrigerant charge Condensation heat transfer correlation from Yan (1998) Evaporation heat transfer correlation from Hsieh (2002) Supercritical heat transfer correlation from Jackson (1979) Limits • Few experimental results on heat transfer and pressure drops with refrigerants at supercritical pressures • High uncertainty of subcritical heat transfer and pressure drop correlations at high pressures
  • 7. ASME ORC 2013 7 AXIAL TURBINE PRELIMINARY DESIGN Hypothesis • Fixed rotation speed : 3000 rpm • Half reaction turbine • Repeated velocity triangles • Subsonic flow for higher efficiency • Simple geometry and manufacturing Goal
  • 8. ASME ORC 2013 8 AXIAL TURBINE PRELIMINARY DESIGN Inputs: ,fluid, ω, Tin, Pin Nstage = i+1 Compute: • Velocity triangles • Thermo properties • Turbine geometry • Blade heights bk … Flow Mach < 1 and bk’s adequate END and cost calculation NO YES Outputs • Number of stages • Geometry of the turbine wheels • Height and number of the turbine blades
  • 9. ASME ORC 2013 9 AXIAL TURBINE PRELIMINARY DESIGN
  • 10. ASME ORC 2013 AXIAL TURBINE COST Fixed cost (valid only in a limited range of power and rotation speed) • Bearings • Mechanical seals • Lubrication system • Other… Variable cost Manufacturing time for the weel and casing Stator Rotor V1 V2
  • 11. ASME ORC 2013 11 OTHER COST FUNCTIONS Refrigerant : from 6.5€/kg to 27€/kg Generator : Pump : Mechanical parts: • Piping (purchase + welding): • Other (skid, insulation, installation…) : fixed cost Electrical equipments, instrumentation and controls : fixed cost Other fixed cost : Engineering, transportation, installation, insurance…
  • 12. ASME ORC 2013 12 GENETIC ALGORITHM OPTIMIZATION Heat source : 15 kg/s of water at T=100…150°C Optimization parameters • Relative evaporation pressure P_evap/P_crit : 0,1 … 1,3 • Superheating : 3 … 30°C • Evaporator pinch temperature difference : 3 … 15°C Objective function Minimize SIC (Specific Investment Cost) = Total Investment Cost/Net output Power Other parameters Condensation temperature : 30°C Condenser subcooling : 3°C Water cooling inlet : 15°C Water cooling outlet : 25°C Turbine efficiency : 85 % Generator efficiency : 95% Pump efficiency : 70%
  • 13. ASME ORC 2013 13 OPTIMIZATION 0 0,2 0,4 0,6 0,8 1 1,2 100 105 110 115 120 125 130 135 140 145 150 P_evap/P_crit Heat source temperature [°C] Optimum evaporator pressure R134a R227ea R1234ze R1234yf R125 R1233zd R245fa
  • 14. ASME ORC 2013 14 OPTIMIZATION 1000 1500 2000 2500 3000 3500 4000 4500 100 105 110 115 120 125 130 135 140 145 150 SIC[€/KWe] Heat source temperature [°C] Specific Investment Cost R134a R227ea R1234ze R1234yf R125 R1233zd R245fa
  • 15. ASME ORC 2013 15 OPTIMIZATION 1000 1500 2000 2500 3000 3500 4000 4500 100 105 110 115 120 125 130 135 140 145 150 SIC[€/KWe] Heat source temperature [°C] Specific Investment Cost R134a R227ea R1234ze R1234yf R125 R1233zd R245fa
  • 16. ASME ORC 2013 16 OPTIMIZATION 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 140 141 142 143 144 145 146 147 148 149 150 SIC[€/KWe] Heat source temperature [°C] Specific Investment Cost R134a R227ea R1234ze R1234yf R125 R1233zd R245fa
  • 17. ASME ORC 2013 17 SPECIFIC INVESTEMENT COST BREAKDOWN – 150°C Net power 706 kW 659 kW 604 kW 601 kW 654 kW 687 kW 523 kW Total Investment 1072 k€ 1042 k€ 941 k€ 991 k€ 1003 k€ 968 k€ 1024 k€
  • 18. THANK YOU THOMAS TARTIÈRE, BENOIT OBERT, LAURENT SANCHEZ ENERTIME 62,64 RUE JEAN JAURÈS, 92800 PUTEAUX, FRANCE WWW.ENERTIME.COM thomas.tartiere@enertime.com