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Organic Rankine Cycle (ORC) Waste Heat Generator (WHG) Presented by Grant Terzer and Marc Rouse

Organic Rankine Cycle (ORC) Waste Heat Generator (WHG) Presented by Grant Terzer and Marc Rouse. 2010 Regional Distributor Review & Conference Americas June 14-17, 2010. Waste Heat Generator (WHG). Converts waste heat into electricity Capable of using ‘low grade’ waste heat.

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Organic Rankine Cycle (ORC) Waste Heat Generator (WHG) Presented by Grant Terzer and Marc Rouse

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  1. Organic Rankine Cycle (ORC) Waste Heat Generator (WHG)Presented by Grant Terzer and Marc Rouse 2010 Regional Distributor Review & Conference Americas June 14-17, 2010

  2. Waste Heat Generator (WHG) • Converts waste heat into electricity • Capable of using ‘low grade’ waste heat • Waste Heat Generator (WHG)

  3. Turbines • Devices that convert fluid flow into work • Gas turbine • Working fluid is combustion products and air • Water turbine (hydro) • Working fluid is water • Steam turbine • Rankine Cycle – water is boiled to vapor before passing through turbine • Working fluid is water vapor (steam)

  4. Rankine Cycle • Thermodynamic cycle which converts heat into work • Working fluid is often steam • Requires high temperatures to vaporize water • 80% of all power in the world is produced with this technology • Low Temperature heat sources produce little useable steam • Inherent problem is high latent heat of water in liquid-vapor phase change • CONDENSER • Water

  5. Organic Rankine Cycle • For many (low temperature) waste heat applications, we need a fluid that boils at a lower temperature than water • Historically, such fluids have been hydrocarbons - hence the name Organic • Modern Working Fluids include: Propane / Pentane / Toluene / HFC-R245fa • These Working Fluids allow use of Lower-Temperature Heat Sources because the liquid-vapor phase change, or boiling point, occurs at a lower temperature than the water-steam phase change

  6. Waste Heat Sources • Waste heat is any source of otherwise unused heat – that is why ‘fuel’ is free • Waste heat from MicroTurbine exhaust • Waste heat from industrial processes • Process stacks from drying or heating processes • Heat from waste fuel • Biomass or Biogas is burned to produce heat directly • Not waste heat • A boiler creates heat for vaporization in a closed loop system – not free fuel

  7. The Complete System • Integrated Power Module • Generate • 125 kW • R245fa • Heat Source • 375F (190C) • 3 MBTU/H • Evaporative Condenser • Evaporator • Pump

  8. How it Works - 1 • Generate • 125 kW • Integrated Power Module • R245fa • Liquid • 85F (29C) • 26psig (1.8bar) • Heat Source • 375F (190C) • 3 MBTU/H • Economizer • Evaporative Condenser • Evaporator • Liquid • 85F (29C) • 230psig (16bar) • Receiver • Pump The working fluid is in the receiver as a liquid at the condensing pressure and temperature. It enters the pump where the working fluid’s pressure is raised to the evaporating pressure.

  9. How it Works - 2 • Generate • 125 kW • Integrated Power Module • R245fa • Liquid • 85F (29C) • 26psig (1.8bar) • Heat Source • 375F (190C) • 3 MBTU/H • Economizer • Evaporative Condenser • Liquid • 118F (48C) • 220psig (15bar) • Evaporator • Liquid • 85F (29C) • 230psig (16bar) • Receiver • Pump The working fluid passes through a heat exchanger (Economizer) to take heat out of the gas leaving the Integrated Power Module. This improves system efficiency. The working fluid is now a warmer, high pressure liquid.

  10. How it Works - 3 • Integrated Power Module • Generate • 125 kW • R245fa • Vapor • 240F (115C) • 220psig (15bar) • Heat Source • 375F (190C) • 3 MBTU/H • Liquid • 85F (29C) • 26psig (1.8bar) • Economizer • Evaporative Condenser • Liquid • 118F (48C) • 220psig (15bar) • Evaporator • Liquid • 85F (29C) • 230psig (16bar) • Receiver • Pump The working fluid enters the Evaporator, where the working fluid is exposed to waste heat which evaporates the fluid to a high pressure vapor. • 9

  11. How it Works - 4 • Generate • 125 kW • Integrated Power Module • R245fa • Vapor • 240F (115C) • 220psig (15bar) • Vapor • 145F (63C) • 26psig (1.8bar) • Liquid • 85F (29C) • 26psig (1.8bar) • Heat Source • 375F (190C) • 3 MBTU/H • Economizer • Evaporative Condenser • Liquid • 118F (48C) • 220psig (15bar) • Evaporator • Liquid • 85F (29C) • 230psig (16bar) • Receiver • Pump The working fluid (now a vapor) enters the turbine of the IPM. The working fluid’s pressure drops across the turbine to the condensing pressure, spinning the turbine (which is connected to the generator) in the process. The driving force is the pressure difference across the turbine.

  12. How it Works - 5 • R245fa • Vapor • 240F (115C) • 220psig (15bar) • Vapor • 85F (29C) • 26psig (1.8bar) • Vapor • 145F (63C) • 26psig (1.8bar) • Liquid • 85F (29C) • 26psig (1.8bar) • Heat Source • 375F (190C) • 3 MBTU/H • Economizer • Evaporative Condenser • Liquid • 118F (48C) • 220psig (15bar) • Evaporator • Liquid • 85F (29C) • 230psig (16bar) • Receiver • Pump The working fluid still has an enormous amount of heat, some of which is transferred to the pumped liquid in the economizer. This helps in two ways: 1) this heat would have otherwise been extracted in the condenser and; 2) there is less heat required at the evaporator due to the liquid being pre-warmed. • 11

  13. How it Works - 6 • Vapor • 85F (29C) • 26psig (1.8bar) • R245fa • Vapor • 240F (115C) • 220psig (15bar) • Vapor • 85F (29C) • 26psig (1.8bar) • Vapor • 145F (63C) • 26psig (1.8bar) • Liquid • 85F (29C) • 26psig (1.8bar) • Heat Source • 375F (190C) • 3 MBTU/H • Ambient Air 75F (24C) • Wet Bulb • Economizer • Evaporative Condenser • Liquid • 118F (48C) • 220psig (15bar) • Evaporator • Liquid • 85F (29C) • 230psig (16bar) • Receiver • Pump The working fluid (still a vapor) then flows to the condenser where heat is extracted and the working fluid condenses to a liquid.

  14. How it Works - 7 • Vapor • 85F (29C) • 26psig (1.8bar) • R245fa • Vapor • 240F (115C) • 220psig (15bar) • Vapor • 85F (29C) • 26psig (1.8bar) • Vapor • 145F (63C) • 26psig (1.8bar) • Liquid • 85F (29C) • 26psig (1.8bar) • Heat Source • 375F (190C) • 3 MBTU/H • Ambient Air 75F (24C) • Wet Bulb • Economizer • Evaporative Condenser • Liquid • 118F (48C) • 220psig (15bar) • Evaporator • Liquid • 85F (29C) • 230psig (16bar) • Receiver • Pump The low pressure, liquid working fluid drains back to the receiver and is ready to be pumped to high pressure and flow towards the integrated power module.

  15. Applications • Turbines Exhaust • Waste heat from exhaust • Industrial Stack Gas • Refineries • Incinerators • Drying processes

  16. Applications • Geothermal • Water or Steam • Solar Thermal • After steam process • Indirect evap source

  17. The ORC Power Skid • Capstone supplies the ORC ‘Power Skid’ • Includes electronics, receiver, economizer, power module and various pumps • Needs external evaporator and condenser

  18. Power Skid Fluid Connections • Hot Vapor from Evaporator • Cool Liquid from Condenser • Warm Liquid to Evaporator • Warm Vapor to Condenser

  19. Power Skid Components • Integrated Power Module • Slam Valve • Inlet Control Valve • Separator • Programmable Logic Controller (PLC) & Magnetic Bearing Controller (MBC) • Receiver • Field Connections • Power • Electronics • Bypass Valve • VFD for Pump • Economizer • Separator Drain Valve • Pump

  20. Power Skid Specs • Turbine Expander and Generator • Hermetically sealed power module – no leaks • Magnetic Bearings – no lubricants • 26,500 rpm – no vibration • Power electronics – 125 kW • Grid Connect only • 380-480V, 3 phase, 3 wire 50/60 Hz • Working fluid HFC-R245fa • Dry weight 7,000 lbs • 46” w x 112” l x 79.5” h

  21. Evaporator • Transfers waste heat energy to refrigerant, resulting in vaporization • Direct, heat transfers directly from the waste heat source to the working fluid • Likely choice for a Microturbine application where waste temperatures are low and exhaust stream is clean • Heat source needs to be near ORC • Indirect, thermal transfer medium is used between the heat source and the working fluid (e.g. thermal oil, hot water, steam) • Requires more ancillary equipment • Less efficient overall • Good fit if heat source is far from ORC

  22. Condenser • Rejects latent heat of working fluid, resulting in condensation • Direct – The working fluid passes through a heat exchanger that rejects heat directly to the environment. • Indirect – A medium such as water is passed through a heat exchanger and takes the rejected heat out of the working fluid. The medium then transfers the heat somewhere else. • Cooling towers, air cooled condenser (Dry Cooler), ground water, evaporative condenser • Cooling towers (if already existing) and direct evaporative condensers are likely the best match for MicroTurbine applications

  23. Installation Considerations • Evaporator & Condenser must be within 50ft of the ORC power skid • Minimize refrigerant run length • Minimize heat loss / absorption • Minimize amount of R245fa used • Condenser must be elevated (flow to receiver) • Qualified technician required to handle R245fa • Internal cleanliness (of R245fa loop) important

  24. Complete Installation

  25. Heating, Cooling, Power • Cycle effectiveness is determined by the heat source and condensing source • Determine total heat and temperature available • Determine total cooling available • Power available is determined by multiplying the heat available by the cycle effectiveness • More heat available => less cooling required • Less heat available => more cooling required

  26. Available Power Output • More heat is required for a given power production as condensing temp increases. • Size heat source and condenser for ambient conditions. • 125kW nominal is at generator terminals (inverter loss approx. 8 kW)

  27. ORC with MicroTurbines • Typical MicroTurbine implementation • 6 to 8 Capstone C65 MicroTurbines • One ORC WHG Power Skid • One direct MT exhaust to refrigerant heat exchanger • One direct evaporative cooling tower or piggyback on existing cooling tower.

  28. Free Electricity? • Or, how to build a ORC WHG value proposition • System uses low grade heat that is usually wasted – no other good use • Increase overall efficiency of systems • Consumes no additional fuel • Produces no additional emissions • Wasted energy into electric power may • Reduce demand charges • Capture carbon credits • Qualify for renewable energy incentives

  29. Calculating New Efficiency • Using waste heat to generate electric power increases overall system efficiency • Low grade waste heat is used, so assume it can not be used for any other purpose • Example, 6 Capstone C65s • Produce 390kW at 29% Electric Eff • A 125kW ORC WHG is added • Assume net output is 110kW (due to system losses, heat source and condensing source. • 500kW is produced, using no added fuel • new efficiency is • (New power/old power)*old Efficiency = 37% • The ORC increases electric efficiency to over 37%

  30. Case Study • Biomass boiler test site in the south east USA.

  31. Case Study Payback • Free fuel and low Maintenance Cost provide payback Annual Run Hours 8,400 Net Electrical Output 107kWe Annual Production 8,400 x 107 = 898,800 kWh Gross Revenue 898,800 x $0.18 = $161,784 Maintenance Cost 898,800 x $0.0075 = $6,741 Net Annual Revenue $155,043 Cost of Project $298,000 Simple Payback < 2 years

  32. Technology Advantages • Very similar to those of Capstone MicroTurbines

  33. For More Information • Contact Capstone Applications or Sales

  34. Question & Answer

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