0. 2010 Regional Distributor Review & Conference
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

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

2. 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)

3. 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

4. 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

5. 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

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

7. Integrated Power Module Evaporative Condenser
How it Works - 1
Integrated Power Module
Generate
125 kW
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.

8. Integrated Power Module Evaporative Condenser
How it Works - 2
Integrated Power Module
Generate
125 kW
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.

9. Integrated Power Module Evaporative Condenser
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

10. Integrated Power Module Evaporative Condenser
How it Works - 4
Integrated Power Module
Generate
125 kW
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.

11. Evaporative Condenser
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.
1111

12. Evaporative Condenser
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.

13. Evaporative Condenser
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.

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

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

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

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

18. Integrated Power Module
Power Skid Components
Integrated Power Module
Inlet Control Valve
Slam 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

19. 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
V, 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

20. 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

21. 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

22. 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

23. Complete Installation

24. 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

25. 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)

26. 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.

27. 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

28. 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%

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

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

31. Technology Advantages
Very similar to those of Capstone MicroTurbines
High Speed Generator
Increased Efficiency, Reliability, no gear box
Magnetic Bearings
Increased Efficiency, Reliability, Reduced losses
Power Electronics
Efficient variable speed operation
No lubrication or lubrication system
Increased Reliability, Reduced parasitic losses, No contamination of process fluid
No coupling
Increased reliability, fewer components
Variable speed operation
Optimized cycle efficiency operating point
Hermetically sealed
Higher reliability, fewer wear components
Single moving part
Increased reliability
Modular Design
Simple Integration into system (like standard piping)

32. For More Information
Contact Capstone Applications or Sales

33. Question & Answer