The Organic Rankine Cycle (ORC) - Ibge

23-02-2010 The 


CHP: Technology Update 

The Organic Rankine Cycle (ORC) 

ing. Bruno Vanslambrouck, 

Howest, dept Masters Industrial Sciences 

Laboratory of Industrial Physics and Applied Mechanics 

1 Cycle Rankine Organic 

Contence 

• The (Organic) Rankine Cycle 

• Working Fluids 

• Relevant applications 

• Conclusions 

• Economic information 

• Our ORC related activities 

Organic Rankine Cycle 2



The Rankine Cycle 


1. Electrofilter 5. Transformer 

2. Boiler 6. Condensor 

3. Steam turbine 7. Cooling tower 

4. generator 

Source: Electrabel 

Steam turbine installation in a power station 


E-production from recovered heat of a gasturbine exhaust 


using a Rankine Cycle 

Source: Electrabel



T-s diagram for a working fluid 



Working fluid: usually water 

Rankine cycle with superheated steam 


Carnot efficiency: 

Advantages: 

• cheap, widely available 

• non toxic 

• high heat capacity: excellent medium for heat transport 

• chemical stable: less material requirements 

• low viscosity: low friction losses 

Disadvantages: 

• due to low condensation t°: very low pressure, high specific volume, big 

installations needed (turbine, condensor…) 

• high pressure drop to become a high enthalpy drop: expensive multi stage 


turbines needed 

• expansion has to start in the superheated area to avoid too high moisture 

content after expansion: need of a high t°- heat source but very partically use 

• because of this: efficiency loss and limited suitability to waste heat recovery

The Organic Rankine Cycle 

Disavantages water probably to correct using other working fluids, mostly of 

organic origin: Organic Rankine Cycle Organic medium 

(ORC) 

Used are: 

Toluene, butane, 

pentane, ammonia, 

refrigeration fluids, 

silicone oils… 

Organic Rankine Cycle 

in the T-s diagram 




7 Cycle Organic 

8 

Rankine 

Cycle Rankine Organic




ORC Working Fluids 

Wet fluid Dry fluid 

• superheating required 

• superheating → efficiency ↑ 

• higher vaporization heat at 

lower pressures → 

evaporation requires a lot 

of heat or high pressures 

• remains superheated 

after expansion of 

saturated vapor 

• superheating unnecessary 

• superheating → efficiency ↓ 

Isentropic fluid 

• superheating unnecessary 

• recuperator unnecessary 

• best choice for ORC from 

this point of view 


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ORC Working Fluids 

Relevant applications 

1. Power production from industrial waste heat 


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Electrical efficiency = ca 16% 

if waste gases are cooled 

down to 120°C 


14 



• Because of high temperature exhaust gases, a steam turbine can be 

considered on bigger plants 




2. Exhaust heat recovery on stationary combustion 

engines or gas turbines 

• Ca 10% increase of electrical output without extra fuel 

• Economical attractive on engines using renewable fuels (landfill gas, 

biogas, vegatable oils…) because of governmental support (Green 

Certificates). Simple PBT of 3 years calculated. 

• Possibility to upgrade old (build before 2002) cogeneration units with 

respect to CHP certificates by adding an ORC (increase of relative 

primary energy savings with 5 %). Very short PBT if feasible (1- 2 years). 

• Some ORC’s are adapted to use jacket cooling water heat 



Ex: 150 kW ORC by Tri-O-Gen (Nl) 

Engine cooling 

LT heat 

Exhaust gas (510°C) 

Electricity 

1550 kWe 

Exhaust gas (180°C) 


(585 kWth, 

incl losses) 

150 kWe

ORC integration in an (existing) CHP: 


180 °C 


CHP 


Flue gas 

T > 350°C 

760 kW th 

Boiler 

325°C 

Generator 

Turbine 

Greenhouse 


Inverter 

Main feed pump 

Recuperator 

165 kWe 

400 V 

Pre-feed pump 


Working fluid: Toluene 

50°C 

600 kWth 

35°C



ORC on exhaust gases 2 MW Deutz gas engine 

Roses farm Olij, De Kwakel – The Netherlands 



Range: TG30(+) 30 kW; TG60(+) 60 kW 

Specific designed to recover biogas engine heat 

(+ means integrated use of engine jacket cooling). 

Fits on biogas engines in the range 250-500 kW. 

Heat source: 

from 230°C (TG30/TG30+) 

from 270°C (TG60/TG60+) 

Cooling source: 

30°C or up to 80°C (CHP-version) 

Tri-O-Gen B.V. 

Nieuwenkampsmaten 8 

7472 DE Goor Nederland 

Heinrich-Hertz-Str. 18 

59423 Unna 

Germany 


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Maxxtec new small series Model 60 Model 80 Model 120 

Waste heat source: 

Thermal need 375 kWth 520 kWth 750 kWth 

Thermal oil in/out 280/140 °C 280/140 °C 280/140 °C 

Electricity output 

Gross 65 kWe 92 kWe 130 kWe 

Net (appr.) 51 kWe 81 kWe 114 kWe 

Condensor heat output 306 kWth 423 kWth 612 kWth 

Condensor circuit in/out 43/64°C 43/64°C 43/64°C 

Gross Electric Efficiency 17,3 % 17,7 % 17,3 % 

Net Electric Efficiency 13,6 % 15,6 % 15,2 % 


22 





ORC with double screw expander 

• Heavy duty design, derived from 

screw compressors 

• Not sensitive to fluid drops: can expand 

both superheated or saturated steam, 

no damage when fluids drops passes 

trough (usefull when large process 

variations are going on). 

• As ORC usable at lower temperatures 

• Adapted to recover jacket water heat 



Double srew expander 

based ORC 

ElectraTherm 

3208 Goni Road 

Carson City, 

Nevada 89706 

BEP EUROPE NV 

Ten Briele 6 

B-8200 Brugge 


24 





3. ORC, fed by biomass combustion 

Many references in CH, A, D, I… (also 1 in NL, 2 planned in Belgium). 

In concurrence with the steam cycle. 

Always designed as CHP. 

Turboden s.r.l. 

Viale Cernaia, 10 

25124 Brescia - Italy 




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Turboden ORC-CHP range: 


MIROM Roeselare : 2,5 MWe net 

by Turboden 

Heat source: water @180°C 

17 % net efficiency 


28 



ORC integration in an (existing) biomass boiler: 




Biomass boiler 


4. ORC, fed by geothermal heat sources 

Many references known, 

from 250 kW to > 100 MW 

Source temperatures from 

75°C up to 300°C. 

Same technology usable to 

recover waste heat on the 

same temperature levels. 

Greenhouse 


30 





Heber Geothermal 

52 MWe 

power station 

(California) 



Geothermal ORC 250 kWe (Ormat) 

Geothermal fluid temperature in/out: 

110/85°C 

Thermal power in: ~ 2500 kW 

ORC working fluid: Isopentane 


32 





ORC derived from a centrifugal chiller (reversed) 

Cheap, reliable, proven technology 




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Pure Cycle 280: 


186-257 kWe net 


5. Power generation from thermal solar energy 

• probably cheaper than photovoltaic solar systems 

• possible to use condensor heat for sanitary heat water… 

• huge potential on desalination systems 

Evacuated tube collector 

fitted to temperatures 

untill 180-200°C 

40 kW solar heat ORC (Turboden, 1984) 




Solar-biomass hybrid ORC 




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Principle design 

combined solar driven 

electricity and domnestic 

hot water production 

system 

(final work HOWEST, 

2004-2005) 



Tests (HOWEST) on a scroll expander (2005) 

(Sanden scroll car airco compressor TRS-090) 


40 





6. ORC driven domnestic micro-CHP 

• alternative to gas engine 

based micro CHP 

• to integrate within a cv-boiler 

• in concurrence with other new 

technologies as stirling engines, 

fuel cells… 



Energetix Group plc 

Capenhurst Technology Park 

Chester 

CH1 6EH UK 

Genlec module: 1 kW scroll expander based ORC to 

integrate in central heating boilers (micro CHP) 

Example: Boiler manufacturor Daalderop (NL) 


42 





7. ORC driven cooling 

Alternative if electrical grid connection big chillers is impossible or not allowed. 

Been proven having better efficiency (COP) compared to absorption chillers. 

Solar powering or hybrid with solar heat feasible. 


Some Economics 

Some budget prices ORC-modules: 

Turboden: 500kW: about € 1900 /kWe 

1000 kW: about € 1350 /kWe 

2000 kW: about € 950 /KWe 

Pure Cycle 280 (ca 250 kWe) : € 335 000 or € 1350/kWe 

Maxxtec/Adoratec: confidential prices, but of the same order of Turboden 

Also attractive priced new 60, 85 and 120 kW units. 

Tri-O-Gen: 150 kW unit @ € 650 000 ca € 4300 /kWe (turn key ?) 

BEP-Europe: 50 kW unit @ € 120 000 (module) or € 200 000 (installed) 

€ 2400 /kWe € 4000 /kWe 

250 kW unit: “lower” price/kWe compared with the 50 kWe unit 


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Some Economics 

• On renewable energy applications, we calculated a simple PBT of 3 

year (IRR ca 25%), with the help of green certificates. 

• For industrial waste heat recovery, a PBT of 5 year is realistic when 

available heat is on ‘high temperature’ (~300°C). So the ROI can 

reach 15%, after taxes, what means that the investment can be 

asked within the benchmarking agreement. This result is strongly 

related to the electricity prices. 

• Other financing methods (third party) could be considered 

Some Conclusions 

- ORC is a proven and commercially available technology for applications 

such as industrial waste heat recovery, ICE heat recovery, biomass 

burning, use of solar heat, geothermal heat sources… 

- main advantage compared with a steam cycle is the higher thermal 

efficiency when using heat sources at lower temperatures. The ORC is 

also less complicated and easier to operate. Occuring pressures are lower. 

- the classical steam cycle should be considered when sufficient 

temperature levels are reachable (fuel burning) combined with turbine 

scale sizes from about 500 kWe…to 2,5 MWe (to discuss, no clear answer 

given when to chose an ORC above a steam cycle) 

- favorable economical perspectives, especially in relation to green 

certificates or energy benchmarking. 

- excellent CHP capability since the condensor heat can be used 


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Our ORC related activities 

• 2 master thesises 2003-2005 

• TETRA project proposal on ORC in 2005. Technically and scientifically 

approved but not financed, had to be cancelled. 

• New proposal in 2007, focused on renewable energy sources. 

Accepted, in progress from Oct 1st 2007 till Dec 31th 2009 

• Second proposal on industrial waste heat accepted (Jan 1st 2010- Dec 

31 th 2011 or 2012). European ERA-SME concept with Ghent University 

and Stuttgart University of Applied Sciences as research partners. 

A TETRA project is 92,5 % financed by the Flemisch Government (IWT) 

and 7,5% by industrial partners (at least 4 SME’s). 


2 scientific researchers can work during 2 or 3 years on it. 

Cofinancing User Group is the preference partner to receive project 

information during project runtime, at the end publical available (by 

publications, seminars, website…) 



2 th ORC Project structure 



Laboratory setup 

For research and demonstrational purposes 



Heat source: 

Maxxtec thermal oil heater 

Max 250 kW @ 340°C 

Flow: 14 m³/h 

10 x 25kW , GC-Heat 


50 



Cooling loop: 

Circulator 

→ 

← 




- water + glycol 

- max. 20m³/h 

- max. 120°C 

3-way valve 

Flow 

sensor 

Cooler 

Flow 


Thanks for your attention. 

Questions ??? 

ing Bruno Vanslambrouck 

HOWEST, dept Masters Industrial Sciences 

Laboratory of Industrial Physics and Applied Mechanics 

Graaf Karel de Goedelaan 5, B-8500 Kortijk 


Mail: bruno.vanslambrouck@howest.be 

Tel: +32 56 241211 or +32 56 241227 (dir)

The Organic Rankine Cycle (ORC) - Ibge

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