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Ing. Bruno Vanslambrouck, MSc.

UGent – Campus Kortrijk , Research

Group on Thermal Energy in Industry bruno.vanslambrouck@ugent.be

Influencing the electricity/heat production ratio

of a biogas plant by using new technologies

PFI Biotechnology Workshop on 19 August 2014 in Pirmasens

«Experience with Heat Pumps in CHPs»

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1. 1. Energy balance of a cogeneration unit

2. 2. The (Organic) Rankine Cycle

3. 3. Alternative: Turbo compound

4. 4. Heat pumps

Presentation Overview

Energy

balance

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Gas input

4705 kW

Electricity

2014 kWe ηE = 42,8%

Turbo cooler 186 kW (4,0%)

40°C

Jacket cooling 1011 kW (21,5%)

85-95°C

Exhaust gases 1013 kW (21,5%)

430°→120°C

Ex.: Deutz TCG 2020 V20

ηQ = 43,0 %

Energy Balance CHP Unit

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If more E is desired:

- transform (waste) heat of the engine in E by using an adapted

technology

If more (or only) heat is desired: - use a boiler

- keep E produced by the engine but increase the heat flow by using

a thermal driven heat pump

- use shaft power or (part of) the E to drive a compression heat pump

Some explanation about adapted technologies:

Energy Balance CHP Unit

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To transform heat into electricity:

Commercially available:

- - Steam expander (Rankine Cycle)

- - Organic Rankine Cycle

- - Turbo Compound

Experimental:

- - Stirling engine

- - Thermo Acoustic Generator (TAG)

- - Thermo Electric Generator

Only available technologies will be presented.

Energy Balance CHP Unit

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Steam turbine

installation in a power

plant

1. Boiler 5. Transformer

2. Electrofilter 6. Condensor

3. Steam turbine 7. Cooling tower

4. generator

Source: Electrabel

The (Organic) Rankine

Cycle

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Combined Cycle: E-production from recovered heat from the

gasturbine exhaust using a Rankine Cycle

Source: Electrabel

The (Organic) Rankine

Cycle

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By using other working fluids, mostly of organic origin, some disadvantages of

water could be avoided:

Organic Rankine Cycle (ORC)

Some candidate fluids:

toluene, butane, pentane,

ammonia, ethanol,

refrigeration fluids (R245fa),

silicone oils…

88

77

66

55

44

33

22

11

7

6

5

4

3

H

21

H

Heat source

Feed pump

Regenerator

Condenser

Expander

Generator

Evaporator

The (Organic) Rankine

Cycle

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ORCs are to classify according to:

1. Power range:

- micro-systems: 0,5-10 kWe

- small systems: 10-100 kWe

- medium range: 100-300 kWe

- large systems: 300 kWe – 10 MWe or more

2. Optimal heat source temperature:

- low temperature systems: 55° to 150°C

- medium temperature systems: 150° to 250°C

- high temperature systems: above 250°C

3. Condensor temperature:

- slightly above ambient: no CHP capability

- from 50° to 90°C: usable a CHP by using the condensor heat

ORC Classification

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Heat source temperature: 85° 130° 180° 300°and >

ORC efficiency estimation: 5-7% 10-12% 15-17% 18-25%

Important parameters:

- Delta T heat source

- Condensor t°

- ORC design

ORC efficiency

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CHP + ORC

Energy

balance

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Gas input

4705 kW

Electricity

2014 kWe

Original:

ηE = 42,8%

Turbo cooler 186 kW (4,0%)

40°C ! hORC = 0% (unusable)

Jacket cooling 1011 kW (21,5%)

85-95°C hORC = 6-8%

Eextra = 70 kWe

Exhaust gases 1013 kW (21,5%)

430°→120°C hORC = 20%

Eextra = 200 kWe

Deutz TCG 2020 V20

hORC = 12 % Eextra = 240 kWe

CHP + ORC

CHP + HT+ LT ORC:

ηE = 48,5% 13,4 % more E (ideal)

CHP + LT ORC:

ηE = 47,9% 11,9 % more E (ideal)

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Gas input

4705 kW

Electricity

2014 kWe

Turbo cooler

186 kW 40°C

Jacket cooling

1011 kW

2213 kWth ηQ = 47,0% ηTOT = 92,2%

Exhaust gases

1176 kW 430° → 70°C

Practical example:

ηE = 46,3% (+ 8,2 % E)

165 kWe

760 kW

416 kW 200° → 70°C

600 kW 50°→ 35°C

ORC Triogen

Deutz TCG 2020 V20

CHP + ORC

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CHP + ORC

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CHP + ORC

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CHP + ORC

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CHP + ORC

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CHP + ORC

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Elektrische Leistung: 35-50 kW

Thermische

Eingangsleistung:

450 - 800 kW

Betriebsdauer: 8.000 h p.a.

Personaleinsatz: 0,05 Mitarbeiter

Eckdaten ORC-IC60-Anlage

ORC-IC60-Anlage zur

Verstromung von Abwärme aus

Biogasmotoren

CHP + ORC

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CHP + ORC

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CHP + ORC

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CHP + ORC

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References:

CHP + ORC

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CHP + ORC

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CHP + ORC

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CHP + ORC

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CHP + ORC

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CHP + ORC

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CHP + ORC

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CHP + ORC

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Feldtestanlage in Kirchwalsede : 2012 wurde das DeVeTec-ORC-System an dem

Blockheizkraftwerk (BHKW) einer Biogasanlage in Kirchwalsede in Betrieb genommen.

CHP + ORC

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BEP Europe (Belgium):

Established in 1980

ORC activities started in 2009

Uses a Z- or mono screw

expander

Range:

ORC 1000 power range: from 55 up to 132 kWe

(11 kWe downscaled model in our lab)

ORC 4000 power range: from 250 up to 500 kWe

Heat source: 80°-150°C

Announced efficiency: 6-13% (depending on heat

and cooling source temperatures)

CHP + ORC

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CHP + ORC

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CHP + ORC

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Alternative: Turbo

compound

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Alternative: Turbo

compound

For vehicles:

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For gensets:

Alternative: Turbo

compound

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Alternative: Turbo

compound

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Alternative: Turbo

compound

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To increase the heat output (or to reach higher t°):

Commercially available:

- - Boilers (E = 0%, Q = 90%)

- - Compression heat pumps delivering Q up to 100 (120)°C

- - Hybrid heat pumps (up to 100°C)

- - Gas fired or thermal driven absorption heat pumps (up to 100°C)

- - Chemical heat pumps (up to 110°C)

Experimental:

- - Compression heat pumps up to 150°C

- - Thermo Acoustic heat pumps up to 250 (650)°C

- - Chemical heat pumps up to 200°C

Heat pumps

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Example:

Waste heat temperature: 30°C

Desired process heat temp: 80°C

COP = 353 / (353 – 303) = 7 (Theoretical optimum according to Carnot)

In fact: about 50-60% of Carnot eff., in this case 3,5 à 4,2

Profit of an electrical driven heat pump:

- Primary energy savings when COP > 1/eff E-production, being about 2,5 or PER > 1

- Gain on energy costs if COP > E-price/Heat cost (2,5 à 4 in industry)

Limit (current market supply): ca 100°C !!

Compressor Heat pumps

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Heat

Exchanger

Combustion

Engine

Waste Heat

Boiler Condenser

Evaporator

Exhaust Gases, 480°C Expansion

Device

Compressor

4 MW

3 MW

500 kW 650 kW

1 MW η=42% Fuel in: 2,38 MW

95 l/s, 60°C

90°C

70°C 71,3°C

75°C

20°C 20°C

COP = 4

Heat Source (Water) 48 l/s, 40°C

25°C

85°C

Heat Sink

72,9°C

Cooled Exhaust Gases, 90°C

η =P + Q

Fuel=

1 + 1,15

2,38= 90,3%

η =Q

Fuel =

4 + 1,15

2,38= 216%

CHP:

CHP + HP:

Compressor Heat pumps

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Source: MAN Dezentrale

Energiesysteme, 1995

Compressor Heat pumps

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Compressor Heat pumps

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Heat source (Ground) water, waste water

Engine VW (VR6) gas engine

Refrigerant R134a

Heating capacity 200, 300 and 400 kW

Compressor type Recipro piston(Bitzer)

Number of compressors 2 (except 200 kW machine)

Power adjustment 25 – 100 % (fully modulating)

Temperature heat source 5°C - 30°C

Temperature heat supply 45°C - 80°C

COP heating 5,22 – 7,48 (PER 2,23)

Cooling capacity 110kW – 230kW

EER cooling 2,66 – 4,47 (PER 1)

Compressor Heat pumps

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4

46 11/12/2012 46

Absorption Heat pumps

Type I

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Absorption heat pumps: example • Where? Bjerringbro gas power plant (Denmark)

• Which HP? absorption heat pump (type I) of Thermax

• Goal? upgrade district heating water from 40° C to 80° C (2150 kW)

• Working pair? LiBr+H2O

Use with CHP: increase of

Q-delivery - exhaust gases as a driver

- no use of E

- jacket cooling water + lower t°

- part of exhaust gases still available

Absorption Heat pumps

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Some suppliers:

• Robur / Ener-G / CoolingWays

• Fulton

• Thermax

• Moretek Systems Inc. / Shuangliang Eco-Energy

• Buderus

• Hitachi

• Yazaki

• Broad USA

• Colibri

www.robur.com

www.broadusa.com www.shuangliang.com

Absorption Heat pumps

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Source: ECN, Petten (Nl)

Chemical Heat Transformer

Use with CHP: increase t°-level of jacket cooling water

Type II

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Ing Bruno Vanslambrouck, MSc.

UGent dept. Industrial Product and System design (ISP)

Research Group on Thermal Energy in Industry (TEI)

Graaf Karel de Goedelaan 5, B-8500 Kortrijk

Mail: bruno.vanslambrouck@ugent.be

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

www.tei.ugent.be www.orcnext.be

www.cornet-w2pheat.eu www.wasteheat.eu

Thanks for your attention.

Questions ???