Presentation of the GMK ECOCAL® ORC-power plant located in Hennstedt / Germany

Power from Biomass Case Study

Content I

Content

1 The Organic Rankine Cycle ............................................................................................ 1

1.1 General description ................................................................................................. 1

1.2 ECOCAL ORC-power plants ................................................................................... 2

2 The company GMK ........................................................................................................ 4

3 The ECOCAL ORC power plant „Hennstedt“ .................................................................. 5

3.1 The Power Plant ...................................................................................................... 5

3.2 The ORC-Module .................................................................................................... 7

3.3 The Heat Supply ..................................................................................................... 8

Chapter 1 The ORC - Organic Rankine Cycle - 1 -

1 The Organic Rankine Cycle

1.1 General description

The ORC process (Organic-Rankine-Cycle) is a thermodynamic process, where instead of

water a low boiling, organic substance circulates as working medium. This can occur at

temperatures from 100°C (212°F) on and pressures far under 20 bar to extract a maxi-

mum work from the organic rankine cycle-process.

With organic rankine cycle-power plants it is possible, to also turn small sources of ther-

mal energy efficiently into electrical energy. This can simply be achieved with an organic

rankine cycle-module mounted on a base frame.

Due to the thermodynamic properties of the synthetic working medium it is possible to

generate power compared to nonorganic rankine cycle-power plants from waste heat,

geothermal sources, combustion of biomass or solar thermal sources.

On the picture below a schematic of the ORC can be seen. Thermal energy in form of hot

thermal oil, hot flue gases or geothermal water is supplied. An organic working medium

starts to boil in the evaporator thus creating a pressure and entering a turbine. There the

potential energy stored in the pressurized and hot working medium is turned into mechan-

ical and electrical energy. After leaving the turbine the superheated working fluid passes

its energy to the recuperator and flows into the condenser where it is liquefied and drawn

by the feed pump to close the cycle.

Picture 1: Schematic of the Organic Rankine Cycle

Chapter 1 The ORC - Organic Rankine Cycle - 2 -

1.2 ECOCAL ORC-power plants

ECOCAL® stands for "ecological caloric" and describes our organic rankine cycle product

line for the electrification of biomass like wood chips, agricultural waste wood and such

from the industry. It is the system based on the organic rankine cyle process for a com-

bined heat and power production being capable to cover a range of heat and power de-

vices from an electrical power output of 0.3 MWel on, more efficient and much more eco-

nomic than the ordinary water steam process (CRC-process).

In comparison of ECOCAL®-organic rankine cycle -technology with the water steam pow-

er process ECOCAL® offers significant advances compared to power plants operating

based on the ordinary water steam cycle. For almost a hundred years it has been possible

to produce heat and electricity by the combustion of piece wood with the help of steam

engines.

Such plants are mainly composed of:

a firing for solid fuels, a steam boiler for the production of water steam, a machine such as

a steam motor or a steam turbine coupled with a generator, and heat or air condensers.

Next to steam powered machines the boiler is the most expensive main component in the

branch of steam power device production. Such systems for the production of high pres-

surized steam are very complex and sumptuous to produce. For the fabrication of steam

boilers, steam pipes and steam boiler armatures, very durable, corrosion withstanding and

ferritic-martensistic steel or high temperature withstanding austenitic power plant steel has

to be used. Additionally, these special parts are only allowed to be mounted by qualified

steam power plant assembling companies.

Contrary to the previous, for the production of electricity in ECOCAL®-power plants do not

require a steam boiler. Furthermore in organic rankine cycle power plants the maximal

pressures amount up to 10 bar. This means that for the production of ECOCAL®- mod-

ules ordinary low cost boiler steel can be used. Based on those pre named properties,

ORC-power plants are much more cost effective to erect.

Also because of the low pressures in ECOCAL®-power plants they do not have to be su-

pervised by specially trained personnel which leads to a much more economic working of

those plants as well.

Chapter 1 The ORC - Organic Rankine Cycle - 3 -

Picture 2: Schematic of an ECOCAL Organic Rankine Cycle power plant

In the Schematic above a typical ECOCAL power plant is visualized. On the left is the fire

box with the thermal oil boiler. The intermediate thermal oil cycle is pumped to the ORC-

module where it passes its energy to the evaporator to start the ORC-process. Next to the

produced electricity the produced heat can be fed into heating networks, green houses,

drying processes or other heat users.

Chapter 2 The company GMK - 4 -

2 The company GMK

GMK is one of the leading ORC-module developers and producers in Europe. GMK offers

the lay out, production, set up and services for complete ORC-modules as a one stop

supplier. The core competence of GMK is the lay out and engineering of ORC-modules,

while the production of the power devices is carried out within the holding. At the location

in Bargeshagen, Northern Germany approximately 25 engineers, scientists and industrial

workers are employed.

In 1994 the company had been founded in the process of a research project which had

the objective of testing the energetical use of biomass, in cooperation with the Rostock

University. Today GMK belongs to Germania Technologieholding with a share of 100%.

GMK’s product portfolio covers

ECOCAL® - power from biomass

GEOCAL® - power from geothermal heat

INDUCAL® - power from waste heat

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3 The ECOCAL ORC power plant „Hennstedt“

3.1 The Power Plant

Picture 3: 3-D view of the ECOCAL power plant located in Hennstedt

In the year 2007 a company founded by farmers build a bio-energy center located in

Hennstedt / northern Germany. The complex consists of photo voltaic power, wind power

and a biogas and wood chips fired power plant that both together supply the nearby city and

greenhouses for the growing of tomatoes with heat.

In the following the wood chip power plant with a GMK ORC-unit is described.

First woodchips from surrounding agricultural wood are fed into an Austrian made fire box

with a stoker grate. After the combustion the hot flue gases enter a thermal oil boiler over a

heat bridge, as can be seen in the 3-D scheme above.

In the boiler thermal oil is heated up to supply the heat from the firing to the ORC-module.

After the flue gases passed through the boiler the rest thermal energy is extracted by the

economizer for heating purposes and enter an electrical filter after being cooled down.

The Boiler room with the firing and the thermal oil boiler can be seen in the back of the

picture 4 and 5 below.

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Picture 4: Internal view of the ECOCAL power plant boiler room located in Hennstedt

Picture 5: Internal view of the ECOCAL power plant boiler located in Hennstedt

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3.2 The Hennstedt ORC-Module

Picture 6: 3-D schematic of the ECOCAL ORC unit located in Hennstedt

The heat produced in the firing of the power plant is turned into electricity in an EC 1.500

ORC unit produced by GMK.

Hot thermal oil enters the machine at a temperature at 590 °F and produces 1.5 MW of

electricity. After producing electrical energy the heat can still be used for district heat and for

the supply of the green houses on a temperature level of 194 °F and 158 °F.

Picture 7: View of the ORC-turbine in Hennstedt

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Picture 8: View of the ORC-feed pump in Hennstedt

3.3 The Heat Supply

After producing electricity with the ORC-unit the heat is supplied to greenhouses and the

city of Hennstedt as can be seen in Picture 9.

Picture 9: View onto the green houses in Hennstedt

Contact

Head of Sales: M.Sc. Nico Timm Phone: +49 38203-775814 E-Mail: timm@gmk.info Internet: www.gmk.info