Equipment for technical education in the field of Energy and Environment
World Renewable Energy Congress XIII London 3-8 August, 2014; Section 5 Policy, Finance, Education & Sustainability
Keywords: technical education, sustainability, energy efficiency, photovoltaic
Kristian Boedecker (GUNT2E Hamburg) Boedecker@gunt.de , PO Box 1125, D-22881 Barsbüttel, Germany
Abstract:
GUNT Hamburg is a leading manufacturer
of technical equipment for engineering
education. In order to promote possible
technical solutions for global challenges
from climate change and progressive
resource depletion the 2E division of
GUNT, concentrates on didactic equipment
for the fields of energy and environment.
The close interconnection between the
fields of renewable energy, energy
efficiency and environmental technologies
is a fundamental aspect of the 2E concept
as indicated in the scheme on the right
side.
Among
the
environmental
technologies the field of water treatment is
of special importance since it is crucial for
the conservation of the human habitat. The
objective of 2E is to integrate the principles
of sustainability into the field of technical training. Covering high didactic demands a carefully thought
out spectrum of teaching and research equipment for the energy and environment sector has been
developed up to now.
This contribution gives an overview on the structure of the 2E curriculum, summarizes basic didactical
and technical concepts and gives short examples for selected training units from different subject
areas. The didactical concept for the development of a 2E technical training unit emphasizes the
respective key training aspects from practice and theory with a special focus on sustainable
engineering. The scope of typical experiments ranges from the commissioning and operation of
important system components to the calculation and optimization of the essential key performance
indicators. The energy efficiency of a process or a system is among the most important and
meaningful key figures. Thus enabling the student to perform appropriate measurements for a step by
step analysis of parameters affecting the energy efficiency is a predominant objective when preparing
the instructional material.
As a typical example for this concept our experiments in the field of photovoltaic energy conversion will
be presented in some detail. The ET 250 trainer enables measurements on typical photovoltaic
modules by means of a basic electrical circuit. Current, voltage, temperature and irradiation intensity
can be measured using a preconfigured measurement unit. Earned knowledge from these
experiments serves as a fundament to understand details like the function of maximum power point
tracking systems which are typical in modern PV installations.
In a next step of our PV course methods and practical components to compensate temporal
fluctuations in the energy demand and offer are investigated. To cover the associated learning
objectives we developed the ET 255 trainer. Beside PC based measurement and analysis software
the ET 255 provides a build in PV Simulator. Thus the effect of varying irradiation on the behavior of
systems components such as grid connected inverters or stand alone charge regulators can be
investigated during a laboratory course without being hampered by actual weather conditions.
At the end of this contribution some remarks on the latest 2E developments will be given. In the field of
energy from biomass the laboratory biogas plant CE 642 was successfully commissioned for the first
two customers. In the field of energy from sea waves our ET 270 was completed which provides a
laboratory system based on the principle of an oscillating water column (OWC).
Keywords: Engineering education, sustainability, energy, environment, curriculum, photovoltaic
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The 2E Curriculum
The essential idea behind the 2E curriculum is the close interconnection between the fields of Energy
and Environment. This idea results from the insight that all facets of the human habitat are parts of one
system. To keep this system available for the future, a sustainable and efficient use of resources is
necessary. For the area of technical education it follows that thinking in systems and use of
sustainable technology must have the highest priority in didactical concepts. To implement this idea in
field of equipment for technical engineering the 2E division of GUNT was established.
As an example for the 2E activities some details of two training systems from the Energy branch of 2E
will be presented in the following. The systems ET 250 and ET 255 belong to the field of Solar Energy
which comprises Photovoltaics and Solar Thermal Energy as Subtopics. Our table of Learning Fields
in Solar Energy with the assigned 2E systems is given below:
Fig. 1) 2E Learning Fields in Solar Energy
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ET 250 Solar Module Measurements
The intention for ET 250 was the preparation of a ground level training system that enables basic
measurements on photovoltaic solar modules and comprises real world components. For the
development of ET 250 the following learning objectives were considered:
•
Practical aspects when using photovoltaic solar modules
•
Familiarization with measurands like short-circuit current, open-circuit voltage, maximum
power
•
Calculation of effective power, fill factor and collector efficiency
•
Influence of the module tilt on the electrical power
•
Effect of shaded cells
The ET 250 trainer contains two standard silicon solar modules. The tilt of the modules can be
adjusted. The modules can be connected in series or in parallel. A slide resistor enables varying
electrical loads. Thus the slide resistor makes it possible to record current-voltage curves. Sensors
attached to the solar modules detect illuminance and temperature.
Fig. 2a) ET 250 trainer
Fig. 2b) ET 250 components
The compact measuring unit provides displays for measurements of voltage, current, illuminance and
temperature. ET 250 accessories include an inclinometer and a complete set of cables. The well-
Current [A]
Voltage [V]
Current [A]
structured instructional material sets out the basic principles and provides a step-by-step guide
through the experiments. Typical experimental results are shown below.
Temperature [°C]
Voltage [V]
Fig. 3a) Voc & Isc vs temperature
Fig. 3b) IV curves from shaded modules
The students can investigate the importance of
the module temperature. The results (Fig. 3a)
show the decrease of the open circuit voltage Voc
and a slight increase of the short circuit current
Isc with module temperature.
The learning objectives for this experiment (Fig.
3b) also includes the function of bypass diodes.
Curves A, B, C and D show how IV behavior
changes when an increasing part of the module
is shaded.
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The instruction manuals
A detailed instruction manual is prepared for every 2E training system. Besides the construction and
the production of a system this work represents a substantial part of the development process. The
preparation of the instruction manuals includes appropriate treatment of fundamentals as well as the
conduction of reference experiments.
The instruction manual starts with an introduction to the system followed by important safety
instructions and detailed description of system components. After that a chapter with fundamentals
and the technical background follows. The typical content of a complete instruction manual is given
below:
•
Introduction and didactical information
•
Safety Information
•
Detailed Description of the Device and essential Components
•
Basic Principles
•
Exercises with Solutions
•
Experiments with step by step instructions
•
Reference Results and technical data
It is strongly recommended that the students prepare themselves using the listed exercises before
they start the practical experiments. The instruction manuals contain carefully compiled information
and reference data for each recommended experiment. For the practical work step by step instructions
ensure the success for each experiment.
Exploring photovoltaic system components with ET 255
The system ET 255 “Using Photovoltaics: Grid connected or Stand-alone” was developed for the
investigation and simulation of photovoltaic systems and its components. The following learning
objectives were considered during the development:
•
Application aspects of electrical components for photovoltaic systems
•
Efficiency and dynamic behavior of system components in grid-connected and stand-alone
operation
•
Grid connected and stand-alone inverters
•
Automated maximum power point tracking
•
Function of inverters
•
Function of solar batteries and charge controllers
•
Behavior of components under varying temperature and illuminance
ET 255 comprises typical components for the usage of photovoltaic current. The photovoltaic current
can be used to be fed into a public power grid (grid-connected operation) or for local consumption
(stand-alone operation). ET 255 can be run both with actual solar modules (such as ET 250) and with
the built-in photovoltaic simulator. Operation and parameterization of the photovoltaic simulator is
carried out via a dropdown menu in the software program. With relatively little effort, the photovoltaic
simulator makes it possible to investigate the effects of changing illuminance and temperatures.
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Grid connected
Inverter
Stand alone
Inverter
Charge
Controller
Combiner Box with
overvoltage
protection
A photovoltaic module, B photovoltaic simulator,
C combiner box, D DC main switch
Components for Grid-connected Operation:
E inverter with MPP tracker, F mains connection
Components for stand-alone operation:
G charge controller, H solar battery, I inverter, J lamp;
Toggle switches:
1 photovoltaic simulator/photovoltaic module,
2 Grid-connected/stand-alone
Solar
Battery
Fig. 4b) ET 255 schematic
Fig. 4a) ET 255 trainer
A variety of software functions are available for capturing and displaying the measurement data. The
efficiency and dynamic behavior of the electrical system components can be studied by analyzing
these results. Actual readings for current, voltage and electrical power are displayed in the system
schematic view of the software (Fig.5a):
Fig. 5a) Screenshot of the ET 255 software
Fig. 5b) Results from ET 255 with ET 250
The ET 255 Software can also be used to record and transfer measured data from longer
measurement periods. As an example results from the combination of ET 255 with ET 250 during a
cloudy day are displayed in Fig.5b. The results show a time resolved measurement of the illuminance
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in kW/m (blue curve) and the supplied electrical energy in Wh (red curve). The data were recorded
under natural sunlight with some clouds passing during the measurement. From the diagram it can be
clearly seen how the clouds affect the photovoltaic generation of electrical energy. The analysis of the
system performance under varying illumination and load conditions is discussed in detail within the
results section of the instructions manual.
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ET 270 Wave Energy Converter
Wave
Generator
OWC
The ET 270 gives an example
for further training systems of
the 2E curriculum. The ET 270
wave energy converter belongs
to the 2E hydropower section.
The system demonstrates the
conversion of energy from sea
waves into electrical energy by
using the so called oscillating
water column (OWC).
Wells
Turbine
Fig. 6) Wave Energy Converter
CE 642 Biogas Plant
Supply Unit
Gas Analysis
Fermenter
Post Treatment
Fig. 7) Biogas Plant
The system CE 642 „Biogas
Plant ” enables the fermentation
of biomass to produce biogas.
CE 642 expands the 2E
programme in the biomass
section. CE 642 is equipped with
industrial standard components
and PLC control to provide
optimized process conditions.
One of the first installations of
CE 642 and ET 270 were done
at the University Leeds/UK.
Training System from the Environment section of 2E
To give some examples from the broad range of 2E training systems in the environmental sector two
systems are shown below: The systems CE 702 and CE 705 belong to the field of water treatment
which will be of increasing importance in sustainable technical education.
Fig. 8a) Activated Sludge Process
Fig. 8b) Anaerobic Water Treatment
The system CE 705 „Activated Sludge
Process”
demonstrates
the
most
important biological process in water
treatment. CE 705 represents a
wastewater treatment plant in laboratory
scale.
CE 702 „Anaerobic Water Treatment”
enables the degradation of organic
substances. The system comprises a so
called “Upflow Anaerobic Sludge Blanket”
reactor.
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Summary
Experiences from vocational schools, technical colleges and universities confirm repeatedly that
practical work with experimental setups is crucial for a successful technical education. In the field of
Energy and Environment the usage of sustainable technologies represents a fundamental requirement
for modern engineering education. It becomes obvious that technical systems can´t be optimized in a
sustainable way unless the complete material and energy balance of the system during its lifecycle is
considered. In this context the 2E Curriculum combines the areas of energy and environment and
provides appropriate guidelines for engineering education. GUNT Hamburg established the 2E division
to implement this concept permanently within development and production of technical equipment for
engineering education.
As shown here for the PV sector, the identification of learning fields and related sets of learning
objectives are prerequisites for a comprehensive portfolio of successful technical training systems.
The ease of use, a clearly predefined range of experiments and the use of modern industrial
components are essential aspects for the development process. A further conclusion that can be
drawn from experiences of more than 30 years is that carefully prepared instructional material is an
indispensable part of a successful technical training system. More information on 2E and GUNT can
be found under www.gunt2e.de or www.gunt.de.
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