Mechanical and Materials Engineering

Impact of climate change on highly renewable large-scale energy systems

Smail Kozarcanin

Denmark is currently on the verge of a transition to a fundamentally different energy system where the share of renewable weather-driven power generation exceeds that of conventional sources. Many rich and developing countries around the world share similar ambitions as renewable energy is the key for solving the global issues of climate change and energy. To achieve a possible solution, a high share of renewable energy sources needs to be taken into consideration and a highly renewable energy system that is robust against climate change needs to be designed.

Typically, existing studies rely on historical weather and energy data from publicly available sources to investigate properties of renewable energy systems - many decades into the future. In this project, newly available climate change projection data from the EURO-CORDEX project will be combined with the existing reanalysis data in the Global Renewable Energy Atlas (REatlas) to produce realistic high-resolution time series of wind and solar power production for all European countries. These will then be used in the weather-driven modelling approach, pioneered at Aarhus University, to analyse the impact of climate change on current and future renewable energy systems. The first study will take offset in the master thesis by Smail Kozarcanin.

ABOUT THE PROJECT


Project title:
Impact of climate change on highly renewable large-scale energy systems

PhD student: Smail Kozarcanin

Contact: sko@eng.au.dk

Project period: Nov 2016 to Oct 2019

Main supervisor: Prof. Martin Greiner

Co-supervisor: Assistant Prof. Gorm Andresen

Research section: Mechanical and Materials Engineering


Techno-economical and market design of a highly renewable large-scale Chinese electricity system

Renewable energy, especially wind power, has been developing rapidly in China due to a series of incentive policies. Now it is the world’s largest producer of wind and solar energy, but the sector has long been criticised for problems connecting to the grid or having its output used fully.

The reason behind this is a combination of system failures, low demand and technical bottlenecks. Older issues are systemic – planning for generation and transmission are not coordinated; the grid fails to keep up with the rising capacity of renewable power, etc. Moreover, wind power is intermittent and to ensure a robust power system, it needs to be complemented with other sources of electricity to sustain a stable supply. 

To achieve this, we will investigate the ability of the existing Chinese energy system to integrate fluctuating wind power and explore how the power system can prepare itself for integrating more fluctuating renewable energy in the future.

ABOUT THE PROJECT


Project title:
Techno-economical and market design of a highly renewable large-scale Chinese electricity system

PhD student: Hailiang Liu

Contact: hll@eng.au.dk

Project period: Sept 2016 to Aug 2019

Main supervisor: Prof. Martin Greiner

Co-supervisor: Assistant Prof. Gorm Andresen

Research section: Mechanical and Materials Engineering


Molecular Adhesive for Strong and Durable Bonding of Rubber to Metal Surfaces

Simon Heide-Jørgensen

The aim of this multidisciplinary project is to develop a new chemical compound that can bond rubber to metal. Such a compound or glue can help the industry with super valves in which rubber coatings remain intact and thereby prevent the gathering of dirt and bacteria.

A cooperation has been established between the Department of Chemistry and the Department of Engineering, both the mechanical and chemical section, at Aarhus University, Radisurf ApS and AVK Gummi A/S to achieve the goal of developing, manufacturing and providing the best design for rubber coating industrial valves.

The idea is to use a chemical nano-adhesive on the metal surface of the valve which bonds to the rubber coating when it hardens. From a chemical point of view, the valve becomes one single piece, which means bacteria are unable to penetrate. The bonding between rubber and metal is then to be mechanically investigated to identify its properties, which would allow determination of the most advantageous design and utilisation.

ABOUT THE PROJECT


Project title:
Molecular Adhesive for Strong and Durable Bonding of Rubber to Metal Surfaces

PhD student: Simon Heide-Jørgensen

Contact: shj@eng.au.dk

Project period: Sept 2016 to Aug 2019

Main supervisor: Prof. Henrik Myhre Jensen

Co-supervisor: Assistant Prof. Michał Kazimierz Budzik

Research section: Mechanical and Materials Engineering


Vibration Analysis and Control of UR Robot Manipulators with the Consideration of Link and Joint Flexibility

Dan Kielsholm Thomsen

Universal Robots develops and manufactures collaborative robots. Collaborative robots have a high safety level that makes human-robot collaboration possible, and the robots are meant to work alongside humans as co-workers. Universal Robots strives to improve its products in productivity, precision and versatility.

This project intends to improve all these points by an effective reduction of mechanical vibrations in the robots. All electromechanical systems experience vibrations and when compared to the conventionally heavy industrial robots, collaborative robots are sensitive to vibrations due to light weight structures.

The improvements are to be obtained by precise dynamic modelling of mechanical deflection in the robot. This dynamic model will be used to slightly change the behaviour of the robot for reducing induced vibrations. This approach is preferable because it will be possible to implement it in all existing and future robots and it is only a software concern.

ABOUT THE PROJECT


Project title:
Vibration analysis and control of UR robot manipulators with the consideration of link and joint flexibility

PhD student: Dan Kielsholm Thomsen

Contact: dkt@eng.au.dk

Project period: July 2016 to June 2019

Main supervisor: Assoc. Prof. Xuping Zhang

Co-supervisor: Prof. (Docent) Ole Balling

Research section: Mechanical and Materials Engineering


Development and Application of Flow Tracing and Cooperative Game Theory Methods for the Market Design of Emerging Renewable Electricity Networks

Bo Tranberg

Fluctuating and decentralised renewable electricity sources represent a challenge for a reliable supply of energy in the current as well as future energy system. Flow tracing techniques, which assign the power flow on a transmission line to the source of its generation and consumption, represent a valuable tool set to analyse and design the future electricity system in terms of grid usage and cost allocation.

We will first use methods from Theoretical Physics to analyse power flow tracing in complex renewable energy networks to obtain a deeper understanding of flow processes in networks in general. These studies prepare the ground for the application of flow tracing measures to weather and load data based models of a future European energy system.

Finally, we will evaluate the incentives and fundamental mechanisms resulting from an implementation of flow tracing based measures into the design of electricity markets, using general economic and game theoretical methods.

ABOUT THE PROJECT


Project title:
Development and Application of Flow Tracing and Cooperative Game Theory Methods for the Market Design of Emerging Renewable Electricity Networks

PhD student: Bo Tranberg

Contact: bo@eng.au.dk

Project period: May 2016 to April 2019

Main supervisor: Prof. Martin Greiner

Research section: Mechanical and Materials Engineering


Modelling of Failure in Composite Materials

Simon Peter Skovsgård

Fiber composites loaded in tension have high stiffness and strength, but when loaded in compression the critical stress is considerably lower than in tension. Structural components loaded in bending are exposed to both tension and compression and since the critical stress is lower in compression this is the failure mode which should be used as a design load.

Several studies have been made in mapping the different failure modes of fiber composites in compression. The most frequently observed failure is do to plastic microbuckling which is a material instability and results in kink band formation. These are bands of material where the fibres inside the band have rotated relative to fibres outside the band. Kink band formation as a failure mechanism is observed in unidirectional fibres as well as in multi layered composites with different layups inside the individual layers.

The critical stress for kink band formation is known to be sensitive to structural imperfections such as misalignments of the fibres relative to the load direction. This make theoretical investigations of kink band formation challenging as they must involve full, non-linear finite element simulations allowing for all possible non-linear behavior of the constituents as deformation evolve.

ABOUT THE PROJECT


Project title:
Modelling of Failure in Composite Materials

PhD student: Simon Peter Hald Skovsgård

Contact: sphs@eng.au.dk

Project period: May 2016 to Jan 2020

Main supervisor: Prof. Henrik Myhre Jensen

Research section: Mechanical and Materials Engineering


Practical methods for collaborating between private consumers and energy companies

Rasmus Høst Pedersen

AffaldVarme Aarhus (AVA) is one of the largest district heating companies in Denmark. About 95 percent of the 325.000 inhabitants in Aarhus municipality receive heat from AVA, including a large number of private companies and large industries. In total 53.000 consumers are installed on a network of around 2.000 km of pipes.

In this project, large-scale demonstrations from the smart city project READY are used to identify business models that will give a positive case for all stakeholders and allow unsubsidised replication. Experience show that these must be found at the interface between engineering, economics and anthropology, as non-economical incentives can play an important role.

As an example, areas in Aarhus where low temperature district heating is most easily adapted will be identified based on both technical and social indicators. In these areas, some costumers will need to reduce their heat consumption by investing in building retrofit solutions. This gives rise to  some different options: Either a positive business case directly via savings on the energy bill or other positive incentives such as improved indoor climate, more attractive architectural appearance, or other soft forms of motivation are needed.

ABOUT THE PROJECT


Project title: 
Practical methods for collaborating 
between private consumers and energy companies

PhD student: Rasmus Pedersen

Contact: raspe@eng.au.dk

Project period: Nov. 2015 to Oct. 2018

Main supervisor: Assoc. Prof. Steffen Petersen

Co-supervisor: Assistant Prof. Gorm Andresen, Adam Brun (AffaldVarme Aarhus)

Research section: Mechanical and Materials EngineeringMechanical and Materials Engineering


Development of Mobile Machining Cell for the Wind Turbine Industry

Kasper Ringgaard

A consortium of Danish universities and companies have come up with an idea that could save billions in the wind turbine industry. The aim of the project, named InnoMill, is to develop mobile machining cells for machining of large wind turbine cast steel components.

Increasing energy consumption
Globally the demand for cheap renewable energy increases, and therefore the wind energy industry struggles to lower the Cost Of Energy (COE) on wind turbines. To lower the COE the size of the wind turbines increases. Current components measures several metres, which causes transportation of components to become a bottleneck – both in terms of ability to fit them on the road, and the cost of transportation to and from machine shops.

Limiting transportation
One way of limiting the amount of transportation is to perform machining operations on-site instead of the current practice of moving components to large scaled machine shops. The InnoMill project aims to develop such mobile machining cells, but it will not be as straight forward as it may seem. The challenge lies in making the machine accurate enough to meet the high quality standards demanded by the wind turbine industry since it will deflect and vibrate significantly during operation.

Solution strategy
The researchers believe that the challenge can be overcome by gaining knowledge of stiffness and vibrational levels in the system throughout the entire machining process. During development of the machine, thorough analyses of the stiffness and vibrations will be used to predict and avoid unsuitable machine designs and machining patterns. During machine operation, different values will be monitored to allow the machine control to adjust such that the quality standards can be fulfilled. Scientists hope that this will enable the machine to meet the stringent quality standards.

The PhD project
The aim of this PhD project is to develop the simulation models necessary to develop the machine. The models must be able to predict the behaviour of both the component and the machining cell during the machining process. To obtain valid models a great deal of research regarding the sensitivity of the final quality to different factors such as loads, supports and temperature is needed. Research into efficient and precise flexible multibody simulation is also needed to make valid simulations of the entire milling process that can be handled using the computational power available today.

ABOUT THE PROJECT


Project title:
Development of mobile machining cell for the wind turbine industry

PhD student: Kasper Ringgaard

Contact: kri@eng.au.dk

Project period: August 2015 to July 2019

Main supervisor: Prof. (Docent) Ole Balling

Research section: Mechanical and Materials Engineering


Vibration and deformation sensor system

The project aims to develop a flexible high precision milling system, priced significantly below current CNC-machines. The new machine needs to operate at smaller tolerances than current robotics, operating at tolerances around 0.2mm. Absolute tool positioning accuracy also needs to be improved. Current CNC-machines are reaching the specimen size limit, giving a large advantage for small flexible CNC-machines that has no upper bound on specimen size.

In the milling process, cutting forces will give deformation and vibrations in the specimen. To stay within tolerances these vibrations needs to be taken into account. The project consists, among other tasks, of the building of a sensor system for vibration and deformation measurement. The sensor system needs to provide feedback to a control system that can do real time adjustments to the cutting speed and feed, and other necessary changes in cutting tool operational conditions. Support to the overall project in terms of global tolerance estimation is also considered.

The project is primarily targeted at Large Scale Machining (LSM) of large wind turbine parts, such as hub and bearing housing, but is expected to be relevant for other market segments. The global market for offshore wind turbines is expected to increase to over € 20 BN in 2020, and the requirement for lower production cost will increase the demand for bigger wind turbines and in turn, small LSM cells. An Innomill derived system is expected to be priced around € 2M, 40% below current CNC systems. With an expected market above 90 units in 2020, this is more than € 180M.

ABOUT THE PROJECT


Project title:
Vibration and deformation sensor system

PhD student: Martin Juul

Contact: mj@eng.au.dk

Project period: June 2015 to May 2018

Main supervisor: Prof. (Docent) Ole Balling

Research section: Mechanical and Materials Engineering


Topological optimisation of near-field-enhancing nano-structures

Joakim Vester-Petersen

The total radiation from the Sun on the surface of the earth is almost 10,000 times more powerful than our global power consumption. The exploitation of solar energy is, however, still not cost-effective compared to nuclear or fossil fuels. To improve this, one may reduce the production cost of solar cells and/or increase their efficiency.  Silicon (Si) based solar cells are widely used today, however in commercial Si-based devices the efficiency is typically 15-20 %, with a theoretical limit of 30% for simple Si-cells.   

This low efficiency is mainly caused by the fact that the very wide spectrum of solar light (photon energies) is simply not fully absorbed and converted into electricity. 

Si-based solar cells mainly generate current by absorbing photons within the visible and near infrared spectrum (400-1100nm). Thus a majority of the solar light spectrum does not contribute to the power generation, as the low energy photons (wave length > 1100nm) simply pass though the cell while high energy photons (300 - 400nm wave length) mainly contributes to heat dissipation.

By applying an additional material layer to the back of the Si-cell, it is possible to convert two low energy photons to one photon with a higher energy, which can be absorbed in Si and thereby contribute to current production. This process is named upconversion and can e.g. take place in some rare-earth doped materials. The efficiency of upconversion is naturally weak and careful nano-structuring of the material is needed for practical applications.

The aim of this PhD project is to develop advanced numerical models for upconversion and utilize the models for topology optimisation of the nano-structures in the up-converting layer to maximise the efficiency while keeping production and environmental constraints in mind.

ABOUT THE PROJECT


Project title:
Topological optimisation of near-field-enhancing nano-structures

PhD student: Joakim Vester-Petersen

Contact: jvepe@eng.au.dk

Project period: May 2015 to April 2018

Main supervisor: Assoc. Prof. Søren Peder Madsen

Co-supervisor: Prof. Ole Sigmund, DTU

Research section: Mechanical and Materials Engineering


Production planning of energy systems – Cost and risk assessment for district heating

Magnus Dahl

The district heating sector is a major player in today's energy system, especially in Scandinavia and Eastern Europe. There is a potential in terms of economic and environmental benefits of operating district heating systems in an efficient way.

The aim of this industrial PhD project is to assess operational costs and risk of a large-scale district heating system. The technical limitations of the district heating system are taken into account through least cost dispatch modelling. Ensembles of weather forecasts and the complex coupling to the electricity market will be used to ensure cost-effective production planning. Results from the analysis will be evaluated based on the day-to-day operation of the district heating system of Aarhus.

In the later phases of the project, the model will be used to explore potential economical and technical benefits of a number of new district heating technologies. These include: low temperature district heating, distributed or central heat storage, low heat consumption housing, solar thermal, power-to-heat and integration of waste heat.

ABOUT THE PROJECT


Project title: 
Production planning of energy systems – Cost and risk assessment for district heating

PhD student: Magnus Dahl

Contact: magnus.dahl@eng.au.dk

Project period: May 2015 to April 2018

Main supervisor: Assoc. Prof. Steffen Petersen

Co-supervisors: Assistant Prof. Gorm Andresen and Adam Brun, AffaldVarme

Research section: Mechanical and Materials Engineering


Sustainability Assessment Tools to Navigate towards Sustainable Development of Food Production

Evelien de Olde

The aim of the project is to analyse the application of sustainability assessment tools in farm management and governance to navigate towards a more sustainable development of food production. A wide range of sustainability assessment tools and frameworks have been developed to accommodate a shift towards sustainable agriculture. Nonetheless, utilisation of the knowledge produced is still one of the main shortcomings of research on sustainability assessments in agriculture.

Operationalising knowledge produced in sustainability assessments into farm management information systems could facilitate precision farming and enable, for example, efficient use of nutrients. Similarly, integration of sustainability assessment tools into policy-making is considered to contribute to decision-making and regional governance for sustainable agriculture. The research will evaluate the sustainability performance of different farming systems to distinguish pathways to apply sustainability assessment tools in farm management and agricultural governance.

ABOUT THE PROJECT


Project title: 
Sustainability Assessment Tools to Navigate towards Sustainable Development of Food Production

PhD student: Evelien de Olde

Contact: evol@eng.au.dk

Project period: March 2014 to Feb 2017

Main supervisor: Senior Researcher Claus Grøn Sørensen

Co-supervisors: Assistant Prof. Frank W. Oudshoorn, Imke de Boer, Wageningen University

Research section: Mechanical and Materials Engineering


Simulation of Composite Structures based on Micro Mechanical Modelling

Alex Møberg

The focus of this project is on the non-linear material model which can be used in calculations of fiber composite. The model has been derived analytically in 2D and has been implemented in the Abaqus finite element software package.

The further work in this project will involve testing and implementing the model in the commercial finite element software Nastran/Marc to be able to efficiently analyse real structural components to final failure. Afterwards, the model will be generalised into a 3D model.

Once the model has been built in, it can be applied to study effects such as buckling including buckling-driven delamination, elastic spring back due to residual stresses, etc.

 

 

ABOUT THE PROJECT

Project title: Simulation of Composite Structures based on Micro Mechanical Modelling

PhD student: Alex Møberg

Contact: alexm@eng.au.dk

Project period: Sept 2013 to Aug 2016

Main supervisor: Prof. Henrik Myhre Jensen

Co-supervisor: Prof. (Docent) Flemming Mortensen

Research section: Mechanical and Materials Engineering