Gunstein Skomedal

Gunstein Skomedal
Universitetet i Agder | UIA · Department of Engineering Science

PhD in Thermoelectric Materials

About

15
Publications
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152
Citations
Introduction
I'm a devoted material scientist working with energy materials. I love technologies converting any form of energy into electricity (and vica-versa), but mostly working on thermoelectric materials now a days. Long experience in silicon PV industry, and also some in fuel cells and batteries. My motivation for all my work is a vision of an ideal world where we use our resources as efficient as possible through reuse and recycling of all energy and material. This is the ultimate goal of my research
Additional affiliations
February 2013 - June 2016
Universitetet i Agder
Position
  • PhD Student
Description
  • PhD on thermoelectric material. Focus on long term stability of novel materials such as skutterudite and silicides.

Publications

Publications (15)
Article
Higher manganese silicide (HMS) alloys (Mnx-αMoαSiy-βGeβ (x = 0.99–1.011, α=0.005–0.02, y=1.75, β= 0.005–0.01)) were studied to elucidate the effect of Mo and Ge pertaining to oxidation. Oxidation experiments were conducted using thermogravimetry and characterized using x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM)....
Article
Full-text available
Thermoelectric modules can be used in waste heat harvesting, sensing, and cooling applications. Here, we report on the fabrication and performance of a four-leg module based on abundant silicide materials. While previously optimized Mg2Si0.3Sn0.675Bi0.025 is used as the n-type leg, we employ a fractional factorial design based on the Taguchi method...
Article
Full-text available
The oxidation kinetics and mechanisms of higher manganese silicides (HMS) MnSi1.75, MnSi (1.75-x)Gex, MnSi(1.75-x)Alx (with x = 0.005 and 0.01)were studied and the effects of densification methods and dopant concentration discussed. Oxidation experiments were conducted using thermogravimetry (TGA), while post characterization with X-ray Photoelectr...
Article
More than 1000 crystalline silicide materials have been screened for thermoelectric properties using first-principles atomistic calculations coupled with the semi-classical Boltzmann transport equation. Compounds that contain radioactive, toxic, rare, and expensive elements as well as oxides, hydrides, carbides, nitrides, and halides have been negl...
Article
Full-text available
Long-term studies on thermoelectric generators based on N-type magnesium silicide (Mg2.01Si0.49Sn0.5Sb0.01) and P-type higher manganese silicide (Mn0.98Mo0.02Si1.73Ge0.02) materials are presented, in the operating temperature range of 200 °C–400 °C. Emphasis is put on the performance and reliability of the current collector configuration, especiall...
Article
Full-text available
Here, we present the performance of a thermoelectric (TE) module consisting of n-type (La0.12Sr0.88)0.95TiO3 and p-type Ca3Co4−xO9+δ materials. The main challenge in this investigation was operating the TE module in different atmospheric conditions, since n-type has optimum TE performance at reducing conditions, while p-type has optimum at oxidizin...
Article
Full-text available
Thermoelectric devices based on oxides are good candidates for energy harvesting technologies for use in aggressive conditions where the materials should withstand high temperatures and corrosive environments over prolonged time. This leads to a natural concern for the stability of the electrical contacts, especially on the hot side of the module....
Article
Full-text available
Buildings in private and domestic use are responsible for about 30% of the global greenhouse gas emissions attributable mainly to their need for heating and cooling energy. This corresponds to about 40% of the global final energy consumption. Therefore, a viable implementation of building energy efficiency policies is inevitable to realize a transf...
Article
Thermoelectric generators are a promising technology for waste heat recovery. As new materials and devices enter a market penetration stage, it is of interest to employ fast and efficient measurement methods to evaluate the long-term stability of thermoelectric materials in combination with metallization and coating (functionalized thermoelectric l...
Article
High temperature oxidation of Mg2Si1-xSnx alloys (x = 0.1 − 0.6) has been investigated. The oxidation rate was slow for temperatures below 430 °C. In the temperature range between 430 and 500 °C all the alloys exhibited breakaway oxidation. The onset temperature of the breakaway region in general decreased with increasing level of Sn in the alloy....
Article
Full-text available
Silicides have attracted considerable attention for use in thermoelectric generators due mainly to low cost, low toxicity and light weight, in contrast to conventional materials such as bismuth and lead telluride. Most reported work has focused on optimizing the materials properties while little has been done on module testing. In this work we have...
Article
Full-text available
We have investigated p-type skutterudite samples with the nominal composition Ce0.6Co2Fe2Sb12 synthesized from elementary constituents by gas atomization and conventional melting, and also those synthesized from ternary and binary phases such as Fex Co1−x Sb2 and CeSb2, respectively, which were mixed and subsequently ball-milled. We conducted measu...
Article
Full-text available
Thermoelectric materials, for example skutterudites and magnesium silicides, are being investigated as promising materials for medium-to-high-temperature waste heat recovery in transport and in industry. A crucial aspect of the success of a thermoelectric material is its stability over time when exposed to rapid heating and cooling. In this work di...
Article
The main goals for the silicon wafering industry are to improve the surface quality of wafers by reducing the total thickness variation and subsurface defects and to increase the production by reducing the wafer thickness. To attain these goals, it is important to understand the material removal mechanisms involved in the process, which at the mome...

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Projects

Projects (6)
Project
ELAG brings together important regional actors in the battery sector to try and develop new technologies and concepts that will aid in the electrification of society and contribute to increase circularity in the Norwegian battery value chain. The overall research aim is to determine how used electric vehicle batteries can be automatically discharged and characterised in order to be integrated into a circular battery value chain that also uses battery energy storage to meet the needs of a low-carbon and electrified society.
Project
Since 2018, the University of Agder (UiA) is involved in several battery related activities among different faculties; in particular the Faculty of Engineering and Science and the Faculty of Business and Law. All activities at UiA focus on automated separation/sorting of (electric vehicle) batteries as well as second use applications. The Faculty of Business and Law concentrates focuses on business and ownership models for second use batteries as well as on recommendations for standards and regulations. The Faculty of Engineering and Science focuses on two connected battery related challenges: automated disassembly and second use applications. Further, the outputs of the research done at the Faculty of Engineering and Science influences the research at the Faculty of Business and Law and vice versa.
Project
The share of electric vehicles increases. Installed batteries are exchanged if they reach 70-80% of their initial capacity. However, these batteries can still be interesting for stationary applications. The proposed study is intended to examine possible applications and their potential as well as the effort necessary for reuse as stationary storages.