From Appropedia

Introduction[edit | edit source]

Originally from the far northern reaches of Houghton in Upper Michigan, I am now based in Stockholm, Sweden as a Postdoc in the Energy Systems Engineering, Economics, and Data Analytics (ENSEED) Research Group at KTH Royal Institute of Technology. My work is focused on sustainable energy systems with the goal of empowering individuals with information and technology to take matters into their own hands.

More specifically, my research is focused on electrical and thermal energy supply in buildings and cities and stems from solar photovoltaic (PV) integration. Technologically, integration extends into heat pumps, stationary batteries, electric vehicles, solar thermal collectors, and seasonal thermal storage. Socio-economically, integration means using traditional engineering economics, business model innovation, energy policy, and decision making behavior. I'm a big fan of stochastic modeling techniques and using probabilistic tools in place of deterministic analysis.

From March 2020 to March 2021, I am "coming home" to be a Visiting Researcher at Michigan Tech in the Michigan Tech Open Sustainability Technology Research Group, working on energy systems modeling for homes, businesses and communities in Michigan's Keweenaw Peninsula. Our goal is to identify strategies for reducing energy costs and increasing security of supply while utilizing local renewable resources.

LinkedIn Profile

Research Gate Profile

The Fine Print[edit | edit source]

The phrase that probably fits me best is jack of all trades, master of none. Seems a bit funny to say when you have a PhD, but my interests and experiences are quite broad. I am trained as an engineer, but spent much of my PhD on economic, finance, policy, and market issues. I'm always thinking through a systems perspective, trying to optimize using multi-disciplinary criteria. I never expected to get into philosophy, but it becomes critical for decision making when working on the sustainable energy transitions and how to design technical systems that do the most good...whatever that means! My professional working experience spans product design, tool manufacturing, software development, and outdoor tourism.

Education[edit | edit source]

PhD in Energy Technology from KTH Royal Institute of Technology (2019)

Thesis: Solar PV in prosumer energy systems

MSc in Energy Technology from KTH Royal Institute of Technology (2012)

Thesis: Demonstrating the significance of microclimate on annual building simulations with RadTherm

BSc in Mechanical Engineering from Michigan Tech (2004)

Capstone Project: ASME Human Powered Vehicle Challenge (1st Place)

Projects[edit | edit source]

Current: Prosumer-centric communication for solar PV diffusion

The goal of this project is to develop the most effective techniques from behavioral economics to create a scalable, prosumer-centric communications framework. A design thinking approach will be used to identify the needs and barriers from multiple stakeholder’s viewpoints, followed by an agile prototyping phase to test ideas and techniques. The resulting framework aims to deliver a scalable method of communication that provides better heuristics to users for complex decision making while nudging them towards sustainable choices and greater PV adoption.

Current: SmartSol2 - Smart Solar Hybrid Solutions for Sustainable European Buildings

The goal of this project is to advance the development of an integrated heating, cooling and electricity system solution for European buildings using solar PVT technology and ground source heat pumps. The project aims at investigating the methods and strategies to reduce both operational and capital cost of the system as well as increasing the system efficiency. A system pilot will be constructed and monitored with sustainable business models developed for diverse applications in domestic and export markets.

Completed: Solar energy and ground source heat pumps for Swedish multi-family housing

To increase the efficiency of solar collectors, self-consumption of PV generation, and heat pump efficiency, the integration of hybrid solar PV/thermal modules on the source-side of the heat pump can be interesting. A PV/thermal hybrid collector affixes a heat exchanger to the back of PV cells, which can increase electricity production by cooling the cells as well as capture thermal energy normally lost to the ambient air. Connecting on the source side of the heat pump will reduce the electricity needed for the compressor and also enable storage of excess heat in the boreholes. The stored heat increases the borehole temperatures such that the compressor runs more efficiently in winter as well. The configuration also opens up interesting possibilities for converting PV over-production into stored heat rather than dumping it to the network.

Completed: Solar PV systems in Swedish cooperative housing

Rapid declines in the cost of solar photovoltaic modules have made rooftop mounted systems economically interesting in Sweden, especially large scale systems for multi-family housing. This project seeks to understand how solar PV can technically and economically integrate into the residential cooperative's energy system.

Teaching[edit | edit source]

Solar Energy Systems for Buildings and Cities (Graduate Level)

Solar thermal systems, including design, dimensioning and system integration
Solar cell systems, including design, dimensioning and system integration
Economy, financing, policies and legislation for solar energy in buildings
Combination of solar energy with auxiliary energy machines, particularly heat pumps
Energy storage techniques for building and city level
Solar energy system modelling and simulation
Technical, economical, and environmental related result indicators

Energy Management (Graduate Level)

Systems thinking and systems analysis
Energy Economics
Uncertainty and scenario analysis
Energy challenges for future cities and districts involving many interested parties and many optimization criteria
Modelling and simulation of energy systems on district and city level
Innovative business models for energy systems
Environment and ecology economy

Modeling Tools[edit | edit source]

Energy Systems System Components Supporting Tools
TRNSYS System Advisor Model Python
HOMER Pro EnergyPlus Matlab
Polysun RadTherm SPSS
Excel VBA

Publications[edit | edit source]

Scientific Journals[edit | edit source]

Sommerfeldt N, Madani H. In-depth techno-economic analysis of PV/Thermal plus ground source heat pump systems for multi-family houses in a heating dominated climate. Solar Energy 2019, vol. 190, pp. 44-62. doi:10.1016/j.solener.2019.07.080

Poppi, S, Sommerfeldt, N, Bales, C, Madani, H, Lundqvist, P. 2018. Techno-economic review of solar heat pump systems for residential heating applications. Renewable and Sustainable Energy Reviews; 81, pp. 22-32. doi:10.1016/j.rser.2017.07.041

Sommerfeldt N, Madani H. 2017. Revisiting the techno-economic analysis process for building-mounted, grid-connected photovoltaic systems: Part one – Review. Renewable and Sustainable Energy Reviews; 74, 1379-1393. doi:10.1016/j.rser.2016.11.232

Sommerfeldt N, Madani H. 2017. Revisiting the techno-economic analysis process for building-mounted, grid-connected photovoltaic systems: Part two – Application. Renewable and Sustainable Energy Reviews; 74, 1394-1404. doi:10.1016/j.rser.2017.03.010

Sommerfeldt N, Madani H. 2015. On the use of hourly pricing in techno-economic analyses for solar photovoltaic systems. Energy Conversion and Management; 102, 180-189. doi:10.1016/j.enconman.2015.02.054

International Conferences[edit | edit source]

Sommerfeldt N, Ollas P. Reverse engineering prototype solar PV/thermal collector properties from empirical data for use in TRNSYS Type 560. ISES Solar World Congress and IEA Solar Heating and Cooling Conference 2017, Abu Dhabi: 2017, pp. 1121-32. doi:10.18086/swc.2017.18.11

Sommerfeldt N. Solar PV for Swedish prosumers – A comprehensive techno-economic analysis. 11th ISES Eurosun Conference, Palma de Mallorca, Spain: 2016, pp. 1339-47. doi:10.18086/eurosun.2016.08.01

Sommerfeldt N, Madani H. Review of solar PV/thermal plus ground source heat pump systems for European multi-family houses. 11th ISES Eurosun Conference, Palma de Mallorca, Spain: 2016, pp. 1382-93. doi:10.18086/eurosun.2016.08.15

Pressiani, M, Sommerfeldt, N, Madani, H. Investigation of PV/thermal collector models for use with ground source heat pumps in transient simulations. 11th ISES Eurosun Conference, Palma de Mallorca, Spain: 2016, pp. 1360-71. doi:10.18086/eurosun.2016.08.19

Sommerfeldt, N. On the economic effects of metering schemes in community owned residential PV systems. ISES Solar World Congress 2015, Daegu, South Korea: 2015. pp. 1364-71. doi:10.18086/swc.2015.09.05

Sommerfeldt N, Muyingo H. Lessons in community owned PV from Swedish multi-family housing cooperatives. 31st European Photovoltaic Solar Energy Conference and Exhibition, Hamburg, Germany: 2015, pp. 2745-50.

Sommerfeldt N, Madani H. 2014. Methodology for long-range electricity market price prediction when analyzing investments in distributed renewable energy systems. Energy Procedia, ICAE 2014, 61, pp.1089-1092. doi:10.1016/j.egypro.2014.11.1029

Sommerfeldt N. Opportunities for large scale solar photovoltaic systems in Swedish multi-family housing. 3rd International Workshop on Integration of Solar Power into Power Systems; 2013; London; Energynautics Gbmh. ISBN: 978-3-9813870-8-7

Technical Reports[edit | edit source]

Sommerfeldt N, Madani H. Effsys Expand Final Report: Ground Source Heat Pumps for Swedish Multi-Family Houses - Innovative Co-Generation and Thermal Storage Strategies. June 2018.

Sommerfeldt, N, Muyingo, H, af Klintberg, T. Photovoltaic Systems for Swedish Prosumers. Stockholm, Sweden: KTH Royal Institute of Technology, 2016. ISBN:978-91-7595-936-8

Sommerfeldt, N, Muyingo, H, af Klintberg, T, Kristoffersson, J. Solceller ur flera perspektive. Stockholm, Sweden: KTH Royal Institute of Technology, 2016. ISBN:978-91-7595-937-5