Juergen Schumacher (1952-2020) was a mathematician with a PhD in physics from the University of Oldenburg in Germany, who spent his life developing software tools for renewable energy simulation. With a keen sense of detail, he researched the background of simulation algorithms widely used in the energy community and provided full derivations of many formulas around solar irradiance, the physics of photovoltaic cells, building simulation and other domains. Dr. Schumacher managed the research center for renewable energy technologies at HFT Stuttgart before moving to Concordia University in Montreal as a senior scientist for urban scale simulations.Ursula Eicker holds the Canada Excellence Research Chair in Smart, Sustainable and Resilient Cities and Communities, at Concordia University, Montreal, Canada. With a PhD in solid state physics, her work has expanded from the fundamentals of photovoltaics to building physics and renewable energy systems to today’s research on decarbonization of cities. Her research focuses on digital twins to model the urban built environment and transportation systems.

• PrologPrefaceIntroduction1 Mathematical concepts and numerical methods2 History of Computing, Programming and Simulation Languages3 Software Architecture14 Simulation Techniques5 Energy Meteorology6 Solar electricity7 Thermodynamics8 Solar Collectors9 Building and city simulationA Appendix

Juergen Schumacher (1952-2020) was a mathematician with a PhD in physics from the University of Oldenburg in Germany, who spent his life developing software tools for renewable energy simulation. With a keen sense of detail, he researched the background of simulation algorithms widely used in the energy community and provided full derivations of many formulas around solar irradiance, the physics of photovoltaic cells, building simulation and other domains. Dr. Schumacher managed the research center for renewable energy technologies at HFT Stuttgart before moving to Concordia University in Montreal as a senior scientist for urban scale simulations.Ursula Eicker holds the Canada Excellence Research Chair in Smart, Sustainable and Resilient Cities and Communities, at Concordia University, Montreal, Canada. With a PhD in solid state physics, her work has expanded from the fundamentals of photovoltaics to building physics and renewable energy systems to today’s research on decarbonization of cities. Her research focuses on digital twins to model the urban built environment and transportation systems.

• PrologPrefaceIntroduction1 Mathematical concepts and numerical methods2 History of Computing, Programming and Simulation Languages3 Software Architecture14 Simulation Techniques5 Energy Meteorology6 Solar electricity7 Thermodynamics8 Solar Collectors9 Building and city simulationA Appendix

Juergen Schumacher (1952-2020) was a mathematician with a PhD in physics from the University of Oldenburg in Germany, who spent his life developing software tools for renewable energy simulation. With a keen sense of detail, he researched the background of simulation algorithms widely used in the energy community and provided full derivations of many formulas around solar irradiance, the physics of photovoltaic cells, building simulation and other domains. Dr. Schumacher managed the research center for renewable energy technologies at HFT Stuttgart before moving to Concordia University in Montreal as a senior scientist for urban scale simulations.Ursula Eicker holds the Canada Excellence Research Chair in Smart, Sustainable and Resilient Cities and Communities, at Concordia University, Montreal, Canada. With a PhD in solid state physics, her work has expanded from the fundamentals of photovoltaics to building physics and renewable energy systems to today’s research on decarbonization of cities. Her research focuses on digital twins to model the urban built environment and transportation systems.

• PrologPrefaceIntroduction1 Mathematical concepts and numerical methods2 History of Computing, Programming and Simulation Languages3 Software Architecture14 Simulation Techniques5 Energy Meteorology6 Solar electricity7 Thermodynamics8 Solar Collectors9 Building and city simulationA Appendix