Browsing NTNU Open by Author "Walnum, Harald Taxt"

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    • Analysis of monthly and daily profiles of DHW use in apartment blocks in Norway 

      Ivanko, Dmytro; Walnum, Harald Taxt; Sørensen, Åse Lekang; Nord, Natasa (Peer reviewed; Journal article, 2020)
      Profiles of domestic hot water (DHW) use give valuable information for achieving energy saving in buildings. In this article, analysis of monthly and hourly profiles in apartment blocks in Norway was performed. The aim was ...

    • Demonstration of a low-cost solution for implementing MPC in commercial buildings with legacy equipment 

      Walnum, Harald Taxt; Sartori, Igor; Ward, Peder; Gros, Sebastien Nicolas (Journal article; Peer reviewed, 2024)
      Model predictive control (MPC) approaches for HVAC systems in buildings have shown potential for significant reduction of energy use and for enabling flexible operation. However, a widespread adoption is long in coming, ...

    • Developing a scenario calculator for smart energy communities in Norway: Identifying gaps between vision and practice 

      Walnum, Harald Taxt; Hauge, Åshild Lappegard; Lindberg, Karen Byskov; Mysen, Mads; Nielsen, Brita Fladvad; Sørnes, Kari (Journal article; Peer reviewed, 2019)
      Key Performance Indicators are important instruments, both in defining high-level goals (international or national) and when planning smart energy communities. However, there is often a gap between the high-level goals, ...

    • Development and analysis of hourly DHW heat use profiles in nursing homes in Norway 

      Ivanko, Dmytro; Walnum, Harald Taxt; Nord, Natasa (Peer reviewed; Journal article, 2020)
      Representative profiles for domestic hot water (DHW) heat use are the main instruments for improvement in operation and design of DHW systems in buildings. To improve the existing method for DHW heat use profiles development ...

    • DHW tank sizing considering dynamic energy prices 

      Nord, Natasa; Ding, Yuemin; Ivanko, Dmytro; Walnum, Harald Taxt (Peer reviewed; Journal article, 2021)
      Due to the rapid development of the building stock in Norway, the energy use in this segment is drastically increasing. Therefore, improving the energy performance of buildings becoming an urgent problem. Among technical ...

    • Energy consumption for domestic hot water use in Norwegian hotels and nursing homes 

      Walnum, Harald Taxt; Sørensen, Åse Lekang; Ludvigsen, Bjørn; Ivanko, Dmytro (Journal article; Peer reviewed, 2019)
      Domestic Hot Water (DHW) production constitutes a significant proportion of the energy demand of modern buildings, and as the building envelope is improved the share increases. This article discusses the results from a ...

    • Energy flexibility potential of domestic hot water systems in apartment buildings 

      Sørensen, Åse Lekang; Walnum, Harald Taxt; Sartori, Igor; Andresen, Inger (Peer reviewed; Journal article, 2021)
      Domestic Hot Water (DHW) storage tanks are identified as a main source of flexible energy use in buildings. As a basis for energy management in apartment buildings, this paper describes the aggregated DHW use in a case ...

    • Experimental and theoretical investigation of a hydrogen liquefaction process 

      Rasmussen, Øystein; Walnum, Harald Taxt (Master thesis, 2009)

    • Experimental and theoretical investigation of a hydrogen liquefaction process 

      Walnum, Harald Taxt; Rasmussen, Øystein (Master thesis, 2009)
      The world approaches a challenging era where new solutions to the arising energy and climate problems must be found. As the need for clean energy carriers increases due to growing energy demand and increased global warming, ...

    • A flexible and robust modelling framework for multi-stream heat exchangers 

      Skaugen, Geir; Kolsaker, Kjell; Walnum, Harald Taxt; Wilhelmsen, Øivind (Peer reviewed; Journal article, 2013)
      Heat exchangers are important units in most industrial processes. They involve physical phenomena such as condensation and evaporation including several boiling regimes. Different types of heat exchangers constructed for ...

    • Heat analysis for energy management in neighbourhoods: case study of a large housing cooperative in Norway 

      Sørensen, Åse Lekang; Lindberg, Karen Byskov; Walnum, Harald Taxt; Sartori, Igor; Aakenes, Ulf Roar; Andresen, Inger (Journal article; Peer reviewed, 2019)
      As a basis for energy management in apartment blocks, this paper characterises heat use in a large housing cooperative in Norway, with in total 1,058 apartments. Heat measurements with hourly resolution are available from ...

    • Identifying typical hourly DHW energy use profiles in a hotel in Norway by using statistical methods 

      Ivanko, Dmytro; Nord, Natasa; Sørensen, Åse Lekang; Plesser, Thale Sofie Wester; Walnum, Harald Taxt; Sartori, Igor (Journal article; Peer reviewed, 2019)
      The aim of this research is to improve the existing approaches of domestic hot water (DHW) energy use analysis in buildings. A comprehensive statistical analysis of hourly DHW energy use for a hotel in Oslo, Norway, was ...

    • Impact of activating energy demand flexibility in the building stock: A case study of Norway as a highly electrified country in the European power market 

      Backe, Stian; Delgado, Benjamin Manrique; Askeland, Magnus; Walnum, Harald Taxt; Sørensen, Åse Lekang; Sartori, Igor (Journal article; Peer reviewed, 2025)
      On the transition towards an electrified European energy system, flexible electricity use is crucial. The building stock, including electric vehicles, can offer flexibility, but it is still unclear towards which objective ...

    • Innovasjonsrapport 2020. Forskningssenteret for nullutslippsområder i smarte byer (FME ZEN) 

      Bergsdal, Håvard; Sørensen, Åse Lekang; Cervenka, Zdena; Holm, Øystein; Thomsen, Judith; Sartori, Igor; Lindberg, Karen Byskov; Stokke, Raymond Andreas; De Boer, Luitzen; Hamdan, Hasan; Holmen, Elsebeth; Wiik, Marianne Rose Kjendseth; Backe, Stian; Kauko, Hanne; Georges, Laurent; Walnum, Harald Taxt; Lien, Synne Krekling; Skaar, Christofer; Wolfgang, Ove; Brattebø, Helge; Lausselet, Carine; Resch, Eirik; Sandberg, Nina Holck; Pinel, Dimitri; Thorvaldsen, Kasper Emil; Alonso, Maria Justo; Askeland, Magnus; Petersen, Sobah Abbas; Favero, Matteo; Carlucci, Salvatore; Liu, Peng (ZEN Report;, Research report, 2020)
      Forord. Forskning og innovasjon er grunnpilaren i vår visjon om å utvikle bærekraftige områder med null klimagassutslipp. Innovasjonskomiteen skal bistå senterledelsen i dette arbeidet gjennom å etablere gode innovasjonsprosesser ...

    • Insights into ZEN pilot projects: An overview and experience summary 

      Thomsen, Judith; Homaei, Shabnam; Aakervik, Anne-Lise; Wiik, Marianne Rose Kjendseth; Rokseth, Lillian Sve; Andersen, Kamilla Heimar; Lien, Synne Krekling; Bø, Lars Arne; Lolli, Nicola; Kauko, Hanne Laura Pauliina; Walnum, Harald Taxt; Lausselet, Carine; Sørensen, Åse Lekang (ZEN Report;66, Research report, 2024)

    • Integrating Thermal-Electric Flexibility in Smart Buildings using Grey-Box modelling in a MILP tool 

      Bagle, Marius; Manrique Delgado, Benjamin; Sartori, Igor; Walnum, Harald Taxt; Lindberg, Karen Byskov (Peer reviewed; Journal article, 2022)
      In a smart grid setting, building managers are encouraged to adapt their energy operations to real-time market and weather conditions. However, most literature assume stationary temperature set points for heating and ...

    • Modelica Emulator for MPC Applications in Buildings 

      Gundersen, Martine Walvik (Master thesis, 2021)
      Bygninger bidrar til verdens energibruk og utslipp av klimagasser. En foreslått løsning for å redusere energibruken i eksisterende bygninger er å implementere avanserte kontrollstrategier. Et forslag er modell prediktiv ...

    • Modelling and simulation of CO2 (carbon dioxide) bottoming cycles for offshore oil and gas installations at design and off-design conditions 

      Walnum, Harald Taxt; Nekså, Petter; Nord, Lars Olof; Andresen, Trond (Peer reviewed; Journal article, 2013)
      Improved energy efficiency is an issue of increasing importance in offshore oil and gas installations. The power on offshore installations is generated by gas turbines operating in a simple cycle. There is an obvious ...

    • Pilot Building Powerhouse Kjørbo - As Built Report 

      Sørensen, Åse Lekang; Andresen, Inger; Walnum, Harald Taxt; Alonso, Maria Justo; Fufa, Selamawit Mamo; Jenssen, Bjørn; Rådstoga, Olav; Hegli, Tine; Fjeldheim, Henning (ZEB Project report;, Research report, 2017)

    • Prediction of DHW energy use in a hotel in Norway 

      Ivanko, Dmytro; Nord, Natasa; Sørensen, Åse Lekang; Sartori, Igor; Plesser, Thale Sofie Wester; Walnum, Harald Taxt (Journal article; Peer reviewed, 2019)
      Domestic hot water (DHW) systems are significant consumers of energy in buildings. This article is dedicated to hourly and daily DHW energy use modeling, with the aim of achieving energy savings in buildings. The methods ...