Blar i NTNU Open på forfatter "Nord, Lars O."
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Method for mean-line design and performance prediction of one-stage axial turbines
Anderson, Lasse Borg; Agromayor, Roberto; Nord, Lars O. (Chapter, 2022)Today, expanders for Organic Rankine Cycles (ORC) are either inefficient or expensive. One reason for this is that expanders of power conversion systems usually operate under different conditions over an annual perspective. ... -
Model predictive control for combined cycles integrated with CO2 capture plants
Rúa, Jairo; Nord, Lars O.; Hillestad, Magne (Peer reviewed; Journal article, 2021)Flexible thermal power plants integrated with CO2 capture systems can balance the intermittent power generation of renewable energy sources with low-carbon electricity. Among these power systems, natural gas combined cycles ... -
Multi-Row Adjoint-Based Optimization of NICFD Turbomachinery Using a CAD-Based Parametrization
Agromayor, Roberto; Anand, Nitish; Pini, Matteo; Nord, Lars O. (Journal article, 2021)Currently, most of the adjoint-based design systems documented in the open literature assume that the fluid behaves as an ideal gas, are restricted to the optimization of a single row of blades, or are not suited to impose ... -
Offshore Power Plants Integrating a Wind Farm: Design Optimisation and Techno-Economic Assessment Based on Surrogate Modelling
Riboldi, Luca; Nord, Lars O. (Journal article; Peer reviewed, 2018)The attempt to reduce the environmental impact of the petroleum sector has been the driver for researching energy efficient solutions to supply energy offshore. An attractive option is to develop innovative energy systems ... -
One-Dimensional Annular Diffuser Model for Preliminary Turbomachinery Design
Agromayor, Roberto; Müller, Bernhard; Nord, Lars O. (Journal article; Peer reviewed, 2019)Annular diffusers are frequently used in turbomachinery applications to recover the discharge kinetic energy and increase the total-to-static isentropic efficiency. Despite its strong influence on turbomachinery performance, ... -
Optimal control of flexible natural gas combined cycles with stress monitoring: Linear vs nonlinear model predictive control
Rúa, Jairo; Nord, Lars O. (Peer reviewed; Journal article, 2020)In future energy markets, traditional thermal power plants are expected to cycle more to adapt their operation to the intermittent power generation of renewable energy sources. Gas turbine load ramps and stresses in ... -
Optimal Design of a Hybrid Energy System for the Supply of Clean and Stable Energy to Offshore Installations
Riboldi, Luca; Alves, Erick Fernando; Pilarczyk, Marcin; Tedeschi, Elisabetta; Nord, Lars O. (Peer reviewed; Journal article, 2020)This paper presents an innovative hybrid energy system for stable power and heat supply in offshore oil and gas installations. The proposed concept integrates offshore wind power, onsite gas turbines and an energy storage ... -
Optimal Design of Flexible Power Cycles through Kriging-based Surrogate Models
Riboldi, Luca; Nord, Lars O. (Chapter, 2018)The paper presents a novel technique to define the optimal design of a power cycle considering design and off-design performance. A Kriging-based surrogate model is developed in order to simulate the power cycle at design ... -
Optimal dynamic operation of natural gas combined cycles accounting for stresses in thick-walled components
Rúa, Jairo; Nord, Lars O.; Agromayor, Roberto; Hillestad, Magne (Journal article; Peer reviewed, 2020)Flexible natural gas combined cycles will play a fundamental role in future electric markets.Stressesinthick-walled components and gasturbine load ramps are arguably the main limiting factors during transient operation.Classical ... -
Optimal operation and control of heat to power cycles: A new perspective from a systematic plantwide control approach
Zotica, Cristina; Nord, Lars O.; Kovács, Jenő; Skogestad, Sigurd (Peer reviewed; Journal article, 2020)In this work, we use a plantwide control framework to systematically identify the control objectives, operational and environmental constraints, and degrees of freedom for a heat to power cycle with a drum, one pressure ... -
Optimal Operation and Control of Heat-to-Power Cycles: a New Perspective using a Systematic Plantwide Control Approach
Zotica, Cristina Florina; Nord, Lars O.; Kovács, Jenő; Skogestad, Sigurd (Journal article; Peer reviewed, 2019)We use a systematic plantwide control framework to analyze optimal operation of a simple heatto- power steam cycle with a single pressure level and a drum. The present control solutions for power plants1 have been developed ... -
Optimal Operation and Control of Thermal Energy Systems
Zotica, Cristina (Doctoral theses at NTNU;2023:43, Doctoral thesis, 2023)This thesis explores broad topics in the area of optimal control and operation of thermal energy systems, and it is divided into three parts. Part I is entitled Optimal operation and control of heat-to-power cycles: a ... -
Optimal scheduling of flexible thermal power plants with lifetime enhancement under uncertainty
Rúa, Jairo; Verheyleweghen, Adriaen; Jäschke, Johannes; Nord, Lars O. (Peer reviewed; Journal article, 2021)Renewable energy sources have been the focal point to decarbonise the power sector. The large deployment of these intermittent power generation units requires mechanisms to balance the grid. Thermal power plants can provide ... -
Optimisation of flexible operation of natural gas combined cycles with postcombustion CO2 capture
Pazos, Jairo Rúa (Doctoral theses at NTNU;2021:184, Doctoral thesis, 2021)Anthropogenic greenhouse gas emissions have continuously grown since the Industrial Revolution. Global warming is the result of increasing concentrations of these gases in the atmosphere, which create imbalances between ... -
Optimization of Organic Rankine Cycles for Waste Heat Recovery From Aluminum Production Plants
Castelli, Alessandro Francesco; Elsido, Cristina; Scaccabarozzi, Roberto; Nord, Lars O.; Martelli, Emanuele (Journal article; Peer reviewed, 2019)This paper presents the optimization of organic Rankine cycles (ORCs) for recovering waste heat from a hypothetical aluminum production plant to be installed in Norway. The case study is particularly interesting because ... -
Part load performance of PEM fuel cell and electrolyser stacks in hybrid energy system for offshore application
Pilarczyk, Marcin; Riboldi, Luca; Nord, Lars O. (Chapter, 2022)Global warming and associated climate change are ongoing processes worldwide, behind which anthropogenic greenhouse gas emissions play the main role. Renewable energy sources integrated in hybrid energy systems (HES) are ... -
A part-load analysis and control strategies for the Graz Cycle
Mitterrutzner, Benjamin; Sanz, Wolfgang; Nord, Lars O. (Peer reviewed; Journal article, 2022)Carbon capture and storage (CCS) plays a uniquely important role in the future clean and dispatchable power generation portfolio to achieve the ambitious goals set at COP21. The Graz Cycle, a zero emission oxy-combustion ... -
Part-load efficiency boost in offshore organic Rankine cycles with a cooling water flow rate control strategy
Motamed, Mohammad Ali; Nord, Lars O. (Peer reviewed; Journal article, 2022)Global concerns regarding greenhouse gas emissions and global warming have necessitated the speed up in using renewable energies and more efficient use of fossil fuels in the oil and gas industry. Harvesting gas turbine ... -
Part-load thermal efficiency enhancement in gas turbine combined cycles by exhaust gas recirculation
Motamed, Mohammad Ali; Genrup, Magnus; Nord, Lars O. (Peer reviewed; Journal article, 2024)Gas turbine power plants are popular for offshore power generation due to high power density and their reliability. However, growing usage of renewable energies put gas turbines in a load following backup operation. These ... -
Preliminary Design and Optimization of Axial Turbines Accounting for Diffuser Performance
Agromayor, Roberto; Nord, Lars O. (Journal article; Peer reviewed, 2019)Axial turbines are the most common turbine configuration for electric power generation and propulsion systems due to their versatility in terms of power capacity and range of operating conditions. Mean-line models are ...