Browsing NTNU Open by Author "Nekså, Petter"
Now showing items 21-40 of 61
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Evaluation of mid-scale hydrogen distribution chains for compressed hydrogen
Koshelkov, Igor (Master thesis, 2022)Hydrogen for industrielle applikasjoner har eksistert i mange år. Det begynte å gå inn i et forbrukermarked som et tilgjengelig bærekraftig alternativ til fossilt brensel for cirka ti år siden. Årsaken til bruk av hydrogen ... -
Evaluation of Rankine cycles with mixed component working fluids
Nikolaisen, Monika (Master thesis, 2017)The thesis evaluates the performance of Rankine cycles with mixed component hydrocarbon working fluids, or hydrocarbon mixtures. The objective is to compare mixtures with pure fluids on the basis of the same total heat ... -
Experimental Evaluation of a Multi-Ejector Trans-critical CO2 System for Supermarkets
Singh, Simarpreet; Hafner, Armin; Banasiak, Krzysztof; Maiya, Prakash; Nekså, Petter (Chapter, 2019)In the present experimental study, the performance of a multi-ejector based trans-critical CO2 cooling system is tested at high ambient temperature up to 46°C for a supermarket application with and without internal heat ... -
Experimental evaluation of multi-ejector based CO2 cooling system for supermarkets in tropical zones
Singh, Simarpreet; Hafner, Armin; Banasiak, Krzysztof; Maiya, Prakash M.; Nekså, Petter (Chapter, 2018)Cooling system for supermarkets, now-a-days in developing countries like India, mainly uses man-made synthetic refrigerants/mixtures such as R134a, R404A and R410A (HFCs). These fluorinated refrigerants possess an outrageous ... -
Experimental investigation of CO2 systems for Indian supermarkets with parallel configuration of multiejectors (INDEE)
Banasiak, Krzysztof; Singh, Simarpreet; Hafner, Armin; Maiya, Prakash; Nekså, Petter; Pardiñas, Ángel Á. (Chapter, 2019)Experimental investigation of transcritical R744 pack for Indian supermarkets was performed. Parallel combination of expansion work recovery multiejector blocks was applied for optimization of energy performance of the ... -
Experimental investigation of the performance of a hydrocarbon heat pump for high temperature industrial heating
Bamigbetan, Opeyemi Olayinka; Eikevik, Trygve Magne; Nekså, Petter; Bantle, Michael; Schlemminger, Christian (Chapter, 2018)A 20 kW heat pump test rig has been built to investigate and validate heat delivery up to 110 °C using a vapour compression cycle. The heat pump is a cascade cycle with propane as the working fluid in the low temperature ... -
Experimental Observation of CO2 Dry-ice Behavior in an Evaporator/Sublimator
Yamasaki, Haruhiko; Yamaguchi, Hiroshi; Hattori, Kazuyuki; Nekså, Petter (Journal article; Peer reviewed, 2017)In the evaporator/sublimator process of CO2 (R744) ultra-low temperature cascade heat pump system, it is known, as a problem, that dry-ice blockage makes the system operation fail. The design of an expanding channel for ... -
Experimental testing and development of CO2 compressors: Eksperimentell utprøving og utvikling av CO2 kompressorer
Ask, Anders (Master thesis, 2012)CO2 is a natural refrigerant and is well suitable in many cooling applications. It has been used within the refrigeration industry from the 1900s, but got replaced as the synthetic refrigerants got introduced. In 1990 these ... -
Feasibility of using Rankine power cycles for utilisation of medium to low temperature heat sources in the industry
Røssland, Kjersti (Master thesis, 2016)In this paper, an overview of different ORC applications is presented, along with a market review that includes major manufacturers, application areas and cost estimates. Focus was laid upon low (100C) to medium ... -
Formation of Hard Grey Scale (HGS) on the Surface of a Cold-finger in the Aluminium Production Industry
Clos, Daniel Perez (Doctoral theses at NTNU;2021:183, Doctoral thesis, 2021)The present work has investigated the formation mechanisms of Hard Grey Scale (HGS) in a duct transporting the off-gas from aluminium production pot cells to the Gas Treatment Centre (GTC). For that purpose, a cooled fouling ... -
Future Low Emission Oil and Gas Platforms
Foulkes, Jason Gordon (Master thesis, 2021)This thesis investigates the use of energy-efficient technologies to reduce the quantity of CO2 emitted by offshore platforms. To do this, an offshore oil and gas platform is modelled on a process simulation software called ... -
Gradient Based Design Optimization of a Radial Inflow Turbine
Hagen, Brede; Cavo, Matteo; Andresen, Trond; Nekså, Petter (Chapter, 2020)The expander is one of the key components of an ORC as the cycle efficiency strongly depends on the expander efficiency. This paper presents a method for design optimization of a radial inflow turbine (RIT) using a mean-line ... -
Gradient-based design optimization and off-design performance prediction of Rankine cycles and Radial Inflow Turbines
Hagen, Brede Andre Larsen (Doctoral theses at NTNU;2022:147, Doctoral thesis, 2022)A major fraction of today's electricity is generated by Rankine cycle power systems utilizing the thermal energy of fossil sources such as coal and natural gas, or nuclear energy. However, the carbon content in the fossil ... -
Heat-to-power conversion from variable surplus heat sources utilizing a thermal energy storage
Lingaas, Simon Johan Nilsen (Master thesis, 2019)Målet med dette arbeidet var å undersøke den potensielle nytten av termisk buffring i et varmegjennvinningssystem. Arbeidet undersøkte muligheten for å integrere en form for termisk lagring inn i et varmegjennvinningssystem ... -
High temperature industrial heat pumps utilising natural working fluids
Nekså, Petter; Bantle, Michael; Schlemminger, Christian; Bamigbetan, Opeyemi Olayinka (Chapter, 2019)There is a large demand for heat typically in the temperature range 100-200⁰C in different industries. This is today often covered by fossil fuel burning or direct use of electricity. Heat pumps has to a lesser extent been ... -
Integrated CO2 solutions for supermarkets
Hafner, Armin; Nekså, Petter (Journal article; Peer reviewed, 2018)Supermarkets represent a refrigeration application area which is spearheading towards the total phase in of natural working fluids. Exposed to demanding customers where reputation is an important part of the business, focus ... -
Investigation of a Concept for Simultaneous Reliquefaction of Boil-Off-Gas and Vaporization of LNG for Marine Atmospheric LNG Fuel Tanks
Battistelli, Arrigo (Master thesis, 2014)The aim of this thesis is to design and optimize a heat pump process to reliquefy Boil-Off-Gas from Liquefied Natural Gas (LNG) cryogenic tanks, and simulataneously vaporize LNG at high pressure.The process is meant for ... -
Investigation of an LNG fuel system for a Norwegian coast guard ship: Undersøkelse av LNG drivstoffsystem for skip i den norske kystflåten
DiRenzo, Joseph (Master thesis, 2014)This report examines the reasons behind Natural Gas (NG) engine de-loading on LNG fuelled vessels. Two instances of NG engine de-loading due to low tank pressure have been document on KV Bergen in the Norwegian Coast Guard. ... -
Investigation of CO2 hybrid groundcoupled heat pumping system for warm climate
Jin, Zhequan (Doctoral theses at NTNU;2017:40, Doctoral thesis, 2017)Environmental sustainability, renewable and clean energy utilization and energy conservation have become key issues facing the development of modern society. In the field of refrigeration, air conditioning and heat pumping ... -
Investigation of Pressure Release Systems for CO2
Ekeberg, Bjørn Danielsen (Master thesis, 2015)A pressure release system for CO2 is designed to release CO2 from a system where the pressure is higher than a predetermined maximum pressure. Precautions has to be taken when designing a pressure release system for CO2 ...