Blar i SINTEF Open på forfatter "Hafner, Armin"
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Modeling of a CO2‐Based Integrated Refrigeration System for Supermarkets
Pardiñas, Ángel Á.; Jokiel, Michael; Schlemminger, Christian; Selvnes, Håkon; Hafner, Armin (Peer reviewed; Journal article, 2021)An integrated energy system that consists of a centralized refrigeration unit can deliver the entire HVAC&R (heating, ventilation, air conditioning, and refrigeration) demand for a supermarket. CO2 (R744) is a natural ... -
Modelling of Crystallization During Freeze-Concentration of Hydrolysates
Khan, Muhammad Umar; Tolstorebrov, Ignat; Widell, Kristina Norne; Hafner, Armin; Nordtvedt, Tom Ståle (Chapter; Peer reviewed, 2022)Dewatering of fish protein hydrolysates is energy intensive process. The freeze concentration is one of the solutions, which provide high quality of concentrate, energy efficiency and sustainability of the hydrolysate ... -
Modified homogeneous relaxation model for the r744 trans-critical flow in a two-phase ejector
Haida, Michal; Smolka, Jacek; Hafner, Armin; Palacz, Michal; Banasiak, Krzysztof; Nowak, Andrzej J. (Journal article; Peer reviewed, 2017) -
Multi Ejector and pivoting-supported R744 application with AC for supermarkets
Contiero, Luca; Hafner, Armin; Pardiñas, Ángel Á. (Chapter; Peer reviewed, 2021)CO2 refrigeration units are gaining market shares thanks to the ability to provide an energy efficient performance for industrial and commercial refrigeration applications in any climate. As with all the applications, the ... -
Multi-Ejector Concept: A Comprehensive Review on its Latest Technological Developments
Gullo, Paride; Hafner, Armin; Banasiak, Krzysztof; Minetto, Silvia; Kriezi, Ekaterini E. (Journal article; Peer reviewed, 2019)The adoption of the EU F-Gas Regulation 517/2014 and the resulting development of the multi-ejector concept have led carbon dioxide to take center stage as the sole refrigerant (R744) in several applications. Therefore, a ... -
Multiejector CO2 cooling system with evaporative gascooler for a supermarket application in tropical regions
Singh, Simarpreet; Hafner, Armin; Maiya, M.P.; Banasiak, Krzysztof; Nekså, Petter (Peer reviewed; Journal article, 2021)In the present study, the performance of a 33 kW multiejector trans-critical CO2 cooling system is experimentally evaluated for a supermarket application with/without internal heat exchanger and evaporative cooling. In ... -
A novel R744 multi-temperature cycle for refrigerated transport applications with low-temperature ejector: Experimental ejector characterization and thermodynamic cycle assessment
Fabris, Francesco; Pardiñas, Ángel Á.; Marinetti, Sergio; Rossetti, Antonio; Hafner, Armin; Minetto, Silvia (Peer reviewed; Journal article, 2023)A novel vapor-compression system concept employing carbon dioxide as the refrigerant is proposed to serve the needs of a typical medium-size refrigerated truck used for multi-temperature (MT and LT) goods delivery. The ... -
Numerical investigation of heat transfer in a CO2 two-phase ejector
Haida, Michal; Smolka, Jacek; Hafner, Armin; Mastrowski, Mikolaj; Palacz, Michal; Madsen, Kenneth B.; Nowak, Andrzej J.; Banasiak, Krzysztof (Journal article; Peer reviewed, 2018)In this paper, the influence of heat transfer in the walls of an R744 two-phase ejector on ejector performance was investigated. A numerical investigation was performed using a computational fluid dynamic (CFD) model of ... -
Overview of the development and status of carbon dioxide (R-744) refrigeration systems onboard fishing vessels
Söylemez, Engin; Widell, Kristina Norne; Gabrielii, Cecilia H; Ladam, Yves; Lund, Thomas; Hafner, Armin (Peer reviewed; Journal article, 2022)Globally, most fishing vessels still use the ozone-depleting and climate-harmful R-22 in their freezing and refrigerated seawater (RSW) systems. However, in some regions, the natural refrigerant ammonia is the preferred ... -
Parallel Work of CO2 Ejectors Installed in a Multi-Ejector Module of Refrigeration System
Bodys, Jakub; Palacz, Michal; Haida, Michal; Smolka, Jacek; Nowak, Andrzej J.; Banasiak, Krzysztof; Hafner, Armin (Journal article; Peer reviewed, 2016)A performance analysis on of fixed ejectors installed in a multi-ejector module in a CO2 refrigeration system is presented in this study. The serial and the parallel work of four fixed-geometry units that compose the ... -
Parametric study of low-temperature thermal energy storage using carbon dioxide as the phase change material in pillow plate heat exchangers
Mastani Joybari, Mahmood; Selvnes, Håkon; Vingelsgård, Erling; Sevault, Alexis; Hafner, Armin (Peer reviewed; Journal article, 2022)Industrial low-temperature freezing applications are often batch processes, requiring a lot of energy, exerting stress on the electrical grid. To relieve this stress, thermal energy storage can be used. However, there is ... -
Performance analysis of high temperature heat pumps and thermal energy storages for a dairy
Ahrens, Marcel Ulrich; Brækken, August; Foslie, Sverre Stefanussen; Moen, Ole Marius; Lovas, Kim Andre; Bantle, Michael; Hafner, Armin; Eikevik, Trygve Magne (Science et technique du froid;, Chapter; Peer reviewed, 2022)This paper analyses the performance of the integrated energy system of an existing dairy in Bergen, Norway. The investigated dairy has an innovative solution for the thermal process supply by using only heat pumps and ... -
Performance evaluation of CO2 ejector system with parallel compressor for supermarket application
Singh, Simarpreet; Banasiak, Krzysztof; Hafner, Armin; Maiya, M.P.; Nekså, Petter (Chapter, 2018)Evolution in modifications for CO2 system configuration came across from the last two decades has proven to hold the potential in order to improve the overall performance of the CO2 cooling system for various applications. ... -
Performance Evaluation of Ejector Based CO₂ System for Simultaneous Heating and Cooling Application in an Indian Dairy Industry
Koti, Dasi; Singh, Simarpreet; Guruchethan, A.M.; Maiya, M.P.; Hafner, Armin; Banasiak, Krzysztof; Nekså, Petter (Peer reviewed; Journal article, 2020)India is ranked first in milk production, and its goal is to increase annual production to 300 million tons by 2024. The dairy industry requires multi-temperature cooling and simultaneous heating. In the present study, the ... -
Performance evaluation of high-temperature heat pump systems for hot water and steam generation in food processing
Ren, Shuai; Ahrens, Marcel Ulrich; Hafner, Armin; Widell, Kristina Norne (Chapter; Peer reviewed, 2022)A large amount of fossil fuels is consumed for hot water and steam generation in food processes such as smoking, scalding, drying, pasteurization, sterilization, cleaning, and cooking, which currently rises both economic- ... -
Performance improvements of supermarket R744 systems by pivoting compressor arrangements
Contiero, Luca; Fabris, F; Pardiñas, Ángel Á.; Hafner, Armin (Science et technique du froid;, Chapter; Peer reviewed, 2022)The adoption of the EU F-Gas regulation 517/2014 and the development of the Multi Ejector concept have led CO2 to take center stage as one of the preferred solutions in several applications, at the expense of synthetic ... -
Performance investigation of a multi-ejector R744 heat pump
Singh, Simarpreet; Reddy, Amshith; Prakash, Maiya P.; Banasiak, Krzysztof; Hafner, Armin; Nekså, Petter (Journal article; Peer reviewed, 2018) -
Performance mapping of the R744 ejectors for refrigeration and air conditioning supermarket application: A hybrid reduced-order model
Haida, Michal; Smolka, Jacek; Hafner, Armin; Ostrowski, Zeimowit; Palacz, Michal; Madsen, Kenneth B.; Försterling, Sven; Nowak, Andrzej J.; Banasiak, Krzysztof (Journal article; Peer reviewed, 2018)The continuous derivation of the ambient temperature and cooling demand in CO2 refrigeration and air-conditioning systems equipped with multi-ejector modules for supermarkets requires the analysis of the fixed ejector ... -
Performance of integrated R744 packs part 2 : ejectors performance, a comparison of data-driven model from onsite measurements with rom model predictions
Khorshidi, Vahid; Kriezi, Ekaterini E.; Schlemminger, Christian; Hafner, Armin (Sciences et technique du froid;2021/1, Peer reviewed; Journal article, 2021)Rising concerns for climate change impacts along with the new legislation aimed at lowering emissions indicates the inevitable transition in the cooling/heating industry towards a more energy-efficient solution with minimal ... -
Performance of integrated R744-packs part 1: compressor mass flow estimation based on data-driven models using analytical methods and actual field measurements
Khorshidi, Vahid; Kriezi, Ekaterini E.; Schlemminger, Christian; Hafner, Armin; Söylemez, Engin (Sciences et technique du froid;2021/1, Peer reviewed; Journal article, 2021)Rising concerns for climate change impacts along with the new legislation aimed at lowering emissions indicates the inevitable transition in the cooling/heating industry towards a more energy-efficient solution with minimal ...