Browsing SINTEF Open by Author "Hafner, Armin"
Now showing items 61-80 of 105
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Integration of gravity-fed evaporators in CO2 based heat-pump chillers
Hazarika, Mihir Mouchum; Bengsch, Jan; Hafsås, Johan; Hafner, Armin; Svendsen, Eirik Starheim; Ye, Zuliang (Chapter; Peer reviewed, 2022)This study is carried out to model a gravity-fed evaporator for CO2 based heat-pump chillers. The gravity-fed evaporator loop consists of a separator, a downcomer, a heat exchanger, and a riser. The working principle is ... -
Investigation and analysis of a CO2 heat pump chiller with novel two-stage evaporator
Bengsch, Jan; Hazarika, Mihir Mouchum; Hafner, Armin; Widell, Kristina Marianne Norne (Chapter, 2023)This study was carried out to investigate the performance of a transcritical CO2 heat pump chiller that provides heating and cooling simultaneously. There are several applications where such CO2 systems are implemented, ... -
Investigation of CO2 refrigeration system and thermal energy storage for passenger ships
Andersen, Henrik; Saeed, Muhammad Zahid; Hafner, Armin; Gabrielii, Cecilia H (Science et technique du froid;2023, Chapter; Peer reviewed, 2023) -
Investigation on heat recovery strategies from low temperature food processing plants: Energy analysis and system comparison
Ahrens, Marcel Ulrich; Selvnes, Håkon; Henke, Leon Hendrik; Bantle, Michael; Hafner, Armin (Chapter; Peer reviewed, 2021)Industrial food processing plants often have significant thermal requirements at both low and high temperatures. These plants can produce a variety of products including frozen, chilled and grilled/steamed foodstuff, ... -
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 an ammonia-water absorption-compression high-temperature heat pump for hot water and steam production in food processing
Ren, Shuai; Ahrens, Marcel Ulrich; Hamid, Khalid; Tolstorebrov, Ignat; Hafner, Armin; Eikevik, Trygve Magne; Widell, Kristina Marianne Norne (Chapter, 2023)To achieve climate neutrality in the food sector, there is an urgent need for eco-friendly steam boilers. The absorption-compression heat pumps (ACHP) using an ammonia-water mixture as working fluid can provide a high heat ... -
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- ...