Browsing Institutt for energi og prosessteknikk by Journals "International journal of refrigeration"
Now showing items 1-17 of 17
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A steady and quasi-steady state analysis on the CO2 hybrid ground-coupled heat pumping system
(Journal article; Peer reviewed, 2017)This article contains the steady and quasi-steady state analysis on a CO2 hybrid ground-coupled heat pumping system for warm climates. The hybrid system uses a combination of ambient air and ground boreholes as a heat sink ... -
Experimental and computational analysis of a R744 flashing ejector
(Journal article; Peer reviewed, 2019)In this paper we present a set of experimental data acquired on a CO2 flashing ejector designed for expansion loss recovery applications. Experimental results are compared with CFD simulations obtained using a Homogeneous ... -
Experimental study on the characteristics of pressure drop oscillations and their interaction with short-period oscillation in a horizontal tube
(Journal article; Peer reviewed, 2018)Long-period oscillations (pressure drop oscillations) and short-period oscillations (superimposed density wave oscillations) have been observed in many studies. However, under which condition the long-period oscillations ... -
General heat transfer correlations for supercritical carbon dioxide heated in vertical tubes for upward and downward flows
(Peer reviewed; Journal article, 2022)Supercritical CO2 is a promising working fluid for many industrial applications. To improve the performances of relevant components and systems, the prediction of the heat transfer of supercritical CO2 is an important ... -
Improved measurements for better decision on heat recovery solutions with heat pumps
(Journal article, 2012)The aim of the study was to show the need for performance documentation, monitoring, and data integration during the lifetime of an energy system to achieve proper decision making. An improved measurement approach for heat ... -
Integrated CO2 system with HVAC and hot water for hotels: Field measurements and performance evaluation
(Journal article; Peer reviewed, 2020)This study investigates the performance of an integrated CO2 (R744) heat pump and chiller unit in a Norwegian hotel. The system consists of a single unit for heating, cooling and hot water with an integrated thermal storage. ... -
Investigation on the performance of fluted tube-in-tube gas cooler in transcritical CO2 heat pump water heater
(Peer reviewed; Journal article, 2021)The utilization of fluted inner tube in tube-in-tube heat exchangers is an effective way to improve the heat transfer performance. Based on the segmented model, the performance of a fluted tube-in-tube gas cooler (FTGC) ... -
Modified homogeneous relaxation model for the r744 trans-critical flow in a two-phase ejector
(Journal article; Peer reviewed, 2017)The proposed modified homogeneous relaxation model (HRM) applied to the numerical model of a CO2 two-phase ejector was numerically investigated and developed based on the optimisation of the relaxation time (RT) correlation. ... -
Next generation of ejector-supported R744 booster systems for commercial refrigeration at all climates
(Peer reviewed; Journal article, 2023)The pernicious effects of synthetic refrigerants on different environmental aspects leave natural refrigerants as the only alternative for vapour compressions systems. Among natural refrigerants, CO2 (R744) has become the ... -
A novel R744 multi-temperature cycle for refrigerated transport applications with low-temperature ejector: Experimental ejector characterization and thermodynamic cycle assessment
(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 ... -
Overview of the development and status of carbon dioxide (R-744) refrigeration systems onboard fishing vessels
(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 ... -
Performance analysis of an R744 ground source heat pump system with air-cooled and water-cooled gas coolers
(Journal article; Peer reviewed, 2016)In order to decrease the earth's energy imbalance degree, a R744 ground source heat pump system (GSHPS) with air-cooled and water-cooled gas coolers was designed, and the performances of this system were analyzed numerically. ... -
Performance operation of liquid ejectors for a R744 integrated multi-ejector supermarket system using a hybrid ROM
(Journal article; Peer reviewed, 2019)Performance maps were generated for designed liquid ejectors installed in a multi-ejector module in an R744 integrated supermarket system using a hybrid of the reduced-order model (ROM). Hybrid ROMs of the investigated ... -
Review of Vapour Compression Heat Pumps for High Temperature Heating using Natural Working Fluids
(Journal article; Peer reviewed, 2017)The use of high temperature heat pumps (HTHPs) operating with natural fluids has been shown to be a potential environmentally friendly solution to increase energy efficiency in industrial processes. Industrial processes ... -
Shape optimisation of a two-phase ejector for CO2 refrigeration systems
(Journal article; Peer reviewed, 2016)The shape optimisation of four CO2 ejectors is presented in this study. The considered ejectors were originally designed for a multi-ejector supermarket CO2 refrigeration system. The objective function was formulated to ... -
The influence of long-term storage, temperature and type of packaging materials on the quality characteristics of frozen farmed Atlantic Salmon (Salmo Salar)
(Journal article; Peer reviewed, 2014)The variations of biochemical, structural, sensory and microbiological characteristics of salmon were examined during the long-term frozen storage at –25 °C, –45 °C and –60 °C. The effects of four different types of packaging ... -
Transcritical R744 refrigeration systems for supermarket applications: Current status and future perspectives
(Journal article; Peer reviewed, 2018)Visible signs of climate change call for urgent actions on food retail industry, since such a sector is characterized by an abundant carbon footprint. Being CO2 (or R744) recognised across the world as the most promising ...