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Dimethyl ether (DME) is a popular medium widely used in industrial applications. Being highly flammable substance, only recently it has again found commercial use as a primary working fluid in cooling and heating systems. Known as refrigerant RE170, it is now considered to be one of the potential natural refrigerants of the future due to minimal Global Warming Potential and zero Ozone Depletion Potential. Two novel azeotropic ternary mixtures of RE170/R1234yf/R152a were developed in order to improve cooling capacity and performance of a dimethyl ether refrigeration cycle. The mass ratios were purposefully selected to offer high cycle efficiency COP, high specific cooling capacity qe, small specific volume of vapour, reduced compressor power requirements, and the smallest possible temperature glide. The mixtures were subjected to experimental analysis in order to establish to what degree the added fluids (R1234yf and R152a) influence boiling and heat transfer performance. Boiling curves and heat transfer coefficients were determined experimentally and compared with the values obtained for pure RE170. Finally, several known heat transfer coefficient correlations (suitable for both hydrocarbons and synthetic refrigerants) were applied to the resulting data and evaluated for accuracy by evaluation of MAPE. The Cooper correlation was the most accurate for for ternary mixtures of dimethyl ether in the broadest range of temperatures, heat fluxes, and compositions (MAPE between 3.5-19.8). In order to improve the accuracy even further, the original Cooper correlation was modified with the acentric factor and the molecular mass power factor was optimised for modern chloride-less refrigerants. Resulting equation, when applied to ternary mixtures, returns errors below 5% in the entire range of experimental data.
Bartosz Gil; Amaury Fievez; Bartosz Zajaczkowski. Pool boiling heat transfer coefficient of dimethyl ether and its azeotropic ternary mixtures. International Journal of Heat and Mass Transfer 2021, 171, 121063 .
AMA StyleBartosz Gil, Amaury Fievez, Bartosz Zajaczkowski. Pool boiling heat transfer coefficient of dimethyl ether and its azeotropic ternary mixtures. International Journal of Heat and Mass Transfer. 2021; 171 ():121063.
Chicago/Turabian StyleBartosz Gil; Amaury Fievez; Bartosz Zajaczkowski. 2021. "Pool boiling heat transfer coefficient of dimethyl ether and its azeotropic ternary mixtures." International Journal of Heat and Mass Transfer 171, no. : 121063.
In this work, which is related to the current European Parliament Regulation on restrictions affecting refrigeration, four new three-component refrigerants have been proposed; all were created using low Global Warming Potential(GWP) synthetic and natural refrigerants. The considered mixtures consisted of R32, R41, R161, R152a, R1234ze (E), R1234yf, R1243zf, and RE170. These mixtures were theoretically tested with a 10% step in mass fraction using a triangular design. The analysis covered two theoretical cooling cycles at evaporating temperatures of 0 and −30 °C, and a 30 °C constant condensing temperature. The final stage of the work was the determination of the best mixture compositions by thermodynamic and operational parameters. R1234yf–R152a–RE170 with a weight share of 0.1/0.5/0.4 was determined to be the optimal mixture for potentially replacing the existing refrigerants.
Bartosz Gil; Anna Szczepanowska; Sabina Rosiek. New HFC/HFO Blends as Refrigerants for the Vapor-Compression Refrigeration System (VCRS). Energies 2021, 14, 946 .
AMA StyleBartosz Gil, Anna Szczepanowska, Sabina Rosiek. New HFC/HFO Blends as Refrigerants for the Vapor-Compression Refrigeration System (VCRS). Energies. 2021; 14 (4):946.
Chicago/Turabian StyleBartosz Gil; Anna Szczepanowska; Sabina Rosiek. 2021. "New HFC/HFO Blends as Refrigerants for the Vapor-Compression Refrigeration System (VCRS)." Energies 14, no. 4: 946.
An important element of a solar installation is the storage tank. When properly selected and operated, it can bring numerous benefits. The presented research relates to a project that is implemented at the Solar Energy Research Center of the University of Almeria in Spain. In order to improve the operation of the solar cooling and heating system of the Center, it was upgraded with two newly designed storage tanks filled with phase change materials (PCM). As a result of design works, commercial material S10 was selected for the accumulation of cold, and S46 for the accumulation of heat, in an amount of 85% and 15%, respectively. The article presents in detail the process of selecting the PCM material, designing the installation, experimental research, and exergy analysis. Individual tasks were carried out by research groups cooperating under the PCMSOL EUROPEAN PROJECT. Results of tests conducted on the constructed installation indicate that daily energy saving when using a solar chiller with PCM tanks amounts to 40% during the cooling season.
F. Javier Batlles; Bartosz Gil; Svetlana Ushak; Jacek Kasperski; Marcos Luján; Diana Maldonado; Magdalena Nemś; Artur Nemś; Antonio M. Puertas; Manuel S. Romero-Cano; Sabina Rosiek; Mario Grageda. Development and Results from Application of PCM-Based Storage Tanks in a Solar Thermal Comfort System of an Institutional Building—A Case Study. Energies 2020, 13, 3877 .
AMA StyleF. Javier Batlles, Bartosz Gil, Svetlana Ushak, Jacek Kasperski, Marcos Luján, Diana Maldonado, Magdalena Nemś, Artur Nemś, Antonio M. Puertas, Manuel S. Romero-Cano, Sabina Rosiek, Mario Grageda. Development and Results from Application of PCM-Based Storage Tanks in a Solar Thermal Comfort System of an Institutional Building—A Case Study. Energies. 2020; 13 (15):3877.
Chicago/Turabian StyleF. Javier Batlles; Bartosz Gil; Svetlana Ushak; Jacek Kasperski; Marcos Luján; Diana Maldonado; Magdalena Nemś; Artur Nemś; Antonio M. Puertas; Manuel S. Romero-Cano; Sabina Rosiek; Mario Grageda. 2020. "Development and Results from Application of PCM-Based Storage Tanks in a Solar Thermal Comfort System of an Institutional Building—A Case Study." Energies 13, no. 15: 3877.
This paper investigates the nucleate boiling process of dimethyl ether and selected hydrocarbons. The main goal of this study is to measure the heat transfer coefficients of RE170, R600a, and R601, and to compare them with R134a. The experiments were carried out for heat fluxes up to 70 kW/m2. Experimental results have shown a typical trend that the heat transfer coefficient of flammable refrigerants increases as the heat flux increases. Among the tested fluids, the highest values of heat transfer coefficient were obtained for RE170. Available correlations describing this coefficient showed a deviation of up to 93%, as compared to the data obtained. The new correlation was developed by regression analysis taking into account dimensionless variables affecting the boiling process.
Bartosz Gil; Beata Fijałkowska. Experimental Study of Nucleate Boiling of Flammable, Environmentally Friendly Refrigerants. Energies 2019, 13, 160 .
AMA StyleBartosz Gil, Beata Fijałkowska. Experimental Study of Nucleate Boiling of Flammable, Environmentally Friendly Refrigerants. Energies. 2019; 13 (1):160.
Chicago/Turabian StyleBartosz Gil; Beata Fijałkowska. 2019. "Experimental Study of Nucleate Boiling of Flammable, Environmentally Friendly Refrigerants." Energies 13, no. 1: 160.
This paper investigates the influence of low-pressure glow plasma water treatment on boiling phenomenon. The presented results show the novel influence and potential new applications of low-pressure glow plasma treated water. Low-pressure glow plasma water treatment affects some of its physical properties such as surface tension, pH, and electric conductivity; this is due to changes in the water structure. An experimental analysis aimed to investigate the effect of such a treatment on the boiling heat transfer coefficient of water, and to assess the stability of GPTW. The experiments were carried out at atmospheric and reduced pressure for heat fluxes up to 70 kW/m2. The analysis shows significant deterioration of the boiling heat transfer coefficient under reduced pressure. In addition, the plasma treatment process had no significant effect on the thermal conductivity of water, as confirmed experimentally. A slight increase was observed, but it was within the measuring error range of the instruments used.
Bartosz Gil; Zbigniew Rogala; Paweł Dorosz. Pool Boiling Heat Transfer Coefficient of Low-Pressure Glow Plasma Treated Water at Atmospheric and Reduced Pressure. Energies 2019, 13, 69 .
AMA StyleBartosz Gil, Zbigniew Rogala, Paweł Dorosz. Pool Boiling Heat Transfer Coefficient of Low-Pressure Glow Plasma Treated Water at Atmospheric and Reduced Pressure. Energies. 2019; 13 (1):69.
Chicago/Turabian StyleBartosz Gil; Zbigniew Rogala; Paweł Dorosz. 2019. "Pool Boiling Heat Transfer Coefficient of Low-Pressure Glow Plasma Treated Water at Atmospheric and Reduced Pressure." Energies 13, no. 1: 69.
Theoretical investigations of the ejector refrigeration system using hydrofluoroolefins (HFOs) and hydrochlorofluoroolefin (HCFO) refrigerants are presented and discussed. A comparative study for eight olefins and R134a as the reference fluid was made on the basis of a one-dimensional model. To facilitate and extend the possibility of comparing our results, three different levels of evaporation and condensation temperature were adopted. The generator temperature for each refrigerant was changed in the range from 60 °C to the critical temperature for a given substance. The performed analysis shown that hydrofluoroolefins obtain a high efficiency of the ejector system at low primary vapor temperatures. For the three analyzed sets of evaporation and condensation temperatures (te and tc equal to 0 °C/25 °C, 6 °C/30 °C, and 9 °C/40 °C) the maximum Coefficient of Performance (COP) was 0.35, 0.365, and 0.22, respectively. The best performance was received for HFO-1243zf and HFO-1234ze(E). However, they do not allow operation in a wide range of generator temperatures, and, therefore, it is necessary to correctly select and control the operating parameters of the ejector.
Bartosz Gil; Jacek Kasperski. Efficiency Evaluation of the Ejector Cooling Cycle using a New Generation of HFO/HCFO Refrigerant as a R134a Replacement. Energies 2018, 11, 2136 .
AMA StyleBartosz Gil, Jacek Kasperski. Efficiency Evaluation of the Ejector Cooling Cycle using a New Generation of HFO/HCFO Refrigerant as a R134a Replacement. Energies. 2018; 11 (8):2136.
Chicago/Turabian StyleBartosz Gil; Jacek Kasperski. 2018. "Efficiency Evaluation of the Ejector Cooling Cycle using a New Generation of HFO/HCFO Refrigerant as a R134a Replacement." Energies 11, no. 8: 2136.
Bartosz Gil; Jacek Kasperski. Performance estimation of ejector cycles using ethers and fluorinated ethers as refrigerants. Applied Thermal Engineering 2018, 133, 269 -275.
AMA StyleBartosz Gil, Jacek Kasperski. Performance estimation of ejector cycles using ethers and fluorinated ethers as refrigerants. Applied Thermal Engineering. 2018; 133 ():269-275.
Chicago/Turabian StyleBartosz Gil; Jacek Kasperski. 2018. "Performance estimation of ejector cycles using ethers and fluorinated ethers as refrigerants." Applied Thermal Engineering 133, no. : 269-275.
Bartosz Gil; Jacek Kasperski. Efficiency analysis of alternative refrigerants for ejector cooling cycles. Energy Conversion and Management 2015, 94, 12 -18.
AMA StyleBartosz Gil, Jacek Kasperski. Efficiency analysis of alternative refrigerants for ejector cooling cycles. Energy Conversion and Management. 2015; 94 ():12-18.
Chicago/Turabian StyleBartosz Gil; Jacek Kasperski. 2015. "Efficiency analysis of alternative refrigerants for ejector cooling cycles." Energy Conversion and Management 94, no. : 12-18.
Jacek Kasperski; Bartosz Gil. Performance estimation of ejector cycles using heavier hydrocarbon refrigerants. Applied Thermal Engineering 2014, 71, 197 -203.
AMA StyleJacek Kasperski, Bartosz Gil. Performance estimation of ejector cycles using heavier hydrocarbon refrigerants. Applied Thermal Engineering. 2014; 71 (1):197-203.
Chicago/Turabian StyleJacek Kasperski; Bartosz Gil. 2014. "Performance estimation of ejector cycles using heavier hydrocarbon refrigerants." Applied Thermal Engineering 71, no. 1: 197-203.
In this paper the overall performance of the solar-powered ejector air-conditioning system, using pentane (R601) and hexane (R602) as a refrigerants, is presented. The modeling process and the efficiency of solar vapor generator (SVG) were shown. The effects of condenser and generator temperatures were examined. Simulation results indicated that condensing temperature had a strong influence on the ejector's performance. Maximum overall systems’ value of COP, obtained for refrigerants R601 and R602, were 0.1 and 0.5, respectively, at Te=12°C, Tc=30°C, and G=800 W·m-2. Generator temperatures were 100–190°C for pentane and 100–200°C for hexane
Bartosz Gil; Jacek Kasperski. Performance Analysis of a Solar-powered Ejector Air-conditioning Cycle with Heavier Hydrocarbons as Refrigerants. Energy Procedia 2014, 57, 2619 -2628.
AMA StyleBartosz Gil, Jacek Kasperski. Performance Analysis of a Solar-powered Ejector Air-conditioning Cycle with Heavier Hydrocarbons as Refrigerants. Energy Procedia. 2014; 57 ():2619-2628.
Chicago/Turabian StyleBartosz Gil; Jacek Kasperski. 2014. "Performance Analysis of a Solar-powered Ejector Air-conditioning Cycle with Heavier Hydrocarbons as Refrigerants." Energy Procedia 57, no. : 2619-2628.