Yuming Zhao¹, Jing Wang¹, Bin Sun², Zhenshang Wang¹, Huashan Li², Jiongcong Chen^2,*

Frontiers in Heat and Mass Transfer, Vol.22, No.4, pp. 1171-1188, 2024, DOI:10.32604/fhmt.2024.054594 - 30 August 2024

Abstract Data centers (DCs) are highly energy-intensive facilities, where about 30%–50% of the power consumed is attributable to the cooling of information technology equipment. This makes liquid cooling, especially in two-phase mode, as an alternative to air cooling for the microprocessors in servers of interest. The need to meet the increased power density of server racks in high-performance DCs, along with the push towards lower global warming potential (GWP) refrigerants due to environmental concerns, has motivated research on the selection of two-phase heat transfer fluids for cooling servers while simultaneously recovering waste heat. With this regard,… More >

Zakaria Triki¹, Ahmed Selloum¹, Younes Chiba¹, Hichem Tahraoui^1,2, Dorsaf Mansour³, Abdeltif Amrane^4,*, Meriem Zamouche⁵, Mohammed Kebir⁶, Jie Zhang⁷

Frontiers in Heat and Mass Transfer, Vol.22, No.4, pp. 1107-1128, 2024, DOI:10.32604/fhmt.2024.052223 - 30 August 2024

Abstract Refrigeration plays a significant role across various aspects of human life and consumes substantial amounts of electrical energy. The rapid advancement of green cooling technology presents numerous solar-powered refrigeration systems as viable alternatives to traditional refrigeration equipment. Exergy analysis is a key in identifying actual thermodynamic losses and improving the environmental and economic efficiency of refrigeration systems. In this study exergy analyze has been conducted for a solar-powered vapor compression refrigeration (SP-VCR) system in the region of Ghardaïa (Southern Algeria) utilizing R1234ze(E) fluid as an eco-friendly substitute for R134a refrigerant. A MATLAB-based numerical model was… More >

Rachedi Khadraoui¹, Latra Boumaraf^1,*, Philippe Haberschill²

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.5, pp. 1115-1128, 2023, DOI:10.32604/fdmp.2022.022674 - 30 November 2022

Abstract A theoretical investigation is presented about a double evaporator ejector refrigeration cycle (DEERC). Special attention is paid to take into account the influence of the sub-cooling and superheating effects induced by an internal heat exchanger (IHX). The ejector is introduced into the baseline cycle in order to mitigate the throttling process losses and increase the compressor suction pressure. Moreover, the IHX has the structure of a concentric counter-flow type heat exchanger and is intentionally used to ensure that the fluid at the compressor inlet is vapor. To assess accurately the influence of the IHX on More > Graphic Abstract

Yuchen Yang^1,2, Lin Ma^1,2,*, Jie Yu^1,2, Zewen Zhao^1,2, Pengfei You^1,2

Journal of Renewable Materials, Vol.11, No.3, pp. 1153-1179, 2023, DOI:10.32604/jrm.2022.022719 - 31 October 2022

Abstract The use of nanorefrigerants in Organic Rankine Cycle (ORC) units is believed to affect the cycle environment performance, but backed with very few relevant studies. For this purpose, a life cycle assessment (LCA) has been performed for the ORC system using nanorefrigerant, the material and energy input, characteristic indicators and comprehensive index of environmental impact, total energy consumption and energy payback time (BPBT) of the whole life cycle of ORC system using Al₂O₃/R141b nanorefrigerant were calculated. Total environmental comprehensive indexes reveal that ECER-135 index decrease by 1.5% after adding 0.2% Al₂O₃ nanoparticles to R141b. Based on… More >

Xiao Wu^*, Zhaoting Wang, Longfei Dong, Yanping Xin, Tianshu Yu

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.1, pp. 25-36, 2023, DOI:10.32604/fdmp.2023.020953 - 02 August 2022

Abstract The Mixed Refrigerant (MR) component is an important factor influencing the performances of natural gas liquefaction processes. However, there is a lack of systematic research about the utilization of propane pre-cooled (C3/MRC). In this paper, this mixed refrigerant cycle liquefaction process is simulated using the HYSYS software and the main influential parameters involved in the process are varied to analyze their influence on the liquefaction rate and power consumption. The results show that an effective way for lowering the power consumption of the compressor consists of reducing the flow through the compressor through optimization of More >

Vijay W. Bhatkar^a,*, Anirban Sur^b,*, Anindita Roy^b

Frontiers in Heat and Mass Transfer, Vol.19, pp. 1-7, 2022, DOI:10.5098/hmt.19.15

Abstract Versatile vapor compression refrigeration system is designed, developed and fabricated such that desired condensing and evaporating temperatures can be obtained by providing different electronic controls for superheating, subcooling, fan speed, air heaters and water heatersto use alternative refrigerants to R134a such as R1234ze, R152a, R600a, R290 and R290/R600a (50/50%) with conventional and minichannel condenser. All the refrigerant are tested for condensing temperature ranging from 40 °C to 55 °C while evaporating temperature changes from -10 °C to 15 °C for both condensers. The total exergy loss for main system components such as compressor, condenser, expansion… More >

Aparna Kottapallia , Ramakrishna Konijeti^b,*

Frontiers in Heat and Mass Transfer, Vol.19, pp. 1-11, 2022, DOI:10.5098/hmt.19.11

Abstract Scroll technology is widely used in refrigerators as compressors. This research paper presents the performance of a scroll-type expander derived from a scroll compressor. The research is carried out at low pressures. The effect of mechanical load on performance has been evaluated using compressed air as a working fluid. Two stages of the evaluation process are carried out in this research. In the first stage, the scroll expander model is numerically simulated using the CFD approach to predict the factors influencing the scroll expander performance. In the later stage, an experiment is carried out on… More >

Ammar Hassan Soheel, Omar Mahmood Jumaah, Ahmed Mustaffa Saleem^*

Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-7, 2021, DOI:10.5098/hmt.17.21

Abstract This paper presents a simulation and investigation of the heat transfer coefficient, pressure drop, and thermal conductivity of two - phase flow. The simulation was performed of mixtures (Al₂O₃ nanoparticles with R134a refrigerant). The size of nanoparticles (Al₂O₃) which is used in this study is 30 nm and volume concentrations are 0.015 and 0.03. The two – phase flowing through a horizontal circular microchannel of (diameter 100 µm, and length 20 mm) under constant heat flux (3000 W/m²) and constant wall temperature (330 K), also in this study used the inlet temperature at -20 oC and mass… More >

Piyanut Saengsikhiao¹, Juntakan Taweekun^1,2,*, Kittinan Maliwan², Somchai Sae-ung², Thanansak Theppaya²

Energy Engineering, Vol.118, No.2, pp. 411-433, 2021, DOI:10.32604/EE.2021.012860 - 23 December 2020

Abstract This paper presents the improvement of eco-friendly and power consumption saving refrigerants for refrigeration systems. The novel azeotropic refrigerant mixtures of HFCs and HCs can replace refrigeration systems, and using the R134, R32, R125, and R1270 refrigerants in several compositions found using the decision tree function of the RapidMiner software (which came first in the KDnuggets annual software poll). All refrigerant results are mixed of POE, which is A1 classification refrigerant, non-flammable, and innocuous refrigerant, and using REFPROP software and CYCLE_D-HX software are under the CAN/ANSI/AHRI540 standards. The boiling point of the new refrigerant mix… More >

Rongge Xiao^a,*, Yanwei Zhang^a , Xu Gao^b , Hongping Yu^c , Wangying Wei^a

Frontiers in Heat and Mass Transfer, Vol.15, pp. 1-8, 2020, DOI:10.5098/hmt.15.22

Abstract In order to improve DMR (double mixed refrigerant) liquefaction process and reduce operation cost of natural gas liquefaction plant, a four-stage DMR process optimization simulation calculation model was established through Aspen Hysys v8.4 and the purpose of the optimization model is achieved by using the segmented compression process in this paper. The minimum energy consumption and the highest exergy efficiency were used as the objective functions. By using the optimizer in HYSYS, the process parameters and ingredient proportion of the mixed refrigerant in the fourstage DMR process was optimized, and the best process parameters and More >