Journal of Refrigeration
ISSN (online) 2097-650X
ISSN (print) 0253-4339
CN 11-2182/TB
Superintended:China Association for Science and Technology
Sponsored:Chinese Association of Refrigeration
Published:Journal of Refrigeration Magazines Agency Co., Ltd.
Quick Entry
Author
Reviewers
Editors
Subscription
- Latest Articles
- Online First
- Archive
2026年第47卷第2期
- 摘要：ObjectiveBattery thermal management is crucial for ensuring the performance， safety， and longevity of batteries， particularly in electric vehicles and energy-storage systems. Direct air-cooling systems are widely used because of their simplicity， cost-effectiveness， and reliability. However， while increasing the air velocity leads to a higher heat-dissipation efficiency， it also leads to higher power consumption and noise. This study aims to experimentally and numerically analyze the flow and heat transfer characteristics of a typical flat fin-and-tube heat exchanger used in battery thermal management. This research focuses on investigating the effects of operational parameters， including air velocity， temperature difference between the coolant and air， and coolant mass flow rate， on the heat transfer performance.MethodsBoth experimental and numerical approaches were employed to evaluate the heat transfer performance of the heat exchanger. The experimental setup featured a copper-fin and 316L stainless steel tube unit with two fans to enhance forced convection， and tests were conducted across air velocities of 2.1-6.1 m/s， coolant-to-air temperature differences of 20-40 ℃， and coolant mass flow rates of 0.35-0.55 kg/s. The performance was evaluated using the heat transfer coefficients， pressure drops， and overall heat dissipation rate， with an uncertainty of 6.5% and repeatability within 2.2%. A three-dimensional steady-state CFD model of a unit was developed by adopting no-slip wall conditions， symmetry/periodic boundaries， and wall contact resistance with the corresponding boundary conditions. Mesh independence was achieved with approximately 1.41 million cells， solver residuals established at 10⁻⁷， and parametric analysis was conducted for tube outer diameters ranging from 3 mm to 6 mm and bundle spacings from 7 mm to 11 mm.Results and DiscussionsThe results illustrate the effects of air velocity， temperature difference， and coolant mass flow rate on the thermohydraulic performance of the heat exchanger. As the air velocity increases， the airside heat transfer coefficient improves owing to the enhanced convective heat transfer， with a maximum increase of 102.1% in the 2.1-6.1 m/s velocity range. Similarly， increasing the temperature difference from 20 ℃ to 40 ℃ leads to a rise in the heat transfer coefficient by 19.1% to 28.9%， showing a nearly linear relationship. A higher coolant mass flow rate enhances the heat transfer rate， leading to a proportional increase in the heat transfer coefficient. Numerical simulations confirm these trends and provide insights into the flow behaviors， including the formation of cross-flow vortices that enhance heat transfer， particularly at higher air velocities. The simulations also reveal that transverse vortices form in the fin gaps， which shrink with increasing air velocity. Furthermore， the simulation results indicate that the optimal pipe diameter for maximizing heat transfer performance is 6 mm， with a tube bundle pitch of 9 mm.ConclusionsThis study concludes that the air velocity， coolant temperature difference， and coolant mass flow rate are the primary factors influencing the heat transfer performance of flat fin-and-tube heat exchangers for battery thermal management. Both the experimental and numerical results indicate that increasing the air velocity and coolant mass flow rate significantly enhances the heat transfer. Furthermore， the temperature difference between the coolant and air directly affects the heat transfer coefficient. Based on these findings， the optimal heat exchanger design should have a pipe diameter of 6 mm and tube bundle pitch of 9 mm. This configuration provides the optimum heat transfer performance and is recommended for improving the efficiency of air-cooled thermal management systems for high-performance battery applications.关键词：heat transfer performance;flat fin-and-tube heat exchanger;battery thermal management system;air cooling648|974|0更新时间：2026-03-30
- 摘要：Although hydrofluorocarbons （HFCs） do not deplete the stratospheric ozone layer， a few of these have high Global Warming Potentials （GWPs） ranging from 12 to 14 000. At present， these chemicals are widespread in air conditioners， refrigerators， aerosols， foams， and other products. This study systematically analyzed HFC allowance allocation systems and the practical experiences from the European Union and United States. The focus is on analyzing HFC control concepts， quota allocation mechanisms， and calculation rules in the EU and US， as well as the characteristics of the two systems. It has been observed that both the EU and US have adopted synergistic approaches to protect the ozone layer and address climate change. They jointly promote the implementation of the Kigali Amendment and achievement of climate neutrality goals， and reduce HFCs through economic measures and market mechanisms. Specifically， the EU was the first to adopt paid quotas， thereby strengthening the market constraints. Meanwhile， the US flexibly used market tools， including free quotas with a quota transfer offset system. Additionally， both have established quota-accounting methods based on the GWP values of substances， and the US has developed a toolbox for HFC quota allocation. China implemented the HFCs quota licensing system in 2024. The experiences of the HFC allowance allocation systems in the EU and US can provide references for China's compliance with the Kigali Amendment.关键词：HFCs;quota;Kigali Amendment;the European Union;the United States454|842|0更新时间：2026-03-30
- 摘要：Superfluid helium （4He） exhibits special phenomena such as anomalous thermal conduction, fountain, and crawling film effects at sub-Kelvin temperatures owing to its quantum properties. Dilution refrigerators utilize 3He as the working fluid for circulation. 3He produces cooling effects as it passes through the phase interface in the mixing chamber. It is then pumped out by a room-temperature pump after evaporation in the still chamber. The superfluid helium inside the still chamber forms a liquid film on the wall and flows toward higher temperatures. This results in significant heat leakage owing to its anomalous thermal conductivity. The superfluid helium liquid film also affects the purity of 3He during the circulation process, thereby influencing the cooling capacity of the dilution refrigerator. The “knife-edge” and “small orifice” structures are the primary means for suppressing superfluid helium films. This study analyzed the impact of the purity of the working fluid 3He on the cooling capacity of the dilution refrigerator and the limitation placed on the system's 3He circulation flow rate by the size of the “small orifice”. Experimental tests were conducted to measure the mass flow rate of the superfluid helium crawling film at 0.95 K with two types of suppression structures: “small orifice” and “knife-edge with small orifice”. The use of “knife-edge with small orifice” resulted in a 35.6% improvement in the suppression effect of the superfluid helium crawling film compared with the use of “small orifice” alone.关键词：dilution refrigerator;superfluid helium film flow;knife-edge;small orifice492|799|0更新时间：2026-03-30
- 摘要：With the expansion of air-source heat pump （ASHP） heating systems， ASHP arrays have become the primary arrangements for medium-to large-scale heating projects. However， the "cold island effect" and "wet island effect" are likely to form at the center of the ASHP arrays. This results in frequent frosting and defrosting in the heat pump units. Conversely， the frequent frosting and defrosting also influence the "cold and wet island effect" in the ASHP array. To evaluate the mutual influences between the "cold and wet island effects" and the phenomena of frosting and defrosting， this study performed an investigation based on a demonstration project using ASHP array in Weihai， Shandong Province. The study established a field-testing platform and conducted field measurements. Typical day-testing results indicate that under the influence of the "cold and wet island effect"， the defrosting frequency of ASHP unit at the center of the array increased by 225% compared with those on the periphery. Frequent defrosting reduced the intensity of the cold island effect of the central units by 4.3% and increased the wet island effect intensity by 3.9%. However， the effect was not significant. Additionally， the nominal heating capacity loss coefficient during the frosting-defrosting cycle for the central units increased by 59.3%， and their average heating capacity and COP decreased by 31.6% and 34.0%， respectively， compared with the peripheral units. This indicates a significant performance degradation in the central units.关键词：air-source heat pump array;cold and wet island effects;frosting and defrosting;field tests456|940|0更新时间：2026-03-30
- 摘要：To resolve the issues of significant throttling loss and performance degradation of a baseline transcritical CO2 air-source heat pump system （Base） for building space heating， an ejector subcooling transcritical CO2 air-source heat pump system （ESH） driven by the waste heat of the compressor discharge gas is proposed in this paper. The thermodynamic performance of the ESH system was optimized and analyzed using four working fluids. Five typical cities were selected for comparison， and the heating season performance factor （HSPF） was analyzed. The results reveal that the coefficient of performance （COP） of the ESH system first increased and then decreased with the increase of discharge pressure， and an optimal discharge pressure exists. Compared with the Base system， the ESH system using R1234ze（Z） displayed the most remarkable improvement in COP （with the highest increase of 20.64%）. The discharge pressure of the ESH system reduced by up to 9.20% compared with that of the Base system， and the exergy efficiency increased by 7.13%-18.61%. The HSPF of the ESH system was 9.68% to 14.21% higher than that of the Base system. The performance improvement was higher when it was used in severely cold regions.关键词：transcritical CO2;ejector subcooling;waste heat of discharge gas;air-source heat pump;heating season performance factor187|300|0更新时间：2026-03-30
- 摘要：Because the driving method of electric vehicles differs from that of conventional ones， the power sources of electric vehicles can be diversified. The Global Warming Potential （GWP） and ozone depletion potential （ODP） values of the refrigerant R290 are lower than those of R134a. Consequently， R290 has become an important option for electric vehicle air-conditioners. In this study， an electric vehicle air-conditioning compressor test system was set up to study the compressor performance of two refrigerants （R134a and R290） under variable evaporating temperatures， condensing temperatures， and compressor speeds. The simulated and experimental values for the two refrigerants were also analyzed. The results reveal that the condensing temperature significantly affected the compressor powers of R134a and R290. As the condensing temperature increased by 1 ℃， the compressor power increased by ~3%. The evaporating temperature had a smaller effect on the compressor powers of R134a and R290： as the evaporating temperature increased by 1 ℃， the compressor power decreased by ~0.3%. The prediction errors of compressor power for R134a and R290 were approximately 5% and 10%， respectively. For the same temperature difference， the compressor performance of R290 was significantly better than that of R134a. Furthermore， the isentropic and volumetric efficiencies of R290 were 10%-15% and 6%-9% higher， respectively. At the same pressure ratio， the compressor performance of R290 was similar to that of R134a. In addition， the compressor performances of R290 and R134a were essentially the same at different compressor speeds. However， further optimization is necessary for the applicability of semi-empirical simulation models in variable-speed compressors， particularly at high compressor speeds.关键词：R290;compressor;isentropic efficiency;volumetric efficiency;simulation model966|922|0更新时间：2026-03-30
查看更多
- Virtual Special Issue
- Special Column
- Video
Microchannel Heat Transfer Technology
12 Jan 2026
Thermoelectric Refrigeration Technology
22 Aug 2025
Cryogenic Technology
3 Mar 2025
Compressor Technology
20 2024
Dehumidification Technology
11 Mar 2024
- Address：10/F, Yindu Mansion, 67 Fucheng Road, Haidian Dist, Beijing, China Postal code：100142
- Tel：010-68711412 Email：editor@car.org.cn
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备09064830号-19
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0