最新刊期
卷 47 ， 期 4 ， 2026
- 摘要：Against the backdrop of global climate change mitigation and the accelerating transition toward low-GWP refrigerants， research on alternative refrigerants for variable refrigerant flow （VRF） systems has emerged as a critical focus in refrigeration and air conditioning. This paper presents a comprehensive review of recent advances in low-GWP refrigerant replacement technologies for VRF systems. A three-dimensional analytical framework encompassing "policy-performance-technology" was developed to systematically evaluate the influence of regulatory policies in major global economies on technological pathways and to assess the thermophysical properties of alternative refrigerants such as R32 and R454B. The findings indicated that R32 offered a 2.1%-10.2% improvement in energy efficiency compared with R410A although stricter control measures were required because of its A2L flammability classification. In contrast， low-GWP refrigerants， such as R454C， met environmental requirements but resulted in a 5.9%-7.6% decline in energy efficiency. Key technological breakthroughs were reviewed， including compressor optimization， lubricant management， and long-distance refrigerant distribution. Special emphasis was placed on safety-enhancing solutions such as intelligent refrigerant charge diagnostics based on deep learning and the application of secondary loop systems to reduce the charge of flammable refrigerants. To address the challenges related to material compatibility and system integration， a phased implementation roadmap was proposed. This review provided a systematic theoretical foundation for the low-carbon transition of the VRF industry and offered valuable insights for future policymaking and technology development.关键词：variable refrigerant flow system;refrigerant substitution;safe application;system optimization551|1877|0更新时间：2026-08-06
- 摘要：This study describes the technical research results on liquefied natural gas （LNG） cold-energy utilization in recent years and highlights the advantages， disadvantages， challenges， and practical applications of these technologies. Based on the intersectionality， comprehensiveness， and practicality of applied research， this study discusses the future development trend of LNG cold-energy utilization. LNG cold-energy cryogenic-storage biotechnology is constructively proposed， and the development trend and research strategy are suggested in terms of a multi-combined generation system based on the current cogeneration system utilizing LNG. It also emphasizes the necessity of accelerating the establishment of a process experimental platform， thereby strengthening research on system performance from multiple perspectives and enhancing the safety assessment of the system. Finally， future applicable fields and overall research directions for LNG cold energy are proposed and analyzed.关键词：liquefied natural gas;cold energy recovery;cascade utilization;cryogenic technology372|2005|0更新时间：2026-08-06
- 摘要：In the context of the global energy crisis and the increasingly severe environmental pollution， the high energy consumption and carbon emissions of air-conditioning systems have become important factors restricting sustainable development. As a crucial component of air-conditioning systems， the performance of terminal devices contributes significantly to the enhancement of the overall energy efficiency of the system. This study examines the latest research progress in terminal technologies for central air-conditioning systems. It systematically reviews the core contents of various types of terminals， such as convective heat-transfer terminals （fan-coil units and variable air-volume units） and radiant heat-transfer terminals， including their operating principles， technological evolution， mathematical-model construction， intelligent-control strategies， and fault-diagnosis methods. The limitations of the existing technical systems are expounded by comparing and analyzing the performance characteristics and applicable scenarios of different terminal technologies. Based on the goals of energy-efficiency improvement and emission reduction， development directions and innovative paths for future air-conditioning terminal technologies are proposed， thus providing a theoretical basis and technical support for promoting green transformation in the fields of heating， ventilation， and air-conditioning.关键词：air-conditioning terminal;simulation;control strategy;fault diagnosis;energy-saving optimization316|3109|0更新时间：2026-08-06
- 摘要：ObjectiveCombined heat and power centralized heating can supply steam to surrounding industrial enterprises by using the steam from turbine， which is an efficient way of steam supply. However， as the supply distance increases， the temperature drop and pressure loss of the steam become severe. This study aims to propose a new absorption-compression coupled high-temperature heat pump cycle system， which uses the existing combined heat and power pipeline network to transport hot water and generates steam at the user site， effectively expanding the coverage of combined heat and power steam supply. In this paper， a thermodynamic simulation model of the heat pump system is established， and the influences of the supply water temperature of the primary network， the temperature of the micro-pressure steam， and the steam supply temperature on the performance of the heat pump are analyzed in detail.MethodsThis study combines the absorption heat exchanger with the vapor compression heat pump， and proposes an absorption-compression coupled high-temperature heat pump cycle system. This paper uses theoretical simulation methods to analyze the influence of key parameters on the performance of the heat pump system. Based on the principles of energy conservation and mass conservation， the thermodynamic steady-state model of the system is established， and the thermodynamic equations are solved using the engineering equation solver （EES） software. Through parameter sensitivity analysis， the effects of the supply water temperature of the primary network， the micro-pressure steam temperature， and the steam supply temperature on the system performance are studied.Results and Discussions The higher the supply temperature of the primary network， the greater the capacity of the absorption heat exchanger to increase the temperature， the larger the COP of the coupled system， and the lower the unit steam consumption. When the supply water temperature is 120 ℃ and the steam generated is 180 ℃， the temperature rise coefficient of the absorption heat exchanger is 0.37. The coupled system COP is 2.56， and the unit steam consumption is 292.5 kW∙h/（t/h）. Compared with the case where the supply water temperature is 95 ℃， the COP increases by 2.7%， and the unit steam consumption decreases by 2.5%. As the temperature of the micro-pressure steam increases from 75 ℃ to 100 ℃， the COP of the coupled system first increases and then decreases， and the unit steam consumption first decreases and then increases. When the temperature of the micro-pressure steam is 80 ℃， the COP of the coupled system is the maximum value of 2.6， and the unit steam consumption is the minimum value of 285.3 kW∙h/（t/h）. As the steam supply temperature increases， the COP of the coupled system monotonically decreases， and the unit steam consumption monotonically increases. When the steam supply temperature increases from 100 ℃ to 200 ℃， the COP of the coupled system decreases from 4.3 to 2.3， and the unit steam consumption increases from 166.2 kW∙h/（t/h） to 316.0 kW∙h/（t/h）.ConclusionsThe absorption-compression coupled high-temperature heat pump system proposed in this paper provides an effective solution for long-distance hot water supply to steam. The supply water temperature of the primary network， the micro-pressure steam temperature， and the steam supply temperature are the key factors affecting the system performance. This system offers a feasible approach for expanding the steam supply range of combined heat and power and improving the comprehensive energy utilization rate.关键词：high-temperature steam heat pump;absorption-compression coupling;long-distance transportation of hot water;terminal steam preparation;large temperature difference320|1701|0更新时间：2026-08-06
- 摘要：The heat pump system， as a core component of the thermal management system in new energy commercial vehicles， plays a critical role in improving vehicle range and economic efficiency through energy efficiency optimization and multi-mode cooperative control. This study employed R134a as the refrigerant and developed a multivariate cooperative control framework based on the proportional-integral （PI） control algorithm. The dynamic performance characteristics of the heat pump system under diverse environmental conditions were systematically investigated using the advanced modeling environment for simulations （Amesim）. Focusing on two typical operating scenarios： high-temperature cooling at 40 ℃ and wide-range low-temperature heating （-15 ℃ to 0 ℃）， a hierarchical control strategy integrating air-， water-， and dual-source coupled heat pump modes was proposed， along with a cascaded waste heat utilization model for motors. The results show that in the dual-target cooling mode， the system achieves simultaneous temperature control for the battery pack and cabin within 200 s， with the compressor power stabilized at approximately 7 000 W and a coefficient of performance （COP） ranging from 2.5 to 3.0. Under low-temperature heating conditions， the dual-source heat pump mode achieved a heating COP of 2.1， representing 60% energy savings over traditional PTC heating systems.关键词：electrical vehicle;commercial vehicle;heat pump;heating strategy333|1949|0更新时间：2026-08-06
- 摘要：To improve heat dissipation in the thermal management of batteries for electric vehicles， this study proposes a bionic structure based on shark scales. The design optimizes a phase-change material （PCM） heat sink in conjunction with axial air cooling to regulate battery temperature. Based on performance tests of the battery， a three-dimensional model was built to investigate and compare the heat dissipation of the battery under different conditions， including natural convection， forced convection， forced convection coupled with PCM， and forced convection coupled with bionics-optimized PCM. The results indicate that the temperature rise of the battery with the forced convection coupled with bionics-optimized PCM is only 33.6% of that with natural convection at a 2 C discharge rate， and the average temperature of the battery is 41.8 °C， which keeps the battery within a suitable temperature range. In addition， the bionic structure can reduce the pressure drop at the inlet and outlet by 4% compared with the traditional method.关键词：battery thermal management;composite phase change materials;bionic optimization;forced convection275|780|0更新时间：2026-08-06
- 摘要：Owing to the transformation of data centers toward intelligent computing， the power density per cabinet has increased， leading to an increment in the proportion of cooling-energy consumption. Reducing the power-usage effectiveness （PUE） of data centers is crucial. This study proposes a cooling system that combines natural water sources with liquid-cooling technology. Considering a data center in Laibin， Guangxi as the research object， a system model is constructed to analyze the system performance under different control methods and operating conditions. Subsequently， it is compared with conventional water-cooled chiller cooling systems. The result shows that controlling the supply-air temperature through the chilled-water pump reduces energy consumption by approximately 10% energy and facilitates waste-heat utilization. Additionally， controlling the chilled water-supply temperature through the cooling water pump is more energy efficient， although the energy-saving ratio decreases as the reservoir water temperature increases. The natural water-source cooling system achieves an annual energy-saving rate of 73.5% with a cooling load factor of 0.05， which is lower than that of the conventional system. When the supply-air temperature setpoint is higher， the system energy consumption fluctuates less. Based on a comprehensive consideration， 28 ℃ is a suitable temperature. This study provides a reference for the design of green and energy-efficient data-center cooling systems.关键词：data center;cooling system;natural water source;liquid cooling;energy-saving ratio318|1290|0更新时间：2026-08-06
- 摘要：The development of high-performance gas-gap heat switches is crucial for improving the refrigeration performance of mK sorption coolers. The effects of structural dimensions as well as cold- and hot-end temperatures on the heat-transfer performance of gas-gap heat switches were calculated and analyzed in this study， and relevant experimental studies were conducted. The results show that the heat-transfer performance of the gas-gap heat switch in the ON state primarily depends on the thermal conductivity of the gas in the gap. Reducing the gap size can improve the temperature gradient of the gas in the gap， and the thermal resistance of the heat switch operating in the 4-10 K range is reduced to 15 K/W. Additionally， the theoretical switching ratio can reach 1 100 when the gap size is reduced to 0.1 mm. The thermal insulation performance is primarily affected by the thermal conductivity and wall thickness of the support tube， with the wall thickness exerting the most significant effect. Additionally， increasing the operating temperature can enhance the thermal conductivity of the heat switch but deteriorates its thermal-insulation performance. Based on these findings， a gas-gap heat switch with a switching ratio of 822 is developed.关键词：mK refrigeration technology;helium sorption cooler;gas-gap heat switch;heat transfer performance180|710|0更新时间：2026-08-06
- 摘要：为解决热泵与电热水器能效评价指标不统一的问题，本文提出一种基于24 h动态用水实验的统一能效评价方法。通过分析我国居民热水使用习惯，建立了包含用水时间分布、温度需求和流量特征的典型用水模式，并设计了基于一次能源利用效率的统一评价指标。实验验证表明：热泵热水器一次能源效率（67.7%~99.2%）显著高于储水式电热水器（31.5%~36.4%），该方法能有效实现横向对比。关键词：heat pump water heater;storage type electric water heater;dynamic water usage mode;primary energy efficiency465|4889|0更新时间：2026-08-06
- 摘要：In recent years， the demand for high-quality fresh agricultural products， such as vegetables， has increased continuously， and the application rate of cold processing in vegetable-producing areas has increased as well， thus resulting in an increase in carbon emissions during vegetable processing. Based on existing models， this study performed sensitivity analysis to calculate the sensitivity of each parameter. The carbon-emission reduction leverage points were identified as refrigerant leakage and vegetable loss rate. Based on the key points of carbon-emission reduction， feasible paths were proposed， and the expected effects were calculated. In terms of refrigerant leakage， a green refrigerant replacement scheme was adopted， with R515B and R744 as the transitional and final solutions， respectively. Based on calculations， the transitional and final solutions can reduce carbon emissions by 28.98% and 26.78% in producing areas， respectively. In terms of vegetable quality loss， an optimization scheme for the vegetable loss rate can reduce carbon emissions by 11.48% in the producing areas. By jointly applying the optimization schemes for refrigerant leakage and vegetable loss rate， the calculation results show that using the combined optimization scheme can reduce carbon emissions by 37.62% in the producing areas.关键词：vegetables treatment;cold processing;cold chain;carbon emission reduction149|584|0更新时间：2026-08-06
- 摘要：Vapor-liquid separation technology can enhance heat transfer while reducing pressure drop. The vapor-liquid separation unit is key to achieving efficient vapor-liquid separation. A visualization experiment of the header-orifice separator is conducted in this study using the zeotropic mixture R1234ze（E）/R32 （mass fraction ratio， 80/20） to investigate the vapor-liquid separation characteristics under different conditions and obtain the effective separation range. The results show that increasing the inlet vapor quality， reducing the inlet mass-flow rate， increasing the flow cross-sectional area of the lower outlet branch， and expanding the separation aperture can improve the separation efficiency， among which the separation efficiency is most sensitive to the inlet mass-flow rate. In the effective separation area， when the flow rate increases from 18 g/s to 12 g/s， the separation efficiency increases by 14.0%. The inlet mass-flow rate， valve opening， and separation aperture minimally affects the size of the effective separation dryness range； however， for the deviation of the effective separation area dryness range， the inlet mass-flow rate exerts the greatest impact， followed by the separation aperture， whereas the valve opening exerts the least impact.关键词：header-orifice vapor-liquid separation unit;vapor-liquid separation;zeotropic mixture;separation efficiency277|1123|0更新时间：2026-08-06
- 摘要：To address the low energy efficiency and significant performance reduction under high-temperature conditions of ejector refrigeration cycles （ERCs）， this study proposed a novel booster-assisted ejector refrigeration cycle integrated with a vapor-liquid separator that exhibited a higher unit refrigeration capacity and reduced generator heat input. A thermodynamic analysis was conducted to compare the proposed cycle with two existing booster-assisted ejector refrigeration cycles， and the applicability of four environmentally friendly refrigerants was systematically evaluated. The results demonstrated that the improved cycle enhanced the performance by reducing the evaporator inlet vapor quality through vapor-liquid separation. Under typical operating conditions （generation temperature： 80 ℃， condensation temperature： 35 ℃， and evaporation temperature： 0 ℃）， the proposed cycle achieved a coefficient of performance （COP） of 1.198， showing significant improvement over conventional cycles. R1234ze（Z） was identified as the optimal refrigerant because of its low Global Warming Potential （GWP） value and superior thermodynamic properties. A parameter sensitivity analysis revealed that the COP of the improved cycle increased with rising condensation temperature （from 1.168 at 30 ℃ to 1.232 at 40 ℃）， whereas conventional cycles exhibited an opposite trend. When the generation temperature increased from 70 ℃ to 90 ℃， the COP of the improved cycle decreased by 28.6%； however， its refrigeration capacity remained higher than that of conventional cycles. This study provided a theoretical foundation for enhancing the energy efficiency of low-grade heat-driven refrigeration technologies and promoting the application of eco-friendly refrigerants.关键词：ejector refrigeration;booster;environmentally friendly refrigerants;performance comparison207|717|0更新时间：2026-08-06
- 摘要：R404A is a widely used medium-temperature refrigerant in low- and medium-temperature refrigeration systems because of its excellent efficiency and ozone-friendly properties. However， its high Global Warming Potential （GWP=3 922） has led to its scheduled phase-out by 2030. R448A has emerged as a key alternative， offering superior thermophysical properties and a significantly lower GWP. This study investigated a refrigeration system in high- and low-temperature test chambers to explore the operating conditions for the case of R404A replaced by R448A. The results showed that the cooling capacity and coefficient of performance （COP） of both systems initially increased and then decreased with increasing refrigerant charge. The optimal charge for R448A was approximately 9.3% higher than that for R404A， and its cooling capacity and COP improved by over 17%. At the same evaporation temperature， the R448A system was less sensitive to ambient temperature fluctuations. A 10 ℃ increase in ambient temperature resulted in a 16.9% decrease in cooling capacity for R404A， whereas R448A only experienced an 8.6% decrease. Additionally， the maximum COP of the R448A system was approximately 9.9% higher than that of R404A.The return on investment for R448A is approximately one year， and as the system's life cycle progresses， the total annualized cost （TAC） of R448A becomes lower than that of R404A， with annual savings ranging from 0.6% to 6.6%. Replacing R404A with R448A can reduce total carbon emissions by over 32%， with approximately 27% of this reduction attributed to refrigerant leakage during operation and end-of-life recycling.关键词：refrigerant replacement;high- and low-temperature test chambers;system characterization;carbon label;economic evaluation284|919|0更新时间：2026-08-06
- 摘要：R290 is an environmentally friendly refrigerant. However， it is flammable， making its wide application difficult. In terms of product development， to address the safety problem of refrigerant leakage in split-type air conditioners using R290， the distribution law of refrigerant leakage was explored by building an experimental platform for detecting the concentration distribution of the refrigerant after leakage， and a refrigerant leakage response system was developed to determine the optimal detection location of the sensor. The experimental results show that when the refrigerant leaks rapidly， it forms explosive clouds above the air conditioner. These explosive clouds can be effectively eliminated by starting the fan and controlling the air outlet angle. However， when the air volumetric flow rate is less than 55% of the standard minimum air volumetric flow rate， the leaked refrigerant cannot be evenly diffused. The selection conditions for the optimal detection position were determined experimentally， and effective explosion-proof measures were formulated that can achieve a rapid response within 17 s， with no explosion risk area. This study provides guidance for the application of R290 and the development of related products.关键词：R290;refrigerant leakage;Explosion-proof measures;split-type air-conditioner444|1540|0更新时间：2026-08-06
- 摘要：To solve the problems of the slow growth rate and low cold thermal energy storage density of refrigerant hydrates， the addition of surfactants is an effective way to promote hydrate formation. Three polyoxyethylene castor oil （EL） surfactants with different hydrophilic-lipophilic balance （HLB） values （EL-20， EL-30， and EL-60） were selected as promoters to study their effects on HCFC-141b hydrate formation. The experimental results showed that the EL series of surfactants significantly reduce the hydrate nucleation induction time. The system with a mass fraction of 1.5% EL-20 exhibited the shortest hydrate induction time of 73 min， and the stability of hydrate formation was good. The micelles formed by the EL surfactants provide more nucleation sites， which accelerate hydrate formation. The hydrate cold thermal energy storage density is related to the HLB value of the surfactants. The system with a mass fraction of 1.5% EL-20 had the maximum cold thermal energy storage density of 246.48 kJ/kg and the fastest hydrate growth rate of 5.06 kJ/（kg·min）， as EL-20 had a suitable HLB value. There is a "memory" effect during hydrate formation and dissociation cycle. The system with a mass fraction of 1.5% EL-20 surfactant exhibited the most favorable performance during the hydrate formation and dissociation cycles. After seven hydrate formation and dissociation cycles， the increase in temperature remained stable during hydrate formation.关键词：hydrate;surfactant;HCFC-141b;Induction time;cold thermal energy storage140|549|0更新时间：2026-08-06
- 摘要：Conventional distillation methods face significant challenges in xenon isotope separation. This paper proposes a cascaded distillation system based on a microchannel distillation （MCD） apparatus for 136Xe enrichment. The relative volatilities， saturation vapor pressures， and enthalpies of vaporization of the nine Xe isotopes were determined， and a corresponding pseudo-component model was validated in Aspen Hyprotech Systems （HYSYS）. A ternary model was then used to optimize the MCD parameters， identifying the optimal operating pressure， reflux ratio， and feed-to-product ratio effects on enrichment efficiency and reboiler power consumption. Subsequent optimization via uniform design， stepwise quadratic regression， non-dominated sorting genetic algorithm （NSGA）-III， and the technique for order preference by similarity to an ideal solution （TOPSIS） reduced power consumption while increasing 136Xe abundance from 8.670% to 13.347%. This microchannel cascaded distillation system overcomes conventional limitations and offers a novel and efficient approach for 136Xe enrichment with significant theoretical and practical implications.关键词：isotope separation;cryogenic rectification column;microchannel;genetic algorithm220|896|0更新时间：2026-08-06
- 摘要：Silica gel desiccant wheel is the main dehumidification technology to realize humidity control of ambient air. Optimizing the wheel size and reducing the operating energy consumption are necessary trends in technology development. In this study， based on computational fluid dynamics （CFD）， we first established and verified a three-dimensional dynamic simulation model of the dehumidification and regeneration process of the desiccant wheel. We conducted a dynamic simulation for the silica gel desiccant wheel used for the protection of bridge cables. We then analyzed and discussed the influence of wheel thickness， wind speed， and regeneration wind volumetric flow rate and temperature on the moisture removal capacity （MRC） and specific energy consumption （SEC） to optimize the design of the desiccant wheel. The results showed that the optimal thickness increased with the increase in wind speed. Compared with the original design， the optimized wheel improved the average MRC by approximately 10% while reducing the SEC by approximately 15%， demonstrating the effectiveness of geometry optimization. Notably， the SEC decreased with increasing regeneration temperature. Therefore， in practical design， the regeneration temperature should be selected in accordance with the dehumidification requirements and maintained as low as feasible to enhance the overall economic performance.关键词：silica gel desiccant wheel;CFD;design optimization;dehumidification;energy saving and emission reduction172|1051|0更新时间：2026-08-06
- 摘要：Human thermal regulation models reflect the physiological response of the human body to the surrounding thermal environment. However， existing thermal regulation models do not account for the non-uniform impact of solar radiation on indoor thermal environments and the human body. Therefore， a new model was established by modifying the thermal regulation model of the human body to include local exposure to direct sunlight in buildings. First， the calculation of mean radiant temperature was revised by distinguishing direct and indirect areas. Second， the calculations of skin and clothing temperatures and heat loss in the model were modified by distinguishing direct and indirect parts. In addition， solar radiation heat gain was added to the heat transfer calculations. After experimental verification， the modified model demonstrated a relative error of less than 5% in predicting mean skin temperature， and approximately 4% in predicting total heat loss. Using the model， the mean skin temperature at different activity levels was predicted， and the thermal comfort zone offset laws of the human body as a whole and in direct parts were explored at different solar radiation intensities. The results show that the acceptable air temperature of the overall body at 400 W/m2 is 2 ℃ lower than that at 200 W/m2. This study provides a theoretical basis for zoning control of indoor environments under direct sunlight.关键词：thermal regulation model;indoor thermal comfort;solar radiation;thermal comfort zone;mean skin temperature168|1240|0更新时间：2026-08-06
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