最新刊期
卷 47 ， 期 5 ， 2026
- 摘要：Under the backdrop of the "dual carbon" strategy， the efficient cascade utilization of liquefied natural gas （LNG） cold energy plays a critical role in facilitating the low-carbon transition of the energy structure and promoting resource recycling. This study systematically reviews the technological progress， application scenarios， and future challenges. Based on a technology maturity assessment framework， comprehensive cold-energy utilization schemes used in different scenarios are proposed. Current research indicates that the cold energy released during LNG regasification can be efficiently recovered through cascade utilization across three temperature ranges， i.e.， deep cryogenic （-162 ℃ to -100 ℃）， mid-cryogenic （-100 ℃ to -50 ℃）， and low cryogenic （-50 ℃ to 0 ℃）. Current mainstream technologies include cold-energy power generation， air separation， freezing/cold storage， and CO2 capture. Among these， air separation has the highest maturity （TRL9）， with large-scale applications achieved in multiple domestic receiving terminals. Cold-energy power generation （TRL8） has significantly improved the efficiency through combined cycle optimization； however， the challenges remain in terms of the system complexity and stability. It is found that the LNG cold-energy utilization rate in China is generally low and is primarily constrained by significant volatility， an uneven spatiotemporal distribution， weak process coupling， and insufficient industrial chain coordination. Future efforts should be focused on three key directions： optimizing the construction layout by establishing the industrial parks for onsite cold-energy consumption， constructing a comprehensive evaluation system to promote the efficient cascade utilization of cold energy with multimode collaboration， and enhancing the flexibility and stability of cold-energy utilization by developing energy-storage systems. This study provides recommendations and guidances for the technological optimization and industrial development of LNG cold-energy cascade utilization.关键词：LNG cold energy;cascade utilization;technology readiness level （TRL）;application scenarios566|2794|0更新时间：2026-10-13
- 摘要：This study performs multiple simultaneous fault （MSF） experiments on refrigeration and air-conditioning systems， including refrigerant undercharge （RU）， refrigerant overcharge （RO）， condenser fouling （CF）， and evaporator fouling （EF）， under conditions that include various combinations of fault types and severity levels. Fault-decoupling models based on the virtual refrigerant charge and virtual airflow rate are evaluated. In addition， a Bayesian classification-based approach for establishing fault-decoupling thresholds is proposed， and the decoupling accuracy under different double- and triple-fault combinations is quantitatively assessed. The results demonstrate that RU and RO should be decoupled separately to achieve a decoupling accuracy of 100%. However， the practical application of mixed models often leads to misdiagnoses. The virtual airflow rate model achieved a decoupling accuracy exceeding 94.38% for single faults and MSFs related to CF and EF. However， it failed to distinguish specific fault severity levels. Further， under severe RU conditions， two-phase refrigerant at heat exchanger outlets significantly impacted working fluid parameters， leading to the failure of decoupling fouling faults. Moreover， RO increased the condensation temperature and widened the temperature differential between fluids inside and outside the heat exchangers， resulting in larger calculation errors for the virtual airflow rate and a substantially reduced decoupling accuracy.关键词：refrigeration and air conditioning;concurrent faults;virtual sensor;Bayesian classification;fault decoupling91|764|0更新时间：2026-10-13
- 摘要：Efficient fault diagnosis of metro train air-conditioning systems is essential for reducing energy consumption and ensuring passenger comfort. This paper proposes an unsupervised transfer learning method based on a domain-adversarial neural network （DANN） to address the challenges involving diverse feature distributions and complex faults. Data obtained from three single faults （condenser fouling， ventilation fouling， and refrigerant leakage） and their concurrent combinations are collected from a multifunctional test vehicle under various operating conditions and compressor frequencies. The DANN achieved accuracy values ranging from 97.30%-98.90% for single faults and 77.80%-86.70% for concurrent faults. Uniform manifold approximation and projection （UMAP） and SHapley Additive exPlanations （SHAP） analyses revealed the underlying reasons for the less accurate concurrent fault diagnosis. Compared with the two baseline transfer learning models， DANN exhibited markedly smaller performance fluctuations， maintaining high accuracy， even under large feature distribution shifts and overlapping concurrent fault features.关键词：subway air conditioning;fault diagnosis;transfer learning;domain-adversarial neural network102|777|0更新时间：2026-10-13
- 摘要：Refrigerant leakage from a refrigeration system not only degrades the system performance and increases the energy consumption， but aggravates environmental hazards and safety risks because of the high global warming potential or flammability of many refrigerants. Therefore， fast and accurate methods are required to detect and rectify refrigerant leaks. This study focuses on a domestic air-conditioning refrigeration system with a cooling capacity of 3.5 kW. Using simulation methods， the dynamic evolution laws of the key node parameters of each component and the system performance parameters under different leakage rates are analyzed quantitatively. Based on the findings， a prediction model of refrigerant inventory is developed for the key components. This model， integrated with the operational data， provides a new leakage detection and diagnosis method based on system modeling. This method aims to evaluate the severity of leakage using a small amount of leakage data. The developed inventory prediction equation of refrigerant charge maintains the prediction uncertainty within ±5% when the leakage rate is below 12%.关键词：refrigerant leakage;refrigerant inventory;refrigeration system;leakage detection123|182|0更新时间：2026-10-13
- 摘要：To achieve the efficient recovery and utilization of low-grade waste heat from data centers， this study systematically investigates the adsorption-desorption characteristics and refrigeration performances of the PbCl2 composite adsorbent -NH3， and establishes a novel system-scale kinetic model. The results indicate that at an ambient temperature of 30 ℃， the PbCl2 adsorbent achieves a cyclic adsorption capacity of 0.295 g/g at 52 ℃， with effective adsorption observed within the evaporating temperature range of 10 ℃ to 25 ℃. The coefficient of performance （COP） of the system increases from 0.26 to 0.44 with the increase of evaporating temperature. There is an optimal range for the desorption temperature， and the comprehensive performance is optimized at 48 ℃. With respect to kinetic modeling， although the pseudo-second-order model adequately described the adsorption process， it exhibited substantial fitting errors during desorption. While the Sigmoid model better captures the typical unimodal kinetic behavior， it lacks the accuracy when describing the variations of initial rate. In contrast， the newly proposed model of incomplete Gamma function， which has a flexibly adjustable shape factor and time-scale coefficient， can control the curve morphology and tailing behavior， achieving goodness of fit values of 99.1% and 97.3% for the adsorption and desorption processes， respectively. This model can accurately characterize the entire kinetic process， effectively overcoming the shortcomings of traditional models， such as large parameter fluctuation， complex calculation， and poor adaptability at the system scale. The proposed model provides theoretical support for the modeling optimization and engineering application of low-temperature adsorption refrigeration systems.关键词：data center waste heat;adsorption refrigeration;PbCl2 composite adsorbent;kinetic model;Gamma function106|402|0更新时间：2026-10-13
- 摘要：To address the common problems associated with traditional chemisorption sorbents， including their loose structure， lack of effective heat and mass transfer pathways， and poor cycling stability， this study developed a novel graphene-based composite sorbent. By embedding strontium chloride （SrCl2） into a three-dimensionally interconnected graphene network， continuous and efficient channels for heat conduction and mass transfer were constructed， significantly enhancing the sorbent's cycling stability and thermophysical transfer performance. The composite sorbent achieved a high ammonia uptake， of 0.577 g/g， at an evaporation temperature of -10 ℃， reaching 84.1% of the theoretical value. The specific cold storage capacity reached 639.89 kJ/kg， which is 1.9 times that of ice storage. Under a desorption condition driven by a 90 ℃ heat source， the ammonia desorption capacity reached 0.572 g/g. In isobaric desorption experiments that simulates hot water supplied by a non-concentrated solar collector， over 90% of the cold storage process was completed within 4 h of stable sunlight. The proposed graphene-based composite sorbent demonstrated excellent performance in terms of both energy storage density and cyclic stability， thus providing solid technical support for engineering applications of solar-driven chemisorption cold storage systems.关键词：sorption cold energy storage;solar energy;composite sorbent;energy storage density;constant pressure desorption182|597|0更新时间：2026-10-13
- 摘要：The transcritical CO₂ heat pump system is regarded as a promising technical solution for the integrated thermal management of passenger cabins and power batteries in electric vehicles owing to its high efficiency and environmental friendliness. An efficient system control strategy not only significantly affects the vehicle's driving range， but also enhances cabin thermal comfort. This paper proposed a model predictive control （MPC）-based solution， in which white noise was applied as an excitation signal to a one-dimensional simulation model of a heat pump system to efficiently construct an explicit system model suitable for MPC implementation. Furthermore， a dynamic-feedback-correction-based MPC algorithm （DFC-MPC） was introduced. The proposed method demonstrated significant improvements in system performance： compared to conventional PI control， overshoot was reduced by 76.8% in cooling mode and 80.1% in heating mode， while the system COP （coefficient of performance） was improved by 8.33% and 1.07%， respectively. Moreover， this method enhanced the real-time protection of the compressor， thereby providing a reference for the implementation of intelligent control in real-vehicle thermal management systems.关键词：model predictive control;electric vehicle;CO₂ heat pump system;dynamic simulation171|1268|0更新时间：2026-10-13
- 摘要：This study systematically investigated the heat transfer performance of gyroid structures with four different porosities （55%， 65%， 75%， and 85%） using conjugate heat transfer numerical simulations and elucidated the underlying heat transfer mechanisms. This research demonstrates that gyroid structures enhance heat exchange by disrupting airflow channels to intensify turbulence and effectively break down the thermal boundary layer near walls， thereby reducing thermal resistance. As porosity decreased， heat transfer efficiency from the heat source to the gyroid structure continually improved， accompanied by an increase in the convective heat transfer coefficient and Nusselt number. However， the friction factor increased significantly. By employing the
- 摘要：With the expansion of air-source heat pump （ASHP） heating systems， ASHP arrays have become the main arrangement for medium-to large-scale heating projects， and their scales continue to expand with the increased demand for heating. However， larger array scales intensify the "cold and wet island （CWI） effect" at the array center， significantly reducing the unit efficiency and threatening the system stability. To investigate the variations of the CWI effect with array scale in ASHP systems， a field-testing platform is established based on two ASHP heating projects with different scales in Weihai， China. Tests under both typical daily and long-term conditions show that increasing the array scale from 44 to 64 units raises the average cold island and wet island intensities at the array center by 1.5-2.7 ℃ and 0.3-0.9 ℃， respectively. The defrost frequency is increased by 10-20 times， with average heating capacity declined by 12.2%-19.4%， COP decreased by 15.7%-16.6%， and heating loss coefficients increased by 0.05-0.07. These results indicate a significant intensification of the CWI effect at the center， leading to more frequent defrosting and reduced heating performance. In contrast， peripheral units show the negligible changes in CWI intensities， heating capacity， COP， and defrosting losses. This study quantifies the CWI effect at different array scales， providing data support for the large-scale application and efficient operation of ASHP systems.关键词：air-source heat pump;cold and wet island effect;array scale;field test;heating performance91|486|0更新时间：2026-10-13
- 摘要：To quantitatively investigate the heat transfer and flow performances of capillary heat exchanger for the seawater-source heat pump， an experimental system was constructed in this study. Various experimental conditions were tested to quantitatively analyze the effects of different factors such as the in-tube flow velocity of the capillary， in-tube medium， tube material， temperatures inside and outside the tube， and seasonal changes in the performances of the capillary heat exchanger. The accuracies of the traditional empirical correlation equations for quantifying and evaluating the heat-transfer performance of capillary heat exchanger were analyzed， and the in-tube empirical correlation equations were modified. The research results showed that the average heat-transfer coefficient and efficiency of the capillary heat exchanger were approximately 91.3 W/（m2·℃） and 87%， respectively. When the in-tube flow velocity of the capillary was 0.11 m/s， the maximum pressure drop was only 8.2 kPa. In addition， the heat transfer coefficient calculated by the traditional empirical correlation equations was higher than the experimental value， where the discrepancy was more obvious at high flow velocities. The modified empirical correlation equation for heat transfer could reduce the maximum simulation error from 17.5% to 3%. This study also conducted a correlation analysis between the operational parameters and performance indices of a capillary tube heat exchanger based on the experimental data， and then determined the optimal operational conditions for winter and summer by combining the research results and seasonal requirements. This research provides guidance for the design and operation of capillary heat exchanger in seawater-source heat pump system.关键词：front-end heat exchanger;heat-transfer coefficient;heat-transfer efficiency;pressure drop;seawater-source heat pump141|673|0更新时间：2026-10-13
- 摘要：In recent years， modular liquid cooling plates have been increasingly used for thermal management in marine electronic equipment. In addition to maintaining the cooling performance， the prevention of surface condensation is critical for the device safety. This study experimentally investigated the surface-temperature dynamics and condensation phenomena under various cooling conditions. A hybrid model that combined the convolutional neural network （CNN） and long short-term memory network （LSTM） was developed to predict the surface temperatures in condensation-prone regions of a liquid cooling plate. The results indicated that such areas were affected by edge effects. Moreover， supercooling and delayed condensation were observed when the temperature fell below the dew point， as well as the actual appearance of condensation. The proposed model reduced the mean absolute error （MAE） by 41.7% and 48.8% and the root mean squared error （RMSE） by 40.7% and 49.1%， respectively， compared to the standalone CNN and LSTM models， while also achieving a higher coefficient of determination （R2）.关键词：cooling plate;condensation prevention;temperature dynamics;temperature prediction166|840|0更新时间：2026-10-13
- 摘要：Simulation researches have primarily focused on flow-field analysis of temperature field in refrigerators and on the refrigeration of spherical fruits， generally under idealized conditions， which leads to significant discrepancies between simulated and actual values. This study employed a combination of numerical simulation and experimental methods to establish a heat and mass transfer model for the storage of peaches in a fan-cooled refrigerator. It introduces the respiratory heat and latent heat of evaporation based on the traditional models， corrects the density， and further adjusts the dynamic viscosity coefficient. These changes significantly reduced the mean absolute error （MAE） of the improved model， from the original model's range of 1.74-2.98 K to the improved model's range of 0.22-0.76 K. The improved model therefore more effectively was characterized by the flow-field distribution and temperature change patterns of the spherical fruits in refrigerated spaces， thereby providing a basis to optimize the airflow organization and temperature and humidity control strategies within refrigerators.关键词：analog simulation;Hypothermic storage;temperature field;relative humidity214|784|0更新时间：2026-10-13
- 摘要：Small- and medium-scale cold stores are widely used and the low-carbon operation of refrigeration units used in cold stores is of great significance. Cascade refrigeration systems， which achieve low temperatures， exhibit high energy efficiency. For example， the R134a/R744 cascade system in use performs well. With the tightening of refrigerant regulations， the exploration of low-GWP refrigerants has become increasingly important. In the study， the refrigerants R515B， R513A， R449A， R448A， and R450A were selected as alternatives to R134a， and their performance was evaluated in terms of energy， exergy， environmental， and economic factors. At an evaporation temperature of -50 ℃， R515B， R513A， and R450A achieved coefficients of performance and compressor powers similar to those of R134a. R515B reduced the high-stage discharge temperature by 9.97 ℃， improving system stability. Relative to R134a， at a condensation temperature of 50 ℃， R450A achieved a 0.41% reduction in exergy efficiency and a 1.38% increase in exergy loss. R450A reduced direct carbon emissions by 57.86%. The thermodynamic performance of R450A was close to that of R134a， and its comprehensive energy utilization rate was optimal， based on analysis of energy efficiency， exergy， environmental， and economic factors.关键词：small-scale cold stores;cascade refrigeration;refrigeration system;refrigerant replacement308|894|0更新时间：2026-10-13
- 摘要：R290 is the main working fluid used in room air conditioners. It is important to study the friction-loss law for compressor-frequency conversion when using R290 as the working fluid， to quantify the correlation between friction loss and motor frequency and to improve energy efficiency and reliability. In this study， a mathematical model for calculating the friction loss of a rolling-rotor compressor was established. The effects on friction loss of the motor frequency， working conditions， lubricating-oil viscosity， and the friction coefficient of the friction pair were analyzed. For a compressor with a displacement of 9.8 cm3/r， the predicted improvement for the friction pair was experimentally verified. Adding a trace amount of specific additives reduced the friction coefficient of the refrigeration oil by 14.35%； the coefficient of performance of the variable-frequency compressor increased by 0.88%-3.80%， and the maximum relative deviation from the calculated results was less than 3.1%. The friction power of the main， auxiliary， and eccentric bearings of the compressor accounted for 41.7% of the total friction loss under low-frequency conditions and 60.9% of this loss under high-frequency conditions. The viscosity and lubrication properties of the refrigeration oil exerted different effects on different friction pairs. The friction loss of the main friction pair varied with frequency， differing notably between R290 and R32 compressors.关键词：R290 refrigerant;inverter compressors;friction loss;lubricating oil;coefficient of friction330|958|0更新时间：2026-10-13
- 摘要：Winter heating of passenger compartments in electric vehicles relies on vehicle air-conditioning systems， in which the air outlet temperature must be rapidly increased to the set value. These systems typically adopt a reverse Carnot heat-pump cycle， which does not achieve sufficient heating capacity in low-temperature environments， thus preventing the air outlet temperature from rapidly reaching the set temperature during cold starts. To ensure that the system provides sufficient heating capacity under these conditions， a hot-gas bypass heat-pump cycle was used to replace the reverse Carnot heat-pump cycle. By bypassing the refrigerant from the high-pressure side to the low-pressure side， the suction pressure of the compressor was increased， ensuring stable operation of the compressor under low-temperature heating conditions. A staged hot-gas-bypass heat-control strategy， with an additional exhaust throttle valve to reduce the time required to establish high pressure， was proposed. A simulation model of this proposed system， using R290 as the refrigerant， was established， and a test bench was built to calibrate the simulation model. Based on this simulation， differences between the hot-gas-bypass heat-pump cycle and the reverse Carnot heat-pump cycle were examined， and the effects of the optimization strategy were verified. Under low-temperature conditions of -25 ℃ and -20 ℃， the proposed system achieved better heating performance than the reverse Carnot heat pump cycle. Relative to the pre-optimization control strategy， the proposed optimized hot-gas-bypass heat-pump cycle control strategy reduced the time required for the air outlet temperature to reach the target temperature by 36%.关键词：automobile air conditioner;hot-gas bypass cycle;control strategy;low-temperature heating;air outlet temperature275|1003|0更新时间：2026-10-13
- 摘要：Condensers， a critical component in refrigeration and heat pump systems， require rapid and accurate performance prediction， which is crucial for system selection and design optimization. Conventional condenser performance evaluation methods， such as computational fluid dynamics simulations and experimental testing， suffer from computational inefficiency and long cycle times. To address such technical limitations， this study developed a synergistic optimization framework integrating genetic algorithms and the condenser models. This approach refined the heat transfer correlations in the single-phase region to enhance the predictive accuracy of the model. The results show that under this optimization method， the average absolute errors in the subcooling degree for the plate and finned-tube condensers are 1.83 ℃ and 2.23 ℃， respectively. In addition， validation results based on 32 sets of experimental data covering a wide range of operating conditions showed that the average relative errors for both the heat transfer capacity and the outlet temperature of the refrigerant were maintained within 5%. This method improved the prediction accuracy of simulation models to some extent， providing effective technical support for the rapid simulation and engineering applications of refrigeration systems.关键词：condenser;thermodynamic model;genetic algorithm;fast prediction85|810|0更新时间：2026-10-13
- 摘要：Inspired by the drag-reducing effect of natural riblet-like structures on shark skin， this study proposes a biomimetic shark skin denticle structure and evaluates its heat transfer enhancement and drag reduction performance in the single-phase flow regime. The bio-inspired denticles consist of longitudinally protruding riblets and streamlined auxiliary riblets arranged in an interlocking， staggered pattern along the inner tube surface. This configuration forms well-organized flow channels that effectively confine near-wall vortices within the grooves， preventing the transverse migration of wall-flow vortices and reducing the momentum exchange caused by vortex cross-flow， thereby achieving drag reduction. Furthermore， denticles generate flow disturbances that enhance the convective heat transfer， leading to improved heat transfer coefficients. The primary factors affecting drag reduction and thermal performance were the denticle height and arrangement density. As the denticle height increased and the arrangement became more compact， the flow disturbance intensified， resulting in a greater heat transfer enhancement. However， the drag reduction effect was initially improved and then deteriorated， indicating the existence of an optimum denticle height and arrangement density. For the studied tube with a 7 mm outer diameter at Reynolds numbers ranging from 4 500 to 9 500， the optimum denticle height was determined to be 0.07 mm， with optimal riblet spacings D2 and P of 2.3 mm and 0.6 mm， respectively. Compared to a smooth tube， the sharkskin denticle tube achieved an approximately 3.0% reduction in flow resistance and an 8.0% improvement in heat transfer capacity.关键词：bio-inspired shark skin denticles;turbulent flow in tubes;convective heat transfer;drag reduction and heat transfer enhancement148|536|0更新时间：2026-10-13
- 摘要：Thermochemical energy storage is a promising solution for addressing the temporal， spatial， and intensity mismatch between solar energy supply and demand. This study experimentally investigates the crystallization-based energy storage characteristics of lithium bromide solution， focusing on the energy storage density， rate， and efficiency， along with a sensitivity analysis of key parameters. The results show that the energy storage rate and efficiency increase with the source temperature. At a 55% mass fraction of lithium bromide， increasing the heat source temperature from 100 ℃ to 140 ℃ enhances the energy storage rate and efficiency by 89.1% and 18%， respectively. The performance response to the solution mass fraction is nonlinear， with an optimal mass fraction range； as the initial mass fraction increases from 55% to 63%， the average storage density decreases by 15.9%， while the efficiency increases by 31%. The storage characteristics are negatively correlated with the cooling water temperature； as it increases from 10 ℃ to 30 ℃， the energy storage rate and efficiency decrease by an average of 46.7% and 35.4%， respectively. Of all the factors， the cooling water temperature exerts the most consistent and significant negative impact on the system performance， making it the primary limiting factor under current operating conditions.关键词：lithium bromide;Solution;Crystallization;energy storage114|815|0更新时间：2026-10-13
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