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The climate in China varies substantially across its extensive territory. However, the traditional thermal design of buildings is primarily based on pure heat calculation that considers only heat transfer. Therefore, the heat transfer of a building envelope should be clarified under the action of periodic external disturbance circulation. In this study, four different climatic factors were selected for heat transfer simulation, including season, solar radiation, air temperature, and relative humidity. The results indicate that the outdoor relative humidity has a significant impact on the difference between coupled heat and moisture calculation and pure thermal calculation. This influence becomes evident in the cooling conditions in summer but weakens in the winter heating conditions. Accordingly, the meteorological data of 270 cities in China were statistically analyzed using Python programming language. The concept of "cooling high-humidity days" was proposed as a zoning indicator for coupled heat and humidity thermal calculation zoning. The coupled heat and moisture thermal calculation design zoning map of China is provided, which affords the specific calculation method in building thermal design. [ABSTRACT FROM AUTHOR]

The STAR GATE archive included an experiment from China of psicho-physical claim reportedly conducted on aqueous object (Wu et al, 1991). Over a time-lapse of approximately 208 seconds, total 7 phases of significant temperature deviation from the baseline temperature of 25 °C may be identified, without an explainable source of thermal generation. Not questioning the genuineness of the experiment, this work analyzes the thermal-energy transfer on the test-object that could have caused the reported temperature changes. A non-adiabatic single-compartment produces first-order low-pass responses between a thermal-input and the object's temperature. Whereas the input determines the steady-state condition, the thermal dissipation dictates the dynamics. Under the assumption of ONLY first-order responses and adjusting the input parameters including DC and AC magnitudes and time-constant of the single-compartment responses, multi-phase temperature changes resembling the reported patterns could be reconstructed. One rising phase and three falling phases with apparent oscillation were reconstructed by considering the thermal input to contain modulatory patterns of 0.4-0.5 Hz in frequency. Such modeled modulation of the thermal inputs would correspond to a correlation coefficient of 0.95 between the DC and AC magnitudes at a varying AC/ DC modulation-depth of ≤94%. The low-frequency may suggest relevance to altered neuro-electro-physiology. [ABSTRACT FROM AUTHOR]

This paper proposes a temperature-adaptive radiative cooling (TARC) coating with simple preparation, cost effectiveness, and large-scale application based on a thermochromic powder. To determine the energy efficiency of the proposed TARC coating, the heat transfer on the surface of the TARC coating was analyzed. Then, a typical two-story residential building with a roof area of 258.43 m2 was modeled using EnergyPlus. Finally, the energy-saving potential and carbon emission reduction resulting from the application of the proposed TARC roof in buildings under different climates in China were discussed. The results showed that the average solar reflectivity under visible light wavelengths (0.38–0.78 μm) decreases from 0.71 to 0.37 when the TARC coating changes from cooling mode to heating mode. Furthermore, energy consumption can be reduced by approximately 17.8–43.0 MJ/m2 and 2.0–32.6 MJ/m2 for buildings with TARC roofs compared to those with asphalt shingle roofs and passive daytime radiative cooling (PDRC) roofs, respectively. This also leads to reductions in carbon emissions of 9.4–38.0 kgCO2/m2 and 1.0–28.9 kgCO2/m2 for the buildings located in the selected cities. To enhance building energy efficiency, TARC roofs and PDRC roofs are more suitable for use on buildings located in zones with high heating demands and high cooling demands, respectively. [ABSTRACT FROM AUTHOR]

Line loss refers to the electrical energy that is dissipated as heat during the transmission and distribution of electricity through power lines. However, unusual causes, such as grid topology mismatch and communication failure, can cause abnormal line loss. Efficient abnormal line loss detection contributes not only to minimizing energy wastage and reducing carbon emissions but also to maintaining the stability and reliability of the entire distribution network. In actual situations, the cause of abnormal line loss is not labeled due to the expensive labor cost. This paper proposes a hierarchical abnormal line loss identification and category classification model, considering the unlabeled and unbalanced sample problem. First, an abnormal line loss identification model-based random forest is established to detect whether the line loss is abnormal. Then, an abnormal line loss category classification model is developed with semi-supervised learning for line loss abnormal category classification, considering the unlabeled samples. The real dataset in China is utilized to validate the performance of the proposed model. Its reliability implies the potential to be applied to real-world scenarios to improve the management level and safety of the power grid. [ABSTRACT FROM AUTHOR]

Blast furnace slag, a by-product of the iron and steel production process, contains a significant amount of untapped heat resources. Currently, China is entering a period of rapid growth in scrap production, making efficient scrap utilization a new research focus. One approach to improving scrap utilization is preheating. This study proposes a new method of preheating scrap using high-temperature slag in a drum. The discrete element method is employed for numerical simulation, which involves constructing a three-dimensional model. The study explores three influencing factors: the mass ratio of high-temperature slag to scrap, the shape of the scrap, and the drum rotational speed. The main objective is to investigate the heat transfer situation between the high-temperature slag and the scrap. The results indicate that the optimal heat transfer effect in the drum is achieved when the mass ratio of high-temperature slag to scrap is 2:1, the scrap is spherical in shape, and the drum rotational speed is 12 rpm. [ABSTRACT FROM AUTHOR]

Besides waste gas and liquid, high-temperature particles are important media of waste heat and their temperature exceeds 1000°C on many occasions. The cross-flow heat transfer is important in this waste heat recovering process, but there are few references reported about the theoretical modeling. Therefore, a theoretical model was developed for the cooling process in a horizontal moving bed of high-temperature particles. The purpose of the study is to estimate the influence of temperature field and flow field on heat transfer and bed resistance in the cross-flow cooling process. Three modes such as conduction, convection and radiation are considered in the model. This model was used to analyze heat transfer in a horizontal moving bed of cement clinker and was verified by comparing some simulative results with the tested and collected data from an actual cement clinker plant in China. The simulative temperature of cement clinker was 200°C as same as that collected in the actual cement clinker plant. In the moving bed, the highest pressure drop occurs at the front top and the strongest heat transfer occurs at the front bottom. In the considered conditions with even distribution of cooling air, the highest pressure drop is 3205.9 Pa/m, the biggest specific heat transfer rate of 1683.1 kW/m³. Thermal radiation plays a minor role in this cooling process with the biggest radiation proportion is only 0.149 at the front top. This mode plays a minor role in this cooling process of the cement clinker, comparing with the thermal convection. With constant flow rate of cooling air, the distribution can regulate the local cooling rate rather than the final temperature of the cement clinker. [ABSTRACT FROM AUTHOR]

We present a deep learning approach based on the physics-informed neural networks (PINNs) for estimating thermal evolution of the crust during tectonic uplift with a changing landscape. The approach approximates the temperature field of the crust with a deep neural network, which is trained by optimizing the heat advection-diffusion equation under boundary conditions such as initial and final thermal structure, topographic history, and surface and basal temperatures. From the trained neural network of temperature field and the prescribed velocity field, one can predict the temperature history of a given rock particle that can be used to compute the cooling ages of thermochronology. For the inverse problem, the forward model can be combined with a global optimization algorithm that minimizes the misfit between predicted and observed thermochronological data, in order to constrain unknown parameters in the uplift history or boundary conditions. We demonstrate the approach with solutions of one- and three-dimensional forward and inverse models of the crustal thermal evolution, which are consistent with results of the finite-element method. The three-dimensional model simulates the post-orogenic topographic decay of the Dabie Shan, China, with constraints from fission-track and (U-Th)/He ages. [ABSTRACT FROM AUTHOR]

China has ranked first worldwide in graphite imports in recent years, facing a graphite supply risk. Coal-hosted graphite is the focus of future graphite deposit exploration. The current research on the enrichment and mineralization mechanism of coal-hosted graphite is superficial, and the identification standard of coal-hosted graphite is incomprehensive, restricting the exploration of coal-hosted graphite mineral resources and the development of coal metamorphic evolution theory. In this study, the Caotangou–Meigoucoal-hosted graphite deposit in western Qinling Mountain was taken as a case study for dissection. Based on the data from 1/50,000 and 1/200,000 regional geological mapping and the data of graphite mines in the study area, the samples were systematically collected and analyzed to explore the mechanism of coal graphitization through a 1:5000 geological profile survey, 1/10,000 geological mapping in key areas, and the investigation and cataloguing of abandoned coal-hosted graphite adit. The result was that there were two main coal-hosted graphite ore bodies, striking from nearly east to west. The Rmax values of the samples were 7.23–8.15%, the average values of Vdaf were around 5.0%, the d002 value of the II ore body was 0.3433–0.3389 nm, the d002 value of the I ore body was mainly 0.3418–0.3429 nm, the graphitization degree G value of the II ore body was 8.14–59.30%, the graphitization degree G value of the II ore body was 12.79–25.58%. The II ore body was coal-hosted graphite, while some samples of the I ore body were coal-hosted graphite, and some samples were coal. The magmatic heat controls the thermal metamorphism of coal seams to form graphite. The closer the distance to the magma body, the larger the crystals, and the higher the euhedral degree, indicating the higher degree of coal seam metamorphism. The nearly north–south compressive structures mainly provided effective tectonic stress for the evolution of coal graphitization during the Yanshan period; the basic structural units (BSUs) rotated and rearranged, eventually forming a straight graphite structure, and tectonic stress catalyzed the graphitization process. The coal-hosted graphite deposits formed under the dual effects of magmatic heat transfer and tectonic stress. [ABSTRACT FROM AUTHOR]

This study aimed to develop a STEM module for eighth-grade middle school learners through the engineering design process. The module was developed based on the ADDIE model, primarily concentrating on the stages of analysis, design and development. The study consisted of two main phases: module development and module evaluation. During the development phase, 26 science teachers and 30 eighthgrade middle school pupils were purposefully selected from a public sector' middle school in China. Subject themes of the EDP-STEM module were determined by data analysis using coding of responses to interview questions and questionnaires seeking to elicit perceived needs. The EDP-STEM module's learning objectives, engineering design process, and STEM knowledge were subsequently developed. In the evaluation phase, five experts and 50 ninth-grade middle school pupils were recruited to verify the reliability and validity of the EDP-STEM module. The Content Validity Index (CVI) for the EDP-STEM module was 0.92, and the Cronbach's Alpha reliability coefficient was 0.76. Based on their feedback and suggestions, the researcher made modifications and improvements to the EDP-STEM module. The results of the study showed that EDPSTEM module has good reliability and validity and can be used as a learning module to carry out STEM learning in eighth-grade classrooms. [ABSTRACT FROM AUTHOR]

A superconducting magnet system is developed for the application of high-frequency gyrotrons at Wuhan National High Magnetic Field Center, China. The operating cost for the magnet is dominated by refrigeration power. To reduce the heat load for cryogenic systems, a pair of YBCO binary current leads is designed by consideration of the industrial concentration of type II high-temperature superconducting YBCO material. In this paper, a simulation model is proposed to perform the electromagnetic-thermal coupling analysis of these YBCO binary leads under different operating conditions by combining a partial element equivalent circuit method and finite volume method. The simulation code can improve computational efficiency and enable high-accuracy coupling between the electromagnetic field and heat transfer process. In the steady state, the heat leakage at the 4.2 K cold end of the YBCO binary leads depends mainly on the geometric parameters of the YBCO tape, especially the cross-sectional area of the copper layer in the YBCO tape. The cooling mode and liquid helium level also have a significant impact on the heat leakage level. The optimal outer diameter of the normal copper section is identified, and the optimum value is largely influenced by the effective cooling power imposed on the cold end of the normal copper section. In the transient state, simulations for the charging process and the loss of cooling accident are performed, along with a detailed analysis of the electromagnetic-thermal response features of the leads under these conditions. The results indicate that the YBCO binary current leads possess high thermal stability and an ample time margin for the magnet system to be demagnetized. [ABSTRACT FROM AUTHOR]

The response potential of demand-side resources is becoming increasingly significant in integrated energy system (IES) operations. In addition, to ensure the effective participation of system devices, their actual responsiveness at different timescales should be considered. Based on these considerations, this paper proposes an IES multi-timescale operation optimization strategy that incorporates multiple forms of integrated demand response (IDR) and considers the response characteristics of the equipment. First, the multi-timescale characteristics of IDR are analyzed. Moreover, a multi-timescale operation model of IES that comprises day-ahead, intraday, and real-time stages is further established. In the day-ahead dispatch, a low-carbon economic scheduling model is developed by considering the shifting demand response (DR) and the cost of carbon emissions. In the intraday scheduling, noting that cooling and heat energy transmission possess slow dynamic characteristics, a rolling optimization model for cooling/heating coupled equipment considering load shedding and substituting DR is established. In real-time scheduling, the output of electric/gas coupled equipment is adjusted. Finally, an industrial park-type IES in northern China was selected as an example for a case study. The results show that (1) the IDR multi-timescale response strategy can exploit different types of demand-side flexibility resources. After implementing the shifting DR, the peak-to-valley difference of the electric load curve was reduced by 20%, and the total system cost was reduced by 2.3%. After implementing load shedding, the maximum load differences per unit period of the electric, heat, and cooling load curves decreased by 18.7%, 40.0%, and 68.9%, respectively. (2) By refining the timescale of IES optimization, the proposed model can effectively ensure the energy supply and demand balance of the system under different load scenarios and reduce the system operation cost. After applying the model to simulation in three typical days (transition season, summer, and winter), the penalty costs of lost loads reduce by ¥3650, ¥3807, and ¥3599, respectively, and the total system costs decrease by 17.4%, 16.1%, and 16.2%, respectively. [ABSTRACT FROM AUTHOR]

Copyright of Journal of East China University of Science & Technology is the property of Journal of East China University of Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Eastern Helan Mountain can be the largest concentrated and contiguous producing areas for the wine grape in China. Specifically, the wine grape planting area reached 388.7 square kilometers in Ningxia by the end of 2022, accounting for nearly 1/3 of the nation, and the comprehensive output value exceeded 30 billion Yuan. However, the extremely low temperatures (down to -30.0℃) in winter in the eastern part of the Helan Mountains can lead to the occurrence of overwintering frost damage, which greatly limits the sustainable development of Ningxia's grape industry. In this study, a gravity heat pipe system was designed using shallow groundwater geothermal energy for the soil warming in the root zone of grapes. Numerical simulation was also carried out to analyze the influence range and distribution of the gravity heat pipe temperature field under different spacing. A series of field experiments were used to verify the working performance of the gravity heat pipe and the warming characteristics of the soil. The results show that the soil temperature field was evenly spread around the gravity heat pipe. The temperature field around the heat pipe was divided into four regions, according to the temperature level: the temperature range was 5.0-8.50℃ high-temperature affected region â… , the temperature range was 0-5.0℃ medium-temperature affected region â…¡, the temperature range was -2.57-0 ℃ low-temperature affected region â…¢, and the temperature field was not affected region â…£. The highest temperature (8.50 ℃) appeared in the temperature field area â…  condensation section pipe wall, whereas, the lowest temperature (-2.57 ℃) was in the temperature field unaffected area â…£. In addition, the diameter of the medium temperature affected area of the heat pipe in the soil was 30.8 cm horizontally and 32.8 cm vertically, where the grape roots were not affected by frost. There were evenly distributed temperature fields around the heat pipes partially overlapped and the temperature fields under the conditions of 10 cm burial depth and 15 cm spacing between adjacent heat pipes. The soil temperature increased by 7.0 ℃ on average in the experimental group during the test period, compared with the control group, indicating the outstanding increase in temperature. The maximum temperature difference was 3.5 ℃ between the evaporation and condensation sections during the normal operation of the gravity heat pipe. The maximum temperature differences were 1.0 and 0.2 ℃ within the evaporation section, and within the adiabatic section, respectively, indicating the excellent isothermal distribution. The average start-up and operating temperature difference of the heat pipe were 5.4 and 2.9 ℃, respectively. The clean and renewable shallow geothermal energy was taken as a source of heating energy in the root zone of grapes, which was in line with the current green development concept. The finding can provide the theoretical basis and technical support to treat the frost damage in the root zone of grapes. In addition, a way was proposed to realize the development and utilization of shallow geothermal energy using gravity heat pipes. The Eastern Helan Mountain can be the largest concentrated and contiguous producing areas for the wine grape in China. Specifically, the wine grape planting area reached 388.7 square kilometers in Ningxia by the end of 2022, accounting for nearly 1/3 of the nation, and the comprehensive output value exceeded 30 billion Yuan. However, the extremely low temperatures (down to -30.0℃) in winter in the eastern part of the Helan Mountains can lead to the occurrence of overwintering frost damage, which greatly limits the sustainable development of Ningxia's grape industry. In this study, a gravity heat pipe system was designed using shallow groundwater geothermal energy for the soil warming in the root zone of grapes. Numerical simulation was also carried out to analyze the influence range and distribution of the gravity heat pipe temperature field under different spacing. A series of field experiments were used to verify the working performance of the gravity heat pipe and the warming characteristics of the soil. The results show that the soil temperature field was evenly spread around the gravity heat pipe. The temperature field around the heat pipe was divided into four regions, according to the temperature level: the temperature range was 5.0-8.50℃ high-temperature affected region Ⅰ, the temperature range was 0-5.0℃ medium-temperature affected region Ⅱ, the temperature range was -2.57-0 ℃ low-temperature affected region Ⅲ, and the temperature field was not affected region Ⅳ. The highest temperature (8.50 ℃) appeared in the temperature field area Ⅰ condensation section pipe wall, whereas, the lowest temperature (-2.57 ℃) was in the temperature field unaffected area Ⅳ. In addition, the diameter of the medium temperature affected area of the heat pipe in the soil was 30.8 cm horizontally and 32.8 cm vertically, where the grape roots were not affected by frost. There were evenly distributed temperature fields around the heat pipes partially overlapped and the temperature fields under the conditions of 10 cm burial depth and 15 cm spacing between adjacent heat pipes. The soil temperature increased by 7.0 ℃ on average in the experimental group during the test period, compared with the control group, indicating the outstanding increase in temperature. The maximum temperature difference was 3.5 ℃ between the evaporation and condensation sections during the normal operation of the gravity heat pipe. The maximum temperature differences were 1.0 and 0.2 ℃ within the evaporation section, and within the adiabatic section, respectively, indicating the excellent isothermal distribution. The average start-up and operating temperature difference of the heat pipe were 5.4 and 2.9 ℃, respectively. The clean and renewable shallow geothermal energy was taken as a source of heating energy in the root zone of grapes, which was in line with the current green development concept. The finding can provide the theoretical basis and technical support to treat the frost damage in the root zone of grapes. In addition, a way was proposed to realize the development and utilization of shallow geothermal energy using gravity heat pipes. [ABSTRACT FROM AUTHOR]

Copyright of Basic Sciences Journal of Textile Universities / Fangzhi Gaoxiao Jichu Kexue Xuebao is the property of Basic Sciences Journal of Textile Universities and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• SACOP of the LDHC-SAHP is about 0.73 smaller than that of the LDHC-HAHP. • Energy transfer process of LDHC-HAHP is more advanced than that of LDHC-SAHP. • Centralized and distributed thermal storages can solve solar energy time-discrepancy. • Half-effect absorption heat pump is more suitable for the new proposed scheme. • SACOP and economic heat transmission distance of LDHC-HAHP are about 11.6 and 18 km. Developing solar energy source for space heating and cooling contributes to achieving the target of China's carbon emission peak by 2030. However, the conventional solar-driven heating systems integrated with heat pump or natural gas boiler are featured by short economic heat transmission distance and small solar fraction, and can't cover the demand of the large-scale solar-driven district heating and cooling systems. To solve the problem, two configurations of solar-driven low temperature district heating and cooling system are proposed. One is integrated with distributed single-effect water-lithium bromide absorption heat pumps, and the other is integrated with distributed half-effect water-lithium bromide absorption heat pumps. The distributed absorption heat pumps are located in the energy stations for reducing return temperature of the primary network, which helps to enlarge temperature difference between supply and return and improve solar collector performance. The analyzed results indicate that, in the energy station, replacing single-effect water-lithium bromide absorption heat pump by half-effect one can improve system annual coefficient of performance by about 0.73, reduce cooling cost by about 6.04 ¥/GJ, and increase economic heat transmission distance by about 2.6 km. Thus, the proposed solar-driven low temperature district heating and cooling system integrated with distributed half-effect water-lithium bromide absorption heat pumps has an advanced energy conversion and transfer process, and its economic heat transmission distance is about 18.3 km. Thus, application of the proposed solar-driven low temperature district heating and cooling system integrated with distributed half-effect water-lithium bromide absorption heat pumps would be promising in Northern China. [ABSTRACT FROM AUTHOR]

Lycium barbarum is one of the most popular herbs in China. The high medicinal value can serve as a functional food rich in nutrients (such as polysaccharides, plant flavonoids, and carotenoids), further promoting glucose and lipid metabolism for better immune system, and mental efficiency, and even preventing neurodegeneration. The berry fruits with high water content can be dried to improve their shelf life using vacuum freeze drying. In this study, a numerical simulation was carried out to explore the heat and mass transfer, stress, and strain of Lycium barbarum during freeze-vacuum drying. Among them, the heat and mass transfer was a benefit to exploring the drying mechanism of Lycium barbarum freeze during vacuum drying. The stress and strain was to explore the cellular changes of Lycium barbarum freeze-vacuum during drying. The temperature experiment was carried out by vacuum freeze dryer. The pre-freezing stage was set at -40 for about 4 hours,°C then the vacuum was drawn at two heating rates (5, and 10 /h). The constant temperature was maintained when the heating°C plate temperature reached 40 . The cell change experiment was carried out by FDCS196 hot and cold table. The whole°C process was combined with the microscope and CCD camera, in order to obtain the real-time image of berry cells. The heat-mass-stress coupling of the drying was dominated by the high quality of the products. The heat-mass-structure coupling model during vacuum freeze drying was established to use binarization processing using the experimental image of fresh berry slices. The temperature, moisture, as well as internal stress, and strain of the fresh berry sample, were analyzed and then verified by experiments during vacuum freeze drying. The results showed that the length shrinkage (Sl) and equivalent diameter contraction (Sd) of berry tissue cells were always negative during the pre-freezing process, indicating the ever-expanding cells. By contrast, the cell shape coefficient (Sf) was increasing all the time. At the same time, the maximum stress was found on the cells, when the cells were completely frozen. The moisture of the sample during the simulation was fitted better with the WangandSingh and HendersonandPabis models, indicating the more suitable WangandSingh model(R² = 0.983). The experimental results show that the temperature of samples during the simulation was highly consistent with the experiment, indicating the better performance of the model. In addition, the cell shape was gradually altered around in the varying position with the decrease of sample temperature in the process of the pre-freezing experiment(R² = 0.857). A better consistency was found with the analysis data of stress and strain of sample cells during simulation.The research results can provide reference for the optimization of vacuum freeze drying system and the scientific formulation of process parameters. [ABSTRACT FROM AUTHOR]

At present, China's high-speed rail is in a period of rapid development. Most of the refrigerants used in Chinese motor train units at this stage are still R134a and R407c, which have an impact on the environment. In response to the environmental protection concept of green travel, it is of great significance to study the air conditioning system of motor train units using CO2 refrigerant. Using CFD simulation analysis technology, the heat transfer performance of the air side of the CO2 finned tube evaporator used in the air conditioning system of the motor train unit is studied. We select the air outlet temperature, pressure drop, heat transfer factor, and resistance factor as the objective function, in addition, monitoring points are set up in the air flow channel to monitor the turbulent flow field and pipe wall pressure. Our research shows that the cooling capacity of the CO2 evaporator can reach up to 29.76 kW, which can meet the heat exchange required in the air conditioning system of the motor train unit. In order to obtain a better structure and the conditions of the heat transfer effect, structural optimization was conducted. The simulation results demonstrate several trends: (i) With the augment of the air inlet velocity, the cooling capacity of the evaporator increases and the heat exchange effect improves; when the air inlet ve > 2.2 m/s, the effect of continuing to augment ve on heat exchange is weak. (ii) Following appropriate reduction of the diameter of the heat exchange tube, the wind resistance is reduced and the cooling capacity of the evaporator is improved. (iii) With the enlargement of the fin spacing, the turbulent motion in the flow channel can be fully developed, there is a peak in the change in the heat exchange tube area optimization factor, and the optimal fin spacing is between 1.6 mm and 1.7 mm; at this time, the average turbulent kinetic energy of the air side is larger and the turbulent dissipation rate is smaller. These results provide a reference for the practical application of CO2 refrigerant in the motor train unit. [ABSTRACT FROM AUTHOR]

Copyright of Nuclear Safety is the property of Nuclear & Radiation Safety Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Due to issues such as heat accumulation, the site area, and project investment, the reasonable determination of the hole spacing for heat exchangers has become one of the key design points of the ground-coupled heat pump system. Based on the definition of heat penetration in heat transfer and the research method of the inverse problem, a direct algorithm of the heat penetration distance in the aquifer was proposed using the analytical solution to the mathematical model for one-dimensional heat convection–conduction problems. Taking a vertical ground-coupled heat pump project in Hefei, Anhui Province, China, as an example, a three-dimensional hydro-thermal coupling numerical simulation model was established, and the influence radius during the refrigeration and heating periods under the action of a single borehole heat exchanger was determined. Comparing the heat penetration distance with the influence radius, the results show that the relative errors of the results obtained by the two methods are less than 10%, which verifies the rationality and effectiveness of the calculated penetration distance in the aquifer. At the end of the cooling or heating period, the heat penetration distance in the aquifer is calculated to be 7.59 m. Therefore, the proposed method is straightforward and efficient, which can provide a convenient approach to determining the reasonable hole spacing of the heat pump system. [ABSTRACT FROM AUTHOR]

This paper introduces the application background of plate-fin heat exchanger and summarizes the research process of plate-fin heat exchanger at domestic and abroad. Furthermore, this paper summarizes the main research direction and existing problems in plate-fin heat exchanger in FLNG. The analysis results show that plate-fin heat exchanger is the main heat exchangers during the natural gas liquefaction process in FLNG, which has a broad application prospect with the extraction of the offshore natural gas in China. [ABSTRACT FROM AUTHOR]

China is a large agricultural country that is leading worldwide in the annual number of agricultural products and exports. However, the growth and harvest of fruits and vegetables are greatly affected by geographical conditions, climate and other factors, which will lead to their rotting in peak season and shortages in the off-season. Therefore, it is necessary to vigorously promote the development of drying technology. The explosion puffing technology at low temperature and high pressure is a kind of compound drying technology which can enable the puffed product to obtain the advantages of honeycomb, good rehydration, a short running time, etc. With the guidance of the theory of heat and mass transfer and relevant thermodynamics laws, this study has established high-pressure extruding technology in low-temperature heating; expanded the two-phase theoretical model, using mass conservation and the law of the conservation of energy to analyze the coupled heat and mass transfer process and influencing factors; and researched the influence of the operation temperature, pressure and time on the properties of dried fruit. [ABSTRACT FROM AUTHOR]

Vertical greening systems (VGS) are considered an effective strategy to enhance the insulation performance of the building envelope. Existing methods predicting the performance of this strategy usually require a combination of mathematical modeling and building performance simulation, hence difficult for practical use. To simplify this work, this study has proposed a prediction method requiring building simulation only, by considering VGS as a shading component in the simulation work. To compare its performance, a model using conventional methods has also been proposed. A further simplification by neglecting the impact of transpiration has been investigated as well. To justify the implementation of the new method, it has been used to optimize the design of VGS for buildings located in the hot summer and cold winter areas in China. The validation result confirmed the accuracies of both methods, with the simpler method giving an insignificant lower accuracy than the conventional method, which can be compensated by its simpler prediction procedure. The implementation justification showed that for buildings in the HSCW area, VGS is suggested to be installed on the west facade, with a leaf area index of 4. This can help to reduce the heat transfer of the wall by 56.6%. • This study proposed and verified two models for vertical greening systems. • The effect of transpiration on the accuracy of predicting VGS performance was analyzed. • A simplified modeling method was presented for evaluating the performance of VGS. • The effects of leaf area index and wall orientation were studied for the HSCW region. [ABSTRACT FROM AUTHOR]

• The hybrid model has a multiphase flow mechanism and a machine learning model. • The model calculates multiphase transport boundaries to ensure pipeline safety. • The Maximum transportable Gas-Oil Ratio is a boundary under different conditions. • Multiphase transport boundaries cover the entire lifecycle of oilfields. • The average relative error of the hybrid model is less than 4.7%. Developing a safe Multiphase Transport Boundary (MTB) is crucial due to the complex flow and heat transfer laws of multiphase transportation of fluids in pipelines. However, there is no efficient, accurate, and widely adaptable method for MTB formulation. This paper proposes a hybrid method based on traditional multiphase flow mechanisms and machine learning models to determine the safe operational MTB for multiphase pipeline transportation processes. The interactive logic enables the efficient and accurate calculation of MTB under real-time measurement data-driven for the proposed new hybrid model. Using a northwest oil field in China as an example, the results indicate that the hybrid model has an average relative error of less than 4.7% compared with simulated data, showing high accuracy. The calculation of a million operating conditions only takes 232 s. The research results can guide promoting the design, operation, and modification of pipeline transportation systems to ensure safety. [ABSTRACT FROM AUTHOR]

Exploiting heat from abandoned mine water using heat pumps is attracting increasing attention worldwide. China has a large number of abandoned coal mines, but there are few applications of geothermal heat recovery from mine water. Here, we report a new case from Shandong, North China. Based on actual geological and underground space structures, numerical analysis is performed to study the flow and heat transfer in the complex connection network among roadways. For given temperature differences on the source side, the underground heat transfer is greatly influenced by flow rates in roadways. Under the acceptable performances and long-term stability of heat pumps, the maximum heat transfer capacity of roadways reaches 697.3 kW at the flow rate of 100 m3/h, with the power per unit length of 151.3 W/m, indicating a promising heat recovery potential. When switching between the extraction and injection well, both fluid directions and the distribution of flow rates in roadways change obviously, thereby affecting the underground heat transfer. Besides dominant flow paths, there exist weak flow paths, which can be identified by numerical analysis, and necessary blocking can be applied to optimize the flow and heat transfer. Excessively long horizontal straight roadways for heat exchange should be avoided. [ABSTRACT FROM AUTHOR]

• A three-dimensional unsteady state mathematical model of the multi-field coupling of backfill body, tube and fracture was established. • A test bench was designed and built to verify the three-dimensional coupling model. • The effects of a single fracture position, aperture and fractured depth on the heat extraction performance of a full-size BFHEs unit in the fully dry or fully saturated conditions were investigated. • The combined effects of multiple fractures on the performance of a BFHES unit were discussed. Thermal hazards in deep mines can be mined synergistically with the deposit as associated geothermal energy resources. Backfill heat exchangers (BFHEs) as a combination of mine backfilling and ground heat exchanger technology are one of the effective methods to realize ore deposit-geothermal energy synergy mining. However, in the complex environment of deep mines, BFHEs will inevitably suffer from fracture damage during long-term heat storage/release cycle operation, which will affect their working performance. To address this problem, this paper established a scaled-down experimental setup for fractured BFHEs units, and used the experimental data to verify the accuracy of the established three-dimensional transient heat transfer mathematical model of the BFHEs unit. Numerical simulation methods were used to investigate the effects of the position, aperture and fractured depth of a single fracture on the heat extraction performance of the BFHEs unit under fully dry or fully saturated working conditions. Significant differences were found in the effect of different fracture positions on the heat extraction capacity of the BFHEs unit. The extraction of geothermal heat by the BFHEs unit was favored when it was in the middle of two tubes, while the opposite was true for other positions. The effect of fracture on the heat extraction capacity of the BFHEs unit increased linearly with fracture aperture. The effect of the fractured depth was relatively greater in the 1/2–3/4 H b range. The presence of groundwater significantly reduced the effect of the fracture. The effect of the fracture on the heat extraction capacity of the BFHEs unit was reduced by more than 80 % by changing the operating conditions from fully dry to fully saturated condition. The overall effect of a fracture on the heat extraction capacity of the BFHEs unit was not significant, with a 5 mm wide fracture having an effect of no more than 2.5 %, even under the fully dry condition. However, there was a combined effect of multiple fractures, and for a deposit size of 900 × 7 × 80 m, ten 2 mm apertures fractures would results in a maximum reduction of geothermal extraction from BFHEs by 8527 GJ in 10 years, which was equivalent to the heat load of a 13,753 m2 building for one winter in the cold climate of China. [ABSTRACT FROM AUTHOR]

As an alternative energy for fossil fuels, geothermal reserve is abundant. In recent years, scholars have investigated geothermal wells through numerical simulations. To the best of our knowledge, many studies have explored the influence factors of thermal power over time, and few studies have investigated the heat transfer mechanism between wellbore and formation in different circumstances. This paper aims to established a transient numerical heat transfer model of U-shaped closed-loop geothermal system with long horizontal section, which can simulate the temperature distribution and heat transfer mechanism during the whole wellbore formation. In the model, the convection term is discretized by using the second-order upwind scheme, and the finite volume method is used to solve it. The numerical results are proven to be correct by comparing with the field data of a well in China. Subsequently, the influence mechanism of fluid type, insulation casing length, fluid injection temperature, flow rate, and horizontal section length on thermal power is explored. The optimal depth of insulation casing under different injection temperatures, flow rates, and horizontal section lengths is suggested so as to provide crucial guidance for engineering practice. [ABSTRACT FROM AUTHOR]

The design of thermal insulation in roofs is very important to reduce energy consumption and decrease the environmental impacts of buildings. An integrated economic and environmental assessment-based optimization design method is presented in this paper to find the best candidate insulation design scheme for building roofs, including the determination of roof thermal insulation type and the optimum insulation thickness. In the optimization design method, a zonal method-based double-skin ventilation roof heat transfer model is developed to predict the roof energy consumption. Economic and environmental benefits due to thermal insulation are calculated by using the economic analysis model, the environmental analysis model, and roof energy consumption. Moreover, an integrated dimensionless economic and environmental assessment index is proposed to evaluate different roof thermal insulation design schemes. The optimum insulation thickness is determined by maximizing the sum of economic benefit and environmental benefit due to thermal insulation. The validation results in a real building show that the predicted data for the zonal-based double-skin ventilation roof heat transfer model agreed well with the measured data, with a maximum relative error of 8.2%. The optimum insulation thickness of extruded polystyrene (EPS), mineral wool (MW), and polyurethane (PU) was between 0.082 m and 0.171 m for the single-skin roof in a low-temperature granary in Changsha region in China. The ranking of the integrated assessment indexes of thermal insulation is EPS > MW > PU. A double-skin ventilation roof can reduce the optimum thickness of thermal insulation. The best result is obtained by EPS for the double-skin roof with a grey outer surface color for the low-temperature granary roof in Changsha region in China. The influencing factors of insulation type, roof structure, and roof outer-surface color should be considered in finding the best candidate insulation design solution for building roofs. The integrated economic and environmental assessment-based optimization design method can help designers to efficiently find the best design scheme of thermal insulation to maximize the sum of economic benefit and environmental benefit for building roofs. [ABSTRACT FROM AUTHOR]

Chinese solar greenhouses (CSGs) are characterized by unique walls to reduce the transmission of heat and promote the energy conservation in winter production, which promotes cultivation in the northeast region of China in winter. Effective selection of insulation material is important for the CSG based on the energy consumption and economic analysis. However, choosing the thickness of the insulation material in walls often discussed with the structure of CSG. There is a lack of research combing the optimal insulation thickness for improving the energy conservation. The aim of this study was to find the optimum insulation thickness during the energy conservation based on the structure of walls, the energy consumption in local climatic conditions, the cost of insulation material, and economic payback period over a lifetime. By the economic analysis of insulation thickness, thermal resistance, lifetime energy saving, and payback period, three kinds of typical walls (clay brick (CB), hollow concrete block (HCB) and fly ash block (FAB)) combed with four insulation materials including the expanded polystyrene, the foamed PVC, the perlite, and the rock wool were calculated. The optimum insulation thickness can be found when energy savings reached the maximum. In the northeast region, the association of FAB with rock wool as the insulation layer was the most economic composite wall structure. The optimum insulation thickness was 0.05 m, with the cost only 5 USD/m2. The thermal resistance of composite wall had a significant effect on the payback period. When thermal resistance increased from 0.2 to 1.2 m2K/W, the payback period varied from 0.4 to 4.3 years. What is more, the energy consumption in local climatic conditions had a more significant effect on payback period. It can be assumed that insulation materials are more favored in cold climatic regions where heating degree-days over 1600 °C days for payback periods is less than 2 years. These results have strong practical and economical significance in saving energy and improving the environment of CSG. [ABSTRACT FROM AUTHOR]

Spectral selective absorption film (SSAF), a solar control film, has a special energy-saving mechanism. In the previous studies of SSAF coated glazing systems, thermal parameters (global thermal transmittance (U) and solar heat gain coefficient (SHGC)) calculated by traditional algorithms were not verified. In order to evaluate the energy-saving effect of SSAF coated glazing systems accurately, U and the SHGC were calibrated and then used for energy consumption simulation. Firstly, the simulation models of the heat transfer process of SSAF coated glazing systems were established by COMSOL Multiphysics, considering simplified linear attenuation of radiative transfer. After being validated, the simulation models were used for the calibration of U and SHGC by the Multiple Linear Regression (MLR) model. As a result, the calibration coefficients of U and SHGC are 1.126 and 1.689, respectively. Secondly, the thermal parameters of SSAF coated glazing systems calibrated by the calibration coefficients were used for a building energy consumption simulation case. The result showed that the inner surface is the best coating position for single glazing systems (SG), while the outer surface is the best coating position for double glazing systems (DG) in hot summer and cold winter zone, hot summer and warm winter zone and the moderate zone of China. [ABSTRACT FROM AUTHOR]

To address the problems of low power generation efficiency and low security of solar photovoltaic cells, a novel and versatile PV panel cooling strategy was proposed; which employed an absorbent hydrogel evaporative (AHE) cooling with 3D porous copper foam (CF) composite structure as an effective cooling component. By comparing natural cooling, comprehensive indoor simulated and outdoor experimental studies were conducted to explore the feasibility of enhancing the electrical output performance of PV cells. The effects of solar irradiation, environment humidity, ambient temperature and wind speed on heat transfer performance and the generated electricity power efficiency of PV with CF-AHE cooling panel were comprehensively analyzed and discussed. Present research demonstrated that the CF-AHE cooling layer of three solar irradiations (0.8, 1.0 and 1.2 sun conditions) could remove 449∼713W/m2 of heat from a photovoltaic cell, which significantly out-performed that of general cooling methodology depending on wind or buoyancy driven ventilation. The results further indicated that CF-AHE significantly reduces the cell temperature, enhancing the temperature uniformity of PV cell modules, i.e., the PV cell temperature ranges from 43–46 °C, markedly lower than the 53–66 °C observed with natural cooling. Additionally, average electrical efficiencies were enhanced by 4.69 %, 8.53 % and 12.84 % compared with that of natural cooling method, respectively. Subsequently, in the field test conducted in Wuhan city of China , current results further showed that our proposed cooling unit has boosted the power generation of PV panels by 14.01 % and reduced PV surface temperature by no less than 10 °C, simultaneously. Therefore, CF-AHE cooling structure can furnish excellent heat transfer characteristics and efficient electrical generation performance of PV panel. This research will provide valuable guidance for design of photovoltaic-AHE cooling systems and verifies the feasibility of such systems. [Display omitted] • Nano structures of porous copper foam and absorbent hydrogel were firstly designed. • An absorbent hydrogel evaporative (AHE) cooling with 3D porous copper foam (CF) was proposed. • Power generation and thermal management of PVs could be simultaneously enhanced by CF-AHE. • Potentials on commercial PVs have been demonstrated both by on-site and lab experiments. • AHE-CF could be especially advantageous in the regions of high temperature and humidity. [ABSTRACT FROM AUTHOR]

Fine flow and heat transfer characteristics are critical to nuclear reactor safety. However, a comprehensive CFD calculation of the entire reactor core requires substantial computing resources, restricting the research domain's scope. To address this issue, we propose a Distributed Parallel (DP) computing scheme, tailored specifically for reactor cores using plate-type fuel assemblies. This study focuses on the thermal-hydraulic calculation of the large domain of a reactor core utilizing plate-type fuel assembly, based on the Computational Fluid Dynamics (CFD) method. This innovative solution enables the completion of extensive domain CFD calculations using modestly equipped personal workstations (8 cores, 128G RAM), which traditionally would require supercomputing platforms. To verify the distributed-parallel computing technique, it is successfully applied to all standard, full-length fuel assemblies in the China Advanced Research Reactor (CARR). In the result analysis, it was observed that detailed results could be obtained with reduced computational resources, demonstrating a significant breakthrough for CFD engineering analysis. [ABSTRACT FROM AUTHOR]

The fluid flow and heat transfer of hydrocarbon fuel play a significant role in developing regenerative cooling technology for advanced aeroengines. Numerical simulations have been conducted to investigate the flow and heat transfer characteristics of China RP-3 aviation kerosene with pyrolysis in a 3D, 90° bend, square cooling channel around the cavity flame-holder of a scramjet. A chemical kinetic model, composed of 18 species and 24 reactions, was adopted to simulate the fuel pyrolysis process. Results indicate that the secondary flow enhances the mixing of the fluid, thus, the transports of heat and components are improved between the near-wall region and main flow field in the curved channel. Compared with a straight cooling channel, fuel conversion and heat-absorbing capacity are higher, and the heat transfer is effectively enhanced in a curved cooling channel. In addition, with the increasing inlet mass flow rate and the decreasing radius of curvature, the velocity of the secondary flow increases. The heat and components are easily transferred from the near-wall region to the main flow. The non-uniformities of fuel temperature and conversion at the cross section decreases, which is helpful for improving the utilization of the level of fuel heat-absorbing capacity, and beneficial for enhancing the heat transfer. [ABSTRACT FROM AUTHOR]

The thermal and optical performance in coating material of exterior walls affected the thermal action from the outdoor thermal environment indirectly, but there was the contrary thermal requirement in winter and summer, which could not be met by the constant-reflectivity coating. To overcome this drawback, the variable-reflectivity coating was analyzed and evaluated by taking three constant-reflectivity coatings as the references. The thermal transfer model with dynamic radiation reflectivity was built to simulate the thermal process of exterior walls in the whole year. Numerical results showed that the constant-reflectivity coating had poor seasonal adaptability with the best performance in some certain months and the poorest behavior in other months, while the variable-reflectivity coating had the better seasonal adaptability to dampen the heat gain in summer and promote the heat gain in winter. Although the variable-reflectivity coating could not show the optimal in all months, its overall performance played the best in the whole year. And compared with constant-reflectivity coating with radiation reflectivity of 90%, 50% and 10%, the variable-reflectivity coating could reduce the annual heating and cooling loads by 2.45%, 16.67% and 46.46%, respectively, in the studied Nanjing City of China. [ABSTRACT FROM AUTHOR]

With the increase of residents' requirements for the living environment, the current indoor thermal environment cannot meet the needs of modern rural residents who live in the northeast of Sichuan, China. Passive energy-saving strategies can not only improve the thermal performance of envelopes but also create high economic benefits. Evaluating the application effect of passive energy-saving strategies for traditional dwellings can provide a guide for local residents and policy makers to select rational passive strategies. Seven energy-saving strategies are proposed based on the current local building construction and heat transfer model, and then their energy-saving potential is evaluated by using EnergyPlus and the dynamic investment payback period method. Results show that adding exterior envelope insulation and setting on-top sunspaces on the roof simultaneously can save 83.9% of building energy consumption. However, the most economic energy-saving strategy is only employing exterior envelope insulation for local traditional dwellings when considering the economy. It can save 842 CNY/m2 during 100 years and its dynamic investment payback period is 14.1 years. In addition, building orientation also affects the energy-saving effects and the energy-saving rate can be increased by 8.4% under the optimal orientation (facing south) compared with the worst orientation (facing west). [ABSTRACT FROM AUTHOR]

Copyright of Journal of Architecture & Civil Engineering is the property of Chang'an Daxue Zazhishe and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this work, effective thermal conductivity (λEff) of fractured rock masses was numerically investigated. A two-dimensional Discrete Fracture Network (DFN) model of the fractured rock masses was established based on the statistic results of natural fracture development in a potential area for high level radioactive waste disposal in China. Steady state heat transfer processes in the fractured granite rock masses were numerically simulated using finite element method (FEM). The calculated λEff values of the fractured granite rock masses in dry and saturated conditions are 1.99 W/(m K) and 2.31 W/(m K), respectively. Compared with the thermal conductivity of intact granite [λIntact, 2.5 W/(m K)], the drop rates are 20.4% and 7.6%, respectively. Sensitivity analysis was conducted on the main model parameters including fracture density (FDensity), trace length (FLength), thermal contact resistance (FTCR), and λIntact. The results indicate the relation between λEff and three fracture parameters (FDensity, Flength and FTCR) can be fitted using power law or negative exponent functions with good consistency. When fracture network parameters remain unchanged, λEff is in linear positive correlation to λIntact. The slop of the fitted line is determined by the fracture network parameters. Due to the fact that distribution of generated fractures in different directions are quite uniform, λEff did not show significant difference in different directions. On the basis of the above-mentioned results, an estimation model was proposed for the determination of λEff of fractured rock masses using P21 (total length of fracture traces per unit area), FTCR, and λIntact. The proposed estimation model shows good consistency to the calculated results of FEM model. [ABSTRACT FROM AUTHOR]

Multi-span plastic tunnel greenhouse has widely been used in the cultivation of vegetables, fruits, and flowers. However, it is easily suffered from freezing damage to crops, particularly from cold waves in winter. In this study, an air thermal energy utilization system was developed with the fan-coil units to effectively control the thermal and humid environment in the shed. A field experimented was also performed on a two-span plastic tunnel in Wenzhou city of China during the cold wave from January 8 to January 13, 2021. The system was composed of fan-coil units, water reservoir, circulating water pump, supply and return water pipes, as well as control devices. The circulation of water in the system was utilized to collect and then store the surplus heat in the shed during the day, while finally released at night to heating the two-span plastic tunnel. In the collected phase, once the air temperature in the shed reached 15 ℃ on the day, or it was 5 ℃ higher than the water temperature in the water reservoir, the system was started until the air temperature dropped to 10 ℃, or it was 2 ℃ lower than the water temperature. In the released phase, once the outside air temperature was below 2 ℃ at night, or it was 4 ℃ lower than the water temperature, the system was started to operate until the air temperature reached 5 ℃, or it was only 2 ℃ higher than the water temperature. The collected and released performance of the system was evaluated using the collection and discharge heat, as well as heat flow, according to the change of water temperature in the experiment. The difference between water and air temperature was taken as the main influencing factor to analyze the heat flow in the collected and released phases. An exergy analysis of condensation dehumidification was also made during this time. The results showed that the system ensured the temperature inside the shed was 5.2-7.8 ℃ to protect crops from freezing damage, higher than that outside the shed in cold waves. The heat collection was 390.6-693 MJ, while the heat release was 361.2-609 MJ. The coefficient of performance (COP) of the system was 4.4-7.2, indicating quite remarkable energy saving. When the difference in water temperature increased by 1 ℃ during the operation of the system, the heat collection flow rate increased by 0.82 kW, while the heat release flow rate increased by 0.58 kW, indicating a larger heat transfer rate per unit time. In addition, the moisture absorption coefficient of the system was about 1.70 in the heat collected phase, due mainly to the presence of condensation and dehumidification. Meanwhile, the exergy efficiency tended to increase rapidly, up to 82.8%, as the temperature difference between water and air increased, indicating high energy utilization performance in the process of condensation and dehumidification. Nevertheless, the condensation and dehumidification gradually weakened until stopped, and concurrently the exergy efficiency decreased significantly, with the increase of water temperature. Consequently, the air thermal energy utilization system with fan-coil units can be expected to serve a safe, low carbon, and controllable heating technology. The finding can provide a potential application to ensure the safe production of multi-span plastic tunnels in winter [ABSTRACT FROM AUTHOR]

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Summary: Closed type assembly leads to complicated core thermohydraulics which are significant for design and safety analysis in sodium‐cooled fast reactor (SFR). Most of the major phenomena can be dealt with by general parallel channel network and two‐dimensional model for inter‐wrapper flow (IWF) in system code transient thermal‐hydraulic code for analysis of SFR (THACS). A main deficiency left is the overestimation of inter‐assembly heat transfer effect due to lump temperature message that one‐dimensional assembly model can only provide. A methodology was thus developed to compute wall‐subchannel temperature for simulating energy transportation through duct wall. Intra‐assembly thermohydraulics were classified as two mechanisms and non‐dimensional parameter was introduced for characterizing each of them. Ratio between linear heat flux density through hexagonal wrapper surface and pin surface qw/p was employed to account for radial heat transfer. Flow redistribution effect arouse in mixed and natural convection was concretized by a importance symbol of buoyancy force, Richardson number Ri. Two criteria were also proposed for dividing flow state into three parts and specific model for each section was defined. Two validation cases against 3‐D computational fluid dynamics (CFD) simulation of China experimental fast reactor whole core and test data from plant dynamics test loop with direct heat exchanger experiment were performed with THACS. Noticeable improvement after incorporation of this model demonstrated its value in system analysis. Although the procedure for parameter computations is geometry related, this method can be reproduced to any type of assembly directly. [ABSTRACT FROM AUTHOR]

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[Display omitted] • The study identifies higher pressure anomalies in the southeastern flank of the Huize fault-fold belt and the core of the Maoping belt, aligning with ore body locations. Zn2+ concentration is significantly higher in the SE flank of the Huize ore deposit and the NW flank of the Maoping deposit, revealing the impact of structural deformation on ore-forming fluid distribution. • Exploration potential is highlighted in specific areas, such as the core and southeastern wing of the Huize fault-fold belt and the core and northwestern wing of the Maoping fault-fold belt. Understanding the intricate relationship between fault-fold structures and ore body localization is paramount in economic geology. However, there is a lack of quantitative data on the influence of the geometry characteristics of faulted fold structures on the migration of ore-forming fluids. In this study, the differential ore-controlling characteristics of the steep flank of the anticline (Huize fault-fold belt,the ore body is located in the SE flank of the anticline) and the overturned flank of the anticline(Maoping fault-fold belt, the ore body is located in the NW flank of the anticline) were studied by using multi-physical finite element numerical simulation method. The findings of the study indicate that:(1) The local pressure anomalies in the core and southeastern flank of the Huize fault-fold belt is relatively higher than in comparable elevations elsewhere, while pressure anomalies in the Maoping fault-fold belt are concentrated in the core of the folds. (2) In the internal fault-fold belt of Huize, there is no significant temperature difference on either side of the folds. However, in the Maoping fault-fold belt, after reaching the core, heat predominantly transfers to the top pressure anomaly zone, resulting in noticeably higher temperatures in the northwest flank compared to the southeast flank. (3) Within the Huize fault-fold belt, ore-bearing fluids initially migrate along the fault, then move towards the core and SE flank upon reaching the mineralized strata. In contrast, within the Maoping fault-fold belt, ore-bearing fluids, after entering the layers, primarily migrate towards the core. (4) In the Huize ore deposit, the concentration of Zn2+ is significantly higher in the SE flank than in the NW flank, while in the Maoping deposit, the concentration is higher in the NW flank. The research results align with geological facts and provides valuable insights into the quantitative analysis of ore distribution controlled by the fault structure. This study provides crucial insights into exploring the control and influence of differential structural deformation on ore-bearing fluid migration, offering favorable exploration targets. [ABSTRACT FROM AUTHOR]

Predictive modeling of mineral prospectivity, which integrates diverse evidence of ore-forming processes based on an ore deposit genetic model constitutes a significant task in mineral exploration targeting. Descriptive deposit models suffer from overwhelming dependence on the explicitly mappable characteristics of a given deposit used to simplify the complex mineral system, but this hinders mineral prospectivity modeling. This study proposes a hybrid approach that combines numerical modeling with machine learning to predict mineral prospectivity. This approach first uses the numerical modeling method to provide more insights and better characterize a complex mineral system. These comprise implicit footprints such as singular stress deformation, heat transmission and fluid flux inherent in the transient geodynamics of ore genesis. The approach then applies a machine learning algorithm as a data-fusion tool to integrate the simulated evidence to minimize uncertainty in the predictive modeling of mineral prospectivity, which fundamentally results from an incomplete understanding of the targeted mineral system. Finally, we use the Fankou Mississippi Valley type Pb–Zn deposit as an example to illustrate the application of the proposed hybrid method. The prospectivity modeling result is critically compared with that of the spatial modeling based on descriptive deposit modeling by means of measures of accuracy, area under the receiver operating characteristic curve, and normalized density of prediction–area plot. It is shown that the overall performance of the prospectivity map predicted using a hybrid method is significantly improved. As such, this study demonstrates that a hybrid framework combining numerical modeling with machine learning provides a useful and novel way of predicting mineral prospectivity. The proposed hybrid method embodies a pioneering paradigm that integrates physics and data, assimilating ore deposit genesis models and reconnaissance data for the prediction of mineral prospectivity in support of exploration targeting. This approach can be implemented to enhance exploration information systems through the predictive modeling of mineral prospectivity in a unified computing and decision-making environment. The hybrid framework combining numerical modeling and machine learning for predictive mapping of mineral prospectivity. [Display omitted] • Here we apply numerical modeling in mineral prospectivity mapping (MPM). • Numerical modeling integrates ore deposit genesis models and exploration data. • Numerical modeling places physical and chemical constrains on MPM. • Numerical modeling-constrained MPM outperforms traditional MPM. [ABSTRACT FROM AUTHOR]

The NHR-200 reactor in China adopts the noncondensable gas self-stabilizing control and the noncondensable gas used for pressure stabilization control can weaken steam condensation heat transfer in the integrated steam-gas pressurizer. A condensation experimental system was established and the heat transfer characteristics of steam-nitrogen and steam-argon condensation under natural convection had been investigated. The pressure ranged from 0.516 to 5.10 MPa. The distributions of nitrogen and argon in the steam/gas mixture were obtained in the experiments, and the results showed that nitrogen and argon were evenly distributed in the steam under different pressure, respectively. The effects of heat transfer temperature difference had also been investigated and it is found that the total heat transfer coefficient difference had little influence on the total condensation heat transfer coefficient. However, the steam condensation heat transfer coefficient decreased with the increase of the degree of supercooling of the wall. The condensation heat transfer coefficient was reduced by approximately 0.11 kW/(m2·K) as the degree of supercooling of the wall changed from 14°C to 36°C. The condensation heat transfer coefficient also decreased with the mass/molar fraction of noncondensable gas increasing and a certain difference between the effect of the mass fraction of noncondensable gas and the effect of the molar fraction of noncondensable gas was discussed in this paper. [ABSTRACT FROM AUTHOR]

Composite hetero-structure wall is widely used for the north wall of solar greenhouse in China. A thermal stable thick layer in this type of wall can greatly weaken the heat storage capacity of the greenhouse wall. This study aims to improve the temperature of the thermal stable layer, and thereby promoting the heat storage capacity of north walls in a solar greenhouse. A new type of wall was proposed for the solar greenhouse with a flat Micro Heat Pipe Array (MHPA) wall or heat storage wall. The wall was made by bending the flat micro heat pipe array into a zigzag-shape while mixing the cement mortar to form an MHPA block. Then, the MHPA block and ordinary blocks were built into the MHPA wall. The evaporation section of the flat micro heat pipe array was placed on the inner surface of the MHPA wall, and the condensation section was placed inside the MHPA wall to achieve the purpose of enhancement heat transfer. Two small-scale greenhouse comparison test-benches were set up on site with the MHPA wall (named as MHPA greenhouse) and the ordinary block wall (named as ordinary greenhouse). The evaluation parameters included the temperature of the greenhouse wall, the daily heat storage/release of the wall, and the greenhouse environmental temperature. A systematic investigation was made to compare the characteristics of heat storage/release of the MHPA wall, and the effect of improving the greenhouse thermal environment on representative days. The results showed that the average internal surface temperature of the MHPA wall on typical sunny days (from 17:00 to 9:00 the next day) was 1.6-2.3 higher than that of an ordinary wall. From indoor to outdoor, the average ℃ temperature inside the MHPA wall for the 0-370 mm area along the wall thickness direction increased by 2.7-4.0 . During ℃ the heat storage period (from 9:00 to 17:00), the average environmental temperature of the MHPA greenhouse was 0.2-0.5 ℃ lower than that of an ordinary greenhouse, and the average ground surface temperature was 1.8-1.9 lower. During the heat ℃ release period, the average environmental temperature of the MHPA greenhouse was 1.2-1.5 higher than that of an ordinary ℃ greenhouse, and the average ground surface temperature was 0.6-1.0 higher. The MHPA wall can play the role of "peak ℃ cutting and valley filling" in the thermal environment of a greenhouse. The total daily heat storage of the MHPA wall was 8.92%-14.35% higher than that of an ordinary wall, and the total daily heat release was 2.24%-8.07% higher. In the heat storage and release rates of a wall on December 27, the maximum and average heat storage rates of the MHPA wall were 9.63 and 10.99% higher than those of the ordinary wall, and the maximum and average heat release rates were 9.23 and 5.60% higher than those of the ordinary wall, respectively. Moreover, the heat release rate of the MHPA wall was higher than that of an ordinary wall between 23:00 and 7:00 the next day, with an average increase of 11.53%. Therefore, the introduction of the MHPA wall into the wall of a solar greenhouse can effectively improve the heat storage and release capacity of the wall materials for a better thermal environment. These findings can provide a sound reference for the application of a flat micro-heat pipe array to the heat storage wall in a solar greenhouse. [ABSTRACT FROM AUTHOR]

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In recent years, the application of membrane structures in industrial storage buildings has been widely praised due to its light weight, high transparency, self-cleaning, and other advantages. The textile membranes consist of polyester fiber substrate and polyvinyl chloride or polyvinylidene fluoride flame-retardant coatings. It occupies the main market of architectural membrane materials in China. However, the fabric membrane material has high heat transfer coefficient, poor thermal insulation, and high light transmittance performance, being affected significantly by solar radiation intensity. These thermal optical properties are lead to a poor indoor thermal environment of industrial storage buildings. This article aims to overcome the difficulties in analyzing the fabric membrane materials solar radiation heat transfer. The complexity of heat transfer is mainly caused by the hourly solar radiation and the curved roofing of fabric membrane structure industrial storage building. Therefore, a solar radiation heat transfer model was established using MATLAB program. In this article, the different directions hourly heat gained of an actual membrane structures storage building located at Wuhan in China was calculated. The calculation results of solar radiation heat gained between the grid generation method with MATLAB and the projection method were compared. This study may provide a reference for analyze the solar radiation heat transfer and design of the practical fabric membrane structures building application. [ABSTRACT FROM AUTHOR]

This study is aimed at carrying out investigations on a domestic gas field, located in Yanchang, China, with a view to optimize the natural gas purification process. The main objectives of this work are (i) to reduce the natural gas purification system's energy consumption and (ii) improve the existing purification levels. Process simulations were carried out using Aspen Plus™ software, and a comprehensive technical and economic analysis was carried out. The single-factor sensitivity analysis method was used to determine the parameters of absorption, such as the reflux ratio and number of stages. The heat transfer process was analyzed using the energy-saving method of the energy system, and a modified process was recommended. The optimization results show that the recommended system has better purification performance, the comprehensive energy consumption is effectively reduced, and the energy efficiency is improved by 9%. [ABSTRACT FROM AUTHOR]

In consumer fireworks, various functions of chemicals create an energetic reaction with a type of colored light, smoke, heat, and the sound to achieve the pyrotechnic effects. Fireworks mixtures may be highly sensitive to external disturbances such as ignition sources, temperature changes, shocks, friction, and static electricity. Approximately 95% of fireworks are imported from China by ocean shipment, taking 4 days to a week to Taiwan. The prediction and assessment for the nth-order reaction, and thermokinetic parameters from thermal safety model for fireworks and pyrotechnic compositions were investigated. This study showed which reaction intensity of the propellant as water was added. It can be seen from the results that water will affect the thermal hazard of propellant. Moreover, the novel findings indicated that the water increased the thermal hazard of the propellant and consequently increased the risk for launching a degradation. Based on the heat transfer theoretical models, the time to maximum rate and time to conversion limit were extrapolated for consideration and discussion. [ABSTRACT FROM AUTHOR]

In China, the energy policy of switching charcoal heating to electric heating is pushing hard. Radiant floor heating system (RFHS) with air-source heat pump system is considered to be a suitable scheme for energy retrofit. A new type of lightweight RFHS with the aluminum layer is put forward in this article, which has the benefit of lowering the supply water temperature by enhancing the heat transfer performance and homogenizing the floor surface temperature distribution. The theoretical model of the new lightweight RFHS is built and solved by the Matlab program. Experiments are conducted to study the thermal performance of the RFHS and verify the theoretical model. The effects of supply water temperature and water flow velocity on the thermal performances of the new RFHS are studied. Then, the effects of aluminum layer on the heat transfer performance of the new system are researched. Finally, comparative research of the new lightweight RFHS and traditional heavy RFHS is carried out. The results show that the average floor surface temperature, heat transfer rate, and annual exploitation cost of the new RFHS are all better than the traditional one. [ABSTRACT FROM AUTHOR]

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