Transient Heat Transfer Model Research Articles

MODELLING DEVELOPMENT OF A RECEIVER-REACTOR OF TYPE R2Mx FOR THERMOCHEMICAL WATER SPLITTING

Abstract This work reports on the development of a transient heat transfer model for a prototype reactor of type R2Mx for thermochemical water splitting by temperature and pressure swing of ceria. Key aspects of the R2Mx concept, which are also incorporated in the prototype design, include a movable monolithic redox structure combined with a linear transport system, a reduction reactor as well as a dedicated oxidation reactor. With the model, the operation of the prototype is simulated for consecutive water splitting cycles, in which ceria is reduced in a continuously heated reactor, oxidized in a separate oxidation reactor and transported in between the reaction zones. A 2D axisymmetric numerical model of the prototype reactor was developed in ANSYS Mechanical. The model includes heat transfer calculations in combination with an approximated simulation of the transport of the redox material during cyclic operation. It incorporates the chemical reaction by means of a modified heat capacity for ceria and accounts for internal radiation heat transfer inside the porous redox material by applying effective heat transfer properties. A parametric analysis has been undertaken to evaluate different modes of operation of the oxidation reactor. Model results are used to size the power demand of the reduction reactor and vacuum pump, to define durations of the process steps as well as to assess operational parameters with respect to achieved temperatures. Findings suggest that suitable operation of the prototype reactor involves reduction durations ranging from 8 to 10 minutes and oxidations of 6 to 10 minutes.

Assessment of evaporative porous clay cooler for Building-Integrated photovoltaic systems via energy, exergy, economic and environmental approaches

A thorough study has been conducted for the energy, exergy, economic and environmental analysis to investigate the feasibility of utilizing an evaporative porous structure cooler for the building-integrated photovoltaic (BIPV) system at different building’s sides and directions. Photovoltaic panels within the BIPV systems dissipate their heat to the building’s sides which contribute to rise the interior building’s temperature. In the proposed system, a water-saturated evaporative porous clay cooler is being installed on the back surface of the PV panels to absorb and dissipate their heat by latent evaporation through an evaporation cooling process. A transient numerical heat and mass transfer model based on energy, exergy, economic and environmental approaches was proposed to assist the feasibility of cooling BIPV system via evaporative porous structure cooler. The model was also validated experimentally in the present study. The results exhibited that, comparing with conventional BIPV systems, the presented BIPV/Clay cooling system achieved a peak photovoltaic temperature reduction of 19.1 °C, with a maximum enhancement in the photovoltaic system’s electrical efficiency, electrical power, and exergy efficiency of 9.8 %, 12.6 % and 11.8 %, respectively. The ultimate reduction in the building’s annual thermal load was around 53.8 % when the clay evaporative cooling approach is applied, while the cost of electricity production reduced ultimately by 7.9 %, (from 0.151 $/kWh to 0.134 $/kWh). Further, the payback period decreased by 2.33 years and the annual amount of CO2 emissions decreased by 10.4 % for the utilized BIPV/Clay cooling system compared with the conventional BIPV system.

A new analytical model for transient heat transfer modeling of geothermal monotube heat exchangers

In this study, we present a new analytical model for the analysis of transient heat transfer (the model is solved after Laplace transformation) in geothermal monotube heat exchangers (GHE). The model accounts for various factors, including the heat exchanger's geometric parameters, the nature of the fluid (air and water), flow characteristics (laminar and turbulent), and heat transfer boundary conditions. Initially, the model's performance is validated by comparing its results with those obtained from computational fluid dynamics simulations using OpenFOAM. This validation process ensures the reliability and accuracy of the model. Additionally, an analysis of the heat transfer mechanisms and key modeling parameters identified from the comparison is provided. In the subsequent section, the analysis is extended by comparing the proposed model to four existing analytical models available in the literature. These reference models employ distinct approaches to simulate heat transfer to the ground. By examining a range of cases, the performance of the model is systematically evaluated against these conventional methods. This work closes by an analysis of the analytical models and the impact on the accuracy of the results highlighting the advantages of the proposed method in geothermal applications.

Evaluating the maximum drilling length of horizontal geothermal wells utilizing temperature constraints

The geothermal industry faces a significant challenge in exploring and developing resources due to elevated temperatures in downhole environments. Successful drilling in high-temperature geothermal wells requires precise thermal management. This research assesses constraints on horizontal section length and temperature during geothermal horizontal well drilling, aiming to formulate effective wellbore temperature management guidelines.The study utilizes thermal resistance analysis to establish a tailored transient heat transfer model for high-temperature horizontal geothermal well drilling. Parameters such as circulation time, horizontal section length, flow rate, drilling fluid properties, formation thermal conductivity, and drill string thermal conductivity are thoroughly investigated. Treating input parameters as triangular distributions, Monte Carlo simulation techniques conduct sensitivity analysis. Tornado diagrams quantitatively determine key parameter impacts on bottom-hole temperature. The research introduces a procedural framework for geothermal well drilling, aiding engineers in swiftly identifying operational parameter combinations for effective wellbore temperature management. This workflow provides practical guidance for geothermal resource development, ensuring drilling safety in diverse conditions.

Investigation on heat transfer performance of flat plate micro-heat pipe phase change heat storage/release device

In the domains of low/zero carbon energy, the ship energy storage system, coupled with phase-change storage and release technology, holds significant importance. The utilization of a flat micro-heat pipe as the primary heat transfer element prompts the development of a test platform and a transient heat transfer model for the heat storage device. This is in response to existing challenges such as a single structure, poor temperature uniformity, and low thermal efficiency in current heat storage technology. The study delves into the impact of varying temperatures and flow rates of heat transfer fluids on the overall performance of heat storage devices and heat transfer efficiency. The findings highlight that the staggered double plate micro-heat pipe structure can enhance total heat storage by 11%, average heat storage power by 19%, and heat storage efficiency by 21% compared to the heat storage device with a single flat micro-heat pipe structure. It becomes evident that the heat storage device with the staggered double heat pipe structure outperforms its counterpart. Additionally, Temperature and flow velocity play pivotal roles in determining the heat transfer performance of phase change materials. As the temperature difference between the heat transfer fluid and the phase change material increases, both the phase transition rate and the equivalent Nusselt number also rise, providing a crucial foundation for examining the heat transfer characteristics of phase change materials during different stages of phase transition.

Exploring energy-saving performance of radiative cooling roofs with a transient heat transfer model

Radiative cooling coatings, serving as building roof exterior surfaces, reflect most solar energy and dissipate heat mainly through the atmospheric window. A roof transient heat transfer model was proposed considering the atmospheric transmittance and spectral properties of radiative cooling coatings within the longwave range by coupling one-dimensional transient heat transfer and a spectral-dependent method. The atmospheric radiation was calculated based on the dew point temperature. Field measurements were conducted to verify the model reliability. The simulation and experimental data matched well. The validated model was employed to analyze the energy-saving performance of radiative cooling coatings in diverse climate zones in China (Guangzhou, Shanghai and Beijing). The results showed that the radiative cooling coatings (solar reflectance β = 0.85 and thermal emissivity ε = 0.95) achieved excellent cooling performance, although they could cause a penalty during the heating period. Compared with conventional exterior surfaces (β = 0.2 and ε = 0.9), the radiative cooling coatings reduced the annual load (the sum of the cooling and heating loads) of roofs by 84.9%, 30.3% and 2.4% in Guangzhou, Shanghai and Beijing, respectively, with roof insulation thicknesses of 40, 80 and 100 mm, respectively. Sensitivity analysis revealed that the solar reflectance determined the roof annual load in Guangzhou, while the insulation thickness determined the roof annual load in Shanghai and Beijing. The numerical model developed herein could be used to analyze the energy-saving potential of radiative cooling roofs with different spectral properties and provide guidance for effectively applying radiative cooling coatings on building roofs.

The role of emissivity of the window surface inside and outside the atmospheric window in the radiative cooling effect

The emissivity design of building surfaces is crucial for radiative cooling (RC) heat dissipation. This work explores regularities of the influence of the emissivity inside and outside the atmospheric window (AW, 8-13 μm) on the window RC effect using a verified transient building heat transfer model. Results show that the RC effect brought by the radiant heat transfer of the window in non-atmospheric window bands (NAW) may exhibit a reversal phenomenon of first improvement and then weakening with the increase of the outer surface emissivity ε‾NAW. The occurrence of this reversal phenomenon is influenced by multiple factors such as meteorological parameters like ambient temperature and solar radiation, as well as architectural features including window orientation and window-to-wall ratio. In addition, as the window-to-wall ratio increases, when no reversal phenomenon occurs, the average RC regulation ability gap between the emissivity inside and outside the AW decreases from 7–40 times, which is observed when the reversal phenomenon occurs, to about 2–5 times, and the relative importance of ε‾NAW greatly increases. Regularities revealed provide more reliable guidance for the performance research and material design of RC windows.

Topography optimisation using a reduced-dimensional model for transient conjugate heat transfer between fluid channels and solid plates with volumetric heat source

Consideration of transient effects is important for industrial applications of heat transfer structure optimisation studies; however, the huge computational cost associated with transient problems is a pressing concern. This paper proposes an extension of a previous reduced-dimensional model to transient conjugate heat transfer between a fluid flow and solid-heated plates in a plate heat exchanger. The extended reduced-dimensional model introduces the temperature field of the plate governed by the heat conduction equation, which is coupled to the temperature field of the fluid, governed by the convection-diffusion equation, through the heat flux balance equation at the contact surface. The model is based on assumptions of fully developed flow and constant temperature profile, reducing the three-dimensional problem to a planar problem and significantly reducing computational costs. The accuracy of the model for the simulation of transient heat transfer is verified by comparison with a three-dimensional model. In this paper, the topography of the heat exchanger plate is optimised for both steady-state and transient conditions by applying the reduced-dimensional model. The effectiveness of the optimised design was demonstrated by the cross-check of both the reduced-dimensional and full three-dimensional models. Furthermore, this work considers the effect of time-independent boundary conditions and time-dependent boundary conditions on transient optimisation. The transient and steady-state optimised designs are analysed and compared for both conditions, and the necessity of transient optimisation is discussed.

Numerical Modeling and Analysis of Transient and Three-Dimensional Heat Transfer in 3D Printing via Fused-Deposition Modeling (FDM)

Fused-Deposition Modeling (FDM) is a commonly used 3D printing method for rapid prototyping and the fabrication of plastic components. The history of temperature variation during the FDM process plays a crucial role in the degree of bonding between layers. This study presents research on the thermal analysis of the 3D printing process using a developed simulation code. The code employs numerical discretization methods with an implicit scheme and an effective heat transfer coefficient for cooling. The computational model is validated by comparing the results with analytical solutions, demonstrating an agreement of more than 99%. The code is then utilized to perform thermal analyses for the 3D printing process. Interlayer and intralayer reheating effects, sensitivity to printing parameters, and realistic printing patterns are investigated. It is shown that concentric and zigzag paths yield similar peaks at different time intervals. Nodal temperatures can fall below the glass transition temperature (Tg) during the printing process, especially at the outer nodes of the domain and under conditions where the cooling period is longer and the printed volume per unit time is smaller. The article suggests future work to calculate welding time at different conditions and locations for the estimation of the degree of bonding.

A new detection method of co-existence of well kick and loss circulation based on thermal behavior of wellbore-formation coupled system

Accurately obtaining wellbore-formation temperature distribution during drilling in fractured carbonate formations is the basis for effectively solving the problem of the well kick and loss circulation coexisting (WK-LC). Therefore, based on the energy conservation law and considering the convective heat transfer and variable mass flow caused by well kick and loss circulation, this paper developed a full transient heat transfer model of wellbore-formation coupled system under the WK-LC. The reliability of model was verified by field measured temperature data. Based on field well, the thermal behavior of wellbore-formation coupled system under normal condition, well kick, loss circulation and WK-LC were compared and studied.The results showed that the bottom-hole temperature of well kick and Case1-2 is higher than that of normal condition, while the bottom-hole temperature of loss circulation and Case3-4 is lower than that of normal condition. The temperature difference between annulus and drill string (TD-AD) shows a “wavy line” trend of increasing-decreasing-increasing-decreasing along the well depth. The TD-AD of wellhead is about 6 °C in normal and WK-LC conditions. The traditional wellhead temperature monitoring method can only distinguish well kick and leakage, and it is difficult to judge whether WK-LC occur.In addition, the influence of the distance and well kick/leakage rate difference between the well kick region and the leakage region on thermal behavior of wellbore-formation coupled system was discussed. Finally, a new auxiliary method is proposed to identify the well kick, the loss circulation and the WK-LC. Which will have a significant implication for well killing and leaking stoppage operations.

Thermal and mechanical investigation of proton exchange membrane fuel cells under combined loading conditions

Mechanical performance of PEM fuel cells under combined loadings is one of critical issues in improving cell performance and reliability. In this study, thermal and mechanical performance of the PEM fuel cell under clamping force and temperature load are investigated by experiments and three-dimensional dynamic simulations. In experiments, pressure distributions between gas diffusion layer and flow field are measured by pressure sensitive films. The experimental results show that the local pressure increases with clamping load, and pressure distribution is much uneven in the midstream. Meanwhile, a three-dimensional model of the cell combined transient heat transfer and mechanical response of components is developed, which is validated by experimental data. The modeling results show that under combined loadings, the porosity of gas diffusion layer under the rib decreases, attributed to compressive deformation caused by thermal gradient and clamping pressure, leading to higher effective thermal conductivity and electrical conductivity. When at a higher temperature, the overall stresses of gas diffusion layer decrease and the minimum stress is located under the center rib, forming a concave stress distribution pattern. Distribution and variation patterns of local deformations and stresses for the membrane are similar to those of gas diffusion layer, but the maximum stress and deformation are much lower. A dimensional stress coefficient is proposed to determine the stress distribution uniformity under the rib. With the increase of clamping torque, dimensionless stress coefficients under lower ambient temperature change slightly. As temperature increases, dimensionless stress coefficients increase significantly and decrease with the clamping torque, indicating the decreasing role of temperature load on mechanical response of the cell.

Data-Driven Contact-Based Thermosensation for Enhanced Tactile Recognition.

Thermal feedback plays an important role in tactile perception, greatly influencing fields such as autonomous robot systems and virtual reality. The further development of intelligent systems demands enhanced thermosensation, such as the measurement of thermal properties of objects to aid in more accurate system perception. However, this continues to present certain challenges in contact-based scenarios. For this reason, this study innovates by using the concept of semi-infinite equivalence to design a thermosensation system. A discrete transient heat transfer model was established. Subsequently, a data-driven method was introduced, integrating the developed model with a back propagation (BP) neural network containing dual hidden layers, to facilitate accurate calculation for contact materials. The network was trained using the thermophysical data of 67 types of materials generated by the heat transfer model. An experimental setup, employing flexible thin-film devices, was constructed to measure three solid materials under various heating conditions. Results indicated that measurement errors stayed within 10% for thermal conductivity and 20% for thermal diffusion. This approach not only enables quick, quantitative calculation and identification of contact materials but also simplifies the measurement process by eliminating the need for initial temperature adjustments, and minimizing errors due to model complexity.

Research on the energy efficiency improvement of closed loop wastewater source heat pump with direct-expansion heat exchanger

The closed-loop wastewater source heat exchanger (WSHE) has advantages such as being non-clogging and resistant to corrosion, but their heat transfer efficiency is relatively low, therefore it is still not the mainstream form of heat exchanger of wastewater source heat pump (WSHP). A novel CO2 direct-expansion wastewater source heat exchanger (DX-WSHE) is proposed in this paper, aiming to significantly improve the heat transfer rate of the heat exchanger and the energy efficiency of the heat pump system. The direct-expansion heat transfer process is complex, large grid number and long calculation time will be required if calculated by conventional numerical simulation software. Therefore, a three-dimensional transient heat transfer model was developed based on the thermal resistance and capacity model, which offers the advantages of fast computation speed and strong flexibility. The heat transfer and energy efficiency characteristics under different parameters were studied. The coefficient of performance (COP) of the direct-expansion wastewater source heat pump (DX-WSHP) can be increased by 31.0% compared to conventional design, and the heat flux of the direct-expansion wastewater source heat exchanger can be up to 250 W/m for the standard group. Compared with conventional designs, the direct-expansion wastewater source heat pump has excellent heat transfer and energy efficiency capabilities, which is a promising building energy saving and emission reduction technology.

Transient Tip Clearance Prediction Model Considering Transient Radial Temperature Distribution of Discs in a Gas Turbine Engine

Abstract The tip clearance of turbomachinery components, such as compressor and turbine, significantly impacts the gas turbine engine performance, including the thrust and fuel consumption. Therefore, an appropriate prediction of the turbomachinery tip clearance is indispensable in improving the accuracy of engine performance evaluations. The traditional 1D transient tip clearance prediction model does not consider the radial temperature distribution of the disk (also called disc). However, as the engine performance keeps improving, the radial temperature gradient of the disk also increases. In order to maintain the prediction accuracy within an acceptable range, a generic transient tip clearance prediction model is developed in this paper. Based on the special treatment of the axial and radial convective heat transfer boundary regions of the disk, a 2D transient heat transfer model is established, and the radial temperature of the disk is predicted. At the same time, the interaction effect of the thermal expansion between the two different layers of the shroud is studied to improve the prediction accuracy further. In addition, the centrifugal deformation of the blade and disk with variable-thickness characteristics is considered in the new transient model. Compared with the traditional 1D transient prediction model, the model developed in this paper further improves the predicting accuracy of the transient tip clearance, which is verified by the high-fidelity fluid–solid–thermal coupling method. The prediction model provides a useful tool for evaluating the transient tip clearance. It may also benefit the future design strategy of active clearance control.

Analysis of dynamic thermal behaviors for multi-stage hydraulic fracturing treatments in horizontal shale oil and shale gas wells

Accurate prediction of dynamic thermal behaviors during multi-stage hydraulic fracturing is profound which can avoid performance deterioration of fracturing fluids or failure of fracturing tools caused by severe temperature variation. This paper establishes a transient heat transfer model for multi-stage hydraulic fracturing in horizontal shale oil and shale gas wells (MFHWM), considering the real construction process of multi-stage hydraulic fracturing, the turbulent flow state, the heat source of viscous dissipation and the complex wellbore structure, which enables the accurate simulation of thermal behaviors in the early time of multi-stage hydraulic fracturing with large flow rate. The verification results of measured temperature data and simulation data prove the MFHWM has good precision. Numerical simulations indicate that the temperature distribution exhibits the characteristics of cyclic “cool-down” and “warm-back” and “stair-step” during the multi-stage hydraulic fracturing. In the “cool-down” period, the temperature drops sharply within the first hour and then the deceleration slows down. In the “warm-back” period, the temperature recovers exponentially relying on the shut-in time. The “stair-step” is caused by changing of heat transfer mechanism from convection to conduction. Moreover, the cyclic cooling has little effect on the total temperature drop and subsequent stages are not significantly cooler than previous stages. Besides, primary factors affecting temperature distributions of wellbore-formation system are discussed thoroughly. Results indicate that the viscous heat source cannot be ignored for multi-stage hydraulic fracturing and the temperature difference exhibits cyclic variation when considering and without considering the viscous heat source. In addition, the minimum temperature during each-stage-fracturing operation decreases first and then increases as the injection rate of fracturing fluid increases because of the compromise between the viscous heat source and forced convection. Furthermore, temperature distributions can be controlled by changing the injection temperature of fracturing fluid. As the injection temperature increases, a positive proportional relationship exists between the minimum temperature of fracturing fluid and the injection temperature. MFHWM can be a standalone tool to analyze temperature distributions of multi-stage hydraulic fracturing. It can also be used to provide better boundary conditions for stress analysis model of casing and cement sheath.

Start-up characteristics of a R290 rotary compressor for an air source heat pump under low ambient temperature condition

Due to its excellent thermodynamic properties, low GWP refrigerant R290 is found to be promising alternative refrigerant. However, due to its special physical properties, high oil discharge rate and throttle valve blockage may occur for the R290 heat pump system under low temperature start-up conditions. In this paper, the transient characteristics, including the temperature, heat exchange rate, phase change rate, oil discharge rate and the liquid level of the oil sump, of a R290 rotary compressor used in the heat pump system under low temperature conditions are theoretically and experimentally studied. A transient heat and mass transfer model in the compressor is proposed, which considers the phase change of refrigerant in the shell. The experiment was carried out on the start-up characteristics of the compressor and the mathematical model was verified. The results show that high rotation speed and low temperature are the main reasons for the condensation of R290 in the shell. The excessive liquid refrigerant in the shell leads to a high oil discharge rate of up to 22 %. This paper will provide guidance for the use of R290 refrigerant under low temperature conditions.

A coupled fluid-thermo-mechanical evaluation of various freeze recovery strategies for molten salt parabolic trough collectors

This research advances the field of Concentrating Solar Power (CSP) by offering a comprehensive assessment of freeze-recovery strategies for molten salt parabolic trough collectors, essential for the next generation of CSP plants. Employing a cutting-edge transient 3D Conjugate Heat Transfer (CHT) model, the research elucidates the significant yet previously underestimated role of natural convection in the phase transition of solidified salts. The study demonstrates that the strategic inclusion of impedance heating not only accelerates the defrosting process but also minimizes thermal stresses within the absorber tubes, ensuring mechanical integrity. Moreover, the dual-method approach, which combines solar and impedance heating, reveals a potential to improve the Levelized Cost of Electricity (LCOE) by 4% annually following a complete freeze event. The research conclusively suggests that this synergistic strategy could yield substantial operational cost savings while maintaining the structural robustness of CSP systems. The presented findings provide a detailed blueprint for enhancing plant resilience and economic viability, opening new avenues for operational excellence in CSP technology.

Investigation of the performance enhancement of building-integrated photovoltaic system using evaporative porous clay applied in different building's directions

The integration of photovoltaic (PV) modules with building's facades and roofs results in significant reduction in the PV module's efficiency owing to its temperature rising, as well as increasing in the building's indoor thermal gain. Thus, this study proposed cost-effective and eco-friendly passive cooling technique utilizing evaporative porous clay material to minimize the integrated PV module's temperature. An experimentally validated numerical study is being performed using different clay thickness and porosity to estimate the expected enhancement in the thermal and electrical performance of the building-integrated photovoltaic (BIPV) system. The experimental tests were carried out using prototype of small rooms integrated with PV panels installed with a water-saturated porous clay material to validate the presented transient numerical heat and mass transfer model. After that, the proposed system is being compared with another passive cooling mechanism using phase change material (PCM), and the results are then analyzed and compared. The findings showed a maximum reduction of 19.1 °C and 12.8 °C of peak PV temperature when the porous clay and PCM are utilized, while the building's side temperature reduced by around 11.2 °C and 10.9 °C, respectively. Further, porous clay achieved up to 9.8 % improvement in PV system's efficiency, with a maximum water consumption rate reached around 3.35 L/h.m2. Moreover, applying such a porous clay cooling approach resulted in a maximum reduction of 53.8 % in the building's annual thermal load. In the outcomes reported here, porous clay with the least thickness and highest porosity achieved more feasible cooling effects compared with PCM.

Influence of selective infrared emissivity design on the radiative cooling effect of windows: Laws exploration based on transient analysis

Most existing material design studies assume that radiative cooling (RC) windows should be ideal radiators with high emissivity (ελ∼1) in wide infrared band (IR, 2.5–20 μm). However, whether this assumption is universal has not been tested. Different from previous studies based on experiments and steady-state theoretical calculation models, a transient building heat transfer model with facade windows verified by experiments is used to explore the optimal design of IR emissivity of RC windows. Results show that the RC effect of windows is not always improved as traditionally expected with the increase of emissivity (ε‾NAW) in the infrared " non-atmospheric window (NAW) " band. In fact, the adjustment trend of ε‾NAW for the RC effect of windows is reversed. Smaller ε‾NAW can weaken the heat flow into the room and prolong the time that windows become " coolers ". A wider range of window-to-wall ratios are also studied, and it is found that the design of selective high emissivity (ε‾NAW ∼0) is more conducive to the RC of windows. It is proved that the current default design of the RC window emissivity in IR band is non-universal, and new laws found provide an enlightening guide for the material development of RC windows.

Developing and solving the mathematical model of transient heat and mass transfer in the freeze-drying of Cordyceps militaris

This study developed a mathematical model of the transient mass and heat transfer of Cordyceps militaris during lyophilization. This mathematical model was solved using a program coded in MATLAB to simulate the relationship between product temperature and sublimation rate over time. The parameters of the drying mode were set in the simulation as follows: heating plate temperature from 273.2 to 303.2 K, the absolute pressure of the drying chamber is from 30 Pa to 60 Pa. The fruiting body of cordyceps analyzed in the study is considered a cylindrical shape with a radius of 1.5 mm and length of 60 mm, which was arranged in 1 layer on a tray with dimensions of 200x300x20 mm. Research shows that the sublimation rate increases when the heating plate temperature increases. Besides, the decrease in sublimation chamber pressure will lead to rapid increases in drying speed. This result can also be used to build software to set the technological mode for the cordyceps drying process by sublimation.