Heat Transfer Law Research Articles

Response of stiffness and viscosity on the energy ratios at piezo-visco-thermo-elastic medium

This article presents a mathematical framework that characterizes a transversely isotropic piezo-visco-thermo-elastic medium within the context of the dual-phase lags heat transfer law (PVID) applied to an elastic medium (ES). Specifically, the study investigates the propagation of plane waves within the elastic medium and their interaction with the imperfect interface of the ES/PVID media. This interaction results in two waves reflecting back into the elastic medium and four waves propagating through the piezo-visco-thermo-elastic medium. The research explores the distribution of energy between the reflected and transmitted waves by analyzing amplitude ratios at the boundary interfaces, considering factors such as phase delays, viscosity effects, and wave frequency. The study illustrates the influence of boundary stiffness and viscosity parameters on these energy ratios through graphical representations. The study's findings are consistent with the principles of the energy balance law, and the research also delves into specific cases of interest. Overall, this investigation provides insights into wave behavior within complex media and offers potential applications across various fields.

Определение коэффициента теплопроводности деревянных клееных конструкций с учетом макроструктуры и плотности древесины

The paper considers calculated and experimental methods of determining the thermal conductivity coefficient of wooden glued structures. The author shows that when designing the thermal protection of building enclosure structures in the form of CLT-panels or wooden glued laminated timber, one uses reference data on the thermal conductivity coefficient for pine or spruce. In practice, the value of the thermal conductivity coefficient may be less than the reference value; as a consequence, the thickness of the building enclosing structures is overestimated. This is not reasonable in terms of material intensity of construction. When considering wood as an anisotropic material, the peculiarities of the macrostructure and differences in the density of individual layers, as well as the wood species, should be taken into account when determining the parameters of structures. Based on the physical description of the thermal conductivity process and the fundamental laws of heat and mass transfer, the author proposes that it is necessary to adjust the results of calculations to the actual values of the thermal conductivity coefficient of multilayer wooden glued structures. The paper presents the results of experimental determination of the thermal conductivity coefficient of pine and aspen wood using steady-state and unsteady heat flow methods. It is shown that, depending on the density and wood species, experimental values of the thermal conductivity coefficient from 0.102 to 0.115 W·m-1∙K-1 can be obtained.

Randomness effect of platinum loading distribution in a proton exchange membrane fuel cell: A numerical simulation

The platinum loading is randomly distributed within catalyst layers because of the fabrication way, whereas the platinum loading is considered to follow the homogeneous distribution in the traditional catalyst layer model. The cell performance and heat and species transport laws of the fuel cell with platinum loading random distribution within catalyst layers are not yet clear. Therefore, in this work, a two-dimensional, non-isothermal proton exchange membrane fuel cell model considering the two-phase flow and agglomerate structure of catalyst layers is established to simulate the fuel cell having the catalyst layer where platinum loading is random distribution in a way that is closer to the actual structure. The effect of random distribution of platinum loading on the electrical property, species transfer and temperature distribution is analyzed. Results suggest that the randomness influence needs to be considered when the local distributions of parameters are studied and the research accuracy of parameters is relatively high. In contrast with the homogeneous distribution of platinum loading, the cell performance for the normal random distribution and uniform random distribution cases is reduced. The effects of catalyst loading random patterns on cell performance, species and temperature distributions are different, and the decrease of cell performance for the uniform random distribution case is more obvious. Furthermore, the influence degree of randomness on each parameter is different. The distributions of electrochemical reaction rate, oxygen concentration and temperature display random characteristics, while the liquid water saturation distribution is less influenced by randomness and does not show an obvious random change. These findings can provide a reference for the randomness verification in random simulations and deepen the understanding of species and heat transfer laws in the catalyst layer which is closer to the reality to improve the accuracy of fuel cell simulations.

Research on heat transfer law of multiphase flow in wellbore under coexistence of overflow and lost circulation in deepwater drilling

A reliable and accurate wellbore heat transfer model is essential for making critical decisions during deepwater drilling operations. This study develops a transient coupled flow model for the coexistence of overflow and lost circulation simulation in deepwater drilling. Through the established theoretical model, this paper studies the influence of gas influx, lost circulation, and coexistence of gas influx and lost circulation on wellbore temperature distribution and gas migration and analyzes the development of gas influx and lost circulation under different engineering parameters. The results show that the gas expansion after gas influx mainly occurs at the depth of 200 m and above. The gas void fraction is reduced with the increase of wellhead casing pressure, but the change range is gradually reduced. After the lost circulation occurs, the wellhead temperature, bottom hole temperature, and bottom hole pressure decrease obviously. The influence of the coexistence of gas influx and lost circulation on the change of wellbore temperature and pressure is greater than that of the two alone. The wellbore temperature under upper gas influx and lower lost circulation is generally higher than that under upper lost circulation and lower gas influx. However, the bottom hole pressure under upper gas influx and lower lost circulation is slightly smaller than that under upper lost circulation and lower gas influx.

Scaling and modeling of the heat transfer across the free surface of a thermocapillary liquid bridge

PurposeThis paper aims to derive a reduced-order model for the heat transfer across the interface between a millimetric thermocapillary liquid bridge from silicone oil and the surrounding ambient gas.Design/methodology/approachNumerical solutions for the two-fluid model are computed covering a wide parametric space, making a total of 2,800 numerical flow simulations. Based on the computed data, a reduced single-fluid model for the liquid phase is devised, in which the heat transfer between the liquid and the gas is modeled by Newton’s heat transfer law, albeit with a space-dependent Biot function Bi(z), instead of a constant Biot number Bi.FindingsAn explicit robust fit of Bi(z) is obtained covering the whole range of parameters considered. The single-fluid model together with the Biot function derived yields very accurate results at much lesser computational cost than the corresponding two-phase fully-coupled simulation required for the two-fluid model.Practical implicationsUsing this novel Biot function approach instead of a constant Biot number, the critical Reynolds number can be predicted much more accurately within single-phase linear stability solvers.Originality/valueThe Biot function for thermocapillary liquid bridges is derived from the full multiphase problem by a robust multi-stage fit procedure. The derived Biot function reproduces very well the theoretical boundary layer scalings.

A Numerical Investigation of the Nonlinear Flow and Heat Transfer Mechanism in Rough Fractured Rock Accounting for Fluid Phase Transition Effects

The study of the seepage and heat transfer law of three-dimensional rough fractures is of great significance in improving the heat extraction efficiency of underground thermal reservoirs. However, the phase transition effects of fluids during the thermal exploitation process profoundly influence the intrinsic mechanisms of fracture seepage and heat transfer. Based on the FLUENT 2020 software, single-phase and multiphase heat–flow coupling models were established, and the alterations stemming from the phase transition in seepage and heat transfer mechanisms were dissected. The results indicate that, without considering phase transition, the geometric morphology of the fractures controlled the distribution of local heat transfer coefficients, the magnitude of which was influenced by different boundary conditions. Moreover, based on the Forchheimer formula, it was found that the heat transfer process affects nonlinear seepage behavior significantly. After considering the phase transition, the fluid exhibited characteristics similar to shear-diluted fluids and, under the same pressure gradient, the increment of flow rate was higher than the increment in the linearly increasing scenario. In the heat transfer process, the gas volume percentage played a dominant role, causing the local heat transfer coefficient to decrease with the increase in gas content. Therefore, considering fluid phase transition can more accurately reveal seepage characteristics and the evolution law.

Modelling the effect of roughness density on turbulent forced convection

By examining a systematic set of direct numerical simulations, we develop a model which captures the effect of roughness density on global and local heat transfer in forced convection. The surfaces considered are zero-skewed three-dimensional sinusoidal rough walls with solidities, $\varLambda$ (defined as the frontal area divided by the total plan area), ranging from low $\varLambda = 0.09$ , medium $\varLambda = 0.18$ to high $\varLambda = 0.36$ . For each solidity, we vary the roughness height characterised by the roughness Reynolds number, $k^+$ , from transitionally rough to fully rough conditions. The findings indicate that, as the fully rough regime is approached, there is a pronounced breakdown in the analogy between heat and momentum transfer, whereby the velocity roughness function $\Delta U^+$ continues to increase and the temperature roughness function $\Delta \varTheta ^+$ attains a peak with increasing $k^+$ . This breakdown occurs at higher sand-grain roughness Reynolds numbers ( $k_s^+$ ) with increasing solidity. Locally, we find that the heat transfer can be meaningfully partitioned into two categories: exposed, high-shear regions experiencing higher heat transfer obeying a local Reynolds analogy and sheltered, reversed-flow regions experiencing lower and spatially uniform heat transfer. The relative contribution of these distinct mechanisms to the global heat transfer depends on the fraction of the total surface area covered by these regions, which ultimately depends on $\varLambda$ . These insights enable us to develop a model for the rough-wall heat-transfer coefficient, ${C_{h,k}(k^+, \varLambda, Pr)}$ , where $Pr$ is the molecular Prandtl number, that assumes different heat-transfer laws in exposed and sheltered regions. We show that the exposed–sheltered surface-area fractions can be modelled through simple ray tracing that is solely dependent on the surface topography and a prescribed sheltering angle. Model predictions compare well when applied to heat-transfer data of traverse ribs from the literature.

Cattaneo-Christov heat and mass fluxes model of Casson fluid employing non-Fourier double diffusion theories with ion slip and Hall effects

It is vitally important to comprehend non-Newtonian fluids flow behaviour from an industrial perspective. Non-Newtonian fluids are needed for a number of industrial and technical processes, including the production of paper, photographic films, and polymer sheet extrusion. There are several industrial applications for heat and mass transfer. However, thermal and solute relaxation time phenomena can't be predicted by classical heat and mass transfer laws (Fourier and Fick laws). This work aims to apply the modified Ohm law to thermal and mass transfer which are based on Fick's and generalized Fourier principles, respectively. The current study examines the three-dimensional Darcy-Forchheimer flow of non-Newtonian fluid “Casson fluid” via porous medium with ion slip and Hall effects across a stretched sheet. Thermophoresis and Brownian motion aspects are also considered. The diffusion phenomena are modelled using the Boungrino model. The modified Buongiorno model (MBM) for nanofluids is used to investigate the enhancement of heat transport. Together with practical nanofluid properties, it covers the mechanics of thermo-migration and random motion of nanoparticles. By adding the appropriate similarity transformations, this collection of (PDEs) that reflect the mathematical model is transformed into an (ODEs) system, which it is subsequently resolved utilizing the Lobatto IIIA technique's powerful computing capabilities via Matlab software. Data visualisations and numerical examples are presented considering many physical restrictions affect the fluctuation of velocities, temperatures, concentration, dimensionless shear stress, Nusselt number, and Sherwood number. According to certain findings, the existence of Hall and ion slip effects, and other factors contribute to an increase in horizontal velocity distribution. Furthermore, Fourier's law produces a wider temperature distribution than the Cattaneo-Christov heat flux model.

Study on coupled heat transfer model and enhanced heat transfer law of liquid metals and supercritical fluids

ABSTRACT The supercritical carbon dioxide Brayton cycle system is being considered for application in the power conversion system of advanced liquid metal fast reactors. One important research topic is the coupled heat transfer characteristics and enhanced heat transfer laws between liquid metals and supercritical fluids. However, the traditional Reynolds analogy hypothesis with a constant turbulent Prandtl number is difficult to satisfy the numerical conjugate heat transfer research of liquid metals and supercritical fluids. Therefore, based on the open-source computational fluid dynamics program OpenFOAM, a numerical method suitable for the coupled heat transfer calculation of liquid metals and supercritical fluids was developed, which can achieve precise conjugate heat transfer solutions by applying different turbulence models and heat flux models to liquid metals and supercritical fluids. Subsequently, based on this method, the coupled heat transfer behavior of liquid metals and supercritical fluids in the straight channel of a typically printed circuit heat exchanger was studied. The focus was investigating the conjugate heat transfer characteristics of liquid heavy metal lead-bismuth eutectic and liquid metal sodium with supercritical carbon dioxide. Some sensitive results, including the inlet temperature and Reynolds number of liquid metals and supercritical fluids, were qualitatively and quantitatively analyzed.

Minimum entropy generation paths for generalized radiative heat transfer processes with heat leakage

Heat transfer processes (HTPes) with generalized radiative heat transfer law (HTL) [q∝Δ(Tn)] and heat leakage (HL) are optimized. With net amount of heat transferred (NAHT) of working fluid at low-temperature side and given process period, optimal path, that is, optimal temperature configuration of reservoir (TCR), for entropy generation minimization (EGM) of HTP is derived. Universal result for optimal path is provided, and results for four special HTLs, that is, Newtonian, radiative, linear phenomenological, and mixed HTLs, are further provided. Optimal path with EGM is compared with traditional ones of constant heat flux rate (CHFR) and constant reservoir temperature (CRT). Effects of HL and NAHT on optimal results are analyzed. Results show that ratio of heat flux rates between reservoir and working fluid to (n1+1)/2 power of reservoir temperature for EGM of HTPes without HL is a constant, but the optimal relationship between temperatures of working fluid and reservoir with HL is significant different. The differences among TCRs with different heat transfer paths increase with increases of HL and NAHT. The path of CHFR is very close to that of EGM, and the two paths are superior to that of CRT.

Thermal and electrical properties of photovoltaic cell with linear phenomenological heat transfer law

Abstract The thermal and electrical properties of photovoltaic cell (PVC) under linear phenomenological heat transfer law between it and the environment is studied through finite time thermodynamics and the volt-ampere characteristic equation. The properties of PVC are affected by heat transfer between PVC and environment. There are optimal solar radiation intensity and PVC output voltage (OV), which make the photoelectric conversion efficiency (PECE) of PVC reach the highest value. When OV and solar radiation intensity are 28.50 V and 700 W/m2, the maximum PECE is 0.156. There is also the best solar radiation intensity, which makes the open-circuit voltage (OCV) reach the maximum. When solar radiant intensity is 669 W/m2, the maximum OCV is 33.14 V. The values of power output and short-circuit current (SCC) are monotonically increasing with solar radiation intensity. Given solar radiation intensity, the power output and OV exhibit a parabolic shape. The operating temperature falls first and then grows with the OV. However, the change of operating temperature with OV is not much. Band gap is a decreasing function of operating temperature. This article can give theoretical support for the design and use of PVCs.

A low-kiloelectronvolt focused ion beam strategy for processing low-thermal-conductance materials with nanoampere currents.

Ion beam-induced heat damage in thermally low conductive specimens such as biological samples is gaining increased interest within the scientific community. This is partly due to the increased use of FIB-SEMs in biology as well as the development of complex materials, such as polymers, which need to be analyzed. The work presented here looks at the physics behind the ion beam-sample interactions and the effect of the incident ion energy (set by the acceleration voltage) on inducing increases in sample temperature and potential heat damage in thermally low conductive materials such as polymers and biological samples. The ion beam-induced heat for different ion beam currents at low acceleration voltages is calculated using Fourier's law of heat transfer, finite element simulations, and numerical modelling results and compared to experiments. The results indicate that with lower accelerator voltages, higher ion beam currents in the nanoampere range can be used to pattern or image soft material and non-resin-embedded biological samples with increased milling speed but reduced heat damage.

Lattice Boltzmann simulation of the Prandtl number effect on the phase change heat transfer of wax in pipeline

Thermal washing is a common method of wax removal in oil fields. The law of phase change heat transfer of wax during the thermal washing process is revealed to be of great significance for improving the melting rate of wax. The lattice Boltzmann method is used to numerically simulate the process of phase change heat transfer in pipe-lines with different angles (90?, 45?, 0?, ?45?, and ?90?) of wax layers based on the enthalpy-porous medium model in the present work. The boundary condition between wax and hot water is considered as convective heat transfer boundary. The effect of the Prandtl number on the law of phase change heat transfer of the wax at various angles is investigated. The simulation results indicate a non-linear decrease in the complete melting time of the wax layer from ?90? to 90?. The heat transfer capacity is enhanced with the decrease of Prandtl number, which effectively shortens the melting time of wax. The complete melting time of the wax layer is reduced by 23.78% when the Prandtl number decreases from 79.4-59.4. The speed of convective heat transfer is increased with the decrease of Prandtl number, which means that the solid zone of wax is accelerated into the loose and porous mushy zone, and the efficiency of wax removal is improved. The research results can provide a reference for improving the efficiency of thermal washing.

Determination of Thermal Conductivity of Nano-ceramic Thermal Insulation Coating on the Surface of a Heat Pipe

In the pursuit of conserving non-renewable fuel and energy resources and mitigating harmful emissions into the atmosphere, thermal insulation is commonly employed in practice for heated elements, including but not limited to building exteriors, boilers and furnaces, thermal power equipment, pipelines, and the like. The primary characteristic of any insulation material lies in its thermal conductivity, particularly under operational conditions. The research object is liquid nano-ceramic thermal insulation located on the surface of a round-section pipeline with a circulating heat carrier. The research subject is the thermal conductivity properties of the insulation material under operational conditions. The research aim is to determine the thermal conductivity coefficient of liquid nano-ceramic thermal insulation coating on the surface of the pipeline. The research method involves the laws of steady-state heat conduction and heat transfer for a two-layer cylindrical wall. Research findings indicate that for a steel pipeline measuring 76×3 mm with insulation thickness of 3.5 mm, the thermal conductivity coefficient of the liquid nano-ceramic thermal insulation material amounted to 0.0145 W/(m⋅K). Disregarding the radiative component, the thermal conductivity coefficient equals 0.0135 W/(m⋅K). Conclusions drawn suggest that the obtained value of the operational thermal conductivity coefficient of the liquid nano-ceramic thermal insulation material aligns with the manufacturer's claimed material thermal conductivity of 0.014 W/(m⋅K) and with the findings of other researchers. Minor discrepancies in magnitudes may be attributed to the extended period of insulation usage on the pipeline surface, which at the time of the conducted scientific investigations was approximately 1.5 years.

Влияние заполнения прослоек малотеплопроводными газами на тепловую защиту оконных блоков с экранами

ISPU scientists have developed energy-saving constructions of window units with heat-reflecting screens, have tested them in a climate chamber, and have carried out simulation modeling of the heat transfer process through these constructions. Despite a large number of scientific papers that consider experimental laboratory studies and numerical simulation of heat transfer processes through translucent constructions, there is no data on the effect of the application of low thermal conductivity gases in the gaps formed by glass and metal elements on increasing the thermal protection of window units with screens. The correct calculation of the reduced heat transfer resistance of window units with screens and low-thermal conductivity gases affects the correctness of the heat balance for premises and, consequently, the quality of the design of energy systems to ensure the indoor microclimate. Thus, the development of models of heat transfer process through a window unit with screens is an urgent task to ensure the indoor microclimate. Simulation numerical modeling is carried out using the finite element method based on the fundamental laws of heat transfer. The authors have developed a two-dimensional simulation model of heat transfer through a window unit with heat-reflecting screens, in which the gaps between the glass and aluminum foil are filled with argon and krypton. The distribution of resistance to heat transfer along the height of a translucent enclosing structure has been studied. The adequacy of the proposed simulation model is confirmed by comparison with data of other scientists and regulatory documentation. Filling the gaps between glass and metal foil with argon makes it possible to increase the zonal heat transfer resistance of a window unit with screens in relation to the base-case scenario (air) by 6–23 %, krypton by 8–58 % (depending on the measurement location and the number of screens). The application of the developed simulation model will make it possible to more accurately determine the potential to use heat-reflecting screens in windows for intermittent heating systems of buildings.

Performance investigation and mass transfer enhancement of a novel cone-type solar seawater still

There are some disadvantages in the operating process of the basin solar seawater still (BSSS), such as long mass transfer distance, large heat indolence, huge floor space, and poor bearing pressure ability. A novel cone-type solar seawater still (CTSSS) is presented to overcome the weaknesses of the BSSS in this study. The CTSSS has the characteristics of seawater liquid film evaporation, short mass transfer distance, the condensation sleeve is parallel to and above the evaporation sleeve, and the condensation area is larger than the evaporation area. In order to clarify the performance of the CTSSS, the influence mechanism of feed seawater mass flow rate, heating power and heating temperature on the fresh water yield of the CTSSS was analyzed, the method of enhancing the mass transfer of the binary mixed gas in the CTSSS was explored, and the law of heat and mass transfer of the binary mixed gas in the annular enclosed small space was investigated. The results indicated that the maximum fresh water yield of the CTSSS is 62.7 g/20 min at the feed seawater mass flow rate of 400 g/h when the input power is 200 W, which is 4.5% higher than that when the feed seawater mass flow rate is 300 g/h. The performance ratio (PR) of the CTSSS is increased as the heating power, the PR of the CTSSS is 0.65 when 180 W heating power is employed. The steady state fresh water yield of the CTSSS with mirror condensation sleeve at 85°C is 84.6 g/20 min, which is 12.1% higher than that with non-mirror condensation sleeve Compared with the CTSSS with non-mirror condensation sleeve, the value of proportions of radiative heat transfer in the total heat transfer of the CTSSS with mirror condensation sleeve decreased by 6.6%, and the value of proportions of evaporative heat transfer increased by 6.4%. This study would provide a reference for small-scale decentralized application of solar desalination in remote areas.

Assessing the deterioration risk of mural paintings in Cave 98 of Mogao Grottoes based on the hygrothermal behavior

Cave 98 is a typical cave in Mogao Grottos with various and serious degradations. This paper aims to clarify the heat and moisture transfer law of Cave 98 and murals and evaluate whether the current hygrothermal environment is conducive to the long-term preservation of murals. In this paper, a coupled heat and moisture transfer 2D model of Cave 98 was first established, and the accuracy of the model was verified by on-site monitoring data. Then, the spatial distributions of the temperature and moisture in Cave 98 were analyzed, and the quantitative evaluation of the deterioration risk of mural paintings in different locations was further evaluated. The results showed that 14% and 13.8% of the time indoor temperature and relative humidity (RH) exceeded the target range. Salt damage occurred more than 10 days a year, mold contamination occurred just a few days a year, and deterioration occurred at its peak in summer. Dehumidification measures can be taken during periods of high humidity to improve the adaptability of the current preservation environment.

Numerical simulation of hot air drying of wheat grain piles based on CFD-DEM and experimental research

In this study, a heat and mass transfer model for hot air drying of wheat grain piles based on the discrete-continuous medium assumption method was established to understand the wet heat transfer law inside the wheat grain pile during the drying process. Simulations using COMSOL Multiphysics software were then carried out to study the heat transfer and moisture migration in the porous pile structure of wheat under the conditions of 20 °C ambient temperature, 60 °C air temperature, and 1 m/s air speed. The model was validated in combination with wheat hot air-drying experiments. The experimental results showed that the established model can reflect the drying process of the grain pile well, and the experimental values were in good agreement with the predicted values. The temperature, humidity, and flow fields in the wheat pile were unevenly distributed. The temperature distribution of the wheat pile showed a high temperature in the edge region and a low temperature in the center region, the maximum temperature difference reached around 8 °C. The moisture distribution of the pile showed the opposite trend, with lower moisture in the edge region and higher moisture in the center region. The humidity of the upper layer of wheat in the grain pile showed an upward trend over a period of time due to the influence of rising steam, the maximum moisture difference reached about 15%. The velocity of the edge region with a large pore rate was large, and obvious vortex regions were found in the grain layer. The local speed reaches about 5 times the inlet wind speed. Based on the CFD-DEM medium coupling method, the complex pore structure within the grain stacking structure can be accurately constructed, and a mathematical model can be established on this basis, providing a new approach for simulating the moisture and heat transfer of grain stacking structures.

Non-local linear response in anomalous transport

The anomalous heat transport observed in low-dimensional classical systems is associated with super-diffusive spreading of the space–time correlation of the conserved fields in the system. This leads to a non-local linear response relation between the heat current and the local temperature gradient in the non-equilibrium steady state. This relation provides a generalization of Fourier’s law of heat transfer and is characterized by a non-local kernel operator related to the fractional operators describing super-diffusion. The kernel is essentially proportional, in an appropriate hydrodynamic scaling limit, to the time integral of the space–time correlations of local currents in equilibrium. In finite-size systems, the time integral of correlation of microscopic currents at different locations over an infinite duration is independent of the locations. On the other hand, the kernel operator is space-dependent. We demonstrate that the resolution of this apparent puzzle becomes evident when we consider an appropriate combination of the limits of a large system size and a long integration time. Our study shows the importance of properly handling these limits, even when dealing with (open) systems connected to reservoirs. In particular, we reveal how to extract the kernel operator from simulated microscopic current–current correlation data. For two model systems exhibiting anomalous transport, we provide a direct and detailed numerical verifications of the kernel operators.

Разработка и верификация имитационной модели процесса теплопередачи через оконный блок с теплоотражающими экранами

Window units account for the largest specific heat losses. The use of movable heat-reflecting screens and photovoltaic solar panels is of particular interest among the existing technologies to improve the thermal protection of windows. Despite the large number of scientific papers on this issue, which consider experimental laboratory studies and numerical simulation of heat transfer processes through window units, there is no data on the influence of the edge zones of a double-glazed window, as well as the areas of interface of the window profile and the light opening on the thermal processes that occur in these energy-saving units with screens. Vertical replacing of specific heat fluxes and temperature on the inner surface of the window unit strongly influences the correctness of determining the value of the minimum allowable temperature of the indoor air. Thus, the development and verification of models of the heat transfer process through a window unit with screens is an urgent task in the context of an indoor microclimate creation. Simulation numerical modeling is performed using the finite element method based on the fundamental laws of heat transfer. The authors have used the results of experimental studies of windows with heat-reflecting screens carried out in a certified climatic chamber. The authors have developed a two-dimensional simulation model of heat transfer through a window unit with heat-reflecting screens located in the partition wall of the climate chamber. The distribution of temperatures, air flow velocities, and reduced total thermal resistance along the height of a translucent structures has been studied. The adequacy of the proposed simulation model is confirmed by comparison with the results of the experiment in a certified laboratory, as well as data obtained by other authors and regulatory documentation. The use of heat-reflecting screens in the window unit increases the resistance to heat transfer by 1,6–3,7 times depending on their number. A significant decrease in temperature in the edge zones of the double-glazed window is revealed. The use of the developed simulation model makes it possible to determine the application of heat-reflecting screens in windows for intermittent heating systems including the case of using pre-drying air technology for humid, wet, or normal operation modes of industrial premises.