Thermal Conductivity Of Gases Research Articles

Effective Thermal Conductivity for Low Density Silicon Nitride Porous Ceramics

Thermal conduction in porous materials generally includes four heat transfer forms, i.e. heat transfer via the gas phase, heat conduction along the solid matrix/skeleton, thermal radiation and gas-solid coupled heat transfer. The size effects on the gas and solid thermal conductivities are introduced to predict the effective thermal conductivity of the silicon nitride porous ceramic at room temperature, and the predictions from the random model present good agreements with the experimental data. The effect of the porosity on the effective thermal conductivity of the low density silicon nitride porous ceramic are studied as well, and the low density porous ceramics can achieve a low thermal conductivity in the range of 0.08-1.2 W/m K for a good performance of thermal insulation.

Thermal conductivity of R-32/R-125 (40/60 wt. %) mixture in the vapor phase

The gaseous thermal conductivity of binary mixture of R-32/R-125 (40/60) was measured with a coaxial cylinders method in the temperature range of 305–426 K and the pressure range of 0.1–1.8 MPa. The thermal conductivity as a function of pressure and temperature was considered. The correlations for thermal conductivity on dew line and in ideal gas state are presented.

Binary Gas Analyzer Based on a Single Gold Nanoparticle Photothermal Response.

Although thermal conductivity gas analyzers are ubiquitous in industry, shrinking the sensing unit to a microscopic scale is rarely achieved. Since heat transfer between a metal nanoparticle and its ambient gas changes the temperature, refractive index, and density of the gaseous surrounding, one may tackle the problem using a single nanoparticle’s photothermal effect. Upon heating by a 532 nm laser, a single gold nanoparticle transfers heat to the surrounding gas environment, which results in a change in the photothermal polarization of a 633 nm probe laser. The amplitude of the photothermal signal correlates directly with the concentration of binary gas mixture. In He/Ar, He/N2, He/air, and H2/Ar binary gas mixtures, the signal is linearly proportional to the He and H2 molar concentrations up to about 10%. The photothermal response comes from the microscopic gaseous environment of a single gold nanoparticle, extending from the nanoparticle roughly to the length of the gas molecule’s mean free path. This study points to a way of sensing binary gas composition in a microscopic volume using a single metal nanoparticle.

Molecular dynamics simulations of energy accommodation between gases and polymers for ultra-low thermal conductivity insulation

Determining the energy accommodation between gases and solids is essential to developing porous thermal insulation materials with ultra-low effective thermal conductivity that reduce energy use, greenhouse gas emissions, and fossil fuel consumption. The energy accommodation coefficients of most gases, however, have been rarely studied, especially with respect to solids that have relatively high thermal resistivity, e.g., polymers. In this work, by using all-atom nonequilibrium molecular dynamics simulations, we reveal the accommodation coefficients of He, Ar, N2, and O2 with polymers, mainly polystyrene. We find that their values are around 0.51, 0.72, 0.79, and 0.90, respectively, suggesting a critical reexamination of the commonly used theoretical maximum value of 1. We have also conducted experiments and validated the value for air, which is about 0.81. Such a change in accommodation coefficients can lead to a reduction of about 70%, 50%, 35%, and 20% in the thermal conductivity of He, Ar, N2, and O2 gases in nano pores (below 100 nm) or at low pressures (below 1 millibar). With these new accommodation coefficients, we find that in a 10 nm pore with ambient pressure at 300 K, the gas thermal conductivity of He, Ar, N2, and O2 in porous polystyrene can be as low as 9.7 × 10−4, 3.4 × 10−4, 7.3 × 10−4, and 8.5 × 10−4 W·m−1·K−1, respectively, which are two to three orders of magnitude lower than their bulk values, promising higher thermal resistivity of insulation materials. This work reveals the fundamental energy exchange between gases and polymers, providing important guidance for designing high-performance thermal insulation materials for various applications.

A Characterization of the Performance of Gas Sensor Based on Heater in Different Gas Flow Rate Environments

The performance of gas sensors based on micro-heater is highly dependent on the environment temperature, heater temperature, and gas flow rate. The performance fluctuation of gas sensors induced by environment temperature drift can be reduced in different ways. In this article, different sizes and shapes of obstacles are placed around the sensitive component of the thermal conductivity gas sensor to study the effect of gas flow rate on the gas sensor performance. Both the simulation and experiment results indicate that the obstacle design can reduce the interference of gas flow rate on gas sensor performance. As the obstacle size increases, the influence of gas flow rate decreases and the dynamic detection accuracy of the gas sensor increases at the same gas flow rate, and the voltage variation of the sensor with quadrangular prism obstacle shape is minimal, and the gas velocity reduction effect is 1.77% better than cylinder obstacle shape. The effect of gas flow rate on the gas response is also investigated by detecting the voltage response of the MG811 gas sensor with and without thermostatical control. The result shows that the gas flow rate not only reduces the temperature of the sensor (direct influence), but also promotes the chemical reaction of the sensor, which releases a large amount of heat (indirect influence). The corresponding relationship between voltage response and gas flow rate is obtained through controlling the temperature of sensitive components thermostatically. This article provides a new angle for improving the accuracy of the gas sensor in different gas flow rate environments, which can improve the detection rate of the wireless monitoring system.

Cross Second Virial Coefficients and Dilute Gas Transport Properties of the Systems (N2+ C3H8), (C2H6+ C3H8), and (H2S + C3H8) from Ab Initio-Based Intermolecular Potentials

The cross second virial coefficients and the dilute gas shear viscosities, thermal conductivities, and binary diffusion coefficients of the (N2 + C3H8), (C2H6 + C3H8), and (H2S + C3H8) systems were...

Numerical investigation of gas thermal property in the gasification process of a spouted bed gasifier

Steam-biomass gasification in a three-dimensional lab-scale spouted bed gasifier is numerically simulated via the multiphase particle-in-cell approach. The spatial distribution of gas thermal properties (i.e., temperature, conductivity, specific heat capacity, density, and viscosity) together with the impact of operating parameters are comprehensively studied. The results show that distinct flow hydrodynamics in the three regions of the spouted bed gasifier lead to different spatial distributions of gas thermal properties. The gas thermal properties show significant transitions in the spout-annulus and fountain-annulus interfaces. Elevating the bed height decreases the gas temperature, density, and viscosity but increases the gas thermal conductivity and specific heat capacity. Among all operating parameters, the bed temperature exerts the most significant influence on the spatial distribution of gas thermal properties. Due to the existence of dead zone in the annulus region of the bed, bed height, biomass diameter, and steam to biomass ratio exert negligible influences on the gas thermal properties in the dense annulus region but noticeable impacts in the dilute fountain region. Based on the relationship between solid transportation and gas thermal property variations, the current work also provides a guideline for the optimization of spouted bed gasifiers, for example, the dead zone is recommended to be optimized by adjusting the inclination angle of the conical part to enhance the solid internal circulation and gasification performance.

Molecular dynamics simulation of the phase transition process in the atomic scale for Ar/Cu nanofluid on the platinum plates

It is important to study the effects of the nanoparticles on Ar base-fluid thermodynamic manner. The outcomes of the atomic properties calculated by using the molecular dynamics approach and LAMMPS computational package. For the study of Ar/Cu nanofluid atomic properties, we reported physical parameters such as total temperature, potential energy, density, number of Ar atoms at gas phase, heat flux and thermal conductivity of Ar/Cu nanofluid. Physically, Cu nanoparticles cause phase transition in a shorter time rather than base-fluid. So, our results show that the presence of nanoparticles in base-fluid is an essential parameter in a nanofluid thermal manner in confined space. Numerically, by adding Cu nanoparticles to Ar fluid, the rate of base-fluid density increases from 0.00018 number/Angestrom3 to 0.00019 Number/Angestrom3. Moreover, the value of thermal conductivity of Ar/Cu nanofluid reaches to 0.016 W/mK. Finally, we concluded that in the confined space thermal manner of Ar/Cu, nanofluid improves with adding Cu nanoparticles to Ar fluid.

Cluster dynamics simulation of xenon diffusion during irradiation in UO2

Diffusion of fission gas in UO2 nuclear fuel impacts several important performance metrics, such as fission gas release, swelling, and thermal conductivity. Current empirical models of fission gas release have significant uncertainty, some of which derives from the bulk diffusion rate and its dependence on, for example, fuel chemistry and irradiation. We have applied the previously-developed Free Energy Cluster Dynamics (FECD) methodology in the code Centipede to calculate xenon cluster concentrations in UO2 under intrinsic (high temperature) and irradiation-enhanced (intermediate temperature) conditions in order to develop a model of the xenon diffusion coefficient based on the atomic scale mechanisms responsible for transport. While the diffusion mechanism for xenon in UO2 is adequately described by the Xe + U2O vacancy cluster for intrinsic conditions, a similar process is not capable of capturing measured in-pile fission gas diffusivity at intermediate temperatures. Therefore, a different diffusion mechanism must dominate under this regime. Using calculated atomistic data, we have shown that irradiation-enhanced diffusion at intermediate temperatures occurs via the larger Xe + U4Oy vacancy clusters, which have lower migration barriers and increase in concentration by several orders of magnitude compared to intrinsic conditions. This mechanism is enabled by the increased uranium vacancy concentration under irradiation due to Frenkel pair production. In addition, the fast migration of uranium interstitials with two attached oxygen interstitials lowers the total uranium interstitial concentration through reactions with sinks. This allows the extended defects, such as Xe + U4Oy vacancy clusters, to maintain high concentrations by limiting annihilation with attached vacancies. Predictions using the Xe + U4Oy diffusion mechanism are in good agreement with experiment, albeit with some differences in the Arrhenius slope, which we believe may be related to either experimental or model parameter uncertainty. Finally, an analytical expression suitable for application in fuel performance simulations was derived to capture the predictions of the Centipede simulations.

Co-gasification of oil palm biomass in a pilot scale downdraft gasifier

The present study focused on co-gasification of empty fruit bunch (EFB), mesocarp fibre (MF) and palm kernel shell (PKS) in a 75 kWth pilot scale downdraft gasifier for possible synergic reactions between the biomass. A series of experiments was carried out using equal blend of EFB, MF, and PKS (particle sizes of 14 and 6.7 mm) and equal blend of MF and PKS. Advanced infrared multi-gas analyser, and thermal conductivity gas analyser were employed to measure the produced gases. The elemental compositions of the raw biomass, ash and slag generated were determined using Scanning Field Emission Gun Scanning Electron Microscopy with accelerating voltage 20.0 kV and working distance 6 mm and the measurements processed using AztecEnergy V2.2 software. The co-gasification of blend of EFB, MF, and PKS, compared to the blend of MF and PKS led to higher gas yield (4.82 and 3.47 m3/kg_biomass), cold gas efficiency (16.2 and 13.37%), and carbon conversion efficiency (56.3 and 34.18%), respectively. When compared to particle size of 14 mm, the PKS of particle size of 6.7 mm in the EFB/MF/PKS blend increased the lower heating value and the higher heating value of the producer gas by 20% and 20.3%, respectively, and the residue yield was 18.6% less. The overall result has provided evidence on the importance of co-gasification of biomass especially EFB, MF and PKS, which will result in increased utilization of EFB.

Mathematical Models for Determining the Distribution of Fluid Flow Temperature along the Wellbore and Horizontal Pipeline

This paper presents a proposed new indirect method determining instantly oil well debit using developed mathematical models. As a result integrated analysis using the models it has been revealed correlation between oil well debit and well throw out flow temperature. Therefore putting purpose was obtained. Mathematical models are developed for the distribution of fluid flow temperature along the length of the tubing from the well bottom to the wellhead and along the length of the oil pipeline from the collector of oil wells to the oil treatment unit. On the basis of experimental data, the authors propose formulas in the form of the relationship between oil emulsion (OE) viscosity, the flow temperature and concentration of water globule in OE and the coefficient of heat transfer from the fluid flow in the wellbore (WB) to the rock, and heat capacity and thermal conductivity of gas, water, rock and steel of the WB walls. This effect is demonstrated in the constructed diagrams. It is shown bottom temperature jump as a result of the Joule Thomson drosseling effect then connective transmitted up at flow rate v. In such case well-head or well outlet oil mixture (OM) flow temperature depend more of volume of stream flow than of bottom hole temperature. Thought in the paper, do not taking into consideration great casing annulus areas influence to the well outlet flow temperature. As shown from supporting paper the relative values og the thermal conductivity of the liquid column and gas column present in the casing annulus order less than well bore (WB) wall thermal conductivity. Consequently well outlet OM flow temperature will depends not only of the volume of stream flow, also of the bottom hole temperature and of the gas column and liquid column.A new method for determining the oil well flow rate by measuring the downstream temperature is developed. A mathematical model is proposed that allows calculating the thermal profile of the fluid along the wellbore for determining the oil well flow rate with account of the geothermal gradient in the rock surrounding the wellbore. It is shown, that unlike the existing methods the new proposed method allows determining the instantaneous discharge of a well very easily. One of the actual challenges in fluid (oil, water and gas) transportation from wells to oil treatment installation is determination of a law of temperature distribution along the length of a pipeline at low ambient temperature. That temperature leads to increase in viscosity and deposition of wax on inner surface of a pipe. To overcome that challenge it is needed to consider several defining characteristics of formation fluid (FF) flow. Complexity of a solution is caused by two factors. From the one hand, in most cases (especially on a late stage of field development) FF is an oil emulsion (OE) that contains gas bubbles. From the other hand, temperature gradient between fluid flow and the environment has significant value (especially in the winter period of the year). At the same time, the higher content of emulsified water droplets (EWD) in OE and lower flow temperature, the higher FF viscosity, and consequently productivity (efficiency) of oil pumping system is reduced. Performed research and analysis of field experimental data showed that a function of oil viscosity versus temperature has a hyperbolic law; a function of OE viscosity versus concentration of EWD has a parabolic one. A heat balance for a certain section of a pipeline in steady state of fluid motion using a method of separation of variables was established taking into account above mentioned factors, Fourier’s empirical laws on heat conductivity and Newton’s law on heat transfer. As a result, unlike existing works, an exponential law of distribution of temperature along the length of a pipeline is obtained. A law takes into account nonlinear nature of change in viscosity of OE from change in temperature of flow and concentration of water in an emulsion. As a result, in contrast to the existing works, the proposed exponential law of temperature distribution along the length of the pipeline is obtained, taking into account the nonlinear nature of variation of OE viscosity with the change in the flow temperature and the concentration of water in the emulsion. The results of the calculation are presented in the form of a table and graphs.

Major sensitivities in FRAPCON-xt modeling of high burn-up fuel rods during dry storage to design and irradiation variables

Abstract Thermo-mechanical performance of fuel rods is a key aspect for assessing the spent fuel safety during dry storage. There is a need of assessing fuel rod behaviour codes for dry storage stage and uncertainty quantification can be a useful tool for this assessment. As a first step of these studies, sensitivity analyses can help to understand the effects and to identify the relevant parameters for the predictions. The present work studies the effect of the scenario on sensitivity analyses focused on the cladding stress at the beginning of dry storage. To make this comparison 10 design parameter’s tolerances and 7 model biases have been studied for 2 different fuel rods in terms of design and irradiation. Cladding diameter tolerance and fuel gas release and thermal conductivity model biases are the more influencing parameters independently of the scenario chosen. Overall, moderate differences between scenarios have been obtained. Results obtained in this work are specifically related to the modelling of the code FRAPCON-xt.

GaN-on-Si Calorimetric Thermal Conductivity Gas Sensor

Introduction Thermal conductivity gas sensors are used in a multitude of fields where identifying concentrations of certain gasses within mixtures is important, such as in exhaust emission monitoring, chemical process control to name some examples. There is also a growing demand to be able to place sensors in more extreme environments closer to the source of the reaction/emissions. Traditionally, silicon-on-insulator (SOI) is the material of choice for MEMS for use in harsh environments, however SOI has a limit of around 300°C before it can no longer reliably sense [1].In this work, we present a Gallium Nitride-on-Silicon (GaN-on-Si) thermal conductivity calorimetric gas sensor. Depending on the specific process, devices fabricated from GaN can survive temperatures up to 1000°C [2] [3]. As a wide band-gap semiconductor, GaN devices do not suffer the adverse effects of excessive carrier generation that silicon-based devices do [4]. Using GaN, it is possible to fabricate heterogenous devices by growing an alloy layer on top of the GaN layer. In the case of this work, the alloy is Aluminium Gallium Nitride (AlGaN). Just below the interface of the two materials, piezoelectric polarisation induced by the lattice mismatch of the two materials causes a thin layer (angstroms) of electrons to form a 2-dimensional electron gas (2DEG) [5]. Currently several factors limit GaN’s mass market appeal, such as yield and cost, although with more development, GaN is a candidate for the harsh environment sensing domain.This work presents for the first time a thermal conductivity calorimetric gas sensor fabricated in a GaN-on-Silicon process, with 2DEG sensing elements on a membrane structure. Thermal Conductivity Sensing Thermal conductivity gas sensors use heat transfer principles to detect specific gasses or gas concentrations. A heating element used in conjunction with one or more temperature sensing elements can be used to measure the transfer of heat from heater to the gas mixture. Measuring this heat transfer is the basis for this method of gas detection. The Sensor The sensor die is square at 1.6 mm x 1.6 mm. The device consists of a heating element placed in the centre of the membrane with thermopile temperature sensor upstream and downstream of the heater [6][7]. The thermopiles are made up of 5 thermocouples where the junction materials are gold and the AlGaN/GaN 2DEG. The combination of upstream and downstream temperature monitoring along with the heating from the hot wire allow the temperature profile of the gas to be detected and thus the concentration. Figure 1 shows an optical image of the sensor die with the specific devices highlighted. Experiment The experiment was conducted using a custom gas rig consisting of 3 mass flow controllers (MFCs) interfaced with a Raspberry pi. The different MFCs enable the gas concentration to be controlled so that measurements can be conducted to measure the sensitivity of the sensor to various gas concentrations. In this work, zero air is used as a carrier gas with Hydrogen being the gas of interest. Hydrogen was chosen principally due to its high thermal conductivity (185 mW/mK) compared to zero air (28 mW/mK). Flow rate was kept constant at 200 SCCM/Min so that the effect of forced convection due to flow velocity on the temperature profile can be discounted.Initial Results will be presented at the conference. Acknowledgments This work was supported by the Innovate UK project “GaN Sense” (file ref. 103446).

Modeling of gap conductance for LWR fuel rods applied in the BISON code

ABSTRACT A new gap conductance model is proposed in this study as a combination of Toptan’s model and the Ross-Stoute model. A variance-based sensitivity analysis is performed to understand how simulation results depend on all input parameters of the proposed model. Additionally, new modeling options (e.g. fill gas thermal conductivity, temperature jump distance, thermal accommodation coefficient, etc.) are added into the nuclear fuel performance code, BISON. The need for further investigation of the gap heat transfer between fuel and cladding in BISON motivated this study to evaluate its impact on the code’s predictions. New gap conductance modeling is proposed. A series of integral-effects validation tests is performed: (1) to demonstrate the impact of the proposed model on the code’s fuel temperature predictions at the beginning of life and through the reactor’s life; (2) to ensure that the proposed model is capable of accurately modeling gap heat transfer characteristics in real-world problems; and (3) to investigate the impact of the estimation of fission gas release on the fuel temperature predictions with the proposed model. The results indicate that the proposed gap conductance model improves BISON’s predictions.

Correction to “First-Principles Calculation of the Cross Second Virial Coefficient and the Dilute Gas Shear Viscosity, Thermal Conductivity, and Binary Diffusion Coefficient of the (H2O + N2) System”

Correction to “First-Principles Calculation of the Cross Second Virial Coefficient and the Dilute Gas Shear Viscosity, Thermal Conductivity, and Binary Diffusion Coefficient of the (H₂O + N₂) System”

Age-related efficiency loss of household refrigeration appliances: Development of an approach to measure the degradation of insulation properties

Despite the omnipresence of household refrigeration appliances, there is still a lack of knowledge about their age-related efficiency loss over time. Past studies provide basic evidence for increasing electricity consumption of cooling appliances with ageing but fail to investigate the associated technical wear. Concentrating on the degradation of the thermal insulation, we first determined the ageing process of sealed samples of polyurethane rigid foam by investigating changes in cell gas composition and thermal conductivity over time. Simultaneously, the main challenge was to develop an approach that investigates the age-related efficiency loss of the insulation without its destruction. This testing procedure is referred to as the Bonn method. The non-destructive Bonn method was applied to varying refrigerator models in a series of successive experiments to evaluate the insulation degradation over time. Subsequently, the physical relationship between the test value of the Bonn method and the heat transfer through the multi-layered compartment walls of domestic refrigeration appliances was established, ultimately characterising the degrading insulation in terms of increasing heat transfer. Our results give substantiated evidence that the efficiency loss of cooling appliances is greatly influenced by insulation degradation over time. The ageing of sealed samples of polyurethane rigid foam indicates a large initial increase of thermal conductivity by 15% within the first year, corresponding to a change in cell gas composition. These results are in line with those of the Bonn method, emphasising an increasing heat flow through the multi-layered compartment walls of domestic refrigerators with ageing. Therewith, the present study is of significance to a wide range of stakeholders and forms the basis for future research.

Click chemistry modified graphene oxide/styrene-butadiene rubber composites and molecular simulation study

In this study, a one-step light-initiated click chemistry method was used to simultaneously connect graphene oxide (GO) and styrene-butadiene rubber (SBR) by pentaerythritol tetra(3-mercapto propionate) (PETMP). For modified GO/SBR composites, the dynamic, static mechanical performances, gas permeability and thermal properties are improved to some extent. By combining simulation and experiment, the mechanisms for the improved gas permeability and thermal conductivity of the modified GO/SBR composites can be attributed to the following comprehensive effects. Firstly, the compatibility between GO and SBR was improved, which contributed to the dispersion of GO and reduced the permeability coefficient. Secondly, the presence of PETMP at the interface increases the interaction and the degree of phonon matching between the matrix and the fillers, which brought greater restrictions on the mobility of the polymer chains, and subsequently the transfer efficiency of thermal energy at the interface was improved. It means that this one-step light-initiated click chemistry method may be used as a simple way to prepare high performance GO/SBR composites. In addition, as a theoretical approach, molecular simulation may help us understand the relationship between the microstructure and performances of rubber composites.

Structure, compression and thermally insulating properties of cellulose diacetate-based aerogels

We report on the relationship for structure, compression and thermal insulation properties of cellulose diacetate-based aerogels (CDBAs), prepared from cellulose diacetate (CDA) cross-linked with 2, 4-toluene diisocyanate (TDI) by using sol-gel and supercritical drying processes. Lower reactant dosage (no matter CDA or TDI), can induce smaller shrinkage (~12%) after supercritical drying, and even to achieve lower density (~0.06 g/cm3) of CDBAs. Monolith CDBAs have typical three-dimensional networks with lamella reinforced fiber-like skeletons and nanometric pores. Such reinforced networking structure with lamellas as reinforcement is responsible for the maximum compression strength of ~1.29 MPa at 10% strain and compressive modulus of 21.86 MPa in CDBAs. Besides, the excessive addition of TDI leads to accelerate the growth of secondary fiber-like skeletons to ultimately divide the large pores into the small ones inside the formed network. This structural evolution enables to synergistically reduce gaseous thermal conductivity by means of Knudsen effect and increase that of solid part due to wider solid contacted area. The minimum total thermal conductivity of ~0.0313 W m−1 K−1 at ambient environment is obtained when the synergetic effects reach up to the critical balance, whose solid and gaseous proportions are calculated as 51.76 and 48.24%, respectively.

Heat and air transport in differently compacted fibre materials

Fibre materials are widely used as insulation materials in both clothing and the building industry. The transport of heat and air through fibre insulation materials are accountable for both the energy need for indoor space conditioning and the indoor environment quality inside buildings. A better understanding of the thermodynamics of those materials can enable higher quality products for improved energy efficiency. By using fast gas permeability measurements and more time-consuming guarded hot plate measurements, this study investigates the link between thermal conductivity and gas permeability for Rockwool, Kevlar and polyester fibres, at different compaction levels. Correlations between gas permeability and thermal conductivity at different total volumes of solid are presented. The experimental results show that the gas permeability and thermal conductivity exhibited a change in their evolution trend, due to compaction, in the same zone of the total volume of solid for all materials. The presence of this transition zone enables to establish a link between the measurement of gas permeability and thermal conductivity. This correlation can be employed to perform rapid thermal conductivity assessment of fibrous material, which can be cost-effective for fibre manufacturers or building contractors, but also quality assessment in the textile industry.

Study on the temperature dependence of gas permeation and adsorption behavior of the vacuum insulation panel with getter materials

Vacuum insulation panel (VIP) is a high-performance heat insulation material that has contributed to the energy efficiency of refrigerators, vending machines, and cooler boxes. Glass wool or fumed silica covered by a laminated film are the core materials of VIP; by evacuating air inside, it is possible to reduce the gas thermal conductivity to be close to 0 and exhibit high thermal performance. In recent years, the research on long-term performance prediction has been conducted for use in building insulation. Specifically, various getter materials have been developed to improve the long-term performance of glass wool VIP. However, there are no studies that clearly show the adsorption behavior or temperature dependence inside VIP with getter materials. We measured the adsorption temperature dependence of two types of getters using the constant volume method and then observed the adsorption behavior inside VIP using VIP equipped with a micro pressure sensor. Regarding the internal pressure of VIPs equipped with the micro pressure sensor, the pressure fluctuation derived from the adsorbent was confirmed by the temperature change, and it was confirmed that the thermal conductivity changed accordingly. If the internal temperature of VIP increases, gases may be released from the getter. Therefore, in the building environment, it is necessary to select a getter that is suitable for the usage environment and to use an appropriate amount of getter.