Thermal Characterization Tests Research Articles

Effect of Magnesium Hydroxide on the Thermal Stability, Latent Heat and Flammability Properties of composite material based on Phase Change Materials

Abstract Polyurethane-Phase Change Materials (PU-PCM) composites are used for thermal regulation aiming to conserve and efficiently manage thermal energy. These materials combine the properties of PU, such as low thermal conductivity, low density and excellent mechanical properties as a thermal insulator, with the benefits of PCM allowing thermal energy storage, which greatly reduce energy consumption in heating and cooling. Adding a flame retardant to the PU-PCM composition improves fire resistance. The objective of this study is the preparation and characterization of a composite material based on PU rigid foam containing 30% by mass of commercial paraffin waxes as PCM, together with magnesium hydroxide as flame retardant. A series of samples were prepared by incorporating different percentages of Mg(OH)2, ranging from 1 % to 5 %, with and without the PCM. Various thermal and chemical characterization tests were carried out. The results indicate that the structure of the PU cells is not affected by the increase of the Mg(OH)2 incorporation rate. In terms of thermal properties, the addition of 1% flame retardant increases the latent heat from 25.9 J/g to 39.68 J/g. As the amount of Mg(OH)2 incorporated increases, the flame retardancy increases.

Investigations into the robustness of the peak turn-on current slope method for junction temperature sensing in p-GaN HEMTs

Abstract In this paper, the robustness of a junction temperature sensing method using the peak of the turn-on current slope for enhanced p-GaN high-electron-mobility transistors is investigated in detail. With the help of a repetitive hard-switching test platform, compared to other temperature-sensitive electrical parameters, it is found that the maximum slope of the flowing current at the turn-on transition shows no trend in degradation, regardless of the applied switching stress. This parameter decreases solely with the increase in junction temperature, showing excellent temperature-dependent linearity. Furthermore, the applicability of this method to the detection of junction temperature under different external gate resistances and drain voltages is verified. The sensed junction temperatures are carried over to calculate the thermal resistance, which is also extracted by advanced thermal characterization test equipment as a reference. Therefore, based on the versatility, convenience and accuracy, the peak of the rising drain current slope has been proven to be the preferred alternative in system applications to detect junction temperatures.

Birefringent optical fibers to decouple thermo-mechanical effects on FBG sensors

Optical fiber Bragg (FBG) sensors are gaining importance in structural health monitoring (SHM) systems due to their compact size and ability to be embedded into the lamination sequences of composite material elements. A significant challenge, widely discussed in the literature, concerns the decoupling of thermomechanical measurements made through these sensors. This work aims to solve this problem using birefringent optical fibers instead of conventional ones. The distinctive characteristics of birefringent fibers allow an FBG sensor, written in such fibers, to present not a single peak but two distinct peaks, each with different responses to changes in strain and temperature. This is due to the different refractive index distribution in the fiber core section, which allows for two axes on which the light signal propagates at different speeds. This property offers a significant advantage: by having two independent equations associated with the two peaks, it is possible to decouple the thermomechanical measurements using only the fiber itself, without the need to introduce additional components to achieve mechanical decoupling (capillaries with through or interrupted fiber). This would ensure that strain and temperature are measured at the same point. In the first phase of the work, an FBG sensor on a birefringent fiber was characterized and subsequently calibrated. Therefore, a dedicated experimental set-up was created to conduct thermal, mechanical, and thermomechanical characterization tests, in order to verify the feasibility and effectiveness of decoupling. In a second step, such sensor was embedded within a sample of composite material (unidirectional glass fibers), which was subsequently subjected to the same characterization tests conducted on the single fiber. The results highlight the ability of this new transducer to decouple the thermal effect from the mechanical effect, allowing this new technology to overcome the problems of FBG sensors made of standard fibers.

Fracture toughness and overall characterization of PLA based biocomposites with natural fibers: A comparative study

Biocomposites based on commercial polylactic acid (PLA) matrix reinforced with three different short natural fibers (coir, fique and sisal) at 1; 3, and 5 % wt, were obtained by compression molding. The idea of keeping additional processing steps as low as possible, thus reducing costs, prevailed. Then, no chemical treatment was performed on natural fibers. Overall performance of composites was evaluated by means of fracture tests along with FTIR and thermal characterization, SEM micrographs, and tensile tests. Results show that the incorporation of short sisal fibers increased more than 130 % the fracture toughness of composite materials, by inducing additional mechanisms of energy dissipation prior to crack growth. This improvement in behavior was observed even though there was no good adhesion between fibers and matrix. Sisal fibers’ composites exhibited the best fracture and mechanical properties compared to coir and fique composites, without a detriment in degradation behavior.

Evaluation of carbonized cotton stalk for development of novel form stable composite phase change materials for solar thermal energy storage

Generating energy from the renewable sources is a pathway to attain sustainable energy systems. Utilizing bio-char produced from pyrolysis process as porous material would not only add great value to the waste discards, but also contributes towards enhancing the thermal properties. This work is focussed on the development of form stable phase change material (FSPCM) through a facile impregnation method by introducing cotton stalk biochar (CSB) as porous matrix along with polyethylene glycol having molar mass 10000 g/mol (PEG10000) as PCM. Cotton stalk is an agriculture waste material and biochar was produced by intermediate pyrolysis method at 550 °C. Thermal, chemical and surface characterization tests were executed on seepage free FSPCM (BCPCM4) as it showed no leakage at 60 °C. XRD, FTIR, FESEM, TGA, DSC, Raman spectroscopy and BET analysis were carried out to characterize thermal, chemical and surface properties of BCPCM4. The microporous structure of CSB was able to accommodate 80 wt% of PEG10000. Surface characterization tests demonstrated that adequate amount of PEG10000 was absorbed into the pores of CSB and the crystal structure of PEG10000 was not modified. The results of TGA illustrated that BCPCM4 was thermally stable. Additionally, cotton stalk derived FSPCM displayed high heat transfer rate which indicates an increase in thermal conductivity. To substantiate thermal reliability, 500 thermal cycles were run on BCPCM4 and about 1 % variation in latent heat has been noticed with meagre change in chemical properties. Therefore, biochar derived FSPCMs would serve as promising materials to accommodate solar thermal energy.

Enhancing sustainability in polymer 3D printing via fusion filament fabrication through integration of by-products in powder form: mechanical and thermal characterization

FFF (fused filament fabrication) is a type of 3D printing that utilizes filament for part creation. This study proposes using by-products or waste to replace part of the plastic in FFF filament, reducing environmental impact. The aim is to maintain a simple manufacturing process involving extrusion on a single-screw desktop machine followed by printing. The plastic matrix comprises polylactic acid (PLA) and polyethylene glycol (PETG), with added powdered by-products: seashells, car glass and mill scale (metal). Additives will be incorporated at 10% and 20% by weight, with two grain sizes: up to 0.09 mm and up to 0.018 mm. Mechanical tests (tensile, flexural and hardness) and thermal characterization tests will be conducted. Findings suggest adding 10%w powder of any variety to PETG increases tensile strength up to 48%, with metal powder (mill scale) showing the highest enhancement, even at 20%w, resulting in a 41% increase. Conversely, adding powder to PLA worsens mechanical properties without stiffening the material; instead, the elastic modulus decreases. Metal grain size has minimal impact, with grain sizes lower than 0.09 mm optimal for PLA. Thermal conductivity in polymers blended with powder additives is lower than in virgin polymers, likely due to air void formation, supported by density and microscopic evaluations. This research underscores the potential of utilizing waste materials with a simple FFF filament production to enhance sustainability in 3D printing practices.

Development and characterization of a composite material with geopolymer matrix obtained by incorporation of microparticles from plastic bottles

The composite material with a geopolymer matrix of 7 M molarity, obtained by incorporating microparticles from plastic bottles is developed and characterized in the present paper. To do this, we made cylindrical specimens whose the diameters are the half of their heights and stored them at a temperature of (31±2°C). The compression test using a hydraulic press is carried out, as well as the thermal characterization test using a device respecting the experimental method of the asymmetric hot plane, which was used to determine the thermal conductivity, the volumetric heat capacity, the effusivity and the diffusivity. Then optical characterization tests on hardened samples were carried out, namely chemical analyses of the composition of the kaolin, and particle size characterization of the raw microscopic imaging of the specimens. The results found showed that as the amount of polyethylene terephthalate increases, the compressive strength decreases by 33.65 % for 10%polyethylene terephthalate and 67.77 % for 20 % polyethylene terephthalate. According to the thermal conductivity, it improves with the percentage of polyethylene terephthalate added as: at 10% it is 1.19Wm−1K−1 and at 20%, one has 0.595Wm−1K−1; similarly for effusivity where we obtained 1376.05 JK−1m−2s−1/2 and 560.81 JK−1m−2s−1/2 for 0 and 20% respectively. According to these results, the use of polyethylene terephthalate aggregates as a partial substitute of aluminosilicate raw material for the development of a composite can be a good alternative for recycling plastic bottle waste. The composite obtained could be used for the manufacture of ceiling lights and brick facings, and therefore would significantly reduce the amount of waste plastic produced every day in environment.

Characterization of commercial thermal barrier materials to prevent thermal runaway propagation in large format lithium-ion cells

In recent years, electric vehicles (EVs) have been rapidly introduced as an environmental measure. It is said, however, one of the challenges to accelerate their spread rests in how to increase their driving range. Recent safety regulations for EVs have been stringent in the wake of the potential risk of thermal runaway of battery packs. The battery pack is expected to withstand intense ignition during the event of thermal runaway while measures to suppress cell-to-cell thermal runaway propagation are also being considered as a mandatory safety standard. Thermal barrier materials are viable system-level solutions to mitigate cell-to-cell thermal runaway propagation via electrical, thermal, and fire insulation to meet regulatory safety needs. Among the various researched thermal barriers, only a few materials are commercially viable. Hence, this paper explores different commercially available thermal insulating materials that can be accommodated in battery packs. The materials selected combine key characteristics such as flame resistance, heat insulation, and thickness. Subsequently, we experimentally investigate the thermal and fire-risk properties of the selected thermal barrier materials via flame torch tests and compare their performances. Among the tested materials, a potential material has been used to further validate its performance in mitigating thermal runaway propagation in battery module/pack level overheating tests. Additionally, the comprehensive results of single-configuration thermal barrier characterization tests aided in combining different thermal barrier materials, which displayed better performance than single-configuration materials.

MECHANICAL AND THERMAL CHARACTERIZATION OF CLAY WITH A VIEW TO POPULARIZING ITS USE AS AN ECOLOGICAL MATERIAL IN CONSTRUCTION

This work is carried out with the aim of enhancing the soils of Djarmaye in order to popularize its use as an ecological material in construction. However, a study of thermo-physical parameters was made to see the influence of cow dung in the mixture. As a result, thermal characterization tests were carried out, using the hot wire method for the determination of thermal conductivity, supported by the hot plane option for the determination of thermal conductivity.supported with the hot plane option for the determination of thermal effusivity was used. The test tubes are made with an incorporation of 0%, 2% and 4% by mass of cow dung. The parameters studied are the thermal conductivity, the thermal effusivity, and the thermal capacity by volume of the specimens. The results showed that the thermal conductivity decreases with cow dung, which confirms its use as an additive to obtain a good thermal insulator.

Investigation of mechanical and thermo-mechanical characteristics of silane-treated cellulose nanofibers from agricultural waste reinforced epoxy adhesive composites

The issue of deforestation has been of considerable concern in recent years. So as to contribute to a solution to this problem a major aim of this study has been to develop a sustainable environment by using agricultural industry waste in structural applications rather than wood. By this way, the study employed cellulose nanofibers (CNFs) derived from red banana empty fruit bunches to solve issues related to landfill gas emissions and the simultaneous utilization of organic wastes. The impact of silane treatment on the physicochemical, thermal, and morphological properties of CNFs was examined. Compression moulding was utilized to make different loading levels of silane-treated CNFs (SCNFs) reinforced epoxy nanocomposites. The resultant nanocomposites were evaluated by using various physical, mechanical, thermal, and micro-structural characterization tests. Properties such as tensile strength, flexural strength, impact strength, glass transition temperature, micro-hardness, thermal stability, and so forth, were evaluated under controlled laboratory conditions. Field emission scanning electron microscopy revealed the size and distribution patterns of the SCNFs in an epoxy matrix. Coefficient of effectiveness, cole-cole plots, and cross-link density studies confirmed the adhesion behavior of SCNFs with epoxy resin as a function of SCNF loading. All the findings led to the conclusion that the SCNF reinforced epoxy composites would make suitable materials for lightweight structural applications.

Thermoforming, characterization, and in-house recycling of multi-layered laminated composites made with polyamide 6/recycled carbon fibers hybrid yarns-based plain weave fabrics

Carbon fiber reinforced plastics (CFRPs) in the form of laminated composites are widely used in various sectors, such as aeronautics and clean energy fields, due to their superior mechanical properties compared to traditional homogeneous composites. In this study, the authors developed a manufacturing process based on thermoforming a 7-layer stack of plain weave fabrics made from hybrid yarns (polyamide 6/recycled carbon fibers) to introduce a new method for reusing end-of-life (EoL) CFRPs and avoid landfilling. Several attempts were made to determine the optimal combination of process parameters, including forming temperature, forming pressure, and holding time. The manufactured multi-layered laminated composites underwent in-depth mechanical and thermal characterization tests to obtain information on their physical properties and identify potential applications for market exploitation. The developed materials exhibit very interesting mechanical properties, which are comparable to or greater than those of commercial carbon or glass fiber-reinforced polymers. Morphological analysis revealed good wettability of PA6 on rCFs and a very low degree of porosity. Finally, the re-use of yarn scraps and fabric remnants generated during the manufacturing process, as well as the recyclability of the manufactured composites once they reach the status of EoL materials, were studied through an in-house recycling process based on comminution and hot pressing of materials.

Investigations of hybrid infill pattern in additive manufactured tablets: A novel approach towards tunable drug release.

The significance of 3D printing has risen exponentially in biomedical and pharmaceutical applications. Its potential in the field of fabricating drug delivery systems, by virtue of processing biocompatible polymers, has been very lucrative. This work aims to tap the interstitial drug delivery kinetics that are often inaccessible through machine-specific infill patterns in additive manufactured tablets fabricated using PVA biopolymer as an excipient. In this regard, a myo-inositol containing tablet has been printed using Fused Deposition Modeling preceded by Hot Melt Extrusion drug loading route. Two machine-specific infill patterns were taken, namely straight and grid. Later, these two distinct patterns were juxtaposed to obtain novel hybrid infill patterns in the tablets. Then, these tablets and their filament were subjected to various thermal, mechanical, imaging and pharmaceutical characterization tests to assess the feasibility of the research attempt. Finally, dissolution tests were conducted to evaluate their dissolution behavior over a time period. The characterization tests proved the scientific viability of this attempt along with amorphous existence of drug in the polymeric filament. The dissolution results showed favorable drug release by achieving interstitial dissolution timings with surface area/volume (SA/V) ratio being found to be the principal factor.

Thermal design analysis for SuperTruck II lithium-titanate battery pack

This paper presents a systematic thermal management analysis for a new lithium-titanate-oxide battery pack to be installed in a SuperTruck II, Class 8 hybrid truck. The authors investigate the feasibility of mounting the battery pack inside the vehicle and air-cooling it with fans supplying conditioned air from the cabin. Moreover, the cells within each module are to be immersed in a heat-transfer fluid to improve temperature homogeneity. A multi-stage thermal analysis is performed to ensure adequate thermal regulation of the battery under the proposed design, considering installation and operational constraints. The authors perform thermal and electrical characterization tests on a single cell. Results inform the development of computational fluid dynamics models of the cells, modules, and pack. Module-level analysis shows that the cell temperatures can be maintained below their upper operational limit of 55 °C with module wall-to-air heat transfer coefficients between 10 and 20 Wm−2K−1. Pack-level analysis of distinct configurations determines effective airflow paths for adequate heat transfer and delivers a final battery pack design that achieves sufficient cooling and temperature uniformity. A reduced-order electrothermal model is developed to rapidly predict the transient battery performance and to develop a temperature control strategy.

강화 단계가 PLA 매트릭스 나노 복합재의 기계적 및 생체 적합성 특성에 미치는 영향

In this study, it was aimed to obtain nanocomposite structure with poly(lactic acid) (PLA) matrix and to improve the mechanical and morphological properties of the PLA matrix nano-reinforced composites. Titanium dioxide (TiO₂) and hydroxyapatite (HA) nanoparticles were used as reinforcing elements. Solvent casting particle leaching method was used for the production of the composites. Thermal characterization and compression test of the composite samples were carried out. Microstructural properties and the phases formed on the surface of in vitro tested samples were examined. As a result of the study, it was observed that nano-reinforced composites with PLA matrix are biocompatible and apatite formation increases gradually every week. Also the highest compressive strength was obtained in PLA/HA samples, while the lowest was obtained in PLA sample. It was concluded that composites prepared within the scope of the study can be used as artificial tissue scaffolds in biomedical and medical applications.

Experimental Data and Simulations of Performance and Thermal Comfort in a Typical Mediterranean House

The number of buildings renovated following the introduction of European energy-efficiency policy represents a small number of buildings in Spain. So, the main Spanish building stock needs an urgent energy renovation. Using passive strategies is essential, and thermal characterization and predictive tests of the energy-efficiency improvements achieving acceptable levels of comfort for their users are urgently necessary. This study analyzes the energy performance and thermal comfort of the users in a typical Mediterranean dwelling house. A transient simulation has been used to acquire the scope of Spanish standards for its energy rehabilitation, taking into account standard comfort conditions. The work is based on thermal monitoring of the building and a numerical validated model developed in TRNSYS. Energy demands for different models have been calculated considering different passive constructive measures combined with real wind site conditions and the behavior of users related to natural ventilation. This methodology has given us the necessary information to decide the best solution in relation to energy demand and facility of implementation. The thermal comfort for different models is not directly related to energy demand and has allowed checking when and where the measures need to be done.

Investigation of White Vaseline as an alternative phase change material for thermal regulation of physiological birth rooms

This research work encompassed the results of experimentation of an innovative composite (Plaster/white Vaseline) for indoor thermal regulation of physiological birth rooms using the Latent Heat Thermal Energy Storage (LHTES) concept. The indoor temperatures of these specific sanitary rooms need to be continually stabilized approximately at 35 °C. Accordingly, white Vaseline (petroleum jelly) was recovered from health facilities and then tested as an alternative PCM for a LHTES application at constant temperatures. The white petroleum jelly used in this work is mainly composed of microcrystalline wax and liquid paraffin; its phase change temperatures were found to be respectively at 36.56 °C and 35.53 °C for melting and solidification cycles with an enthalpy value of 95.38 J/g (±1.23). In addition to these suitable thermal properties, the substance is safe and available at low-cost. A mineral matrix prepared essentially from plaster was experimented to trap the PCM into its microstructure in order to prevent any risk of leakage during the phase change process. Finally, the innovative composite (Plaster/white Vaseline) underwent thermal and physico-chemical characterization tests that identified its properties and revealed a potential efficiency of the novel material for passive thermal regulation of physiological birth room's indoor environments.

Electrospun Silsequioxane-grafted PVDF hybrid membranes for high-performance rechargeable lithium batteries

Microporous electrospun membranes have certain advantages of higher porosities and electrolyte wettability owing to their high specific surface areas, but these materials suffer from insufficient mechanical strength and dimensional stability when they are employed in advanced lithium batteries. In order to improve the material characteristics and electrochemical performance of these materials, we report the fabrication of silsesquioxane modified electrospun hybrid poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF(HFP)) membranes via the combination of concurrent electrospinning/electrospraying techniques and a UV-initiated grafting polymerization method. The fabricated electrospun hybrid membranes were systematically characterized via various techniques, including thermal characterization, morphology observation, dimensional and mechanical property tests, as well as electrochemical measurements. Silsesquioxanes were covalently integrated onto the surface of electrospun fibers to obtain rigid sheath-like hybrid shell architectures and enhanced cross-linked networks, thus imparting these electrospun hybrid membranes with superior mechanical properties, thermal and dimensional stabilities, as well as remarkable electrochemical performance. Through an in-depth investigation into the electrochemical performance differential of separator prepared by different molecular-topological silsesquioxanes, we discovered that octa-silsesquioxanes (SQ-T8) decorated separators offered superior cycling performance while deca-silsesquioxanes (SQ-T10) exhibited a higher capacity. Through these investigations, we hypothesized that SQ-T8 and SQ-T10 assembled into different configurations via intermolecular stacking arrangements as they were grafted onto electrospun fibers. On the basis of these promising results, these electrospun hybrid membranes could find practical applications in advanced lithium batteries.

The photo response properties of shape memory alloy thin film based photodiode

In this work, the CuAlMn shape memory alloy (SMA) composed as Cu-12.28Al-2.84Mn in wt.% (=72.49Cu-24.70Al-2.81Mn in at.%) was used as a thin Schottky contact layer on an n-Si wafer to produce a Schottky type Al/CuAlMn/n-Si/Al photodiode. To do this, in the first stage of the experimental route, the CuAlMn alloy was prepared in succession by casting in arc melter, homogenizing in β-phase region and lastly by quenching in iced-brine water. Then, the shape memory effect characteristics were revealed by the widely-used thermal (DSC and DTA) and structural (EDS and XRD) characterization tests that been carried out on the alloy. Then, the alloy was thermally evaporated and deposited on the n-Si wafer as a thin film nano layer to make the Al/CuAlMn/n-Si/Al photodiode. The current-voltage (I-V) analysis of the diode taken under dark and different light intensities revealed the rectifying behavior of the diode. The work function value of CuAlMn alloy film was determined as 4.747±0.17 eV. The reverse bias current values of the diode under light were found to be greater than the value observed under dark. The results showed that the diode has a considerable photoconducting feature. The characteristic electrical diode parameters of the junction were computed by using the traditional I-V method. By taking into consideration the literature works related to SMA layered photodiodes, some of the photodiode parameters such as responsivity, photosensitivity, and detectivity, not been reported so far, were determined for the first time. The SMA/n-Si device showed an excellent photosensitivity (~105) performance, and also good merits of responsivity, and detectivity. Which implied that the produced device can be used in various optoelectronic applications. The transient photocurrent (TPC) measurement was performed under the various light intensity conditions and the related characteristic photodiode parameters were determined. Additionally, the capacitance-voltage (C-V) measurement of the SMA-layered photodiode was also carried out at room temperature and different frequencies. The capacitance of the device was observed to be quite sensitive to frequency. Furthermore, a solution suggestion for SMA film cracks and related fractures was also discussed.

Assessment of moisture barrier, mechanical, and thermal property of base/nanophased carbon-epoxy composites in seawater

Polymeric composites absorb moisture by quick surface absorption followed by slow diffusion through the matrix in humid environment. Moisture absorption damages the matrix and interface of fiber reinforced polymer (FRP) composites and consequently, weakens their mechanical and thermal properties. Effects of seawater on mechanical and thermal behavior of base and nanophased carbon fiber reinforced epoxy polymer (CFRP) composites were investigated in this study. It was observed that moisture barrier property of carbon/epoxy composites can be improved by adding a small amount (1 to 3% by weight) of nanoclay as filler. Base and nanophased carbon/epoxy composite panels were fabricated by the vacuum assisted resin transfer molding (VARTM) process and samples were prepared from these panels for mechanical and thermal testing according to ASTM standards. Some of these samples were exposed to seawater for 180 days. Moisture intake by the samples was measured every 10 days for 90 days by which time samples reached a saturated state. Mechanical and thermal behavior of base and nanoclay-infused carbon/epoxy composites with exposure to seawater for 180 days were compared with those with no exposure to seawater for 180 days. Mechanical characterization was performed by compression test. Thermal characterizations were carried out by dynamic mechanical analysis, thermo-gravimetric analysis, and thermo-mechanical analysis tests. Results showed that the 2 wt% nanoclay loading is optimum in terms of moisture barrier capability, compression, and thermal properties. After 90-day exposure to seawater, the 2 wt% nanophased composite absorbed 0.39% moisture compared to 0.67% moisture absorption by the base carbon/epoxy composite. Compressive strength and modulus were decreased by 8.20% and 7.11% respectively, for 2 wt% nanophased composites submerged in seawater for 180 days compared with identical samples with no exposure to seawater. Corresponding data from thermal characterization tests indicate storage modulus and glass transition temperature to be 6.59% and 6.1 °C lower respectively, and the coefficient of thermal expansion to be increased by about 6% for the 2 wt% conditioned sample. SEM study revealed that the nanophased composites exhibited a better bonding between the fiber and matrix compared to the base one even after exposure in the seawater. It is concluded that the excellent barrier capacity, higher surface area, and high aspect ratio of nanoclay are responsible for enhanced durability of the nanophased carbon/epoxy composite in seawater compared to the base one in the same condition.

Development of a low-cost movable hot box for a preliminary definition of the thermal conductance of building envelopes

In the recent years, very promising envelop solutions are available for energy-efficient buildings. Particular interest is risen by the use of innovative natural or bio-based materials. Even if, in some cases, they are wastes coming from industrial or agricultural processes, they can be effectively applied as by-product for the creation of new more sustainable insulation panels and composite materials. In this context, the thermal characterization of a new building material, actually needs of very expensive equipment, with fixed installation, requiring expensive usage and periodic calibration and maintenance. Development of alternative methodologies to determine thermal properties, even in a preliminary way, seems important in order to reduce the costs and to make the tests accessible to wider number of researchers. This paper describes the development and the validation test of a low-cost movable hot box suitable for a preliminary assessment of the thermal conductance of wall elements and insulation panels with dimensions about 1 m × 1 m. The prototype of the hot box has been realized and then tested in the conductance range 0.5–10 W/(m2 K) by adopting two commercial panels used in the building sector. The availability of a low-cost, low-size and moveable equipment allowing a quickly and preliminary assessment of the thermal characteristics of a by-product is useful to understand if the material has suitable properties for future re-use. All this allows the reduction of laboratory time and costs needed for the thermal characterization tests.