# Experimental Characterization of Thermal Conductivity with a New Compact Hot-Box Prototype
## 5 Conclusions  
In this study, a new experimental cell prototype with a volume of 0.602 m\({}^{3}\) was developed to characterize the thermal conductivity of specimens with a fixed area of 25 cm \(\times\) 25 cm and variable thickness up to 10 cm. To validate the prototype's operability, a 3.81 cm thick oak wood specimen was tested.  
The main findings are summarized as follows:  
1. The PWM-based thermal regulator, designed to adjust the internal atmosphere of the hot chamber by supplying a heat flux, performed well, maintaining the air temperature close to steady-state conditions.
2. The temperature difference between the hot and cold surfaces of the specimen remained close to 30.18 \({}^{\circ}\)C in the steady-state regime identified during the experimental test.
3. A thermal conductivity of 0.1695 W/m\(\cdot\)K was obtained, with an expanded uncertainty of \(\pm\)0.0183 W/m\(\cdot\)K at a 95% confidence interval. The experimental value was confirmed by certified commercial equipment (Hot Disk TPS-500S). In addition, the obtained thermal conductivity value fell within the reference range reported by other laboratories using an oak wood specimen.  
The developed prototype offered several advantages, including the ability to provide preliminary thermal conductivity values with increased flexibility and faster testing times for different specimens while occupying less laboratory space and maintaining a cost-effective setup. Compared to traditional methods, this system allowed greater adaptability in testing diverse materials, making it particularly useful for studies on sustainable construction materials.  
Despite its promising performance, the prototype presented some limitations, such as the potential need for improved temperature stabilization mechanisms and the evaluation of samples with greater thicknesses. Future work should focus on refining the system to reduce measurement uncertainty and enhance automation in data acquisition.  
Moreover, this prototype represented a valuable tool for characterizing the thermal properties of bio-based and recycled materials. Future research will focus on testing specimens derived from agricultural waste to assess their viability as sustainable insulation materials, contributing to energy-efficient building solutions.  
Conceptualization, investigation and methodology, F.A.R.-R., N.G.-R. and Y.G.-F.; software, validation, formal analysis, F.A.R.-R. and N.G.-R.; resources, D.V. and M.M.; data curation, D.V. and M.M.; writing--original draft preparation, D.V. and M.M.; writing--review and editing, F.A.R.-R. and N.G.-R.; visualization, D.V. and M.M.; supervision and project administration, Y.G.-F.; funding acquisition, F.A.R.-R. and Y.G.-F. All authors have read and agreed to the published version of the manuscript.  
This research was funded by National Fund for Innovation and Scientific and Technological Development (FONDOCyT), a program of the Ministry of Higher Education, Science, and Technology (MESCYT), Project codes: AgroAislantes 2020-2021-3B1-085, WasteBlocks 2022-3A11-153 and Evaluation of the energy performance of a low-power cooling production system using organic refrigerants assisted by photovoltaic solar energy 2023-1-3C2-0697.  
Not applicable.  
The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.  
The authors declare no conflicts of interest.