## 7 Conclusions  
The paper presents a mathematical model describing the coupled transport of temperature, humidity, and bound and condensed water within a cold-protecting garment. A one-dimensional formulation of the mathematical problem is utilized, assuming that the transport in a normal direction to the human body dominates. The thermal radiation transport is explicitly considered by the subdivision of the heat flux into radiative and conduction parts to take into account the effect of infrared reflective textiles. The study was carried out for a sandwich garment construction, including a very thin undershirt, an air layer, and batting. Two techniques of improvement of the heat-insulating properties of protective garments were examined: the use of aerogel material and infrared reflective linings (thin infrared reflective textile layers). In the first technique, an aerogel material is used which possesses a thermal conductivity much lower than the air one. By displacing the air within the batting by the aerogel material, one can substantially reduce the thermal conductivity of the whole garment. In the second technique, a thin infrared reflective layer is inserted at the inner boundary of the batting, and reflects the heat radiated by the human body back. The technological aspects of manufacturing such reflective textiles are discussed. The numerical investigations show that:  
* The use of aerogel has been proven to be a possible way to improve the protective properties of clothing. However, it has the serious disadvantage of increasing the weight of the garment by displacing light air with the heavier aerogel material. * The use of the infrared reflective textile is the most effective of the two methods studied. Due to the reflection of the radiant heat flow coming from the human body, the skin temperature rises and the thermal insulation of clothing is significantly improved. It allows a substantial reduction of the thickness and weight of the garment, keeping the human skin temperature constant. Figure 13: Influence of the volume fraction of aerogel \(\varepsilon_{ds}\) on the skin temperature at different \(\zeta_{2}\) and insulation layer thickness. **Author Contributions:** Conceptualization, J.P. and K.R. ; methodology, I.C. ; software, N.K. ; formal analysis, N.K. and K.R. ; investigation, I.C. and G.J. ; writing--original draft preparation, I.C., G.J., N.K. and J.P.; project administration, K.R. All authors have read and agreed to the published version of the manuscript. **Funding:** This research was funded by the Federal Ministry for Economic Affairs and Climate Action (BMWK) within the IraSME program, grant number KK5037208 CD1. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** The data presented in this study are available on request from the corresponding author. **Acknowledgments:** The authors thank [PERSON] (Leibniz IPHT) for supporting the wet chemical metal deposition, [PERSON] (Leibniz IPHT) und [PERSON] (Leibniz IPHT) for SEM and EDX measurements. **Conflicts of Interest:** The authors declare no conflict of interest. **Nomenclature**