Design of passive radiative heating nanocomposite films by managing natural radiation energy

Purpose

Personal thermal management by controlling the radiation energies of both the body and the sun can be used in all environments and contributes to sustainability components with the advantages of energy saving, low chemical usage and comfort enhancements under dynamic conditions. In this study, passive radiative heating nanocomposite films were produced using sodium alginate as the matrix and zinc oxide (ZnO) and aluminum oxide (Al₂O₃) nanoparticles as nanofillers having far infrared radiation reflecting, hence passive heating functions.

Design/methodology/approach

Nanocomposite film solutions were prepared by stirring sodium alginate powder, deionized water, ZnO and Al₂O₃ nanoparticles (20% wt of matrix polymer) with surfactant using magnetic and ultrasonic stirrers in turn. Films produced within Petri dishes after drying at room temperature were analyzed by FT-IR, UV-VIS-NIR spectroscopy and SEM for chemical, radiation management and morphological characteristics, respectively. Emissivity values giving idea about the heating performances of the films were determined with an IR camera and a hotplate system. Moreover, direct heating performances were measured by the hotplate system including a far-infrared lamp.

Findings

Results showed that the emissivity of the films increased by approximately 18% and 16% with ZnO and Al₂O₃ nanoparticles, respectively. Moreover, NaAlg–Al₂O₃ nanocomposite film exhibited passive radiative heating performance of 3.58 °C, higher than the heating performance of NaAlg–ZnO nanocomposite film which is 2.97 °C when compared to the reference NaAlg film. These results indicate that both NaAlg–ZnO and especially NaAlg–Al₂O₃ nanocomposite films have excellent far-infrared emission and absorption properties ensuring a significant heating effect.

Originality/value

In addition to other clothing types, the heating performance obtained with the produced nanocomposite structures may be applied to different types of cosmetic/medical applications (beauty mask, wound dresses, etc.) enabling skincare/healing with the advantage of the sodium alginate matrix.