NIR-shielding and Visible-light-tranmitted Tungsten Bronze Particles

Hao Tu, DA-REN CHEN, Virginia Commonwealth University

     Abstract Number: 133
     Working Group: Nanoparticles and Materials Synthesis

Abstract
Solar radiation, specifically near-infrared (NIR) radiation, through transparent media (e.g, glass windows) is one of heating sources for transportation vehicles, buildings and houses. HVAC systems are used to control the temperature in the above indoor environments. The effective shielding of NIR from entering the indoor environments could save energy consumption and operational cost of HVAC systems. Tungsten bronze is a NIR shielding material which absorbs the whole NIR and transmits visible light. In the particle form, tungsten bronze particles can be applied on transparent media as a means to control the temperature of indoor environments under the solar radiation. However, liquid-based methods for the production of tungsten bronze particles are energy- and time- consuming. They are also batched. More, tungsten bronze particles are randomly suspended in a transparent carry media for NIR shielding applications. The optical performance of tunstgen-bronze-particle-suspeded media has not been investigated via the modeling.

In this work, we proposed various setups for the continuous production of tungsten bronze particles via aerosol-assisted synthesis. Multiple setups are presented for working with different precursors and solvents. The effects of precursor and solvent were also experimentally investigated. It is shown that tungsten bronze particle in high quality can be produced by cheap and environmentally friendly precursor and solvent. In addition, based on the previous works on the NIR-shielding particles of different metrails, we hypothesized that the size of tungsten bronze particles will have its effect on the optical performance. MOUDI were used to classify as-prodiced particles and the optical performance of classified particles was evaluated. It is shown that the most suitable size of tingsten bronze particles for the NIR shielding can be found via the index of SETS (Solar Energy Transmittance sSelectivity). As a result, the improved optical performance of tungsten bronze particles can be achieved by tuning the particle size. The modeling approach was applied to study the optical performance of tungsten-bronze-particle-suspended madia. Different from the previous works focused on a single particle, this modeling took into consideration of multiple light scattering in the media. The effects of the particle size, concentration and shape on the optical performance of tungsten-bronze-particle-suspended madia were studied. The detail of our work will be presented.