Performance of roof‐cool paints prepared using organic acrylic polymer binder and inorganic additives for the thermal reduction in buildings

Abstract

The passive cooling strategy has gained significant attention in recent years due to the dreadful impact of active cooling on energy demand and global warming. This work reports on preparing water‐based new roof‐cool paints and studying their utility on thermal and reflectivity performance. The acrylic binder was synthesized via free‐radical water‐based emulsion polymerization using vinyl acrylic monomers ‐three new paint formulations prepared using the as‐prepared acrylic polymer binder with inorganic pigments. To study the roof‐cooling performance of the prepared paints, a cubical plywood‐box model fitted with the painted cement panel was considered the roof with a halogen lamp to simulate the sunlight. The digital thermal sensors are used to record the temperature at the exterior panel surface, interior panel surface, and model box center point to record temperature with time. The study revealed that the prepared roof‐cool paints showed a synergistic effect in reflecting the incident light and heat rejection with peak temperature reduction in the internal air reaching up to 2.8° C inside the model. These type roof‐cool paint coatings on a roof‐top could undoubtedly bring the temperature down inside the building and achieve substantial savings from the energy utilized for cooling comfort.

Construction of Reversible Cross-Linked Polyurethane Composite Coating with Recyclability and Passive Radiative Cooling Performance

“…17 ambient temperature. 18 Sun et al prepared a typical polydimethylsiloxane composite containing 20 wt % of silica/ titanium dioxide (3/7) compound filler and found that this coating showed relatively higher solar reflectivity (0.91) and atmospheric transparent window emissivity (0.83), leading to a cooling effect of 5.3 °C in an outdoor cooling test. 19 Although the addition of multiple functional fillers can enhance the radiative cooling ability of polymer-based materials, large amounts of fillers must be added to achieve an acceptable cooling effect due to the inherent poor compatibility between inorganic filler and polymer matrix.…”

“…The incorporation of functional fillers with high refractive index (e.g., titanium dioxide, zirconium dioxide, zinc oxide) and wide electron band gap (e.g., alumina, silica, barium sulfate) into the polymer matrix is regarded as a cost-effective way to achieve efficient subambient radiative cooling. − For example, Dias et al claimed that the addition of 50 vol % titanium dioxide can remarkably enhance the solar reflectance of acrylic coating with maximum values of ∼0.9 . Suwal and Ramaswamy fabricated acrylic composite coating with 40 wt % of titanium dioxide and mica powders as roof-cool paints; such composite coating exhibited a synergistic effect in reflecting the incident light, resulting in a 2.4 °C reduction of internal ambient temperature . Sun et al prepared a typical polydimethylsiloxane composite containing 20 wt % of silica/titanium dioxide (3/7) compound filler and found that this coating showed relatively higher solar reflectivity (0.91) and atmospheric transparent window emissivity (0.83), leading to a cooling effect of 5.3 °C in an outdoor cooling test .…”

Passive-Cooling Building Coating with Efficient Cooling Performance and Excellent Superhydrophobicity

“…Passive-cooling technology has proven that it is a low-cost, green cooling method to achieve indoor cooling for buildings without additional energy consumption [7][8][9][10]. However, the cooling capability of this method was not significant.…”