Cementitious Cooling Paint Using Radiative and Evaporative Cooling
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Solution Overview
Problem
Existing passive radiative cooling technologies are limited by high dependence on ambient conditions, poor mechanical properties, and environmental impact, while conventional construction materials face inefficiencies in solar reflection and cooling performance, especially in tropical regions with high humidity and solar radiation.
Innovation Solution
A cementitious cooling paint and construction material incorporating composite cement, structural filler, water-absorbing polymer, water capture material, and dispersant, with specific ratios, enabling dual passive cooling through radiative and evaporative methods, and using environmentally friendly materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If passive radiative cooling paint is used, then cooling effect is achieved, but performance is highly dependent on ambient conditions such as relative humidity
Solution Approach 1:
The cooling function is segmented into two independent mechanisms: radiative cooling (through high thermal emissivity in atmospheric window) and evaporative cooling (through water evaporation from porous structure). This segmentation allows the system to maintain cooling performance under varying ambient conditions, as one mechanism can compensate when the other is less effective.
Solution Approach 2:
The patent uses composite cementitious material containing cement, sand, water-absorbing polymer, and water capture material. This composite structure combines the radiative cooling properties of cementitious materials with the water storage and evaporation capabilities of polymers and hygroscopic materials, creating a system that is less sensitive to ambient humidity variations.
2Strength
If organic solvents are used for coating fabrication, then robust structural and adhesive properties are achieved, but environmental friendliness deteriorates
Solution Approach 1:
The patent replaces expensive and environmentally harmful organic solvent-based coatings with inexpensive, environmentally benign cementitious materials. The cementitious coating achieves adequate adhesion and structural properties through its composition (cement, sand, polymers) without requiring toxic solvents, effectively substituting a harmful system with a safe one.
Solution Approach 2:
The patent changes the fundamental chemical composition parameters of the coating from organic polymer-based to inorganic cementitious-based. This parameter change transforms the coating from an environmentally harmful organic system to an environmentally friendly inorganic system while maintaining functional performance through adjusted composition ratios and curing conditions.
3Temperature
If high solar reflection is achieved, then cooling performance improves, but light pollution increases
Solution Approach 1:
The patent optimizes the solar reflection properties at specific wavelengths rather than across the entire solar spectrum. The cementitious coating with neutral white color reflects sufficient solar radiation for cooling while allowing certain visible wavelengths to pass through, thereby reducing light pollution. This selective reflection approach addresses both cooling performance and light pollution concerns.
4Quantity of substance
If hydrogel type coating is used for evaporative cooling, then water content is extremely high, but mechanical properties deteriorate
Solution Approach 1:
The patent merges two previously separate systems: the high water content evaporative cooling function of hydrogels and the high mechanical strength function of cementitious materials. The resulting composite cementitious coating contains water-absorbing polymers and water capture materials embedded in a cement-sand matrix, achieving both high water content for evaporative cooling and high mechanical strength for durability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The cementitious cooling solution provides efficient, long-lasting, and mechanically robust cooling, reducing surface temperatures by up to 12°C under intense sunlight, with reduced solar reflectance and minimal light pollution, suitable for various construction applications.
Implementation Method 1
a water-absorbing polymer; a water capture material
Implementation Method 2
water evaporation is another passive process that continuously consumes thermal energy
Implementation Method 3
Passive radiative cooling technology is a novel approach for continuous energy-saving surficial cooling
Data Source
AI summary
A cementitious cooling paint is provided. The cementitious cooling paint comprises a composite cement; a structural filler; a water-absorbing polymer; a water capture material; and water wherein the water to composite cement ratio is from 0.4 to 1.2 by mass; the composite cement to structural filler ratio is from 0.4 to 0.7 by mass; the composite cement to water-absorbing polymer ratio is from 0.01 to 0.03 by mass; and the composite cement to water capture material ratio is from 0.05 to 0.3. The cementitious cooling paint may further include a dispersant, wherein the composite cement to dispersant ratio is from 20 to 50 by mass. A cementitious cooling construction material and a cement-based building product comprising the cementitious cooling construction material are also provided.