Color changing system for structures and method therefor

Abstract

A coating system and method for assisting in the heating or cooling of an underlying structure includes applying a first seamless, elastic solar reflective membrane over the structure, applying a second seamless, elastic thermochromic membrane over the first membrane, and applying a third seamless protective membrane over the second membrane. The second membrane has a color changing material with a clear state above a first transition temperature to permit transmission of solar radiation to the first membrane to reduce structure cooling requirements, and an opaque state below a second transition temperature to absorb radiant energy and reduce structure heating requirements. In addition, a method of detecting defects in a structure includes applying a layer of thermochromic material to the structure, observing a localized area of non-uniform color associated with the thermochromic layer, and ascertaining whether a defect is associated with the localized area.

Description

BACKGROUND OF THE INVENTION[0001]This invention relates generally to waterproof coating systems, and more particularly to a coating system that changes color in response to ambient temperature changes to assist in the heating or cooling of underlying structures as well as ascertaining defects in the underlying structures.[0002]Exterior coatings are exposed to the vicissitudes of weather from the very moment they are applied to protect an exterior surface. Water-based coatings are favored over solvent borne coatings for a number of well known reasons. They offer ease of application, reduced toxic solvent emission, lower raw material and application costs, and easy cleanup of site and equipment.[0003]In more recent years, white water-based coatings have become extremely popular and in some areas are required due to their ability to protect a roof against excessive temperatures by reflecting solar radiation, to thereby significantly reduce cooling costs of the underlying building. The ...

AI Technical Summary

Benefits of technology

[0008]According to one aspect of the invention, a method of passively heating or cooling an underlying structure includes applying a solar reflective base layer over the underlying structure to form a first seamless membrane; applying a color changing layer over the base layer to form a second seamless membrane that is contiguous with the first seamless membrane, the color changing layer having a clear state above a first transition temperature and an opaque state below a second transition temperature; reflecting radiant energy from the base layer by exposing the color changing layer to a temperature above the first transition temperature to thereby prevent absorption of heat into the underlying structure; and absorbing radiant energy into the base layer by exposing the color changing layer to a temperature below the second transition temperature to thereby heat the underlying structure.

Problems solved by technology

Although white reflective roof coatings are ideal for summer conditions, they also block much desired solar radiation during cooler periods.

Although it may be desirous to seasonably or even daily replace the roof surface from reflective white to absorptive black depending on the ambient temperature, such a practice would be impractical to implement and extremely expensive.

However, the inelastic nature of such laminates (the Khaldi patent for example discloses an aluminum foil base) do not lend well to large roof areas where expansion and contraction of the underlying structure due to extreme temperature fluctuations, wind or other weather conditions may occur.

In addition, the provision of separate laminates are not only difficult to store, transport and lift to the roof surface, they also must be manually installed with roof-penetrating mechanical fasteners and / or adhesives and joined together at their seams through appropriate sealers, thus increasing the amount of material, time and labor for installing such laminates.

Such systems are also prone to leakage and separation, especially during extreme weather conditions.

Another challenge associated with thermochromic materials is their normally quick deterioration when exposed to ultraviolet (UV) rays.

Although a clear top layer would be desirable to maximize the effectiveness of the lower thermochromic layer, many materials with UV blocking or absorbing additives are unfortunately too opaque to allow effective use of the thermochromic layer.

However, such scanners can be expensive, have a limited field of view, and require significant labor to operate, especially over large area roofs on manufacturing buildings or the like.

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