Passive Solar Flooring
The warmth of wood flooring taken into a logical future.


The basic concept is founded on the perception that wood is a "warm" surface... then taking this perception to the next level and actually make it warm.

If one micro-encapsulates specifically designed phase change material (like inexpensive wax) and mold it into a wood/polymer composite, you get a floor that absorbs passive solar heat in the day and slowly gives it back that heat  to the room at night. This heat is "recycled" at a very constant temperature, set by the melting point (MP) of the phase change material. 75 degrees F is typically used.... so the floor stays at approximately 75 degrees throughout the day, night, and year.

Note that this material can be molded (or extruded, or rolled) can, therefore, be just about ANY color, shape, and texture.... think stained cedar shakes, parquet wooden tiles around the pool, or even diamond plate. Covering the above-described oriented fiber composite construction with a high quality veneer top laminate would provide the look of natural wood grain. A thin layer of super insulation on the bottom keeps the heat from transferring into the subfloor. 

Optional feature 1. Now if we wish to take this composite material to another level of functionality, we add a thin foil of copper or graphene between the substrate and super insulation layers. This layer of high thermal conductivity would allow heat to be taken from the sunny area of the room to the entire floor.... or even into other rooms.

Option feature 2. We also propose that the surface could include thermochromatic material so that the color would change. This would allow the floor to self regulate in temperature and not absorb too much solar energy and make the room hot...or vise versa...maybe it can help warm up a cold room by turning a dark color while there is no sun you can still have a light colored floor for a brighter room. Also by being darker, it may reduce glare

Option feature 3. But don't stop with the nu-imaginative restriction that attractive wood belongs only on the floor. These phase change wood components could also be put on walls and other surfaces (cabinets/ built in furniture) just as easily... without looking like cheap wood paneling of the '60's.

This material actually provides temperature regulation to the room, as discussed below. Using roof overhangs (see illustration), curtains, or blinds to keep excess sunshine fro entering the room helps ensure proper temperature control throughout the change in seasons.

Warning: Boring technical stuff follows.... Might be worth reading, if you wish to gain some knowledge

The selected Phase-Change Materials (PCM) use plastic capsules filled with a wax to absorbs and releases energy by melting and solidifying. (See Illustration) PCM's rely on simple melting and freezing, just as ice melts to form water when warmed and freezes again when the temperature drops below 32 degrees Fahrenheit.

The wax microcapsules work in the same way, except the melting and freezing occurs at 78.5 degrees Fahrenheit. When used inside a building room heat is readily absorbed when interior temperature starts to climb just above the wax's melting point. While the wax is absorbing the room's heat to melt, the room temperature stays constant, thus modulating temperature swings in the room. This system works in daily cycles so that at night, when the room temperature drops below 78.5 degrees Fahrenheit, heat energy stored in the microcapsules' liquid wax is released as the wax freezes. Consequently, the floors would provide a dampening effect on the room's temperature during the day and night because it reversibly absorbs energy (e.g., from the air and sunlight), stores it, and later releases it as the ambient air temperature drops.

Therefore, floors constructed with PCM provide greater comfort for the occupants, and reduce air conditioning system energy needs by up to one-third, depending on the overall design of the construction.

"Manufacturers of interior building materials can utilize BASF's Micronal phase-change microcapsules to create new product categories that can give them a competitive advantage," said Michael Guibault, a Marketing Manager for BASF's Construction Polymers business in North America.

Micronal was made possible by a new microencapsulation technology that holds microscopic wax droplets inside hard acrylic polymer shells. The small, 2 to 20 micrometer sized microcapsules are impervious, making them safe to process, and far too small to be damaged by sanding, drilling or cutting of the construction material.

Guibault said that for architects, these tiny capsules add a new, innovative tool to address the growing 'green building' trend. He said home owners and architects can now design modern, flexible, light-construction buildings that have the energy-efficiency advantages that previously only came by using thicker, traditional materials.

Which problem does your idea solve?

Maintaining a comfortable ambient heated (or cooled) temperature throughout the day/night cycle while minimizing fossil fuel energy inputs and the expense of complex solar storage arrays.

How does your idea solve the problem?

Problem: Exposed floors tend to be cold at night... and hot in daytime, if exposed to sun. This idea incorporates phase change materials and materials with high thermal conductivity to both help stabilize the room temperature and move heat around the house. An inexpensive phase change material (PCM) is micro encapsulated and included into a composite base substrate. This PCM melts when exposed to the sun and re-solidifies when cooled by night air.

What is the benefit of your idea for the target group?

The warmth of wood at all times of the day and night. Think of getting out of bed and stepping onto a nice, comfortable, 75 degree warm floor during any time of the year.

Which aesthetic does your idea follow?

The flexible nature of the material, heat absorption characteristics, and full pallet of color choices allow for nearly any aesthetic desired. It can be used in new, renovation, and remodeling.