One of my favorite science fiction ideas is in a short story called Light of Other Days about something called “slow glass.” Light took decades to pass through. In this story, the idea was that people could buy glass windows that took so long for the light to pass through, that they could nostalgically watch long gone scenes, such as their children playing outside as toddlers long after they had gone off to college, or green fields with horses where now ugly cities grew.

It was about the speed of light

Here is a concept that is similar. Instead of slow windows, it is slow walls. RavenBrick has made a nanotech wall that can slow down the day’s heat coming into a building. Using phase-changing material at the molecular level, you get to transfer the warmth of the sun’s heat from the afternoon well into the night.

RavenBrick makes several clean tech materials for building that greatly reduce energy needs, most notably windows that turn off the sun, like Sage Electrochromics windows do. The one that is new to me is this “slow wall”. They claim that their glass-clad Smart Wall: RavenSkin could literally reduce your heating bill to zero! (Coupled with good building design, of course, you can’t expect a zero bill if you put leaky windows in their wall!)

Their wall can delay solar heat gain from hot afternoons, to later that night, when you need it more. This helps regulate the internal temperatures of buildings. It has excellent R-values to begin with (R-11 or more) so it insulates like a normal wall limiting the conduction and convection of heat.

The magic – or science fiction – part is achieved by converting incoming sunlight to infrared, and then directing the flow of energy inward only when you want it to come through the walls. The problem with super well-insulated buildings is that sometimes you do want the suns heat getting in, and regular insulated walls are dumb walls that don’t know when to send the heat in and when to shut it out.

The Smart Wall knows because you can tell it.

Cleantechnica.com