Phase change materials that regulate temperature are everywhere -- in gloves, in coats, even in coffee mugs. These little waxy particles are engineered to keep items cool or warm at specific temperatures, depending on the need.
And despite their impressive capabilities and widespread use in everyday products, they have yet to make it into construction. Imagine the energy savings that could be achieved if walls could absorb the sun's heat, so that a building's temperature stayed cool, or vice versa.
Effectively incorporating phase change materials into buildings has been tough, though, because for a long time it was simply too flammable. But a new process promises to transform this changeable material.
An inch of phase change material has the same heat storage capacity as a foot of concrete. Adding it to walls can reduce the amount of heat that naturally enters a building by 40 percent and energy consumption by 20 percent, depending on the building's location. The material functions kind of like a high-tech adobe, keeping interior temperatures comfortable throughout the day and night.
PCM Innovations, a startup in Longmont, Colorado, is working on making phase change material safer and easier to use for construction. Their esBits -- the ES stands for "energy storage" -- give phase change capability to all kinds of building materials.
"Here in Colorado I'm going to put it in my attic as soon as I can," says PCM Innovations cofounder and CEO Joe Parker.Early phase change materials contained salts, which were problematic because they could damage building structures if they leaked. Current versions use paraffin instead, which Parker says is effective but still problematic. Paraffin (think: candle wax) burns easily, making it a fire hazard. Manufacturers tried to solve this by adding fire retardants, containing the liquid in metal tubes, or formaldehyde shells, which offgas. Not great, either.
Parker says that Oak Ridge National Laboratory combined a dry form of phase change material in micro-bubbles with cellulose insulation that had been fireproofed. Unfortunately, the insulation stops heat flow, reducing the material's effectiveness.
"Our goal now is to duplicate something from Oak Ridge and do it better," he says.
Originally Parker, a Virginia native, was working on locking up the toxins in coal ash by making it into an aggregate when Ciba Specialty Chemicals approached him about finding a way to use a binder with their material. To make the material, Ciba micro or macro-encapsulates paraffin wax in acrylic instead of formaldehyde. The paraffin expands and contracts within little bubbles that contain it. Then PCM uses a proprietary process to attach the phase change material to building materials with a mineral-based binder. EsBits are the result. Ultimately, they can be ground up and recycled.
The cost will depend heavily on the building material, Parker says. But it is durable and should save building owners money in the long run. The company has done testing with insulation manufacturer Johns Manville and is talking with Creighton University in Omaha about using esBits on photovoltaic panels to make them more efficient. Parker adds that they hope to build a small plant to make products and conduct more testing until they can get a license agreement. PCM Innovations is a regional finalist in the Cleantech Open, along with Verdant Earth Technologies. The startups find out later this year if they're good enough to go on to the national finals.
In addition to marveling over the cost, I've often wondered how safe "smart" building materials are for human health and the environment. With a little bit more time and investment in the kind of technology PCM is developing, we could all have high-tech adobes.
Photo: PCM Innovations makes esBits, shown here in a larger particle size for a specific application. Courtesy PCM Innovations.
Tags: Buildings and Structures, Energy Efficiency, Green Building, Green Tech, Materials
comments ( )