Well both actually.
It is hard to say that phase change materials are themselves an innovative material in their own right, when the definition of phase change materials can cover a broad spectrum of materials. One of the most simplest being water, or in its frozen form ice.
Ultimately, that is all a phase change material is. It’s a material that transforms from one state to another, i.e. from solid to a liquid and back to a solid. Or even a liquid to a gas back to a liquid. To this extent they are naturally occurring events which have happened since time began. So why class it as innovative?
The argument comes from the science behind being able to control the exact point at which that phase change occurs, and then, how these modified materials can be applied to useful end user products. Such as ceiling tiles, wall panels, natural ventilation systems.
The material on its own is of little use until it is put into a form which suits the environment it needs to work it. Companies such as BASF Chemicals, who manufacture a microencapsulated phase change material, can modify the point at which the PCM material changes phase to suit the application its intended for.
PCM products entering the market today become more mainstream as the potential of their benefits become understood.Take the built-environment. Architects and M&E specialists have to consider the Therrmal Mass of a building. Thermal Mass is the capacity for a building to retain heat. A building with little thermal mass heats up quickly and cools down quick too.
This is great for the type of building which is only used at certain points of the day. People come home from work and want to heat up their homes quickly, to spend the evening watching TV and eating their evening meal in warmth before going to bed. However, when it comes to schools and office buildings, these buildings need to retain their heat throughout the day. Where buildings will be occupied for the majority of the day, low thermal mass here means there is a danger of overheating in the summer and a lack of thermal comfort in the winter.
Phase change Materials have the ability to passively manage the internal temperature of a building to improve the thermal comfort by artificially giving buildings thermal mass, that would otherwise be missing either due to its lightweight structure and tighter regulations around airtightness and insulation.
However, phase change materials need the correct environment and conditions for them to work. Buildings that are highly sealed, have little or no ventilation and are at risk of substantial overheating both through the day and night will struggle to benefit from phase change materials, as they will not have the opportunity to release the stored latent heat that is captured though the day. Look at it as a thermal sponge – great for soaking up the water but unless you squeeze the water out, the sponge remains saturated with water for long periods of time.
It’s the same principle for phase change materials. They will absorb and store heat as the room temperature increases until they reach their capacity. But if the temperature does not cool sufficiently at night for the heat to be released, then that heat will remain in the small microcapsules of phase change material and become effectively useless the following day. This makes it essential that the application of phase change products, from ceiling tiles to wall panels, are specified in the right environment where suitable purging of the internal space can be achieved either naturally or through forced ventilation.
With new legislations and regulations only making this a more pressing issue, we must revisit the way we construct and make use of buildings. The pool of technologies that have been around for some time now such as LED lighting or BMS controls are already incorporated as standard. But, to make an impact, more innovation, such as the adoption of PCM technology is needed.
Early adopters of innovative technology are the ones who have the most to gain, opening doors to innovation in other areas which may be able to provide a competitive edge. For example, it opens up the door to the benefits of light-weight structures for education and commercial. Sustainability benefits such as lower carbon expenditure, savings on the cost of the foundation and the speed, ease and safety of construction.
At a time where the environmental impact of both commercial and domestic buildings is under scrutiny more than ever, phase change materials have a vital role towards achieving Government targets. Building owners and tenants can reduce their energy consumption and carbon footprint drastically through how their buildings are designed. The smallest of innovations can begin accumulating to leverage big outputs.
This is the attitude which is desperately needed with today’s challenges, where the need for schools to be built quickly to meet demand and comply with the Facilities Output Specification – such as those on the Priority Schools Building Programme – needs to be balanced with the sustainability agenda. Because of this, phase change materials in the built environment are slowly becoming a common feature in any new build or retrofit specification.
