How phase change materials can improve energy efficiency of buildings. Focus on energy savings in buildings – a project supported by Innovation Norway.
There is an increased focus on the environmental aspects of the building industry. One action that will benefit energy usage globally is to increase the energy efficiency of buildings. In EU, the building sector is a major energy consumer and accounts for around 40% of the total energy usage. The energy consumption for buildings can be significantly reduced by using construction materials with high heat capacity that absorb and release heat.
Phase change materials (PCMs)
Phase change materials (PCMs) are materials that can absorb, store and release heat at a constant temperature. These materials utilize the principle of latent heat in melting and solidifying of the PCMs.
When a PCM is in its solid phase it will absorb heat as the external temperature rises. The temperature of the PCM will follow the external temperature until the PCM’s melting point is reached. When the external temperature reaches the melting point of the PCM, the PCM will begin to melt, i.e. “phase change”.
During the phase change process, the PCM will absorb large amounts of energy with almost no change in temperature. During this time, the PCM is providing a cooling effect. The amount of time the PCM will provide a cooling effect is determined by the PCM’s enthalpy of melting, also called the latent heat of fusion of melting. The enthalpy varies depending on the PCM material itself.
The reverse cycle occurs as the external temperature cools. The PCM, now in its’ liquid phase, can release the heat it absorbed as the external temperature decreases. During this time, the PCM solidifies, release energy and provides a warming effect.
The phase change materials are commonly divided in three categories such as organic, inorganic and eutectic PCMs. Organic PCMs can be found among paraffins, fatty acid, esters, alcohols, glycols, etc.)
Market and application of PCMs
Europe is currently the largest market for PCMs, which on a global scale represented a 810 M$ market in 2016 foreseen to grow 20% by 2021. The increasing demand for energy efficiency in buildings and for a reduction in greenhouse gases to reach Europe’s 2020 target is expected to be a key factor in the high market share of PCMs, and the construction and building sector along with the packaging is expected to contribute in the coming years growth.
In general, PCM's can be used everywhere where there is a need for saving energy on heating and cooling. These materials are most frequently used within the building and construction sector due to the huge potential for reduction of heat loss through walls; less energy is needed during cold periods and overheating can be avoided during hot periods. Furthermore, PCMs can be used for commercial refrigeration, in smart textiles, in solar and geothermal energy storage structures and in heating, ventilation and air condition systems.
Norner research and innovation solutions
In a current project, Norner is exploring a novel solutions for industrial production of both green and conventional materials to be used as PCMs. The solutions comprise both materials used in the core of the PCM and the protective layer for encapsulation of PCM. In the project which is supported by Innovation Norway, we are utilizing our competence on polymers, chemicals and polymer processing to explore new concepts. One of the targets is to utilize plastic waste and environmentally friendly polymers to develop green and sustainable PCM’s.