Phase Change Materials in building science

A new innovative type of material is the PCM. Indeed, one of the advantage is their ability to store heat and release it when there is demand. This is really useful to be able to control the release of heat in order to take advantages from solar heat which is uncontinuous. PCMs are able to store the calories and release it by changing from one state to another depending on the temperature conditions without it affects the external temperature of PCM. The most interesting point about them is that this type of material can store  3 to 4 times more than traditional construction materials for the same thickness by increasing the building inertia.

In this project, I have introduce the concept of phase change materials in order to consider their performance in the construction field. In a second part, I have tried to simulate the efficiency of gypsum plasterboards with microencapsulated PCMs with the energy modeling software IES-VE.

PCMs are a type of material that enables thermal energy storage, heat or cold. One important fact is that it has to be a reversible melting/freezing cycle in order to be able to released the stored energy. The physical process in this case is latent heat because of the phase change. In this paper, I have focused on solid-liquid PCMs. For this type, the phase melting/solidifying can store a large amount of heat or cold. The advantages are the possibilities to find such PCMs with the following characteristics during the phase change: small volume change, small pressure change, constant temperature.

PCMs can be microencapsulated or macroencapsulated in order to prevent leakage of the liquid during the melting phase in other materials. There are also three types of PCMs: organic, inorganic, eutectic.

We are now aware that energy storage in building envelopes can be enhanced by the utilization of PCMs. They can fulfill two functions: thermal energy storage unit and element of construction. PCMs by increasing the thermal inertia can improve thermal comfort in summer as well as in winter.

An application of PCMs in building science that I describe in greater details in my paper can be the use of them in windows. In fact, a layer of PCM can be inserted in the glazing system and then improves its performances b absorbing solar radiation, reducing the cooling and heating demands, and enabling the daylight to be enjoyed inside of the building. There is an example of such glazing unit in this publication (http://www.sciencedirect.com/science/article/pii/S221260901300023X). This study deals with a four-pane glazed system with the insertion of a PCM layer and also a smart layer that regulate the solar transmittance. They are taking advantages of the transparent even translucent aspect of paraffin as PCM.

vertical section of four pane glass

I also describe the application of PCMs in walls and the possibility to simulate it on energy simulation software such as IES-VE.

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