Lowering Building Temperature by 2.5℃ Using Phase Change Materials

[Asia Economy Reporter Junho Hwang] A technology has been developed that utilizes phase change materials (PCM) on building exterior walls to delay the absorption of heat by buildings during summer heatwaves by absorbing heat when the surrounding temperature rises and releasing heat when the surrounding temperature drops. If commercialized, it is expected to contribute to reducing cooling costs in summer.

On the 7th, the research team led by Dr. Sangwoo Kang of the National Infrastructure Technology Research Division at the Korea Institute of Science and Technology (KIST) announced that they succeeded in reducing heat penetration through building walls by applying phase change materials (PCM), and their related research paper was published in the international academic journal Energy Conversion and Management.

The research team developed a technology that enables the use of phase change materials as exterior wall insulation materials. Since solid-state phase change materials absorb heat from the surroundings while changing into liquid, if the melted phase change material is contained in a case to prevent it from flowing down and applied to the building wall, it can block external heat from penetrating inside.

However, there is a problem that the material does not melt uniformly from the outside to the inside of the building when it changes to liquid. As a result, the hot part moves upward while the cooler part moves downward. Heat then penetrates indoors through the already melted upper part.

The research team solved this problem by injecting bubbles. During the phase change, bubbles were injected into the lower part to circulate the liquefied material. As a result, heat penetration was stopped until the material completely melted, lowering the indoor temperature by about 2.5℃.

Dr. Sangwoo Kang said, "The insulated wall using the phase change material bubble generator applied in this study is expected to contribute to reducing building heating and cooling energy," and added, "Insulation technology using phase change materials can be used together with insulation materials on building walls to enhance heat penetration reduction performance and can also be used as exterior wall materials for zero-energy buildings."