Phase Change Materials: One of Solutions to Reduce Electricity Consumption for Building

Paraffin wax is one of the Organic Phase Change Materials (PCM)

The construction of building in many cities around the world has increased the demands of electricity for every building which is constructed. Consequently, the energy consumption increases as soon as the demands of people who utilizes the building. However, most of the energy consuming are generated from the HVAC system.

HVAC is an abbreviation for Heating, Ventilation and Air Conditioning. It is a system that creates the atmosphere inside the building for each room feels comfortable. Today’s buildings use this system not only for the skyscrapers, or office building but also it is used for hotels, public facilities and medium to large scale industries. HVAC system is responsible to provide thermal comfort and good quality of air since it is designed throughout the thermodynamics aspect so that heat and fluids transfer can be controlled.

Interestingly, the HVAC system which is applied in many buildings has produced high demands of electricity since it needs electricity to start the operation. To produce the good quality of air, the ventilation system integrated to the HVAC is operated from transforming the electrical energy into kinetic energy throughout the propeller. The HVAC system also uses the air conditioner installed in many buildings to provide comfort temperature either it is warm or cold depends on the weather. So basically, the needs of decreasing electricity consumption occurred on the HVAC system which is installed in many buildings has been main topic in several governments around the world.

Many strategies have been implemented and one of the most promising solution is by replacing the materials and re-designing the architectural aspect. For example, researchers from Department of Civil and Environmental Engineering of Worcester Polytechnic Institute (WPI) used the Phase Change Materials (PCM) in gypsum boards as a method to reduce the demands of energy in building. This method can achieve the comfort temperature in indoor because it reduces the energy caused by weather such as sunlight, rain, snow or wind through the walls. PCM has been introduced to constructing method since its properties on heat transfer is low. It means, when the wall receives heat through the increasing of temperature it absorbs the heat and turns it into a liquid phase which can reduce the temperature gradually.

PCM is a latent heat storage which means it has capability to store the energy and it can release the amount of energy. The energy which can be stored is either heat or cold energy. The process of saving energy is from liquid to solid or the opposite, solid to gas and liquid to gas. Technically speaking, when the PCM absorbs for example the heat energy and it makes the material melts then the solid-liquid transitions store the heat. The liquid phase will be achieved if the PCM given absorbs the heat so it means equal to the energy which is absorbed. But, what will happen when the surrounding temperature is decreasing, then the PCM which is in liquid phase will release the heat and find the equilibrium point of temperature. So, instead of using electricity to operate the air conditioner or air vent, PCM automatically controls the temperature.

Overall, the use of PCM based on the research in controlling the temperature depends on many factors including the thickness of the walls, composition of PCM used and the differences between the indoor and outdoor peak temperatures. Furthermore, the research shows that the use of PCM can reduce the demands of electricity for HVAC system.