Application of Soy Wax Phase Change Material as Thermal Energy Storage in Wall Building

High solar radiation in the tropics area buildings and inappropriate selection of building materials cause an increase in room temperature which interferes with thermal comfort. This study aims to reduce the absorption of heat received in the building with the modification of building walls by adding Phase Change Material (PCM) as Thermal Energy Storage (TES). Soy wax is an organic PCM that is abundant in Indonesia, cheap, and has a melting point of 43.92°C and a freezing point of 38.49°C, which are the range of solar heat radiation in buildings. The application of soy wax on the walls of the building is carried out using a prototype room 80x105x60 cm made of Plywood with a 1 cm thickness of soy wax in the middle of the wall. The test was carried out by comparing the prototype without and with a layer of soy wax pack on the wall. Based on the tests carried out for 24 hours, it was found that the addition of soy wax on the prototype wall can decrease the room temperature to 37°C from 41°C during the day. The use of soy wax can absorb the heat received by the building by 10% at peak load and has a small heat transfer rate of 15.56 W so the heat transferred into the room is small. Soy wax walls function as insulators on the walls and can withstand heat absorbed from outside the building so that it is not completely transferred into the room.