University of Twente Student Theses


Combination of Phase Change Material with concrete for foundation uses

Hadisaputro, Yosia Giovanni (2016) Combination of Phase Change Material with concrete for foundation uses.

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Abstract:Globally, energy demand has increased each year due to increasing economic activity. In four season’s countries, a lot of energy is spent for heating purposes. The heating process for buildings is not always efficient because there are heat losses through the foundation, walls, and windows. This is most often the case in old houses. This study focuses on introducing phase change material (PCM) in renovated foundations of old houses. The heating system from an old house will possibly have to be renewed while the house is being renovated. One of the methods is adding phase change material (PCM) in concrete, in this study, the PCM will be paraffin. Through literature study, it is found several ways to combine PCM with concrete, but the best way is using macro-encapsulation. Porous lightweight aggregate (LWA) is used as a medium to store PCM in its pores and prevent direct contact between PCM and the concrete mix. Direct contact between PCM and the concrete mix could significantly reduce the strength of concrete. To prevent leakages of PCM while it is melting, LWA that is filled with PCM is sealed with epoxy, graphite powder, and silica fume. It is possible to improve the conductivity of concrete by adding a small amount of fiber in the concrete mix. Adding 0.5% of the fiber in the mix will not reduce the mechanical properties of the concrete. To improve the insulation level of concrete, rubber can be added as an extra layer in the bottom of concrete. The addition of rubber as an extra layer can improve the insulation level by 18.5%. The combination of rubber and fiber in concrete mix theoretically can reduce the amount of heat losses to the soil and increase the heat transfer through the concrete. A small house must be built to study the effect of a combination between PCM, fiber, and rubber in the real situation. The amount of heat can be stored in the foundation depend on many variable. In this study to estimate how much energy can be stored in the foundation, several assumptions are used. The LWA has a porosity of 78%. The Paraffin-LWA used in this study has melting and freezing temperatures at 25°C and 28°C respectively. A typical foundation thickness in a house is 30 cm. The percentage of PCM in the concrete in this study is 26% and the heat capacity of PCM is 149 kJ/kg. If a room has a size of 4 m x 4 m, it will have a total foundation volume of 4.8 m3 and 300MJ of heat can be stored during the phase change period (melting) of PCM. This amount of energy is capable of holding the room temperature stable at 20°C for 36.5 hours while the average outside temperature is 5°C and assuming that the losses only occur from the wall. Extra cost of €21,060 is needed to install this system. Through the study above, it is found that combine PCM with concrete is possible and the best method is macro-encapsulate PCM. Additional study by created a prototype is necessary to prove if the calculation correct or not.
Item Type:Internship Report (Master)
Envita Almelo B.V., the Netherlands
Faculty:ET: Engineering Technology
Subject:52 mechanical engineering
Programme:Sustainable Energy Technology MSc (60443)
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