Document Details

Document Type : Project 
Document Title :
APPLICATION OF PHASE CHANGE MATERIALS FOR BUILDING INSULATION TO REDUCE COOLING LOADS
استخدام مواد متغيرة الطور كعازل حراري في المباني لتخفيض الطاقة المستخدمة في التكييف
 
Subject : Department of Thermal 
Document Language : Arabic 
Abstract : This project is concerned with developing a new technique for insulation of buildings. The first part of the report discusses the importance of using building insulation in the Kingdom of Saudi Arabia. A review of the important insulation techniques along with the methods for thermal conductivity measurements are presented. The available literature in the field of phase change materials (PCMs) have been reviewed in order to utilize such materials in forming an insulation layer that would store heat during day time and release it to the ambient during the night time. Most of the literature is found to be concerned with using PCMs as a storing medium not as a an insulation (barrier) system. It is found that developing a mathematical model for such materials is an involved task due to presence of the so called free boundary layer. In order to evaluate the currently used insulation techniques that use polystyrene bars to fill the holes in buildings bricks a mathematical model was developed. A building brick of 20x20x20 cm with nine holes was modeled. Each hole is 5x5x20 cm. The model shows that internal convection currents help in transferring heat through the brick and the polystyrene bars stop such convection. Comparing the air cavities with polystyrene filled cavities showed that the latter reduces the heat transfer through the brick by 15% (relative to air cavities). Experimental analysis showed that a reduction of 26% can be reached. The part concerning using the PCMs started by solving the problem of heat transfer though a PCM slab of 15x15x25 cm of a wax manufactured by Rubitherm company of Germany having a melting point temperature of 43oC. The slab thickness was selected to be 30mm. An experimental measurement was performed on the selected PCM when subjected to a light source of 650W/m2. The PCM temperature reached a high degree of superheating which should be avoided when the PCM capsules are made. Three identical capsules have been made and installed with in a building brick. When heating the brick by a light source of 1070W/m2 the hot side of brick with air cavities reached 60.8oC. This value increases to 67.7oC when polystyrene bars are installed and reduces to 53oC with PCM capsules. In all experiments the cold side of the brick maintained its temperature by free convection. 
Publishing Year : 1424 AH
2004 AD 
Sponsor Name : kau 
Sponsorship Year : 1424 AH
2004 AD 
Added Date : Monday, November 9, 2009 

Researchers

Researcher Name (Arabic)Researcher Name (English)Researcher TypeDr GradeEmail
ماجد معلا الحازميAlhazmy, Majed M.InvestigatorDoctorate 

Files

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 24449.doc doc 

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