International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056 Volume: 03 Issue: 04 | Apr-2016 www.irjet.net p-ISSN: 2395-0072 © 2016, IRJET ISO 9001:2008 Certified Journal Page 903 Economic optimization of Wall's Insulation Thickness on Energy Performance of Green buildings G.R.K.D. Satya Prasad 1 , Manas ranjan Panda 2 , Hirok Jyoti Sarmah 3 , Nishant Ku. singh 4 , Hailendra Prasad 5 1 Asscoaite Professor, Department of Electrical Engineering, GIET, Gunupur, Orissa, INDIA 2 Asssiant Professor, Department of Mechanical Engineering, GIET, Gunupur, Orissa, INDIA 3,4,5 Final Year UG student, Dept. of Mechanical Engineering, GIET, Gunupur, Orissa, INDIA ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract: Heat losses of a building envelope are mainly depends on the heat penetration of the buildings. These heat losses can be minimized with proper insulation thickness of the walls. The insulation thickness and energy savings are calculated by using the life span of the building. Passive energy technologies will plays a vital role in deciding the insulation thickness of the buildings. In this paper, a study has been done on energy saving in different types of building walls by using optimum insulation thickness with suitable insulation material. Key words: Insulation thickness, Life-cycle cost analysis, Sustainable homes, Energy consumption. 1. INTRODUCTION Buildings wall insulation thickness plays an important role in buildings energy consumption. The majority of the building designers are not aware of the importance of walls insulation thickness and to optimize the size of insulation thickness. Inappropriate insulation thickness of the wall leads to a bad design of the building and hence consumes more energy by air-conditioning equipment of the building. Insulation materials are preferred in terms of geographical area of the building, local weather conditions, number of floors, wall to window ratio, capacity of the air handling units etc., 1.2 How insulation works Insulation material of the wall depending on its thickness will depend on radiation, convection and conduction. Radiation: This type of heat penetration depends on indirect contact heat process. Conduction: Conduction type of heat penetration directly depends on direct contact of the heat process. Convection: This type of heat process is by using an intermediate agent like air or fluids to transfer the heat in to buildings. 1.3 Performance Insulation material performance mainly depends on the flow of heat energy in to the buildings. They are closely associated with the materials R-values and U-values. In other words; insulation material thermal resistance may resist the transfer of heat in to the buildings with proper optimization of the insulating material. Thermal conductivity: Thermal conductivity of the insulation material is an important parameter to decide the heat penetration in to the building. It is a constant measured in W/mK. The higher the thermal conductivity of the material the better the thermal conductivity of the building. Thermal resistance: Thermal resistance of the material is a product of thermal conductivity and insulation thickness. It is expressed in m 2 K/W. U-value: This value is applicable to any type of building material; like roofs, walls, basement, window glasses, doors etc., It is a measure to calculate the transmission of heat through any material. It is measured in W/m 2 K and gives an insight in to heat transfer through any medium. 2 Thermal insulation: Thermal insulation in buildings is major causes for the excess energy consumption and increased electricity bills. A proper design of the thermal insulation of the building not only reduces the unwanted heat loss or gain and also it will