[Madane, 4(5): May, 2015] ISSN: 2277-9655 (I2OR), Publication Impact Factor: 3.785 (ISRA), Impact Factor: 2.114 http: // www.ijesrt.com© International Journal of Engineering Sciences & Research Technology [301] IJESRT INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY THERMAL ANALYSIS OF EARTH AIR HEAT EXCHANGER USING CFD Vaibhav Madane *, Meeta Vedpathak, M. D. Nadar * Mechanical Engineering Department, PIITMS&R, New Panvel 410 206, India. ABSTRACT This project focuses on Earth Air Heat Exchanger which is reducing energy consumption in a building. The air is passing through the buried tubes and heat exchange takes place between air and surrounding soil. This equipment helps to reduce energy consumption of an air conditioning unit. This project analyses the thermal performance of earth air heat exchanger by using computational fluid dynamics modeling. The model is validated against experimental observations and investigations on an experimental setup in Ajmer. Simulation results are in fair agreement with experimental data. Effects of pipe materials on thermal performance of earth air heat exchangers are also studied for summer conditions in Mumbai. Results have shown that the performance of earth air heat exchanger is not significantly affected by material of buried pipes. KEYWORDS: Earth Air Heat Exchanger, CFD. INTRODUCTION Energy is very much essential for existence of our society. It is important and urgent to find alternative sources to replace conventional fuel or to reduce its continous consumption due to their limited reservoirs and bad impact on environment. So, we have to find alternative source of energy. This energy shoud be available in abundance on earth and it should be available at all parts of the earth. Nowadays use of airconditioning is increasing in commercial as well as in residential buildings. Vapor compression machines are used to achieve it. Vapor compression machines are the source of chorofluorocarbon (CFCs) gases which are harmful for ozone layer depletion and also contributing to global warming. The air conditioning is used in large scales across the world which is consuming large portion of electrical energy. Electricity consumption reaches to peak value in summer, requiring new power plants for electrical energy production as well as increasing the cost of peak electricity. In addition, entire world is also concerned about climate change and trying to find alternative clean and green sources of energy. As a matter of fact, among the various energy sources, electricity is characterized by the highest GHG emission factor. Many alternative techniques are used to reduce high grade energy consumptions. One such method is earth air heat exchanger. Earth air heat exchanger exchanges heat with underground soil. It uses earth’s constant underground soil temperature and it is used to heat or cool air or other fluids for commercial or residential purposes. It comprises of long tubes that are buried into the ground, through which air is passed. Because of high thermal inertia of the ground, the temperatures of underground soil remains almost unchanged as compared to ground surface. Time lag also occurs between the temperature fluctuations in the underground soil and at the surface. So at certain depth from upper ground surface, underground soil temperature is lower than outside air temperature in summer and higher in winter. The fresh air can be cooled by passing through the earth air heat exchanger and can be supplied to air conditioning unit to reduce energy consumption. The effectiveness of earth air heat exchanger depends upon material of tube, air inlet temperature, soil temperature, depth, arrangement of pipe etc. Computational fluid dynamics (CFD) is an effective method to study heat and mass transfer analysis. Computational fluid dynamics can be used to carry out thermal analysis of earth air heat exchanger. LITERATURE REVIEW Mihalakakou G,Santamouris M et al.[1] found that pipe depth and pipe length turned out to affect overall cooling rate while pipe radius and air flow rate mainly affects earth tube inlet temperatures. M. D. Paepe, A. Janssens et al.[2] derived a relation for sp. pressure drop, linking thermal effectiveness with pressure drop of air inside the tube. The relation is used to obtain optimum thermal effectiveness with acceptable pressure loss. Girija Sharan, Ratan