Geothermal air coolers have been identified as efficient, economical and environment friendly alternative to the conventional heating and cooling systems. These are attractive because the total energy output is greater than the energy used to drive it. This book therefore, provides the basic concepts, design, modeling and analysis of a geothermal air cooling system in summer climates. The design and fabrication of the ground loop heat exchanger for cooling has been explained. The development and implementation of a module for handling heat transfer and soil temperature algorithms for the simulation of underground pipe is also discussed. Also using this model the effect of parameters like pipe radius and length, air flow rate and pipe depth under the ground surface on the performance of the ground loop heat exchanger were quantitatively assessed. Further the book explains the experimentation performed which includes the experimental verification of the developed underground pipe model and the investigation of the heat transfer characteristics of the underground pipe during heating season. The results obtained are helpful in design and fabrication of geothermal air cooling system