Comparison of U-tube boreholes and a thermosiphon on heat pump performance in an aquifer

Reducing our energy consumption and dependence on fossil fuels has become a common social, political and engineering goal. Heating and cooling of buildings account for a large percentage of the energy consumption in the United States. Improving HVAC efficiency in buildings can play a major role in reducing energy use. Small scale geothermal systems that utilize low-grade heat have gained popu-larity as a way to reduce HVAC energy consumption. U-tubes and thermosiphons are two di fferent technologies designed to transfer heat to and from the ground in order to provide building heating and cooling. This thesis presents a short and long term experimental analysis. The short term analysis compares the performance of these technologies. The long term analysis focuses on the U-tubes, looking at the COP of the overall system during the course of a heating season and comparing temperatures for a theoretical air source heat pump system.