Seasonal underground thermal energy storage using smart thermosiphon arrays

With oil prices high, and energy prices generally increasing, the pursuit of more economical and less polluting methods of climate control has led to the development of seasonal underground thermal energy storage (UTES) using pump-assisted smart thermosiphon arrays (STAs). With sufficient thermal storage capacity, it is feasible to meet all air-conditioning and heating requirements with a trivial fuel or electrical input in regions with hot summers and cold winters. In this dissertation, it is described how STAs can provide seasonal energy storage to meet all climate control needs. STAs are analyzed and compared with current similar technologies. The objective of this research was to create a methodology to design STA systems for any cooling load in any climate. Full year simulations were performed to model the charging and discharging processes to minimize total pipe length. The modeling results were validated with analytical solutions and some experimental data. The model developed was successfully able to simulate the heat transfer in and out of the soil through thermosiphon pipes over the course of one year using actual weather data and loads. Based on initial modeling results, a pilot-scale thermosiphon system was implemented. A description of this system and limited temperature data is put forth in Chapter 4.