The U.S. Energy Information Agency estimates that buildings consume more than 40% of all energy used in the United States. This includes considering energy used for transportation and heavy industry. As a result, many people across the world have invested significant time and resources developing tools for predicting building performance so energy usage and costs can be optimized. One of these tools are whole building energy simulation (WBES) programs which model building geometry, building construction, and usage to estimate performance. WBES are used by 10's of thousands of architects, designers, and engineers throughout the world each day. Yet, despite this, WBES models for ground heat exchangers (GHE) suffer from a number of limitations. Often, these models rely on third-party tools to generate required data needed for simulation. They also are limited in the ability to model a significant number of common GHE configurations. This limits the abilities of designers to specify and accurately compare ground source heat pump systems to other common building conditioning systems.This study focuses on developing GHE models for use in WBES, which adds an important emphasis to minimize simulation time. In addition, the study seeks to eliminate the need for external tools to improve the accuracy of the simulation methods. This is done in three distinct parts.Load aggregation methods are characterized, a large parametric study is performed, and the results are summarized. The work performed makes recommendations for optimal load aggregation methods and parameters to minimize simulation time and maximize simulation accuracy.An enhanced ground heat exchanger model is developed and validated. The enhanced model allows users to simulate GHE at short and long simulation time steps. The model is validated against experimental data from a multi-flow rate thermal response test. A simplified dynamic borehole heat exchanger model is also developed and validated.A method for simulating the interference between thermally interacting GHE is developed and validated. A case study is presented demonstrating the method usage
