There is a need for more efficient and low-carbon heating and cooling and this can be achieved by renewable energy adoption such as solar power. However, renewable energy is time-dependent hence, requires an efficient and cost-effective storage system. In its inexpensive and efficient nature, shallow ground thermal energy storage (SGTES) is identified as an alternative solution. Therefore, this research aims to conduct field experimental studies of improved vertical and horizontal shallow ground thermal energy storage (GTES) systems. The data from these experiments were used to calibrate a detailed TRNSYS model for both configurations. In addition, a simplified inverse model was developed, trained, and tested in MATLAB using TRNSYS-generated and field experimental data. While the detailed TRNSYS model calibrated with experimental data yielded the best results, all results were compared with a few models in previous studies and the acceptable CVRMSE from the ASHRAE guidelines. The results indicated that the models were sufficiently calibrated for heating and cooling application.