An effective control strategy with a non-homogeneous soil profile for horizontal Ground Source Heat Pumps (GSHPs) was investigated in this paper. Steps toward development of a comprehensive model to consider the effects of an intermediate blanket on top of the ground pipes were described. The model incorporates the effects of a variety of surface energy fluxes to provide an accurate estimate of the ground thermal regime. The developed model was successfully utilized in conjunction with the Genetic Algorithm (GA) evolutionary search method to obtain the optimized operational parameters for a GSHP in three different climate conditions. A properly sized and engineered non-homogeneous soil profile demonstrated the potential to boost the capacity of GSHP systems to a significant level. The potential benefits of a recycled product of tire industry, Tire Derived Aggregate (TDA), as an insulation blanket was assessed via the optimization algorithm. TDA demonstrated to be more effective in heating mode in a cold climate (Buffalo) by increasing the energy extraction rates by about 15 % annual. TDA’s effectiveness was less pronounced in a relatively moderate climate (Dallas) for heating purposes with efficiency improvements of about 4 % annual. The annual percentage increase in efficiency for cooling season with TDA blanket was higher for Buffalo (7.6 %) compared to Dallas (3.5 %). For the cooling only purposes (Miami), a high conductive intermediate layer (saturated clay) exhibited greater potential to enhance the efficiency in coldest months in a warm climate. The results are highly suggestive of the beneficial application of a layered system to increase the performance of GSHPs. A shift in design perspective toward consideration of more control strategies for the ground pipe side of GSHPs is suggested based on the model results. A field demonstration project with TDA blanket is constructed at the University at Buffalo to further investigate the findings with regard to field conditions and other characteristics of TDA material.
Available at: http://works.bepress.com/amir_rezaei-bazkiaei/5/