EVALUATION OF SMART GEOTHERMAL SYSTEM WITH IMPROVED THERMAL CHARACTERISTICS OF BACKFILLING LAYER

Geothermal surficial looping system is used for conducting heat exchange process between water circulating in cooling/heating systems of buildings and ground. It is considered as one of the most effective and economic renewable and environment friendly techniques. According to proposed climatic conditions, backfilling soil temperature and available backfilling material that can improve heat transfer process the current experimental investigation was carried. The effectiveness of two suggested techniques that may enhance system performance will be investigated. The first uses an inelegant control unit that chooses one of the two looping tubes at different depths that provide maximum temperature difference compared to that of inlet water. The second adopts using limestone powder as a backfilling material in direct contact to ground loops. It was concluded that ground temperature of compacted sand backfill is affected by ambient temperature. Nearly equals it at ground surface and gradually underestimates it with depth until being constant at 1.0 m under soil surface. Considerable reduction in particle size and change in material type between sand backfill and limestone powder backfill resulted in 4 times increase in thermal conductivity. Providing ground heat exchange system with inelegant control unit and two circulating water looping levels effectively enhanced system performance. Increasing thermal conductivity of backfilling material that is in direct contact with circulating water looping by using available raw materials such as limestone powder effectively improve heat exchange process between circulating water and surrounding backfill.