Investigation of performance parameters of nano fluid supported ground source heat pump system

Limited fossil fuels and economic factors have led people to use renewable energy in air-conditioning of residential or commercial buildings. In addition, due to the need to reduce carbon emissions, new technologies have been developed to meet residential thermal demands in recent years. The ground-source heat pumps (GSHP), which have benefited from these developments and use renewable energy, have become popular for area air conditioning applications in many countries due to their economic and environmental advantages. GSHPs are systems that use a relatively stable ground temperature to save energy. In this study, ground heat transfer exchange rates of nanofluids (NF) having different concentration values prepared with aluminum oxide-based nanoparticles (0.1% and 0.2% applied successfully in literature) were investigated. Horizontal ground heat exchangers (GHE) were used in the study in order to reduce the initial installation cost and balance the cost / efficiency. Horizontal GHEs have different designs such as U-type, spiral and slinky etc. When the studies are examined, the two designs that stand out in the rate of heat exchange per unit length are U-type and sprial GHE. In this study, the performance of these designs according to summer and winter conditions were compared separately, energy and exergy efficiencies were calculated, ground temperature distributions and system efficiency according to GSHP system COP values were analyzed. For the experiments, a test room of 21 m2 was prepared in the campus of Sivas Cumhuriyet University and GSHP system was installed in this room. According to the results of heating and cooling experiments, the nanofluid with a concentration of 0.1% gave the highest performance. This increase is valid for both GHE designs that are examined experimentally, independent of the GHE design. In addition, according to the analysis results, U type GHE showed more successful results than spiral GHE. As a result, it has been determined that the use of low amounts of NF in GHE for GSHP system provides performance increase independent of GHE design.