IDENTIFICATION OF RIVER SAVA TEMPERATURE INFLUENCE ON GROUNDWATER TEMPERATURE OF THE ZAGREB AND SAMOBOR-ZAPREŠIĆ AQUIFER AS A PART OF SHALLOW GEOTHERMAL POTENTIAL

Abstract

Based on the statistical analysis of the time series of data, the influence of the change of Sava River temperature and geothermal anomalies on the changes of the groundwater temperature of the Zagreb and Samobor-Zaprešić aquifers is described. In the analysis, data were used from daily measurements of the Sava River temperature and from the quarterly measurements of the groundwater temperature. Statistical methods of correlation, cross-correlation and linear regression were applied and the maximum, mean and minimum groundwater temperatures were analysed. Obtained results are presented in the form of statistical parameters, diagrams and maps of isotherms. This data is indispensable for development of shallow geothermal applications related to open loop groundwater heat pump systems. Since efficiency of the heat pump is directly dependent source temperature, presented analyses is necessary for prefeasibility study of geothermal projects and comparison between different designs. Furthermore, currently operating projects in the Zagreb and Samobor-Zaprešić are systematically elaborated, giving first approximation of energy consummation from this renewable energy resource.

Keywords

• shallow geothermal energy
• groundwater temperature
• open loop heat pumps