NEW ON-SITE TEST-PROCEDURE FOR FIELD INVESTIGATIONS ON GROUNDWATER INAQUIFER THERMAL ENERGY STORAGE SYSTEMS WITH MOBILE TEST EQUIPMENT

摘要

Operational experience with High-TemperatureAquifer Thermal Energy Storage (HT-ATES)systems sometimes revealed technical problems dueto calcite precipitation in heat exchangers. However,no satisfying prediction of scaling behavior in heatexchangers is possible. In order to gain reliableinformation on the behavior of groundwater in heatexchangers during heating at scheduled HT-ATESsites a mobile test rig has been constructed forpreliminary investigations on groundwater for use inHT-ATES plants. Furthermore, a new on-site testprocedure - scaling test - has been worked out bywhich an uncritical temperature level in respect tocalcite formation in heat exchangers can beevaluated. Up to now, results of experiments withdiverse groundwater types have shown both a distinctinfluence of groundwater chemistry and oftemperature level on calcite precipitation in the testrig. It is estimated that carbonate containinggroundwater might be heated up to about 60°C(140℉), whereas saline groundwater can be heatedup to more than 70°C (158℉) without causing calciteprecipitation. However, it is not yet recommended,not to transfer these results on scheduled HT-ATESplants with similar groundwater, but to carry outspecial investigations.