Independent thesis Advanced level (professional degree), 20 credits / 30 HE credits
Ground Source Heat Pumps (GHSPs) is a relevant application and around 3 million
installations are setting up at the beginning of 2010 (IEA ECES Annex 21). The
improvements in GSHPs are currently focused on the optimization of the system and
the reduction of costs installations. The thermal conductivity of the ground and
thermal resistance of the Borehole Heat Exchanger (BHE) are important design
parameters for Borehole Thermal Energy Storage (BTES) systems. The Thermal
Response Test (TRT), which has been used up to now in the GHE design, only allows
estimating mean values for thermal conductivity of the surrounding ground and
borehole resistance. However, the ground thermal conductivity and borehole thermal
resistance may present local variation along the borehole depth. For improving
conventional TRT, the optical fiber technology is applied to collect information about
the temperature profiles in the borehole. Thermal Response Test (TRT) logs the inlet
and outlet fluid temperatures; meanwhile, the Distributed Thermal Response Test
(DTRT) carries out a profile of the temperature along the borehole depth, in this case
with fiber optic cables.
This Master of Science Thesis focuses on the comparison and analysis of DTRT
measurements in a U-pipe borehole in order to estimate the thermal conductivity and
the borehole thermal resistance along the borehole. The comparison and the analysis
are carried out by:
•Comparing the differences of TRT results depending on the heat power rate
considered – constant and by steps-.
•Comparing the results from two different resolution Distributed Test Sensing
(DTS) equipments: Halo and Sentinel DTS.
•Comparing the differences of TRT results as depending on the analytical
procedure based on the line source theory: line source model and line source
2011. , 97 p.
Borehole Thermal Energy Storage, Borehole Heat Exchanger, Ground Heat Pump System, Thermal Response Test