Abstract: A method, device, and system for quantifying thermal properties of subsurface geologic materials are disclosed, addressing challenges in geothermal energy applications. The method involves deploying an array of temperature sensors and heating elements encapsulated within an inflatable sleeve into a borehole, activating the heating elements to inject heat into the enveloping formation, and measuring a time series of temperature data for subsequent analysis. The device includes an array of temperature sensors, at least one heater element, a power source, and an interrogator configured to measure temperature using data from the sensors. The system incorporates the inflatable sleeve with fiber optic sensors defining a fiber Bragg grating, heating elements, a power source, and a computing unit programmed to perform numerical inversion for calculating thermal conductivity and specific heat capacity, thereby optimizing borehole heat exchanger designs for geothermal heat pump systems.

Abstract: Methods, systems, and devices for quantifying geothermal heat flux using shallow subsurface temperature measurements are provided. A method can include deploying vertical temperature probes with fiber optic sensors, strain sensors, and advective sensors at measurement sites. Time-series temperature data is then recorded, processed to determine equilibrium temperature profiles, and corrected for climate-driven signals, strain, and advection effects. Geothermal heat flux is calculated by combining the corrected temperature gradient with subsurface thermal conductivity, and a heat flux map can be generated to identify geothermal energy resources.

Abstract: Methods, systems, and devices for quantifying geothermal heat flux using shallow subsurface temperature measurements are provided. A method can include deploying vertical temperature probes with fiber optic sensors, strain sensors, and advective sensors at measurement sites. Time-series temperature data is then recorded, processed to determine equilibrium temperature profiles, and corrected for climate-driven signals, strain, and advection effects. Geothermal heat flux is calculated by combining the corrected temperature gradient with subsurface thermal conductivity, and a heat flux map can be generated to identify geothermal energy resources.