Radiator Enhanced Geothermal System: From Numerical Modeling to Construction

We have developed and introduced Radiator Enhanced Geothermal System (RAD-EGS), a new method of extracting geothermal energy (Hilpert et al. 2016). The strength of RAD-EGS stems from its structure emulating a natural hydrothermal system. A major structural component of RAD-EGS is an artificially generated vertical square-shaped vane/heat exchanger located in a deep hot sedimentary aquifer (HSA). This geothermal setup consists of injection of cold water to the bottom of the vane and an extraction of super-heated water from the top of the vane. To have an economic geothermal system, the extracted water temperature should be above 150 ˚C. Our simulations, using COMSOL finite element package, demonstrate that RAD-EGS is capable of producing energy for more than 80 years, a longevity that renders significantly higher economic viability than currently available EGS. We have tested various parameters of RAD-EGS and determined that the proposed geothermal system is efficient in generating clean energy for geologic settings with background heat flux of >150 mW m^-2. Moreover, our simulations show that for regions with very high background heat flux (>200 mW m^-2), even smaller and thinner vanes (than the setup previously described in Hilpert et al. 2016) are capable of producing economic energy for a long time.

The heat flow map of the United States depicts vast areas with high background heat flux suitable for extracting geothermal energy using RAD-EGS. Among these areas, we are only looking for hot sedimentary aquifers mainly due to two reasons: i) thermal recharge that may occur due to heat advection of fluid flow significantly increases the longevity of the system, ii) the technology of imaging subsurface sedimentary rock is available and much easier than igneous rocks. After careful examination of the various appropriate regions, we will select a sedimentary setting for conducting the initial RAD-EGS field test.

As demonstrated by the numerical modeling, RAD-EGS is capable of a sustained high-energy production. The careful implementation and subsequent usage of RAD-EGS is at the core of opening the world to a clean and endless supply of energy.