Quantifying the Influence of Near-Surface Water-Energy Budgets on Soil Thermal Properties Using a Network of Coupled Meteorological and Vadose-Zone Instrument Arrays in Indiana, USA

Poster presented at American Geophysical Union Meeting, 2012.Weather stations that collect reliable, sustained meteorological data sets are becoming more widely distributed because of advances in both instrumentation and data server technology. However, sites collecting soil moisture and soil temperature data remain sparse with even fewer locations where complete meteorological data are collected in conjunction with soil data. Thanks to the advent of sensors that collect continuous in-situ thermal properties data for soils, we have gone a step further and incorporated thermal properties measurements as part of hydrologic instrument arrays in central and northern Indiana. The coupled approach provides insights into the variability of soil thermal conductivity and diffusivity attributable to geologic and climatological controls for various hydrogeologic settings. These data are collected to facilitate the optimization of ground-source heat pumps (GSHPs) in the glaciated Midwest by establishing publicly available data that can be used to parameterize system design models. A network of six monitoring sites was developed in Indiana. Sensors that determine thermal conductivity and diffusivity using radial differential temperature measurements around a heating wire were installed at 1.2 meters below ground surface— a typical depth for horizontal GSHP systems. Each site also includes standard meteorological sensors for calculating reference evapotranspiration following the methods by the Food and Agriculture Organization (FAO) of the United Nations. Vadose zone instrumentation includes time domain reflectometry soil-moisture and temperature sensors installed at 0.3-meter depth intervals down to a 1.8-meter depth, in addition to matric potential sensors at 0.15, 0.3, 0.6, and 1.2 meters. Cores collected at 0.3-meter intervals were analyzed in a laboratory for grain size distribution, bulk density, thermal conductivity, and thermal diffusivity. Our work includes developing methods for calibrating thermal properties sensors based on known standards and comparing measurements from transient line heat source devices. Transform equations have been developed to correct in-situ measurements of thermal conductivity and comparing these results with soil moisture data indicates that thermal conductivity can increase by as much as 25 percent during wetting front propagation. Thermal dryout curves have also been modeled based on laboratory conductivity data collected from core samples to verify field measurements, and alternatively, temperature profile data are used to calibrate near-surface temperature gradient models. We compare data collected across various spatial scales to assess the potential for upscaling near-surface thermal regimes based on available soils data. A long-term goal of the monitoring effort is to establish continuous data sets that determine the effect of climate variability on soil thermal properties such that expected ranges in thermal conductivity can be used to determine optimal ground-coupling loop lengths for GSHP systems

Monitoring near-surface thermal properties in conjunction with energy and moisture budgets to facilitate the optimization of ground-source heat pumps in the glaciated Midwest

This poster was presented at the American Geophysical Union Fall Meeting 2011, San Francisco, Calif., on December 7, 2011. It was part of IN33C, Geothermal energy research and discovery II posters session.By exploiting the near-surface heat reservoir, ground-source heat pumps (GSHP) represent an important renewable energy technology that can be further developed by establishing data sets related to shallow (<100m) thermal regimes. Although computer programs are available for GSHP installers to calculate optimal lengths and configurations of ground-coupling geothermal systems, uncertainties exist for input parameters that must first be determined for these models. Input parameters include earth temperatures and thermal properties of unconsolidated materials. Furthermore, thermal conductivity of sediments varies significantly depending on texture and moisture content, highlighting the need to characterize various unconsolidated materials under varying soil moisture regimes. Regolith texture data can be, and often are, collected for particular installations, and are then used to estimate thermal properties for system design. However, soil moisture and temperature gradients within the vadose zone are rarely considered because of the difficulty associated with collecting a sufficient amount of data to determine predominant moisture and temperature ranges. Six monitoring locations were chosen in Indiana to represent unique hydrogeologic settings and near-surface glacial sediments. The monitoring approach includes excavating trenches to a depth of 2 meters (a typical depth for horizontal GSHP installations) and collecting sediment samples at 0.3-meter intervals to determine thermal conductivity, thermal diffusivity, and heat capacity in the laboratory using the transient line heat source method. Temperature sensors are installed at 0.3-meter intervals to continuously measure thermal gradients. Water-content reflectometers are installed at 0.3, 1, and 2 meters to determine continuous volumetric soil moisture. In-situ thermal conductivity and thermal diffusivity are measured at 1.5 meters using a differential temperature sensor that measures radial differential temperature around a heating wire. Micrometeorological data (precipitation, insolation, ambient air temperature, relative humidity, and wind speed) are also collected to determine surface energy and water budgets that drive fluxes of energy and moisture in the shallow subsurface. By establishing continuous, year-round data, fluctuations in seasonal energy budgets and unsaturated zone soil moisture can be considered such that GSHP system designers can establish accurate end members for thermal properties, thereby optimizing the ground-coupling component of GSHPs. These data will also provide empirical controls such that soil moisture and temperature regimes can be spatially distributed based on mapped soil units and hydrogeologic settings in Indiana

Indiana Shallow Geothermal Monitoring Network: A Test Bed for Optimizing Ground-Source Heat Pumps in the Glaciated Midwest

This poster was presented at the 46th Annual Meeting of the North-Central Section of the Geological Society of America, April 23-24, 2012.Ground-source heat pumps (GSHP) represent an important technology that can be further developed by collecting data sets related to shallow thermal regimes. Computer programs that calculate the required lengths and configurations of GSHP systems use specific input parameters related to the soil properties to enhance the accuracy of models and produce efficient system designs. The thermal conductivity of sediments varies significantly depending on texture, bulk density, and moisture content, and it is therefore necessary to characterize various unconsolidated materials under a wide range of moisture conditions. Regolith texture data are collected during some installations to estimate thermal properties, but soil moisture and temperature gradients within the vadose zone are rarely considered due to the difficulty of collecting sufficient amounts of data. Six monitoring locations were chosen in Indiana to represent unique hydrogeological settings and glacial sediments. Trenches were excavated to a depth of 2 meters (a typical depth for horizontal GSHP installations) and sediment samples were collected at 0.3-meter intervals for a laboratory analysis of thermal conductivity, thermal diffusivity, bulk density, and moisture content. Temperature sensors and water-content reflectometers were installed in 0.3-meter increments to monitor changes in temperature and soil moisture with depth. In-situ thermal conductivity and thermal diffusivity were measured at 1.5-meters using a sensor that detects radial differential temperature around a heating wire. Micrometeorological data were also collected to determine the surface conditions and water budgets that drive fluxes of energy and moisture in the shallow subsurface. Preliminary results indicate that increases in water content can increase thermal conductivity by as much as 30% during wetting front propagation. Although there is a change in temperature associated with the infiltration of wetting fronts, thermal conductivity appears to be independent of soil temperature. By establishing continuous data sets, fluctuations in seasonal energy budgets and unsaturated zone soil moisture can be determined. This information can then be used to establish accurate end members for thermal properties and improve the efficiency of geothermal systems

: Bringing a novel research into the classroom: Carbon sequestration as a new opportunity for science education

This poster was presented at the 41st Annual Conference of the Hoosier Association of Science Teachers, Inc. (HASTI), Indianapolis, Ind., February 9-11, 2011.Carbon sequestration technology is an emerging area of research that is rarely presented in the current middle and high school curriculum. This poster complements a concurrent lecture at HASTI (Kevin Ellet and Cristian Medina) and presents three objectives: (1) to introduce the topic of carbon sequestration as a promising area of research for the mitigation of global warming; (2) to show how this technology draws from different science disciplines (e.g. earth science, physics, chemistry, and mathematics) and thus offers new opportunities for science education; (3) to present skills study can learn by studying this technology, such as the use and display of quantitative data and the use of online resources to perform literature searches. This poster presents issues raised in the HASTI position paper “Science Institutions in Indiana: Global Perspectives” (http://www.hasti.org/paper1.html) and encourages discussion on how to maximize science learning in Indiana classrooms

Modeling Water Flux at the Base of the Rooting Zone for Soils with Varying Glacial Parent Materials

Poster presented at American Geophysical Union meeting in 2013.Soils of varying glacial parent materials in the Great Lakes Region (USA) are characterized by thin unsaturated zones and widespread use of agricultural pesticides and nutrients that affect shallow groundwater. To better our understanding of the fate and transport of contaminants, improved models of water fluxes through the vadose zones of various hydrogeologic settings are warranted. Furthermore, calibrated unsaturated zone models can be coupled with watershed models, providing a means for predicting the impact of varying climate scenarios on agriculture in the region. To address these issues, a network of monitoring sites was developed in Indiana that provides continuous measurements of precipitation, potential evapotranspiration (PET), soil volumetric water content (VWC), and soil matric potential to parameterize and calibrate models. Flux at the base of the root zone is simulated using two models of varying complexity: 1) the HYDRUS model, which numerically solves the Richards equation, and 2) the soil-water-balance (SWB) model, which assumes vertical flow under a unit gradient with infiltration and evapotranspiration treated as separate, sequential processes. Soil hydraulic parameters are determined based on laboratory data, a pedo-transfer function (ROSETTA), field measurements (Guelph permeameter), and parameter optimization. Groundwater elevation data are available at three of six sites to establish the base of the unsaturated zone model domain. Initial modeling focused on the groundwater recharge season (Nov–Feb) when PET is limited and much of the annual vertical flux occurs. HYDRUS results indicate that base of root zone fluxes at a site underlain by glacial ice-contact parent materials are 48% of recharge season precipitation (VWC RMSE=8.2%), while SWB results indicate that fluxes are 43% (VWC RMSE=3.7%). Due in part to variations in surface boundary conditions, more variable fluxes were obtained for a site underlain by alluvium with the SWB model (68% of recharge season precipitation, VWC RMSE=7.0%) predicting much greater drainage than HYDRUS (38% of recharge season precipitation, VWC RMSE=6.6%). Results also show that when calculating drainage flux over the recharge period, HYDRUS is highly sensitive to model initialization using observed water content from in-situ instrumentation. Simulated recharge season drainage flux is as much as 3.5 times higher when a one-month spin-up period was performed in the HYDRUS model for the same site. SWB results are less sensitive to water content initialization, but drainage flux is 1.6 times higher at one site using the same spin-up analysis. The long-term goals of this effort are to leverage the robust calibration data set to establish optimal approaches for determining hydraulic parameters such that water fluxes in the lower vadose zone can be modeled for a wider range of geomorphic settings where calibration data are unavailable

Bifunctional Small Molecules Enhance Neutrophil Activities Against Aspergillus fumigatus in vivo and in vitro

Aspergillosis is difficult to treat and carries a high mortality rate in immunocompromised patients. Neutrophils play a critical role in control of infection but may be diminished in number and function during immunosuppressive therapies. Here, we measure the effect of three bifunctional small molecules that target Aspergillus fumigatus and prime neutrophils to generate a more effective response against the pathogen. The molecules combine two moieties joined by a chemical linker: a targeting moiety (TM) that binds to the surface of the microbial target, and an effector moiety (EM) that interacts with chemoattractant receptors on human neutrophils. We report that the bifunctional compounds enhance the interactions between primary human neutrophils and A. fumigatus in vitro, using three microfluidic assay platforms. The bifunctional compounds significantly enhance the recruitment of neutrophils, increase hyphae killing by neutrophils in a uniform concentration of drug, and decrease hyphal tip growth velocity in the presence of neutrophils compared to the antifungal targeting moiety alone. We validated that the bifunctional compounds are also effective in vivo, using a zebrafish infection model with neutrophils expressing the appropriate EM receptor. We measured significantly increased phagocytosis of A. fumigatus conidia by neutrophils expressing the EM receptor in the presence of the compounds compared to receptor-negative cells. Finally, we demonstrate that treatment with our lead compound significantly improved the antifungal activity of neutrophils from immunosuppressed patients ex vivo. This type of bifunctional compounds strategy may be utilized to redirect the immune system to destroy fungal, bacterial, and viral pathogens

The Importance of Modeling Carbon Dioxide Transportation and Geologic Storage in Energy System Planning Tools

Energy system planning tools suggest that the cost and feasibility of climate-stabilizing energy transitions are sensitive to the cost of CO2 capture and storage processes (CCS), but the representation of CO2 transportation and geologic storage in these tools is often simple or non-existent. We develop the capability of producing dynamic-reservoir-simulation-based geologic CO2 storage supply curves with the Sequestration of CO2 Tool (SCO2T) and use it with the ReEDS electric sector planning model to investigate the effects of CO2 transportation and geologic storage representation on energy system planning tool results. We use a locational case study of the Electric Reliability Council of Texas (ERCOT) region. Our results suggest that the cost of geologic CO2 storage may be as low as Dollat 3/tCO2 and that site-level assumptions may affect this cost by several dollars per tonne. At the grid level, the cost of geologic CO2 storage has generally smaller effects compared to other assumptions (e.g., natural gas price), but small variations in this cost can change results (e.g., capacity deployment decisions) when policy renders CCS marginally competitive. The cost of CO2 transportation generally affects the location of geologic CO2 storage investment more than the quantity of CO2 captured or the location of electricity generation investment. We conclude with a few recommendations for future energy system researchers when modeling CCS. For example, assuming a cost for geologic CO2 storage (e.g., Dollar 5/tCO2) may be less consequential compared to assuming free storage by excluding it from the model.ISSN:2296-598