Progress 09/01/23 to 08/31/24

Outputs
Target Audience:The target audiences are: the Ohio State University (research partners), industry manufacturers of heat pumps for geothermal heating and cooling systems,HVAC contractors who are contracted to install geothermal ystems, including the installers of the ground-loop portion of the overall system for heating and cooling on farmsteads. Changes/Problems:We requested and were granted a one-year no-cost extension. The reasons for the extension request are: * OSU wanted to continue their research of the ground-loop heat-exchange for as much as one more year. This will enable them to collect additional data to support academic research. * Otisco Engineering wants to further explore advancement of its manifold design. What opportunities for training and professional development has the project provided?We have a verbal agreement in place with an Indiana ground-loop installation contractor to beta test our manifold and related installation approach. We developed a professional relationship with the installer during the time in 2021 and 2022 when we were preparing the application for this grant project. At the time, the installer was working for a manufacterer of geothermal heat pump mechanical equipment (Water Furnace). In a June 2024 video conference with Water Furnace and the installer, we presented the benefits of our design, installation, approach, and the Otisco Ground-loopmanifold design. In addition to educating Water Furnace and the installer about our manifold and approach, we are working with installersto beta test our manifold. The verbal agreement is that, once we jointly identify a horizontal ground-loop system to be installed, we will move forward with the installation using our system design, our installation approach (with possible variations as suggested by the installer), and our manifold. How have the results been disseminated to communities of interest?In September 2023, we displayed a poster board at the Farm Science Review (see Products), wihchis an educational program of the Ohio State University College of Food Agricultural, and EnvironmentalScience. The event allows sharing of ideas, services, and equipment to improve agricultural business--covering areas of livestock, grain, fruits, vegetables, and much more. In February 2024, we filed a provisional patent ofour manifold invention. As mentioned in the previous response in this report, we have begun to explore installation of our manifold in systems in the field. We have developed a PowerPoint presentation laying our approach, our manifold design, our system design, and its benefits. That presentation was made to Water Furnace and an Indiana ground-loop installer, in the previously mentioned video conference. We plan to use that presentation (or variations of that presentation) to others with interest in geothermal heating and cooling, including but not limited to designers, manufacturers, suppliers, HVAC contractors, ground loop installers,and materials suppliers. We continue toworkwith a graduate student from OSU. He has been on site for the ground loop installations and heat transfer testing. He has gained a wealth of hands-on field experience in working with us. He has submitted an academic article for publication and has advanced a 3D heat-transfer model about/of the Otisco Ground-loop system. Additionally, we have introduced a horizontal directional drilling company (contractor) to our way of installing the Otisco Ground-loop system. We expect to engage that same contractor in the future. We hope to build similar relationships with other installers, geothermal heat-pump manufacturers, and geothermal heating and cooling system practitioners. One way we plan to do that is byattending the international ground source heat pump association (IGSHPA) conference in March 2025 to meet practitioners and share our ideas with others. What do you plan to do during the next reporting period to accomplish the goals?We installed the two systems at the two OSU properties in a very hands on approach. We consider these "prototypes" and the data collection and analysis to be alpha tests. Over the next annual reporting period, we plan tobeta test our manifold and installation approach in collaboration wtih the previously mentionedIndiana ground-loop installation contractor. This beta test will help in meeting Goal 2:

Impacts
What was accomplished under these goals? OBJECTIVE 1: To supplement the progress of researching subtractive and additive manufacturing as reported in the 2023 progress report, we have completed the folllowing. Subtractive Process Since we were successful in utilizing the block-shaped high-density polyethylene prototype developed in early 2023 in our systems installed in mid-2023, we have focused on improving the means of improving the field method of connecting the ground loop to the manifold. The connection approach has been improved by adding machined grooves with metallic rings in the groovesat theconnection location (i.e., the housing). This improved designwill allow for relatively easy insertion and mechanical connection of the interior tube of the dual-tube ground loop to the manifold. This new connection will replace the need to perform a difficult socket-fusion weld inside the manifold "block" in the field, significantly reducingthe time and nearly eliminating the chance for error in the field when making theconnection. Improving theconnection has required several iterations of design and testing. As of July 2024, the testing has been performed on sacrificial cylinders of HDPE. The next step is to machine the grooves and insert the mechanical "connector" rings into the manifold and perform a beta test on a functioning geothermal heating and cooling system. We have a verbal agreement in place with an Indiana ground-loop installation contractor to beta test our manifold and related installation approach. Additive Process The following has been completed over the past year with respect the the additive (3-D printed) process. * We performed test fusing of HDPE tubingto the manifold with mixed sucess. * We completed a followup conference call with the ElK3D, the company that had 3D printed the manifold in 2023 to explore the material and possibly determine why the welds were not completely successful. We identified two possible reasons for the mixed success are: 1) the chemical formulation of the 3D-printed manifold does not exactly match that of the HDPE tubingbeing fused; and 2) the honeycombed profile of the manifold does not allow for the correct heating to allow for a proper fusion. * We provided more details on the Elk3D about the HDPE material of the tubing to be sure they are using the correct source material for the 3D-printed manifold. * We plan to move forward soon with another test 3D print of the manifold. We have sought a no-costextension on the grant to allow time for this additional research and development. OBJECTIVE 2 We have advanced a draft of a procedure for field installation of the manifold. Otisco is treating this procedure as confidential at this time. As we complete the installation of our continually advanced prototype systems under this grant, we will continue to evaluate and make modifications to the procedure. To protect our ideas, we are treating the installation procedure as proprietary. We have shared the procedure with one contractor; and have a verbal agreement to beta test our manifold and installation approach with that contractor. OBJECTIVE 3 Ground loops were installed in 2023 at the following two OSU facilities, as proposed in our grant application. • Molly Caren Agricultural Center (Fendrick Building), near London, Ohio • the enCORE House on OSU's Main Campus, Columbus, Ohio. Since September 1, 2023, we have collected performance data on the two systems. The data verifiesthat the systems meetthe expected performance of ground-loop systems in the geothermal heating and cooling industry.

Publications

• Type: Journal Articles Status: Published Year Published: 2024 Citation: Q. Victoria Chen, Ph.D., LEED AP BD+C; Patrick Nortz, CPG, PE; and Gregory Nortz, PE, Geothermal Heating and Cooling on the Farm, Ohio Country Journal, April 1, 2024 Nortz, P., Nortz, G., Chen, Q. (2023). "Advanced Research and Commercialization of the Otisco Ground Loop SystemTM for Geothermal Heating and Cooling for Farmstead Applications." Poster presented at 2023 Farm Science Review, Sept. 19-21, London, Ohio. Akram, W. (2023). â¿¿Numerical Simulation and Experimental Investigation of Seasonal Impact on Heating and Cooling Performance of Horizontal Coaxial Ground Coupled Heat Exchanger.⿝ Poster presented at the EmPOWERment Research In Sustainable Energy (RISE) summer program, The Ohio State University, Columbus, Ohio. Akram, W., Chen, Q., Nortz, G., Nortz, P. â¿¿Experimental investigation and numerical modeling of an innovative horizontal coaxial ground heat exchanger (HCGHE) for geothermal heat pump applications.⿝ Journal article submitted to Applied Thermal Engineering, under revision.

Progress 09/01/22 to 08/31/23

Outputs
Target Audience:The target audience is the Ohio State University (research partners). Until we are patented with the invention being advanced under this grant, we will not be reaching out to industry or consumers. Our target audience will be HVAC contractors who are contracted to install geothermal systems, including the ground-loopportion of the overall system for heatng and cooling on farmsteads. The invention being advanced under this grant would be part of the Otisco Ground-loop system for which Otisco Engineering can design for a specific site application. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?We have been working with a graduate student from OSU. He has been on site for the ground loop installations and heat-transfer testing. He has gained a wealth of hands-on field experience in working with us. He has drafted an academic article and created a 3D heat transfer model about/of the Otisco Ground-loop system. Additionally, we have introduced a horizontal directional drilling company (contractor) to our way of installing the Otisco Ground-loop system. We expect to engage that same contractor in the future. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?Additional installation activities. Activatemonitoring for both the Molly Caren and enCORE systems, including the following. Supply air temperature to the building. Return air temperature from the building. Ground-loop fluid temperature Fluid temperatures into and out of the geothermal heat pump Power consumption (amp draw) of the heat pump and flow center, and Outdoor ambient air temperature. Flow rate through the system. We will utilize GRTI's report data and future collected data (e.g., temperatures, electrical draw, ground-loop fluid flow rates, etc.)to help with the following. Calculate Coefficient of performance of the system. Model the thermal heat transfer in the ground (OSU researchers) and evaluate the adequacy of the system ground-loop arrangement. The OSU grad student has drafted an academic publication using results from our Phase I research. This paper should be submitted for publication soon. The student developed a three-dimensional heat transfer model of the Otisco Ground-loop system and will validate the model using data being collected on recent ground-loop installations. With the variety of data being collected for each of the prototype system, wewill evalute the performance of the Otisco Ground-loop Systemso it's operation and efficiency can compared to the performance of other types of ground-sourceand air-source heating and cooling systems.

Impacts
What was accomplished under these goals? Otisco is on track with the goals and milestones presented in the grant application. Below is asummary of the progress toward meeting the three objective and the remaining activities/research to be performed. Progress toward Objective 1: We performed desktop research of various manufacturing methods for our manifold. We concluded that subtractive [Computer Numerical Control (CNC)] and additive [3D printing] should be further explored. We developed a computer model of the manifold that enabled fabrication through both subtractive and additive methods. Both methods allow for production of a single manifold that will direct flow to and from the geothermal ground-loop piping. This single combined supply and return flow manifold will be in place of the need for two manifolds (one for supply and another for return) and will reduce the amount of field welding of pipe and pipe fittings and, with it's compact size, require much less excavation to accomodate installation We approached outside manufacturers for subtractive and additive manufacturing of the manifold, as detailed below. Subtractive Prototype The manifold was manufactured subtractively by a company called Selecteon (Columbus, Ohio) using Computer Numerical Control (CNC) machining, based on the 3D model that we developed.In this case, we started with a block of high-density polyethylene (HDPE) and machined out the interior chambers that allow for flow of fluid through the manifold.This version of the manifold is what we will install in our prototype ground-loop systems to complete what we proposed under this grant. We paid Selecteon $400 per unit to create five prototype manifolds.We have not found on the market a manifold that directs supply and return flows in one unit, so we cannot make a direct cost comparison.We are confident that the cost per unit for our manifold will compete well with the cost of other manifolds on the market. Specifically, the Otisco manifold will compete with the purchase of two individual supply and return manifolds by other manufacturers. Also, our unit would be fusion welded to the HDPE pipe, in the field, which we understand to be more desirable than manifolds on the market that have mechanical connections.The mechanical connections are often more subject to failure during operation in the field than an HDPE-fusion-welded manifold. Additive Prototype The manifold was manufactured additively in HDPE by a company called ELK3D (Toledo, Ohio) utilizing three-dimensional (3D) printing. See Photograph 2.ELK3D modified Otisco's 3D model so that far less material would be needed to produce the manifold and with little waste. Elk3D's model only affected the outside configuration of the manifold and not the interior flow pathways.The resulting 3D- printed manifold weighs approximately one third of the prototype created with CNC subtractive method or conventional hand-welding of pipe as with Otisco's "NIFA-Phase I" grant-project prototype.To reduce the amount of material and simplify the 3D manufacturing process the sidewalls of the chambers in this manifold are not solid but "honeycombed" with varying degrees of infill in the walls. Elk3D charged approximately $200 per unit to 3D print the manifolds, but we are not sure this is the cost we should expect to pay moving forward.We believe that ELK3D gave us a low price to try to demonstrate to Otisco that 3D printing of the manifold is possibleand, knowing that it works, to attempt to convince Otisco to utilize Elk3D (and 3D printing) for future production. Before completion of this Phase II project, we will conduct testing to determine whether the 3-printed manifold will hold up under high pressures and stresses. Preliminary fusion welding of HDPE material to the 3D printed HDPE manifold has produced mixed results. Additional fusion weld testing will be necessary to verify that the welds hold up under stress and pressures. Progress toward Objective 2: We have prepared a draft of a procedure for field installation of the manifold. Otisco is treating this procedure as confidential at this time.As we complete the installation of our prototype systems under this grant, we will continue to evaluate and make modifications to the procedure. Our manifold design is currently proprietary. Sharing of the installation procedure would require that we reveal our manifold design. Therefore, it is premature to share the procedure with an outside contractor. Weverified that themachined maniffold canbe efficiently connected to the ground loops, as well as thesupply and return lines to/from the building. Further testing needs to be performed in year 2 of the project to verify performance of the ground-loop system, including the manifold. Progress toward Objective 3: Ground loops were installed at the following two OSU facilities, as proposed in our grant application. Molly Caren Agricultural Center (Fendrick Building), near London, Ohio the enCORE House on OSU's Main Campus, Columbus, Ohio. The ground-loop piping installations were completed in early June 2023 with the assistance of a third-party directional boring contractor (Precise Boring of Ohio) under contract with and at the direction of Otisco Engineering. Three 280-foot long, 9-foot deep (average depth) approximately horizontal bores were drilled at Molly Caren and two 280-foot long, 9-foot deep (average depth) bores at enCORE. On July 10 through 12, 2023 Otisco completed thermal conductivity testing of one of the three Molly Caren ground loops. The testing required filling the tube-in-tube loop with water to complete a formation thermal conductivity test, utilizing equipment rented from GRTI.The equipment included a pump to circulate water through the loop at approximately 2.3 gallons per minute, a water heater to introduce a constant heat source, and thermal couples to measure fluid temperatures. The flow rate, amperage draw, voltage, and temperatures were recorded every 10 seconds over the 48-hour test period. The results of the testing determined the thermal conductivity of the soil and the performance of the tested horizontal tube-in-tube ground loop.Further, the testing verified that the ground-loop system will provide adequate transfer of heat for heating and cooling the building. The geothermal systems have been installed and operational at theMolly Caren Agricultural Center's Fendrick Building since August 2023 and at the enCore House since September 2023. Datacollection in year 2 will enable study and verification of performance of the system overseasonal heating/cooling cycles.

Publications