Progress 10/01/19 to 09/30/20
Outputs
Target Audience:During current grant period, we have focused on: 1. Mentoring and training opportunities to UDC undergraduate and graduate students to engage them in STEM, 2. Outreach to local high school and community college students, UDC students, and general audience to raise the awareness of geothermal energy; and 3. Conference presentations to researchers and stakeholders in similar field or interested in use of geothermal energy for agriculture and other applications. Changes/Problems:The ongoing COVID-19 pandemic has caused the delays in our planned experimental work because of the restrictions of the on-campus activities, which has an impact on the rate of expenditure. Because of the ongoing pandemic issue, we expect a one-year non-cost extension will likely be needed for this project. What opportunities for training and professional development has the project provided?We have developed presentation slides to teach high school students about the utilization of geothermal energy. We have incorporated the research on the geothermal energy and its applications into our existing outreach activity to District of Columbia Public Schools (Columbia Heights Educational Campus) and Summer Risk and Resilience Academy (a virtual workshop hosted in July 2020 for high school and community college students). We have also shown the developed geothermal system at the PI and Co-PI's labs to UDC students who are interested in geothermal energy utilization. How have the results been disseminated to communities of interest?The results obtained have been disseminated to the targeted audience (i.e. DC residents and high school students) through two events during this report period: 1. Over 40 local high school and community college students and UDC students have attended the virtual Summer Risk and Resilience Academy workshop hosted in July 2020 and 3D printing of geothermal system was showcased in the workshop. We have also delivered a presentation about the utilization of geothermal energy for various applications in the virtual outreach event to Columbia Heights Educational Campus in December 2020. More than 30 students and teachers from the Columbia Heights Educational Campus attended the virtual outreach event. 2. The research on the developed geothermal system has also been presented at International Mechanical Engineering Congress and Exposition (IMECE 2020) hosted by the American Society of Mechanical Engineers (ASME) during November 16-19, 2020 (the conference went virtual in 2020 due to the COVID-19). The audience include professionals in geothermal energy design and management, stakeholders, students and faculty members across the nation. The estimated total number of people have attended the virtual presentations are over 40, and the readers of the published work are even more and are not counted here. What do you plan to do during the next reporting period to accomplish the goals?So far, we are able to make good progress for the main objectives we planned for the second year. However, due to the ongoing COVID-19 pandemic, the on-campus research activities were significantly restrained. In the next reporting period, we will continue to work to optimize the design for the geothermal system and print the refined model for implementation at UDC Firebird Research Farm. We will also continue to work on the dissemination of the research results to the targeted audience through various outreach activities and conference and journal publications.
Impacts
What was accomplished under these goals?
Between 1/1/2020 and 12/31/2020, the following progress has been made, based on the project timeline, the second year's work is focused on Objective 2 and Objective 3. Objective 1: To conduct the literature review and data collection for usage of geothermal energy in US. Completed: Major activities completed: We have conducted a further literature search and evaluate the recent development of geothermal energy utilization in the agriculture and related field, with a focus on the new advances in the field to improve the efficiency of the geothermal system. Data collected: We have collected data from various literature studies especially the recent publications for investigate the new ways to improve the heat transfer efficiency and reduce the cost for installation. Discussion of the results: We identify that the current heat exchanger for ground source heat pump requires large areas and needs to excavate the soil for placing it into the ground. However, the novel additively manufactured compact heat exchanger can use minimal area, and there will be no need for excavating the land for installation compare to the current heat exchanger. Objective 2: To design a new and optimal geothermal system for firebird farm at UDC. Completed: Major activities completed: We have designed an additively manufactured heat exchange with a novel way of installation to improve the efficiency and reduce the cost. Traditionally ground source heat exchanger placed in the ground by removing soil. However, the designed new heat exchanger is screw type, which can screw into the ground without removal of soil. Data collected: The sizing of the heat exchanger was determined by paying attention to both heat transfer considerations and manufacturing considerations. We develop a Python model consists of nested loops to calculate the thousands of iterations in a few seconds. The model helps to optimize the best performing combination of different design factors for heat exchanger design of the geothermal system. Discussion of the results: Through the current design, it is possible to achieve 16 feet of a fluid channel within 4 in diameter by 10 in the height of cylindrical volume. The internal channel of the heat exchanger is designed by combining helical and spiral contour. This enhances the heat exchange to save building material (powder), decreases the overall mass of the heat exchanger, and increases the surface area for the internal fluid. Objective 3: To further optimize the designed geothermal system and build the geothermal system using 3D printing technique. Completed: Major activities completed: The prototype of the proposed geothermal heat exchanger was designed using CREO software and then the model was imported to COMSOL-Multiphysics to conduct numerical analysis. Data collected: Three types of meshes were developed to analyze the simulation, including finer, fine, and normal. For heating scenario, the bulk temperature of water increases gradually, and it exits the heat exchange at a temperature around 291K, which results in a roughly 20K temperature increase based on this current design and it is almost the ground temperature. For the cooling scenario, the similar decreasing trend for the bulk temperature of water is also observed. The fluid flow velocity flow is about 0.01 m/s and the slice of velocity magnitude is about 1 m/s. Discussion of the results: From the COMSOL simulations, the prototype of the additively manufactured heat exchanger was able to achieve the desired heat transfer capability. The prototype of the heat exchanger was produced through a direct metal laser sintering (DMLS) method, which builds metal parts from a CAD file using a laser source to fuse fine metal powder selectively. Objective 4: To demonstrate the developed prototype of geothermal system at UDC firebird farm and evaluate its performance. Completed: Major activities completed: The research team are still working on the performance evaluation of the developed prototype of heat exchanger based on the simulation results to assess its feasibility for usage to supply the geothermal energy at UDC firebird farm. Data collected: we are in the process of collecting data related to temperature requirements and energy demands for heating and cooling of high tunnels at UDC farm and evaluate them with our numerical simulations. Discussion of the results: we are still in the process of collecting data
Publications
- Type:
Other
Status:
Published
Year Published:
2020
Citation:
Xu, J., Gemeda, T., Estrada, S., Demisse W., Wang, L. (2020). Design and Development of an Additively Manufactured Geothermal Heat Exchanger for Improved Efficiency and Easy Installation, Proceedings of International Mechanical Engineering Congress & Exposition 2020, Paper ID IMECE2020-21425 (published).
- Type:
Other
Status:
Submitted
Year Published:
2020
Citation:
Gemeda, T., Kabir, M.M., Demisse W., Estrada, S., Wang, L., Xu, J. (2020). Design and Development of a Novel Additively Manufactured Geothermal Heat Exchanger, Applied Thermal Engineering (submitted).
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Progress 01/01/19 to 09/30/19
Outputs
Target Audience:During current grant period, we have focused on: 1. Mentoring and training opportunities to UDC undergraduate and graduate students; 2. Outreach to local high school and community college students and visitors, UDC students and faculty, and general audience who are interested in geothermal energy; and 3. Technical information to researchers in similar field or interestedin use of geothermal energy for agriculture and other applications. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This geothermal heat pump system has been shown to various visitors to the PI and Co-PI's labs including high school, community college students and teachers, PI's collaborators, and UDC students who are interested in geothermal energy utilization. How have the results been disseminated to communities of interest?The results obtained have been disseminated to the targeted audience (i.e. DC residents and high school students) through one event during this report period: Over 30 local high school students, local community college students and UDC students have toured the PI and Co-PI's labs at the Summer Risk and Resilience Academy workshop hosted at UDC in July 22-July 24, 2019 for the showcase and demonstration of geothermal system. What do you plan to do during the next reporting period to accomplish the goals?So far, we were able to achieve the planned objectives for the first year. We will continue to work to improve the design of the geothermal system for higher efficiency and reduced cost and work with the professor and staff at the UDC Firebird Research Farm to further refine the design that is effective for existing high tunnels at UDC farm. The results will be further disseminated to the targeted audience through various outreach activities, including conference, demonstration and workshop.
Impacts
What was accomplished under these goals?
Objective 1: To conduct the literature review and data collection for usage of geothermal energy in US. Completed: Major activities completed: We have conducted a comprehensive literature survey and review for the usage of geothermal energy in the US. Special focus was placed on the use of geothermal energy for agriculture applications. Data collected: We have collected data from various existing theoretical and experimental studies for evaluating the performance of geothermal systems such as ground resource heat pump systems about heat exchange rate, energy efficiency, CO2 emission, cost benefit, and applicable range of different loop systems (e.g., closed loop, open loop, pond loop systems). Discussion of the results: From the existing studies, especially those studies from Europe, the geothermal system has shown to have good economical advantages compared to conventional heating methods considering a 20-year lifespan of the system. Geothermal system can have a high initial cost because of the cost of installation of ground geothermal loop (e.g., trenching for horizontal loop or drilling for vertical loop) and heat pump system costs. But it has low cost for long-term operation. The geothermal system has also shown reduced CO2 emission compared with conventional heating methods in many existing studies. Objective 2: To design a new and optimal geothermal system for firebird farm at UDC. Completed: Major activities completed: We have worked on designing a modular ground source heat exchanger based on additive manufacturing technologies and a manufacturing demonstration and evaluation of the ground-source heat exchanger design. Data collected: The geothermal system uses the ground as a heat source throughout the year. The loop of the heat exchanger is made of material that is durable but allows heat to pass through efficiently. Loop manufacturers typically use high-density polyethylene with heat fuse joints. The fluid in the loop is water or an environmentally safe antifreeze solution. Other types of heat exchangers used directly for heating and cooling utilize a copper piping placed underground. Design Additive manufacturing (AM) through layer-wise fabrication (such as powder-bed fusion) can allow efficient geothermal designs that increase heat exchanger performance and reduce part weight while limiting the number of individual components required for the final part, as well as conformal geometries for space-limited applications. Discussion of the results: Current results have shown that additive manufacturing based on a laser-based powder bed fusion process can be an efficient tool for developing the geothermal system. We have explored various designs of additive manufacturing-based ground resource heat exchanger. The next step is to further optimize the system to improve its efficiency and test its performance. Objective 3: To further optimize the designed geothermal system and build the geothermal system using 3D printing technique. Completed: Major activities completed: We have performed some preliminary thermal analysis about heat transfer rate using the log mean temperature difference (LMTD) method and the ε-number of transfer units (NTU) method. Data collected: The formulations for both log mean temperature difference (LMTD) method and the ε-number of transfer units (NTU) method are used to relate the total heat transfer rate to quantities such as the inlet and outlet fluid temperatures, the overall heat transfer coefficient, and the total surface area for heat transfer. Discussion of the results: We are still in the process of summarizing the data. Objective 4: To demonstrate the developed prototype of geothermal system at the UDC Firebird Farm and evaluate its performance. Completed: Major activities completed: The research team have conducted some preliminary assessment to evaluate the feasibility to implement the designed geothermal system at UDC Firebird Farm. Data collected: We are in the process of collecting data related to temperature required for the crops to grow in the farm and the energy demand for heating and cooling at UDC farm. Discussion of the results: We are still in the process of collecting data.
Publications
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