An official website of the United States government
As this NSF LCDLM dissemination, development, and assessment project matures going into our fourth year of support we are moving forward in parallel on several fronts. We are developing and testing an injection-molded shell-and-tube heat exchanger for heat transfer concepts, an evaporative cooler to expand to another industrial-based heat exchange system, and a bead separation module to demonstrate principles of fluid mechanics in blood cell separations applications. We are also comparing experimental data for our miniaturized hydraulic loss and venturi meter LCDLMs to predicted values based on standard industrial correlations. As we develop these new learning components, we are assessing differential gains based on gender and ethnicity, as well as how students learn with existing LCDLMs in a virtual mode with online videos compared to an in-person hands-on mode of instruction.
more »
« less
Development and Implementation of a Low-Cost, Visual Evaporative Cooling Desktop Learning Module
Evaporative cooling, used in many industrial and residential applications, is a complex coupled heat and mass transfer process where fluid cooling occurs due to water vaporization and the conversion of sensible to latent heat. In this paper, the development, testing, and implementation of a small, highly visual, Low-Cost Desktop Learning Module (LCDLM) for demonstration of evaporative cooling phenomena in the undergraduate classroom will be presented. The newly developed cross-flow direct evaporative cooler module is constructed from inexpensive expanded aluminum packing media, an off-the-shelf, battery-powered computer fan, a simple water distribution system with a battery-powered pump, and clear acrylic housing. The LCDLM is operated in a non-steady-state recycle mode where a small volume of water is circulated and, depending on the water temperature, either heats or cools incoming air. Preliminary data for simple experiments that can be repeated in the classroom are presented showing the effect of varying the initial water temperature, water flow rate, and air velocity on the cooling rate and temperature profiles in the module. These variables can be easily controlled in the classroom so that students can quickly observe their effect on the performance of the evaporative cooler. Finally, we outline worksheet and conceptual assessment questions to accompany classroom activities and present conceptual assessment results from a spring 2022 pilot classroom implementation of the evaporative cooler LCDLM in a Fluid Mechanics and Heat Transfer course. Significant student learning gains were observed after implementation, suggesting a positive influence of the LCDLM on understanding.
more »
« less
- Award ID(s):
- 1821578
- PAR ID:
- 10354624
- Date Published:
- Journal Name:
- ASEE Annual Conference proceedings
- ISSN:
- 1524-4644
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Over the past year we continued, under support from the NSF Division of Undergraduate Education, to emphasize implementation of Low-Cost Desktop Learning Modules LCDLMs for fluid mechanics, heat transfer and biomedical applications. Here we present implementation data from concept tests and surveys, details on new designs and insights gained. Through these activities our team progressed beyond original expectations that were outlined in our original set of NSF-sponsored objectives. We analyzed data from several institutions added from the south central and mid-eastern portions of the US through a combined University of ***-L** and -P** training hub conducted in a virtual mode held in September 2020 with regional communications spearheaded by respective faculty from these institutions. Much of the data analyzed results from support through a 2020 NSF supplement where we engaged in a study to compare direct hands-on implementations of LCDLMs to virtual synchronous and asynchronous implementations augmented with short conceptual videos, a tact necessary because of COVID-19 in-person restrictions. Surprisingly, both in-person and virtual modes show similar conceptual gains. A publication is being developed with intent for submission to the International Journal of Engineering Education where we compare the virtual and in-person modes of instruction. We added a few more institutions through a northeastern training hub held in August 2021 with faculty from the University of *** managing regional communications; again, this hub was held virtually given uncertainty about the lifting of COVID-19 related restrictions. Regarding new LCDLMs we added a shell and tube heat exchanger and fabricated a large number for distribution and implementation and began analyzing conceptual gains and survey results. We prototyped a new evaporative cooler and continue to develop new broader impact units to demonstrate stenosis in an artery and blood cell separations and began implementing them in the classroom. Regarding LCDLM publications a paper was published in Chemical Engineering Education on a study where we compare heat transfer data for the miniature double pipe heat exchanger to predictions based on correlations for industrial scale heat exchangers and included classroom assessment data.more » « less
-
Although there is extensive literature documenting hands-on learning experiences in engineering classrooms, there is a lack of consensus regarding how student learning during these activities compares to learning during online video demonstrations. Further, little work has been done to directly compare student learning for similarly-designed hands-on learning experiences focused on different engineering subjects. As the use of hands-on activities in engineering continues to grow, understanding how to optimize student learning during these activities is critical. To address this, we collected conceptual assessment data from 763 students at 15 four-year institutions. Students completed activities with one of two highly visual low-cost desktop learning modules (LCDLMs), one focused on fluid mechanics and the other on heat transfer principles, using two different implementation formats: either hands-on or video demonstration. Conceptual assessment results showed that assessment scores significantly increased after all LCDLM activities and that gains were statistically similar for hands-on and video demonstrations, suggesting both implementation formats support an impactful student learning experience. However, a significant difference was observed in effectiveness based on the type of LCDLM used. Score increases of 31.2% and 24% were recorded on our post-activity assessment for hands-on and virtual implementations of the fluid mechanics LCDLM compared to pre-activity assessment scores, respectively, while significantly smaller 8.2% and 9.2% increases were observed for hands-on and virtual implementations of the heat transfer LCDLM. In this paper, we consider existing literature to ascertain the reasons for similar effectiveness of hands-on and video demonstrations and for the differing effectiveness of the fluid mechanics and heat transfer LCDLMs. We discuss the practical implications of our findings with respect to designing hands-on or video demonstration activities.more » « less
-
Although there is extensive literature documenting hands-on learning experiences in engineering classrooms, there is a lack of consensus regarding how student learning during these activities compares to learning during online video demonstrations. Further, little work has been done to directly compare student learning for similarly-designed hands-on learning experiences focused on different engineering subjects. As the use of hands-on activities in engineering continues to grow and expand to non-traditional virtual applications, understanding how to optimize student learning during these activities is critical. To address this, we collected conceptual assessment data from 763 students at 15 four-year institutions. The students completed activities with one of two highly visual low-cost desktop learning modules (LCDLMs), one focused on fluid mechanics and the other on heat transfer principles, using two different implementation formats: either hands-on or video demonstration. To examine the effect of implementation format and of the learning tool used, learning gains on conceptual assessments were compared for virtual and hands-on implementations of fluid mechanics and heat transfer LCDLMs. Results showed that learning gains were positive and similar for hands-on and video demonstrations for both modules assessed, suggesting both implementation formats support an impactful student learning experience. However, a significant difference was observed in effectiveness based on the type of LCDLM used. Score increases of 31.2% and 24% were recorded on our post-activity assessment for hands-on and virtual implementations of the fluid mechanics LCDLM compared to pre-activity assessment scores, respectively, while smaller 8.2% and 9.2% increases were observed for hands-on and virtual implementations of the heat transfer LCDLM. In this paper, we consider existing literature to ascertain the reasons for similar effectiveness of hands-on and video demonstrations and for the differing effectiveness of the fluid mechanics and heat transfer LCDLMs. We discuss the practical implications of our findings with respect to designing hands-on or video demonstration activities.more » « less
-
Forced immersion cooling, where a dielectric fluid flows in contact with the cells, is an effective cooling approach for lithium-ion batteries. While previous models demonstrated effectiveness, they generally focused on thermal-fluid aspects and often neglected the coupling between temperature, cell potential, and heat generation (in other words, the electrochemistry remained unaffected by cooling conditions). Here, we use a fully coupled modeling approach that solves the detailed electrochemical model (with temperature-dependent properties) in conjunction with the thermal-fluid transport models at each time step. For an 18650 cell, we compare forced immersion cooling (water and mineral oil) to forced air cooling. Improved temperature control with immersion cooling leads to higher heat generation with increased capacity loss: a 3 K temperature rise corresponds to 10% loss, whereas 42 K temperature rise results in 0.4% loss at 5C discharge. Neglecting two-way coupling prohibits accurate analysis of the effectiveness of immersion cooling. Furthermore, the thermal conductivity and heat capacity of the fluid most significantly impact the electrochemical and thermal response. Finally, we define a new metric to compare performance with different flow parameters without computationally-expensive numerical simulations. Overall, this study provides insights that will be useful in understanding and design of immersion-cooled battery systems.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Conference Paper:
- The DOI is not currently available.
