ABSTRACT
The case study learning methodology has been used for more than 20 years in teaching science and engineering. This methodology is known to be highly effective in promoting students' understanding of the concepts and improving their ability to make connections between the concepts. In 2020 and 2021, the limited access to laboratory equipment and facilities due to the COVID-19 pandemic encouraged instructors to implement alternative methods. One of the alternatives considered in the current institution is the use of case studies to enhance students' understanding of thermodynamics and fluid mechanics topics during the online and hybrid implementations of those courses. In this study, an industry-based air-conditioning (AC) unit is facilitated to prepare a case study to teach refrigeration cycles in the laboratory part of thermodynamics. All four components of the AC unit, which include a compressor, a condenser, an expansion valve, and an evaporator, are assembled on a single platform. In an actual application, the compressor and condenser are part of the outside unit while an evaporator and expansion valve would be located indoors. In the first phase of the case study, students analyze temperature and pressure data for the normal operation of the unit to understand the function of each component in the cycle. In addition, by using thermodynamics property tables, they determine enthalpy and entropy values at different stages of the process, generate a temperature versus entropy (T-s) diagram, and calculate the efficiency of the AC unit. In the second phase of the study, they are provided with temperature and pressure data collected for the cases corresponding to when there is a problem with the AC unit. They perform analysis of those cases. The examples of issues introduced include part of the condenser or evaporator coils being disabled or using a partially blocked air filter. The equipment used in the case study is modified by the manufacturer to simulate those issues. During data analysis, student teams are tasked with identifying the issue introduced by looking at the changes in temperature, pressure, and T-s diagram. This paper provides detailed information about the case study, data collection, and analysis. Copyright © 2022 by ASME.
ABSTRACT
Due to the COVID-19 pandemic, educators all around the world searched for effective ways to continue teaching. Although switching to online learning seemed to be the safest and most appropriate method at the time, the virtual setting is inadequate for providing active learning. Hands-on learning is indispensable especially for engineering programs. In Fall 2020, synchronous online mode was augmented with HyFlex instruction for the first time. HyFlex is short for Hybrid learning and Flexible course structure. The HyFlex course model provides students with the following options to choose from: (1) face-to-face, (2) online, or (3) a mixture of face-to-face and online. For the HyFlex instruction, instructors at the current institution divide the class into groups to follow social distancing in the classrooms, which reduces the number of students present in the classroom to roughly half of its maximum capacity. Depending on their assigned group, students take turn attending face-to-face classes in with the instructor present. When the student is not physically in the classroom, they join the class through Zoom meetings. In this study, our focus is on the HyFlex instructional model that our school implemented recently. Two engineering classes selected for this study are Electricity and Magnetism, a sophomore level Engineering Physics class, and Fluid Mechanics, a junior level class. Both classes have students from various engineering disciplines. The study group includes 103 students in Physics and 48 students in Fluid Mechanics. It should be noted that in Fall 2020, the semester started a week earlier and all the breaks were removed to encourage students to stay on campus in an effort to prevent spread of COVID-19. As the end of the Fall semester was approaching, both instructors noticed that some students were having more difficulty with the HyFlex instruction in comparison to traditional face-to-face instruction. These difficulties included not being able to complete assignments on time, lack of motivation, and having trouble obtaining and retaining information. To investigate this further, a survey was administered to study the influence of the HyFlex instructional model combined with the shortened semester on the mental and emotional health of the students. Documenting the advantages and disadvantages of this model will help us to shape a better instructional model that could be used more widely in the future. The instructors will discuss their observations on the HyFlex instructional model as well as feedback for future semesters. © American Society for Engineering Education, 2021