Project - Based learning in introductory thermodynamics

Abstract

The sophomore year is a critical decision point for engineering students. In freshman year, they might have been given exciting introductions to engineering design and applicable science by faculty dedicated to teaching. In sophomore year, they encounter traditional lecture presentation of challenging engineering science courses, probably by faculty more dedicated to research than undergraduate teaching. This may present either a threat or opportunity for retention of students. Introductory thermodynamics is usually such a 'gateway' course that must introduce to students both a new branch of science and an unfamiliar abstract method of scientific reasoning. Test scores, surveys, and classroom assessments indicate that many students did not really understand the laws of thermodynamics until the end of the course, if at all, even if they could apply the 'formulae'. A supplemental or alternative approach such as project-based learning may be very useful. This paper describes a design project in a mechanical engineering program at an urban research university. It was initially supplemental, but became a framework for alternative presentation of thermodynamics in a problem-based learning approach. The design project is intended to apply key topics in thermodynamics to a familiar domestic problem of heating, ventilation, and air conditioning (HVAC) system design for a residential application, based on manufacturer's specifications, second-law principles, and actual climate data. Students work in small teams of 2-3. The project is assigned and discussed at the beginning of the semester, so that it naturally motivates the learning of needed concepts throughout the semester. Teams were given annual climate data for different locations and defined home insulation, infiltration, and heat source properties. They were required to perform an energy audit and equipment thermodynamic performance evaluation to select specific units appropriate to the calculated heating and cooling loads. They recalibrate manufacturer ratings of the chosen units for local climate, and calculate the average cost of heating and cooling as well as the lifetime cost of the systems. This involved identifying the vendor and obtaining the necessary performance and cost data from them. Discussions were encouraged among the teams using an online discussion forum. Each student team was required to submit a final project report at the end of the semester and present their data. This project was implemented for a number of years by four different instructors. This holistic design and teamwork experience at the sophomore level appears to have given students a springboard benefit in the curriculum that persists into later courses and professional practice. Direct and indirect assessments of the project-based method were conducted and the results will be presented in the paper. The design project is assessed based on classroom presentations and a written report with technical analysis, design process, and professional conclusions. It is intended to continue restructuring the course syllabus around this project in the future.