Abstract
A desalination design project was developed as part of a thermodynamics lab course for junior level engineering students. The principle behind the process is that when salt water is used in an evaporative cooler freshwater vapor is produced leaving the salt behind. By using a heat exchanger the freshwater vapor can be cooled and condensed into liquid freshwater. The project’s main objective was to give student teams first-hand experience incorporating lessons learned in lecture with the practical constraints of designing, building and testing a realistic application. Student teams were given the task of designing a heat exchanger to be attached to an evaporative cooler so as to condense and collect freshwater. This allowed an objective way to compare performance while providing students an opportunity to see multiple solutions to a common problem. The open-ended project relied heavily on team-based learning and allowed students to be creative while addressing issues during the design phase. A student survey and graded assignment were utilized to assess the resultant student learning. The project culminated in a final report incorporating three main components: Design Analysis, Lab Analysis, and Reflective Analysis. During this project students were given a first look at topics which will be covered more thoroughly in following engineering courses such as heat transfer and fluid mechanics. Additional benefits of the project included its ability to appeal to a variety of learning styles and exposed the capacity for engineering solutions to be applied in new or alternative ways. The project sought to add everyday relevance to the labs and allowed students to place engineering in a global perspective. Introductory thermodynamics instructors have the difficult task of presenting challenging, and often times dry, material to students in a way that exposes its relevance and excites their interests. One strategy for bringing the thermal/fluid sciences to life for the students is via hand-on projects in which students design, build and test (DBT) a product1, 2, 3, 4. DBT projects present a valuable opportunity to learn about the obstacles and compromises engineers address when working to make an idea a reality during the design and build phases. The testing phase supplies concrete feedback on how well a design works and generates discussion on any errors in judgment during the design process and how one might improve on the design. An additional strategy is to show students how thermodynamics ties in with inventive solutions for meaningful problems. The idea for the current project was inspired by a program on the Discovery Channel titled: Building the Future: The Quest for Water5 which discussed an idea for an innovative full scale desalination plant called the Teatro