The underlying goal of the research conducted at the Sustainable Thermal Systems Laboratory is to develop practical, climate friendly technologies that optimize thermal energy utilization in a variety of systems and processes. This research is driven by the core belief that the current defining issue facing humankind, sustainable energy, can be addressed not simply through the eternal quest for new sources of fossil and renewable energy, but also through better stewardship of thermal energy utilization and the organization of end-use applications in "near-lossless" energy cascades. Examples of applications being addressed include residential and commercial space conditioning, automotive propulsion and climate control, chemical process industries, and other energy-intensive applications.