Polymeric Hollow Fiber Heat Exchangers (PHFHE) have recently been proposed as a new type of heat exchanger that can overcome constraints and offer the same or better thermal performance than metallic shell and tube or plate heat exchangers while occupying a much smaller volume. Heat transfer in PHFHE with both parallel and cross flow in the shell side of the device were presented. Fibers made of polypropylene and polyetheretherketone were tested. In addition, steam condensation studies in PHFHE were reported for the first time. Modeling of heat transfer performance of the PHFHE developed was also performed. Possible application fields include desalination, solar, and offshore heat transfer applications. This is an abstract of a paper presented at the AIChE Annual Meeting and Fall Showcase (Cincinnati, OH 10/30/2005-11/4/2005).