Design and Performance of a High-Temperature Regenerator Having Very High Effectiveness, Low Leakage and Negligible Seal Wear

A high-temperature regenerator has been designed under MIT and WTPI patents (figure 1). These call for the ceramic-honeycomb regenerator disk to rotate incrementally, in this case through 90 degrees, for each movement. The seals, which can conform to the profile of the sealing surface, are firmly pressed to the regenerator seal faces during the stationary periods, here about fourteen seconds (figure 2). The seals then lift marginally, just enough to allow free disk movement, during the 0.75 second of the indexing period. Thus no sliding wear can take place. In the demonstrator unit tested the measured effectiveness was over 98%, the pressure drops of the hot and cold flows were under 2%, and the leakage was low within experimental error. The demonstrator was tested at a top temperature of 910° C. (The final temperature after development should be well above 1000°C). The paper describes design methods that are substantially different from those in general use, and discusses design choices for materials and actuation systems. This regenerator was designed to be compatible with a high-temperature 5-kW solid-oxide fuel cell. Our design studies indicate that, when applied (in a considerably larger size) to micro turbines it would enable electrical efficiencies of 50% to be exceeded. Other industrial applications that require too high a temperature for currently available recuperators would also become viable.Copyright © 2006 by ASME