The Performance of an Enthalpy Recovery Wheel in Ventilation of CMU’s IW

Abstract

The operating performance of an enthalpy recovery wheel exchanging heat and moisture between outside and exhaust air streams in the ventilation system of Carnegie Mellon University (CMU)'s Intelligent Workplace (IW) has been measured during the winter of 2006. The test has been performed using manufacture-installed instrumentation and supplementary temperature and humidity data loggers placed at various locations in the machine. The testing indicates that the operation of this wheel has reduced the heating load for ventilating the IW by 77%. Field testing performance agrees well with the lab testing data, which shows 82% heat recovery effectiveness under the same air flow settings used in field testing. The measured data have been analyzed to establish the heat balance over the wheel and to determine the effect of wheel purge on this balance. The measured data have also been analyzed on the basis of heat transfer principles to relate the performance of the wheel to its design parameters and operating conditions. Finally, the lessons learned in field testing of a commercial enthalpy recovery wheel are presented.