Abstract
Synopsis: Multiple measurement methods for effective ventilation rate ratio of heat exchangers were defined and tested on five commercially available units. A method to keep tracer gas concentration around the heat exchanger unit the same as the return air by covering whole unit and return duct with test chamber turned to be useful in evaluating the carry-over flow effect around the unit to supply air. Significant difference of identified effective ventilation rate ratio was observed among the tested units. It will be predicted that effective ventilation rate ratio will be changed because of the length of duct or the changing of the pressure balance that is caused by outer environment in the duct. Also, a flow network model of air to air heat exchanger unit was developed and successfully applied to reproduce experimented conditions.
