Patent ID: 7886986
Filing Date: 2011-02-15
Classification: F24F,Y02B

Abstract:
1. A method of controlling a recovery wheel in a variable air-volume ventilation system to reduce energy consumption and simultaneously limit the carry-over of exhaust air contaminants into a supply airstream, the method comprising at least the steps of: setting an initial fixed purge angle of the recovery wheel for a high-flow condition of the variable air-volume ventilation system; automatically varying at least one airflow rate within the ventilation system based on a need for ventilation wherein the at least one airflow rate passes through the recovery wheel; and using an automated process, modulating rotational speed of the recovery wheel as a function of at least one of a pressure, a pressure differential, a flow rate, or a fan speed, within the ventilation system; wherein the step of modulating rotational speed of the recovery wheel includes repeatedly changing the rotational speed, and reducing the wheel speed for flow conditions having airflow rates lower than the high-flow condition; and wherein the step of modulating rotational speed of the recovery wheel further includes providing adequate purge flow to limit the carry-over of exhaust air contaminants into the supply airstream to meet an applicable contaminant carryover standard, while avoiding having more than twice the purge flow needed to meet the applicable contaminant carryover standard.