Patent ID: 8727031

Claim:
A method comprising: (a) providing an initial gas mixture comprising oxygen and nitrogen by supplying a portion of ambient air of an enclosed room to a mixing chamber and by mixing the portion of ambient air of the enclosed room with fresh air in the mixing chamber; (b) flowing the initial gas mixture provided in step (a) to a gas separation system comprising a nitrogen generator; (c) separating at least a portion of the oxygen from the initial gas mixture via the nitrogen generator, thereby producing a nitrogen-enriched gas mixture having a residual oxygen content; and (d) flowing the nitrogen-enriched gas mixture of the gas separation system having the residual oxygen content into the enclosed room, wherein the method further comprises the following steps: (i) measuring an oxygen level of a spatial atmosphere of the enclosed room; (ii) measuring the residual oxygen content of the nitrogen-enriched gas mixture at an outlet of the nitrogen generator; (iii) controlling the operation of the nitrogen generator so as to achieve a gas mixture having a residual oxygen content, wherein the operation of the nitrogen generator is controlled based on the measured oxygen level of the spatial atmosphere of the enclosed room and also based on the measured residual oxygen content of the nitrogen-enriched gas mixture at the outlet of the nitrogen generator.