Patent ID: 6946288

Claim:
A ventilation system for an enclosure in which people live, comprising: a first ducting means for ducting fresh air from outside to inside the enclosure; a second ducting means for ducting stale air, comprising a stale air inlet for receiving stale air containing carbon dioxide from inside the enclosure and an exhaust manifold having a first vent to exhaust air outside the enclosure and a second vent in fluid communication with the first ducting means to return clean air into the first ducting means; catalysing means for catalysing hydration of carbon dioxide contained in at least a portion of the stale air into a solution of carbonate ions and hydrogen ions, and thereby removing carbon dioxide from said portion of the stale air and obtaining clean air; the catalysing means being located in the second ducting means upstream from said second vent, said catalysing means comprising a bioreactor comprising air inlet means for receiving said at least a portion of the stale air; dissolving means for dissolving the carbon dioxide contained in said at least a portion of the stale air into an aqueous liquid; an enzymatic reaction chamber filled with carbonic anhydrase or an analog thereof to catalyse the hydration of said dissolved CO 2 into said solution bicarbonate ions and hydrogen ions; a liquid outlet in fluid communication with the enzymatic reaction chamber for discharging said solution of bicarbonate ions and hydrogen ions out from the bioreactor; and air outlet means for exhausting clean air out from the bioreactor into the second ducting means; and wherein the dissolving means comprises a liquid inlet located in a top portion of the bioreactor for receiving an aqueous liquid; a dissolution chamber located between the air inlet means and air outlet means, and over the enzymatic reaction chamber, the dissolution chamber being in fluid communication with the air inlet means and the air outlet means whereby said at least a portion of stale air is allowed to flow across the dissolution chamber; and a liquid outlet in a bottom portion of the dissolution chamber and in fluid communication with the enzymatic reaction chamber whereby an aqueous liquid containing CO 2 is supplied to a liquid inlet of the enzymatic reaction chamber, the liquid outlet of the dissolution chamber is at a predetermined distance from the liquid inlet of the enzymatic reaction chamber chosen so as to prevent the dissolved carbon dioxide contained in said aqueous liquid to return to a gaseous phase; and evacuating means for evacuating said solution out of the ventilation system.