Adsorption　of　CO2　using　zeolite　13X　as　adsorbent　has　been　studied　extensively,　but　little　attention　has　been　paid　to　CO2　adsorption　at　very　low　concentrations　such　as　in　the　ambient　air.　Furthermore,　there　is　almost　no　information　on　CO2　desorption　characteristics.　In　a　carbon　enrichment　for　plant　stimulation　system,　ambient　CO2　is　enriched　from　400　to　1000　ppm　to　provide　an　enriched　CO2　stream　for　plant　growth　in　greenhouses.　To　provide　essential　design　data,　systematic　performance　tests　were　carried　out　to　evaluate　both　the　adsorption　and　desorption　capacity,　enrichment　factor,　moisture　content,　and　cyclic　performance.　It　was　found　that　the　adsorption　capacity　and　CO2　concentration　in　the　enriched　air　are　a　function　of　adsorption　temperature　and　the　difference　of　adsorption　and　desorption　temperatures,　for　a　given　adsorbent　loading　at　a　properly　selected　gas　flow　rate.