Energy　consumption　can　be　reduced　effectively　if　ambient　energy　is　used　to　cool　the　telecommunication　base　station.　A　thermosyphon　heat　exchanger　was　adopted　as　a　promising　technique　to　utilise　ambient　energy.　A　prototype　was　developed,　and　the　experimental　system　was　constructed.　Relations　between　dimensionless　entropy　generation　rate,　heat　transfer　rate　and　energy　efficiency　ratio　of　the　thermosyphon　heat　exchanger　were　discussed　theoretically　and　experimentally.　Ambient　temperature　and　facing　air　velocity　were　also　examined.　Results　indicated　that　dimensionless　entropy　generation　rate　decreased　by　8-9%　when　temperature　difference　increased　by　3　degrees　C　and　increased　by　8%　when　the　ambient　temperature　increased　by　3　degrees　C.　The　errors　were　in　the　range　of　5.7-14.2%.　When　the　facing　air　velocity　increased　from　2　m/s　to　3.5　m/s,　the　test　dimensionless　entropy　generation　rate　increased　from　0.4　to　0.53　and　the　errors　were　0.53-9.56%.　Simulation　and　test　results　showed　similar　trends　under　different　working　conditions.