Patent ID: 7051946

Claim:
A method for controlling air re-circulation in a data center, said method comprising: receiving inlet temperatures and outlet temperatures for one or more racks, said one or more racks comprising inlets and outlets; receiving a reference temperature; calculating a first index value of air re-circulation based on the inlet and outlet temperatures and the reference temperature, wherein the step of calculating the first index value of air-recirculation comprises: determining an enthalpy rise due to infiltration of heated air into the inlets of the one or more racks; determining a total enthalpy rise of the heated air from the outlets of the one or more racks; and dividing the enthalpy rise due to infiltration of heated air into the inlets of the one or more racks by the total enthalpy rise of the heated air from the outlets of the one or more racks; and manipulating one or more actuators in response to the calculated first index value of air re-circulation to thereby control air re-circulation in the data center.