Energy efficient CRAC unit operation using heat transfer levels

An air conditioning unit comprising:

• a first sensor configured to detect a temperature of return air (Trat);
• a second sensor configured to detect a temperature of supply air (Tsat);
• a component for cooling the return air prior to being supplied from the air conditioning unit;
• and
• a controller configured to calculate a caloric heat transfer level (Q) in cooling the supplied air from the return air based upon the Trat and the Tsat, wherein the controller is also configured to determine whether the Q is within a predetermined setpoint caloric heat transfer range, said controller being further configured to determine whether the Q is below a minimum setpoint caloric heat transfer level in response to the Q being outside of the predetermined setpoint caloric heat transfer range, said controller being further configured to at least one of decrease a temperature of air delivered by the air conditioning unit and increase a volume flow rate of air delivered by the air conditioning unit in response to the Q being above the minimum setpoint caloric heat transfer level.

A system for controlling an air conditioning unit, said system comprising:

• means for detecting a temperature of air returned (Trat) into the air conditioning unit;
• means for detecting a temperature of air supplied (Tsat) by the air conditioning unit;
• means for cooling the air returned into the air conditioning unit prior to being supplied by the air conditioning unit;
• and
• means for calculating a caloric heat transfer level (Q) in cooling the supplied air from the returned air based upon the detected Trat and Tsat, wherein the means for calculating comprises means for determining whether the Q is within a predetermined setpoint caloric heat transfer range, the means for calculating further comprising means for determining whether the Q is below a minimum setpoint caloric heat transfer level in response to the Q being outside of the predetermined setpoint caloric heat transfer range the means for calculating further comprising means for at least one of decreasing a temperature of air delivered by the air conditioning unit and increasing a volume flow rate of air delivered by the air conditioning unit in response to the Q being above the minimum setpoint caloric heat transfer level.

A tangible computer readable storage medium on which is embedded one or more computer programs, said one or more computer programs implementing a method for controlling an air conditioning unit for energy efficient operation, said air conditioning unit being configured to receive return air, cool said received air and supply the cooled air, said one or more computer programs comprising a set of instructions for:

• detecting the temperature of the air returned (Trat) into the air conditioning unit;
• detecting the temperature of the air supplied (Tsat) by the air conditioning unit;
• calculating a caloric heat transfer level (Q) based upon the Trat and the Tsat;
• determining whether the Q is within a predetermined setpoint caloric heat transfer range;
• determining whether the Q is below a minimum setpoint caloric heat transfer level in response to the Q being outside the predetermined setpoint caloric heat transfer range;
• and
• operating the air conditioning unit to at least one of decrease a temperature of air delivered by the air conditioning unit and increase a volume flow rate of air delivered by the air conditioning unit in response to the Q being above the minimum setpoint caloric heat transfer level.