AHU temperature controlControl of air handling unit discharge air temperature

This function block controls the discharge air temperature of air handlingunits with or without mixing dampers. Heating coil, cooling coil, dampers andfan speed are modulated in sequence to control the temperature. Thefunction block supports 2 major temperature algorithms: constant dischargeair temperature control and return air compensated discharge airtemperature control.

BenefitsEnergy Performance  • The air handling unit air volume is controlledto keep optimum indoor air quality conditions with minimum air volume.  • The economizer control function reduces coolingenergy costs by choosing the most economical air for cooling indoor space. • The summer compensation function reduces cooling energy costs by increasing indoor space temperature in summer seasons.

Comfort  • Optimum comfort is ensured by adjusting the compensated discharge air temperature according to changes in the outdoor air temperature. • An increased indoor space temperature during summer seasons avoids climate shocks when entering or leaving buildings. • An increased discharge air temperature during winter seasons increases human comfort by compensating conductive cold from walls during winter seasons.

Operating principle At startup, the freeze protection and recovery functionprevents the AHU for cycling due to low outdoor airtemperature conditions. The AHU can operate inconstant discharge air temperature control mode or ina return air compensated discharge air temperaturecontrol mode. The temperature is controlled bysequencing heating coil, damper, cooling coil and fanspeed.

CharacteristicsThe function block is designed to be used with theM168 controller. The user interface is provided via thebuilt-in or remote display. It can be used with all typesof AHU.

Typicalapplications• Air Handling Units

Typicalarchitectures• Optimized HVAC/ AirHandling UnitCompact / Hardwired / Logiccontroller / M168

Schneider Electric Industries S.A.SHead Office35 rue Joseph MonierCS 3032392506 Rueil-Malmaisonwww.schneider-electric.com

As standards, specifications and designs change from time to time,please ask for confirmation of the information given in this publication.Design : Schneider ElectricPhotos : Schneider Electric