The purpose of this project is to develop and demonstrate an integrated Heating, Ventilating, and Air Conditioning (HVAC) system for commercial buildings that optimizes occupant comfort, and can reduce energy use and peak demand. Cooling and heating buildings to achieve comfortable indoor conditions accounts for a large portion of the electricity bills of California commercial ratepayers. This project applies a combination of Variable Refrigerant Flow (VRF) technology with Indirect Evaporative Cooling (IEC) integrated and operationally optimized through the building control system. The VRF technology eliminates inefficient ducting by circulating refrigerant to individual “cassettes” that can either cool or heat an office or zone. The IEC technology reduces outdoor air loads and provides “free night cooling” by pre-conditioning the fresh air required by the building. Control algorithms that monitor and optimize the operation of these two systems together will enable substantial reduction in annual energy use and peak demand.

These two products—VRF and IEC—have not been combined to create an integrated solution, though they are complimentary. The integration must be accomplished with both design and controls. This project will develop both design guidelines using EnergyPlus modeling as well as develop and demonstrate control systems algorithms which can provide these solutions. The project also evaluates cost effectiveness of the integrated solution for new and retrofit buildings including the cost of control system integration.