Synergization of air handling units for high energy efficiency in office buildings: The theory and analysis

An air handling unit (AHU) along with its downstream terminals is considered as the primary independent thermal processing and air distribution system in buildings. The outside air intake, supply air temperature control, and fan modulation are performed within the individual AHU for an associated region to integrally achieve the energy efficiency and indoor air quality (IAQ). The conventional zoning and AHU operation strategy in office buildings lowers the energy waste probability due to the heating and cooling mode compromising among the zones. However, this AHU oriented practice limits the utilization of heat surplus in building regions and operation difference across the AHUs. To break the frame and bring in synergization among them in office buildings, an integrated AHU (IAHU) control is proposed in this study. The theory is revealed in three steps: (1) the critical ventilation constraints of the new control are quantitatively defined; (2) the supervisory decision making schema for optimum energy efficiency are provided analytically; (3) the parameters are briefly discussed in terms of their influences on the system performance. This innovative operation of IAHU could notably improve the building level energy efficiency through significant heat gain transferring, and sensible and latent load decoupling.

► We propose an AHU synergization strategy for open space office buildings.
► We obtain the quantitative expressions of the constraints and operation schema.
► IAHU operation can improve the energy efficiency by utilizing the regional heat gain.
► IAHU operation can be adopted into continuous commissioning as low cost retrofit.
► Parameters and feasibility of IAHU are further discussed to guide the application.