TECHNICAL FEATURE FIGURE 4 Office building with personal air distribution in Atlanta climate. Cooling 13% Lighting 15% FIGURE 5 Office building with personal air distribution in Portland, Ore., climate. Cooling 5% Lighting 13% Heating 19% Plug Load & Office Electrical 25% Fans 11% Misc. 17% Average Annual kWh/ft2 = 5.8 Average Annual Occupant h/ft2 = 11.5 Average OA cfm Each Occupied Workspace = 45.6 specific comfort requirements of each occupant, the need for manual intervention under normal operating conditions will be greatly reduced. Such occupant-centric closed loop VAV control systems can reduce energy use by directing conditioning according to actual occupancy conditions and by continuously comparing and optimizing the marginal energy cost of the multiple measures available to thermally satisfy each workspace. At the system and plant levels, information from the occupant network is aggregated and used to optimize operations by simultaneously adjusting both flow and temperature outputs from the water and airside system components with direct multivariable control23 that optimizes these systems in accordance with constraints of the currently occupied space conditioning requirements. Significant energy performance improvements are shown to result in simulations discussed below. With these operational strategies, improved occupant environmental satisfaction-along with the increased efficiency of part-load operation and reductions in overall conditioning energy requirements-can result from focusing conditioning and control on occupants instead of the building. A preliminary energy analysis of an ASHRAE Standard 90.1-202224 compliant office building envelope with 10 floors of office space totaling 180,000 ft2 (16 723 m2) was developed with an in-house hourly simulation program. 34 ASHRAE JOURNAL ashrae.org S E PTEM B ER 2023 Heating 35% Plug Load & Office Electrical 22% Fans 10% Misc. 15% Average Annual kWh/ft2 = 6.7 Average Annual Occupant h/ft2 = 11.5 Average OA cfm Each Occupied Workspace = 45.7 The simulated VAV system uses control of two local workspace comfort measures (air temperature and air movement) with individualized, informed occupantcentric control. Air-to-water electric heat pumps provide heating and cooling conditioning for the building perimeter and interior space heating. Interior space cooling is provided by water-cooled chilling. Heat recovery is applied to building exhaust. The space types and the ASHRAE Thermal Control Classification for each are shown in Table 1 (page 33). In operation, the building perimeter is thermally neutralized with convection conditioning. Workspace thermal comfort is achieved by ensuring the space air temperature is adequate to satisfy the occupied workspace in each zone that requests the warmest conditions; then a combination of reduced air temperature and air movement is applied to satisfy the zone's other occupied workspaces. The simulation program uses probability functions each hour to establish realistic workspace occupancy status and the number of occupants in each occupied workspace type from the occupancy range listed in Table 1 over the course of each day. Occupancy probability for each space type is based on office workspace occupancy pattern research.25 The simulation results in Figures 4 and 5 illustrate the potential for low energy use with this individualized workspace operation strategy. These figures show the simulated energy use intensity (EUI) in kWh/ft2,http://www.ashrae.org