The Application and Energy Savings Potential of Occupancy Counters/Transmitters in Office Buildings

Abstract

In conventional office building design, fresh air requirements are estimated for full occupancy in the building. Typically, fresh air requirements range from 5 to 15 cubic feet per minute per person expected to occupy the building. While the design total amount of fresh air used is satisfactory for full occupancy of the building, there are many instances less than the design occupancy. Thus, there may be many instances in a commercial building where more fresh air is used than is actually required because the occupancy is below the design occupancy. In hot and humid climates, such as the Gulf Southwest, a considerable portion of the cooling energy in a commercial building is expended cooling and dehumidifying the air needed to maintain fresh air requirements. If the total amount of fresh air could be reduced to just match that needed by the number of occupants in a building, it would be possible to reduce the energy use for cooling. This paper summarizes the design and use of an occupancy counter/transmitter that can be used to count the number of people entering/leaving a building and make adjustments in the amount of fresh air used in the building. Sample economics of the system, including initial costs and savings are also provided.