A Model for Evaluation of Life-Cycle Energy Savings of Occupancy Sensors for Control of Lighting and Ventilation in Office Buildings

Abstract

Lighting and ventilation represent the majority of the air conditioning loads in office buildings in hot humid climates. Use of motion sensors is one way to minimize the energy used for these loads. This paper describes the methods used for simulation a case study building with motion sensors installed and the monitoring of system on-off statistics related to occupant patterns. It also describes the development of the Monte Carlo model used to predict the on-off status of sensors. The building using the motion sensors is compared to a building that controls the lights and ventilators by a conventional pre-programmed schedule. The conventional methods of simulation were shown to generate misleading information regarding electric demand charges and life-cycle costs of the building. When comparing to actual use patterns, the Monte Carlo process was shown to represent an adequate way to represent the on-off patterns. Computer simulations further demonstrate the potential life cycle cost savings from the use of the motion sensors.