Hardware-Based Emulator for Building Energy Cyber-Physical Control with Occupancy Sensing

Abstract

Heating, ventilation and cooling (HVAC) is the largest source of residential energy consumption. Occupancy sensors’ data can be used for HVAC control since they indicate the number of people in the building. HVAC/sensor interactions show the essential features of a typical cyber-physical system (CPS). However, there are communication protocol incompatibility issues in the CPS interface between the sensors and the building HVAC server. Through either wired or wireless communication links, the server always needs to understand the communication schedule to receive occupant number from sensors. In this paper, we will use hardware-based emulators to investigate all wired and wireless communication interfaces for occupancy sensor-based building CPS. The typical synchronization between sensors and HVAC server requirements will be introduced. We have built two hardware/software emulation platforms to investigate the sensor/HVAC integration strategies. The first emulator demonstrates the residential building’s energy control using sensors and Raspberry pi boards to represent the functions of a static thermostat. In this case, room HVAC temperature settings could be changed in real-time with a high resolution with the collected sensor data. The second emulator is built to show the energy control in commercial building by transmitting the sensor data and control signals via BACnet in HVAC system. Additionally, sensor data can also be transmitted in a large build’s multi-hop wireless network. Both emulators discussed above are portable (i.e., all hardware units can be easily taken to a new place) and have extremely low cost.