Pang, Z., Chen, Y., Zhang, J., O’Neill, Z., Cheng, H., & Dong, B. (2020). Nationwide HVAC energy-saving potential quantification for office buildings with occupant-centric controls in various climates. Applied Energy, 279, 115727.
The occupant-centric control (OCC) is receiving an increasing attention since it could reduce building heating ventilation and air-conditioning (HVAC) system energy consumptions while not affecting the occupant thermal comfort. This paper aims to quantify the nationwide energy-saving potential of implementing the occupant-centric HVAC controls in typical office buildings. First, the medium office and large office from the Department of Energy (DOE) Commercial Prototype Building Models (CPBM) were enhanced to have detailed layouts and dynamic occupancy schedules. Then, a comprehensive simulation plan was created by incorporating the multiple zone-level and system-level occupant-centric building HVAC controls recommended by the updated ASHRAE Standard 90.1 – 2019 and ASHRAE Guideline 36 – 2018. Three control scenarios with different occupancy sensing methods were identified in this simulation plan. A nationwide parametric analysis, which includes two building types, three occupancy sensing scenarios, two building code versions, and 16 U.S. climate zones, was carried out. The simulation results of the key control variables and HVAC energy consumption suggest that generally, both the occupancy presence sensor and occupant counting sensor could achieve energy savings for the office buildings in the majority of the scenarios. However, compared with the occupancy presence sensor, which could support both the temperature setpoint reset and operational breathing zone airflow rate reset for the unoccupied zones, the occupant counting sensor only brings a marginal benefit. Besides, a higher HVAC energy-saving ratio could be achieved in the heating-dominated zone, since the energy reduction brought with the minimum outdoor airflow rate reset is stronger in the heating mode.
Ye, Z., Hu, F., Zhang, L., Chu, Z., & O’Neill, Z. (2020). A Low-Cost Experimental Testbed for Energy-Saving HVAC Control Based on Human Behavior Monitoring. International Journal of Cyber-Physical Systems (IJCPS), 2(1), 33-55.
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 values from sensors. This paper proposes two hardware-based emulators to investigate the use of wired/wireless communication interfaces for occupancy sensor-based building CPS control. The interaction scheme between sensors and HVAC server will be discussed. The authors have built two hardware/software emulation platforms to investigate the sensor/HVAC integration strategies. The first emulator demonstrates the residential building’s energy control by using sensors and Raspberry pi boards to emulate the functions/responses of a static thermostat. In this case, room HVAC temperature settings could be changed in real-time with a high resolution based on 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. Both emulators discussed above are portable (i.e., all hardware units can be easily taken to a new place) and have extremely low cost. This research tests the whole system with YABE (Yet Another BACnet Explorer) and WebCTRL.
Pang, Z., Chen, Y., Zhang, J., O’Neill, Z., Cheng, H., & Dong, B. (2021). How much HVAC energy could be saved from the occupant-centric smart home thermostat: A nationwide simulation study. Applied Energy, 283, 116251.
Ye, Y., Chen, Y., Zhang, J., Pang, Z., O’Neill, Z., Dong, B., & Cheng, H. (2021). Energy-saving potential evaluation for primary schools with occupant-centric controls. Applied Energy, 293, 116854.
Recent studies demonstrated that there is significant energy-saving potential for primary schools, which heating, ventilation, and air-conditioning (HVAC) systems with occupant-centric control (OCC) is an excellent candidate to save energy. However, such an energy impact has yet to be evaluated for different climate zones as well as different energy code versions, but is critical for technology transfer and deployment. Therefore, this paper conducts comprehensive evaluation on the energy-saving potentials for the primary schools with two advanced OCC strategies: presence-based and counting-based. Ninety-six building energy models with stochastic behavior of occupants are developed and simulated, which consist of two building energy code versions, 16 climate zones, and baseline case (without OCC) and two advanced cases (with OCC). To evaluate the energy saving potentials for OCC, primary schools in the U.S. are used as an example. The results show that there is significant energy-saving potential for primary schools by considering OCC strategies, especially the counting-based case. The energy-saving potential is up to 10.2% for presence-based OCC and 12.41% for counting-based OCC. Furthermore, both climate and code version have a significant impact on energy savings from OCC strategies. The energy-saving potentials vary from 1.79% to 12.41% for different climates and code versions. This evaluation can also contribute to quantify the nationwide energy saving potential for other countries.
Pang, Z., Chen, Y., Zhang, J., O’Neill, Z., Cheng, H., & Dong, B. (2020). Nationwide Energy Saving Potential Evaluation for Office Buildings with Occupant-Based Building Controls. ASHRAE 2020 Winter Conference. Orlando, FL.
Pang, Z., Chen, Y., Zhang, J., O’Neill, Z., Cheng, H., & Dong, B. (2020). Nationwide Energy Saving Analysis for Office Buildings with Occupant Centric Building Controls. ASHRAE 2020 Virtual Conference. Austin, TX.
Pang, Z., Chen, Y., Zhang, J., O’Neill, & Xie, Y. (2020). Development Of Baseline Building Energy Models For The Advanced Occupant-Centric Building Control Research In The Various U.S. Climates. 2020 Building Performance Analysis Conference and SimBuild. Chicago, IL.
Ye, Z., O’Neill, Z., Zhang, L., Hu, F., & Chu, Z. (2020). Hardware-Based Emulator for Building Energy Cyber-Physical Control with Occupancy Sensing. In 17th International Conference on Information Technology–New Generations (ITNG 2020) (Vol. 1134, p. 493). Springer Nature.