Ventilation and Energy Simulation Analysis of an Occupancy-Based Smart Vent for a Residential House

• Published in: ASHRAE transactions Vol. 130; no. 1; pp. 86 - 93
• Main Authors: Deng, Zhipeng, Jiang, Zixin, Sulik, Max, Dong, Bing
• Format: Journal Article
• Language: English
• Published: Atlanta American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. (ASHRAE) 01.01.2024; American Society of Heating, Refrigeration and Air Conditioning Engineers, Inc
• Subjects: 3-D printers; 3D printing; Air flow; Air quality; Air supplies; Architecture, Domestic; Building automation; Building management systems; Commercial buildings; Computational fluid dynamics; Control systems; Cooling; Cooling loads; Design; Design and construction; Energy conservation; Energy efficiency; Fluid dynamics; Geometry; Green buildings; Houses; HVAC; HVAC equipment; Indoor air pollution; Indoor air quality; New York; Occupancy; Payback periods; Residential buildings; Sensors; Simulation; Simulation methods; Smart sensors; Technology application; Three dimensional printing; Turbulence models; Ventilation; New York; United States > US
• ISSN: 0001-2505

In New York State, more than 750000 homes feature outdated with inefficient HVAC systems. The energy savings potential through occupancy-based ventilation control ranges between 5% to 20%. While commercial buildings frequently use occupancy sensors and smart controls, these devices are rarely installed in residential buildings without building automation system. Additionally, implementing complex control systems is not practical for the numerous homes equipped with antiquated HVAC systems. To tackle this issue, we developed a smart vent system specifically for the air distribution in residential buildings. This includes a vent register equipped with a basic occupancy sensor and a Raspberry Pi Zero. The system can adjust the vent position open or closed locally by a gear-operated micro controller based on detected room occupancy status. When the room is unoccupied, the vent is closed without airflow and saves energy. We designed and built the prototype of this smart vent by 3D printing. To confirm the ability to effectively manage house airflow, we conducted computational fluid dynamics simulations. We built the geometry model of a typical US house and simulated the airflow from the smart vent in the living room and study room. We simulated both warm and cool air supply for typical design and new design of the smart vent. We also used energy simulation to analyze the energy-saving potential of this occupancy-controlled vent. Our findings showed that the airflow of this new vent was almost the same as the typical design of a grill vent. As for the energy-saving potential, we found that it could save heating and cooling load by 34.6-62.2% in living room, and 81.9-90.8% in study room. Therefore, the payback period was highly satisfying. Future work will include further tests of the system with a CO2 sensor to enhance indoor air quality in residential houses.