Setting the Standard for Sensor-Driven HVAC Control
University of Alabama looks to reduce energy usage with improved sensors
Supported by the Saving Energy Nationwide in Structures with Occupancy Recognition (SENSOR) program of the U.S. Department of Energy’s (DOE’s) Advanced Research Projects Agency-Energy (ARPA-E), a University of Alabama team of researchers aims to ensure sensors work efficiently when detecting human movement and occupancy to control HVAC systems and applications.
According to team leader, Zheng O’Neill, assistant professor of mechanical engineering at the University of Alabama, when the study is complete, they should be able to say that using this kind of sensor-driven control can achieve HVAC energy savings of at least 30 percent.
SENSOR project teams can take advantage of existing low-cost wireless and electronic communication technologies and reduce HVAC energy usage by 30 percent, while simultaneously addressing user requirements for cost, privacy, and usability.
With that in mind, Zheng O’Neill and her team are looking to develop standards and control strategies for the sensors used to control the HVAC systems in both commercial and residential buildings.
University of Alabama researchers connected with collaborators from a range of backgrounds in order to address both the technical and applied challenges of the project.
“The research team is comprised of members with expertise in sensors, building controls, and building energy modeling and simulations from the University of Alabama; the University of Texas, San Antonio; Pacific Northwest National Laboratory (PNNL), Tacoma, Washington; Leaptran Inc., San Antonio; and Delos Living LLC, New York,” said Zheng O’Neill. “The team has been collaborating over the last five years on a variety of projects to improve building energy efficiency.”
The proposed sensor project was built off of the team’s unique experience in developing ASHRAE Standard 90.1, ASHRAE Standard 62.1, and ASHRAE Guideline Project Committee (GPC) 36 as well as their implementation of sensor-driven control sequences and simulation-based nationwide energy savings analysis for ASHRAE Standard 90.1 and Advanced Energy Design Guides.
“Our engineering team brings together a unique combination of people and facilities from traditional HVAC groups and nontraditional engineering fields, bringing experience in high-performance research and development,” said Charles O’Neill, assistant professor of aerospace engineering and mechanics, University of Alabama. “Each partner brings unique capabilities.”
Over the next three years, the DOE’s ARPA-E SENSOR program will provide $1.5 million to support the projects, allocating the funds among the following four categories: human presence sensors for residential use (category A); occupant-counting sensors for commercial use (category B); low-cost, stable, easily deployable CO2 sensors for commercial use (category C); and testing and validation for residential and commercial applications (category D). Zheng O’Neill said they are designing a novel testing and validation protocol and simulation suite that spans a comprehensive range of operating conditions for occupant sensing.
Over three years, the team will have the following three tasks to accomplish during testing: system-level testing protocol and simulation suite development to test and evaluate sensor performance and associated HVAC energy savings from sensor-driven controls; system-level controlled lab testing of sensor and sensor-driven HVAC controls; and system-level field trial testing and simulation validation of sensor and sensor-driven HVAC controls and simulation validation in four commercial buildings and four residential homes in two climate zones — Alabama and Texas.
Zheng O’Neill explained the testing and validation protocol will have an eight-level diversity and simulation suite. That suite, which can be used for any sensor-driven HVAC energy-efficient technology, will be tested and validated in side-by-side, laboratory-controlled environments at the Delos Well Living Lab and PNNL’s Lab Homes as well as with the field trial testing.
“Our sensor development and testing bring together real-world conditions and sensors in an instrumented environment,” said Charles O’Neill.
The project is intended to transform the HVAC industry and prompt those who manage HVAC systems to utilize sensor technology for energy savings.
“The ultimate goal is to facilitate the industry to adopt the technology and accomplish ARPA-E’s mission through the technology-to-market (T2M) initiative led by our industry partners,” said Jeff Xu, president and CEO, Leaptran Inc.
Hwakong Cheng, Taylor Engineering principal, agreed, stating the goal is not just to get everyone onboard with sensor technology but to obtain the 30 percent HVAC energy savings.
Ultimately, the team expects results from the proposed testing protocol for sensor-driven HVAC control will be adapted into standards and guidelines that encourage accelerated adoption by designers, system providers, and owners. The field projects will focus on standardizing installation and configuration procedures to make a technician’s job easier.
HOW AND WHEN IT WORKS
Human presence sensing and people counting have a huge impact on HVAC energy savings, according to Zheng O’Neill.
“Both human presence sensing and people counting have significant potential to generate HVAC energy savings (e.g. > 30 percent) by eliminating the over-ventilation of unoccupied and partially occupied buildings and by avoiding the unnecessary conditioning of empty spaces,” she said.
Because HVAC systems are manufactured with a range of operational design constraints — not all of which are necessary to maintain at all times of operation — these types of occupancy sensors are critical in order to achieve lower energy consumption and higher cost savings, according to Charles O’Neill.
“Knowing that humans are present or not allows the HVAC system to optimize its operation and save money and energy,” he said.
The proposed lab testing will be conducted in two state-of-the-art testing facilities that can perform the testing within a controlled environment that represents both commercial and residential building settings.
“The sensor readings and actual occupancy status are used to verify the sensor performance,” said Jian Zhang, senior research engineer, PNNL. “A side-by-side comparison between the baseline and the proposed occupancy-based control will be conducted. The end goal is a testing protocol that can be adopted to examine the sensor performance and control savings.”
Cheng said the testing protocol will provide feedback on sensor accuracy and guidance on proper installation in a wide range of applications to minimize the risk of improper temperature control due to sensor error.
“Achieving our goal gives HVAC technicians a tool for identifying and mitigating energy inefficiencies associated with human activities,” said Charles O’Neill.
And with the project due to be completed by summer 2021, Zheng O’Neill feels the future of sensor technology is near.
“There are a number of interesting and innovative occupancy sensor technologies already commercially available for both commercial and residential applications, but we anticipate the next generation of advanced sensor technologies to be available by the summer of 2021,” she said. “The current pace suggests a future of massively integrated sensors with advanced HVAC systems as common as light switches nowadays.
“The business advantage to building owners will push the technology,” she added.
Publication date: 4/9/2018