UC develops tool for energy-efficient HVAC systems

In the United States, buildings consume nearly half of the energy in the country, significantly more than the industrial or transportation sector. Non-renewable resources such as natural gas and coal generate most of this energy, so buildings’ energy consumption has a dramatic impact on air pollution, fossil fuel depletion and building operation costs.

Since most modern buildings are fitted with building automation systems – computer-controlled systems that monitor and control a building’s mechanical and electrical features – many buildings collect data on their energy use and efficiency. The problem is utilizing that data in the best way possible.

“Most buildings have automation systems that collect tons of data, but that data is never used,” says University of Cincinnati architectural engineering associate professor Nabil Nassif, PhD. “Our objective is to develop a data-based model or data-based energy solution tool to allow the building to operate at maximum efficiency.”

To close the gap between building operators and the data they can use, Nassif is developing a tool to assess, control and optimize the operation of a building’s heating, ventilation and air conditioning (HVAC) systems. The project is supported by UC and the National Institute of Standards and Technology.

The building automation system is the brain of a building, says Nassif. It collects and stores data that pertain to a building’s plumbing, lighting, heating, cooling and security systems, among many others. Motion-sensor lighting, air-handling units and temperature controls are all examples of adjustable automation features.

Just because a building has all of this data, though, doesn’t necessarily mean it knows what to do with it. That’s where Nassif comes in. “Most building automation systems don’t have a high level of computation,” he says. “They just collect data, set alarms, trade data – that’s not significant for high-level computation.”

By adding another layer of computational intelligence to building system monitoring, Nassif’s tool will assess a building’s operations to determine if the building is operating optimally.

“We get the data [from the building automation system], put it in our tools and process that data,” says Nassif. “If we detect a fault in the building’s operations, we can include it in an assessment report that we send to the building’s owner.”

For example, if a building has a constant reading on air supply temperature, this tool can factor in a number of variables like time, weather condition and number of occupants to find the optimal controller set point and change the ventilation rate. In other words, the system will adjust the fresh air supply based on the number of people in a space. The same goes for water. Based on factors like the local weather and the time of day, the optimization tool can adjust the water temperature in different parts of the building.

As a full detection and diagnosis tool, Nassif’s optimization tool can identify problems, recommend adjustments to owners and eventually save energy and money. In an era of increasing fuel costs and the alarming climate implications of burning fossil fuels, these energy-saving solutions will serve both the building owners and the greater global community.