Artificial intelligence (AI) is proving useful for teaching old dogs new tricks in the existing buildings sector. Energy management and decarbonization specialists speaking at The Buildings Show in Toronto last week highlighted some AI applications that can be effective ahead of comprehensive retrofits, to find and deliver energy savings and emissions reductions while legacy HVAC and building envelope systems are still in place.
Notably, some older buildings are now leveraging thermal mass to offset heating and cooling. Tobias Janes, director of technical services with the AI-based energy management service, EcoPilot Canada/US, explained how the technology now rapidly interprets outdoor conditions, energy sources and the thermal conductivity of materials within a space to derive a more precise reading of HVAC requirements and more efficiently control the supply of heating and cooling.
He likened it to using buildings as batteries, with AI supplying the insight on how to draw on stored energy and when to recharge. That’s based on the premise that allowing for a 3-degree Celsius swing in building temperature can reduce HVAC energy requirements by 25 to 40 per cent.
“Using free energy and artificial intelligence, we can optimize HVAC efficiency and comfort,” Janes said. “We never want to heat and cool at the same time, and we want to push those periods farther apart so that we don’t heat and cool in the same hour or we don’t heat and cool in the same four-hour window.”
A range of energy performance variables underpin how proficiently that might occur, but data is the critical element to reveal how it can be realized. The energy-saving approach, based on thermodynamic principles, was long ago identified as theoretically possible, but has only more recently become practically achievable.
Janes noted that pioneering 1970s-era research at Sweden’s KTH Royal Institute of Technology remained largely aspirational until technology caught up. The first step — the outside air reset control — arrived in the 1980s, but it would be a few more decades before other enabling technology was commonplace.
“In 1975, computers were these massive things that cost hundreds of thousands of dollars. It just wasn’t practical to do these strategies they thought could be implemented,” he observed. “Now you can buy an industrial computer with an expected lifespan of 10 years for $2,000.”
Today, wireless temperature sensors can deliver a detailed breakdown of variations throughout a building, while AI-based systems factor in variables such as the current outdoor temperature, forecasted weather conditions, heat output from solar radiation, plug load and the building occupancy and how various building materials store and release energy. Using that information, the EcoPilot system uses standard open protocols (BACnet over IP or Modbus TCP) to disable or enable heating and cooling and control the supply temperature setpoint. That compares to the conventional building automation system (BAS) approach of disabling the boilers when the outdoor temperature hits 15⁰ C and enabling the chillers at 18⁰ C.
“Each building — how it’s laid out, where it’s positioned, what it’s made from — has its own dynamic structure and you’ve got to be able to measure that,” Janes advised. “It’s looking at how much energy is stored in the space, how long it’s going to take that energy to dissipate out of the space and how the dynamic effects — solar radiation, outside air, temperature, occupancy — are going to affect it in the future. So instead of constantly reacting to this outside air temperature, it’s constantly preparing for what’s going to happen in the future.”
Although a more finely tuned HVAC control system cannot rectify building design or systems inadequacies that undermine energy performance, it does deliver data that can help to identify imbalances, system failures and other chronic issues. “We’re able to pull all of the data for the building automation system — pump speeds, damper positions, valve positions, all of these things — all in one place where it can be visualized,” Janes said.
Looking at energy savings and emissions reductions, he cited the example of a 1970s-vintage, concrete office building in Halifax achieving a 25 per cent reduction in HVAC costs for a two-year payback on the investment. That came with combined emissions reductions from gas and electricity equivalent to 1.2 million kilowatt-hours in the first year. Since then, the building owner, Crombie REIT, has adopted the system in other buildings in its portfolio.
Other Buildings Show presenters commended the role AI can play in developing cost-effective building- and portfolio-level decarbonization plans. Marine Sanchez and Ian Miller, principals with the consulting firm, RDH Building Science, stressed the importance of such plans to help owners/managers plot out and prepare funding strategies for emissions-reducing interventions. They also highlighted the virtual energy modelling and decarbonizing planning tools from the digital data service provider, OPEN Technologies.
“We’ve done energy modelling the long and detailed way and we’ve also used their AI tool and found it’s coming up with very similar results,” Miller reported. “You essentially plug in the parameters of the building — the size; the construction; your energy bills; all those sorts of things — and it uses artificial intelligence by comparing it to other projects that they’ve done in the past. It’s allowing the audits to be done and these plans to be developed for a much lower cost.”
“They are technically a competitor to us, but, the truth is, there is so much work (to achieve industry-wide decarbonization) that we need everything to get faster and cheaper,” Sanchez concurred. “What they are providing is information that is good enough for us to then add value with our expertise.”
For owners/managers in Toronto, it’s expected that Toronto Hydro will soon unveil an incentive covering up to 100 per cent of the cost of a decarbonization plan through OPEN Technologies. “This is one great way that you can get a fairly basic virtual decarbonization plan that may be zero cost to you. So it’s definitely something to look into,” Miller urged.
