Hitting the heights of efficiency in London
By Adam Freill
What do you do with an 850,000 square-foot decommissioned cereal plant? Well, if you’re in London, Ont., you turn it into an entertainment mecca, of course.
The former Kellogg’s plant is now The Factory, Canada’s largest indoor family fun centre, sporting an indoor adventure park with a high-ropes course, a trampoline park and a brew pub. Turning the old industrial facility into an entertainment complex would take a
lot of creativity in all aspects of the build, however.
To tackle the mechanicals for what was then an empty shell of a factory, the property owners approached Oxford Energy Solutions’ president Ben Kungl. A fan of going beyond traditional approaches, he could envision a system that would not only breathe life and comfort into the rebirthed structure, but would do so efficiently with an elegant simplicity of design that included built-in redundancy for both heating and cooling, with the ability to accommodate future needs.
”There’s no negative to oversizing some of the permanent features that can’t be changed later, like the main piping loop and the main trunk lines,” he says.
What had formerly been a steam-based central power plant with chillers would become a more efficient distributed system with multiple mechanical rooms feeding into a main glycol loop at
different locations in the structure, all supported by a network of sensors throughout the building.
The owners really like the system,” he says. ”There’s remote access to everything, and it’s really
- London, Ont.
- 850,000 square-foot entertainment complex
- Emerson E2 Control Platform
- 400,000 BTUH Laars mod/con boiler (1)
- 2 million BTUH Laars mod/con boiler (3)
- 4 million BTUH Laars mod/con boiler (3)
- 200,000 BTUH Daikin chiller (3)
- Danfoss VFDs
- Greystone Sensors
Controlling for comfort
The HVAC system includes more than 18 million BTUH of heating capacity and more than 500 tons of cooling capacity. It relies on the Emerson E2 automation platform to get feedback from system sensors to target optimal efficiency.
”For us, information is key,” says Kungl. ”You spend the money on automation and information so that system decisions can be made based on that information.”
The system includes sensors that provide temperature and humidity readings at the inlet and outlet of most of the equipment, as well as CO2 levels on the return air.
”Instead of just firing up all these exhausts because we’re still using a manual that was written 40 years ago, the only time we need to run exhaust is if we have a temperature issue or a CO2 issue,” he says. ”Why not make that decision based on real facts from sensors instead of guessing?”
Chasing comfort is a far more complex puzzle than simple dry-bulb temperature, however, so that’s where the additional information about outside conditions and indoor RH can help drive the system.
”It doesn’t matter what the temperature is when it comes to human comfort; it’s more about how that air feels. If it is warm and wet, it is going to feel terrible,” he says. ”We can make the decision whether we are going to use fresh air for free cooling based on the moisture content in
Free costs less
The more closely you can match a heating and cooling system’s delivery to the actual load in a building, the more efficient the system will be, so Kungl added in variable frequency drives to modulate the movement of BTUs based on what the sensors in the building are reporting back to the central management system.
”With condensing boilers, running two boilers at 40 per cent is way more efficient than running one boiler at 90,” he explains. ”On the coldest days of the year, we’ll have three or four boilers chugging away at 40 or 50 per cent at massive efficiencies.”
The heating plant is not the only system that’s been decentralized. He took a similar
approach to the chillers.
”For the chilled loop, instead of having one massive system and pumping it all the time, we split it into two distinct systems, which reduced our piping by more than 70 percent,” he says. ”Now, we are not trying to keep 10,000 gallons of glycol cooled. We are trying to keep two loops cooled – each has 2,500 gallons in it.”
Kungl loves to explain that ”Nothing saves money like when something is off,” so he uses the feedback from the sensors to only pump when necessary. ”When there is no call for cooling, the chillers and the pumps shut off.”
And he’ll make use of free economized cooling with fresh air as much as he can, which also adds to the efficiency picture.
”Nothing is ever running until one air handler calls for mechanical cooling,” he says. ”We are not doing process cooling. We are cooling for conditioned air and nobody feels a five-minute difference in delivery time because it was shut off.”
Aside from the automation system, of which Kungl is a major fan, one of his favourite aspects of the HVAC system is the way that perimeter heat was handled.
The system for heating along the exterior walls and windows that had been in place at Kellogg’s was part of the main loop, since the old system was steam based. That would not work with the new system, since perimeter heat is usually considerably hotter than the main loop temperature.
”We had the perimeter heat loop set up off the main loop, running it in parallel with a separate circulator pump.” This, he explains, allows the main loop to pressurize the perimeter loop.
”We have an independent 400,000 BTUH condensing boiler just doing the step-up temperature so that we don’t have to run the main loop at 160°F.”