Chic Alors! Warms up to Geothermal
By Denise Deveau
When Quebec City-based Chic Alors! owner Hugues Philippin had the chance to build a new restaurant, he decided a geothermal system would be the perfect choice. A mechanical engineer by education, the pizza restaurant owner says he was determined to build the most environmentally sustainable operation he could.
”My old restaurant was in a strip mall where the HVAC system was really deficient and not adapted for heavy restaurant use,” he says. ”When it came time to build a new one, I thought, let’s go all out and crazy and make it very efficient, from the building envelope to the lighting.”
While he had never actually worked on energy systems, ”I certainly understood what I was looking at. I had geothermal at my house and loved it so it was a no brainer when it was proposed to me.”
Using a creative mix of pumps and piping, as well as some advanced air components, the system takes the energy generated inside the building and applies it elsewhere in the structure, an innovative approach that won the project an international sustainability award.
A responsive system
Comprised of 6,700 square feet in a three-storey building, Chic Alors! has its prep kitchen and mechanical rooms in the basement, the dining room and kitchen on the main floor, and a private dining room and bar on the upper floor. Both upper levels also feature an outside patio.
The HVAC system uses seven geothermal wells connected to a hot and cold circuit, as well as a heat recovery system that captures the heat generated by the ovens. Thermal pumps manage the heating and cooling in 14 different zones within the building.
”The thermal pumps can work forward or backward, taking heat in or out,” Philippin says. ”They can make or extract heat depending on the area’s need.”
Because the kitchen is always hot, the generated heat goes into the coolant circuit. The heat pump in the dining room on the other hand may use the heating circuit to warm the area near the windows during colder weather.
The best part, Philippin says, is that it’s all automated. ”The computer controls it all.” Moïse Gagné, president of LGT, the firm that designed the system, notes that the mechanicals have a relatively small footprint.
”Overall, the system is really basic,” he says. ”It has only two manifolds – one for supply and one return. Other than the pump between the two manifolds, thermal pumps are decentralized.”
Gagné says that the system was an unusual choice for the size of the business.
”It’s not common to see a geothermal and energy recovery system in a restaurant. As a mechanical engineer, the owner knew how to use the concept to its full potential.”
Recovering the heat
The system uses a heat recovery air makeup unit with a rotating wheel that extracts heat from the hood over the four pizza ovens. Each oven generates 30,000 BTUs of heat when they are turned on. It then captures the vented air to preheat cool air coming from outside by 10°C.
At this point only the oven hood is connected to the heat exchanger. While there are three additional hoods over the dishwasher, prep area and pasta areas, ”We don’t need those for heat right now,” Philippin says.
The pumps are then programmed to give and take what they need from the extracted heat.
The entire mechanical system at Chic Alors! Uses a sophisticated control system that controls the temperatures and functions of the heat pumps and other components within the building.
Among other functions, the system has a pressure differential probe that will adjust the fan speeds to balance the air pressure between the inside and outside of the building.
”When a range hood is on high, you have to make up for that differential or your doors won’t open,” Philippin explains.
The control system also manages the heat pumps and the circulation of the coolants through the loops. It will adjust usage depending on peak demand times of day and turn selected systems off to ensure that not all are working at the same time. It can also adjust the temperatures in the pipes to avoid condensation.
And for dessert…
The quest for energy efficiency never ends for Philippin. He’s been looking at adjustments to his glycol mix in the secondary circuit. ”That would give us a 20% rise in efficiency. We’re looking into that now.”
Given the system is generating more heat than it can use, Philippin says the best option for now may be to vent the excess heat outside, but Gagné says a potential option is to use that excess energy to heat the water in the kitchen.
”When it was first installed, the energy calculation didn’t amount to enough so we didn’t recommend that at the time. If there is enough energy to heat fresh water, this would be an option.”
- 7 geothermal wells, 500 feet underground
- 2 circuits using glycol/water mix
- 1 principle circuit for interior pumps
- 1 secondary circuit between the wells and 2 heat pumps at the junction that balance the
quantity of heat in the first circuit
- 14 heat pumps in the dining rooms, takeout section, gelato area, dishwashing area,
mechanical room, common areas, and break rooms
- 4 liquid pumps – 2 on the loop inside the facility, 2 larger ones beside the wells
(1 is used for redundancy)