By Bruce Nagy
In 1519, during the Spanish conquest of Mexico, commander Hernán Cortés ordered his troops to burn their ships after landing so that they’d be forced to conquer or die. It was his way of getting his team to focus on the outcome without distraction, fix their eyes on the prize, garder l’oeil sur le but (Keep your eye on the goal).
Focus is also critical to construction and mechanical professionals, especially those working on large institutional projects, over long timelines, with seemingly impossible objectives. Quebec City engineering firm EcoSystem continues to win awards, including two in 2018 from ASHRAE, for their work on complex asset renewal projects for a group of Quebec hospitals.
We don’t like change orders, so we focus on the day-to-day details, and we have gotten good at setting a cost target and then hitting it.
They’re not burning ships and are not expected to die for the company, but one of the ways they remain focused is by putting the expected outcomes right in the written contract with the customer. It helps rule out the option of making excuses or falling short. “We guarantee the savings, the costs and the subsidies in writing,” said Cedric Bertrand, project director for one of the hospital projects. “So far it has worked for us. We send an engineer about a year early, because an integrated design approach is necessary to meet our targets.”
Improvement without interruption
Bertrand was responsible for Laval University Hospital (Centre hospitalier de l’Université Laval), a 1.3 million square foot facility that’s almost 100 years old. The mechanical equipment positioning and some of the HVAC equipment seemed as if they were equally ancient. It’s really a children’s hospital, specializing in obstetrics, digestive disease and chronic pain.
Improvements were done largely without interrupting operations and, in cases where sections could be closed, the schedule windows were very short. During some of the implementation period, 2012-2015, the hospital was dealing with infection outbreaks and local disease epidemics.
Meanwhile the upgrade needs were extensive. Ecosystem converted most of the old steam system to hot water, updating old boilers, replacing miles of piping, and also about 900 radiators on six floors.
They installed a new externally compounded York CYK heat recovery chiller with two centrifugal compressors in series, for an increased temperature lift and higher condenser temperature output. In general, the new hot water network was designed for the lowest possible hot water temperature to optimize the efficiency of the heat recovery chiller.
“This model was originally designed to work with a dry coolers in the water-scarce Middle East, so it goes up to 160F on the condenser side,” added Bertrand. “We’re doing a lot of heat recovery.”
The main cooling network and many smaller cooling zones originally managed by separate compressors are connected to the cooling loop and the CYK evaporator. The condenser side is connected on the hot water heating loop return, upstream from the boilers. He notes that prior to the project up to 250 tons of cooling was used year-round by conventional chillers and wastefully rejected outside by the cooling towers.
They also added a geothermal field that handles about 10 to 15 percent of the heat load, and a solar wall that increases ventilation air temperature by 15F. The solar wall, which wraps around a rooftop penthouse, is about 2,500 square feet. The geothermal field consists of 60 wells, each about 600 feet deep, which potentially contribute 140 tons of pre-warming or pre-cooling.
They installed sensors in the laboratory fume hoods to modulate air frontal speed, minimize air and energy exhaust and meet air quality standards.
They also optimized ventilation, reducing air changes to about four per hour from approximately 12 previously, when it was 100 percent constant flow fresh air. And they eliminated heating/cooling conflicts and reviewed sequencing to optimize the existing Delta/Siemens control systems.
Near the beginning of the project implementation, they undertook a lighting upgrade. “If we were doing the lights today, we would have gone to LED. But they weren’t the best choice at that time (2012). Since then efficiency has increased and the LED price has dropped,” said Bertrand.
Hôpital de l’Enfant-Jésus
“We also did geothermal and it was an innovative approach, with diagonally drilled wells under the parking lot, without affecting hospital operations during construction,” said Simon Verville, another Ecosystem project designer. He is talking about Hôpital de l’Enfant-Jésus, for which he was the project director. “Unfortunately, they are now demolishing it for excavation and major expansion of the campus. We’re hoping the geothermal will be redeployed in another location on the site.”
At this one million sq. ft. hospital many of the radiators were already hot water, but most of the other equipment had to be changed and, because the institution specializes in traumatology, blood diseases and neuroscience (nervous system), implementation was perhaps even trickier.
Cancer wards require constant positive pressure. Some patients have no immune systems. Others are burn victims that are highly sensitive to slight temperature changes. In some areas, supplementary heating was required even during summertime. Special fans and HEPA filters were brought in as well.
Key changes included the replacement of two 1300 BHP, asbestos-clad steam boilers with eight new 120 BHP Buderus Logano G615 hot water units by Bosch.
Again, they were converting to hot water but were able to reuse many of the steam pipes. The condensate system was too small, however, and most of it had to be upgraded. At this site they again implemented a high level of heat recovery, with two new high-temperature Daikin McQuay heat recovery chillers, at about 200 tons each, that can supply hot water up to 160F.
“It was all worth it,” says Verville. There was a drastic drop in gas consumption and greenhouse gas emissions.”
Savings measured and tabulated
The overall project included four hospital sites. To date, energy savings have been measured for several years at three of the hospitals and one year at the fourth. Together the four hospitals slashed energy consumption by 29 per cent, generated $3.7 million in savings each year, and reduced greenhouse gas emissions by 52 percent (14,320 metric tons per year). “At Laval University Hospital they were using 5.2 million cubic metres of gas before the renewal,” reported Bertrand. “Afterwards it was 2.4 million.”
“Our actual results were 99, 100 and 102 percent of the targeted savings, so we were accurate. We hit our cost and savings targets and we obtained more subsidies than promised. The overall payback was around seven years, but that does not consider the asset renewal.”
The existing systems were all failing and leaking, and the hospitals didn’t have the budgets to fix them. The needed equipment changes would have cost $10 million without energy upgrades. “With this consideration, the payback for the energy efficient portion is around four years.”
“We don’t like change orders, so we focus on the day-to-day details, and we have gotten good at setting a cost target and then hitting it,” says Bertrand. “I think the bigger achievement on these projects was implementing major enhancements without interrupting hospital operations. That was really a challenge.”
Ecosystem never lost sight of the goal, and they didn’t have to burn their ships.