Finding suitable conditions for a DLWC system isn’t always simple.
Location is the first hurdle to making the technology feasible. Much of the East Coast of the United States, for example, has a shallow, sloped ocean shelf that makes it difficult to position a system at the depths necessary. There also must be enough cooling demand to justify a system.
Then there are the enormous upfront costs. Cornell University’s lake water cooling system — the largest and oldest in the United States — cost $58.5 million. The investment, though, “has easily already paid for itself,” said Todd Cowen, an engineer at the university, because operating and maintenance costs are so low.
Toronto’s system costs (CAD) $170 million, and unlike Cornell, Enwave needed customers. Lou Di Gironimo, general manager for Toronto Water, says the question was, “Would this be a sustainable economic activity?" But any fears of failure were short-lived. Starting with only a few customers in 2004, Enwave’s DLWC customer base has since expanded rapidly.
DLWC doesn’t come without potential pitfalls. Alex Horne, an environmental engineer and lake expert, points out that if the warmer, nutrient-rich water coming from DLWC systems is released too close to the surface of the lake, it can lead to issues such as blooms of algae, including potentially toxic variants. But Horne, a professor emeritus at the University of California Berkeley, says the fix is fairly simple — discharge the water deeper in a lake and through diffusers in the pipes. “It’s sort of common sense,” he said. “But if you’re a heating-cooling engineer, you don’t think about it.”
There’s plenty of potential for source water cooling to keep growing, said Hermann Kugeler, with Makai Ocean Engineering, Inc., a company that designs and installs piping for the systems. He added that there has also been progress on salt water air conditioning (SWAC), which utilizes ocean instead of lake water as coolant.
While they may not have proliferated on the scale of other types of climate-friendly technologies, DLWC and SWAC systems are now up and running in dozens of locations around the world, from Hong Kong to Bahrain. “I think the big thing is informing people that it exists," Kugeler said. “People don’t know it’s an option.”
Toronto has celebrated the city’s success — not only in the form of DLWC energy savings and a planned expansion, but also with its basketball team. While the team ended up narrowly losing Game 5, it closed out the 2019 NBA title three days later and brought Toronto its first major sports championship in more than a quarter-century.