ASU researchers seek to build model that can help cities plan for data center heat waste

Data centers create more heat waste than any other development — just one facility can emit more heat than all of Phoenix’s downtown core. That’s according to an Arizona State University study on data center heat impacts.

Anytime energy is used in a building, it creates heat that must be expelled. This is what’s known as urban heat waste.

David Sailor, director of the School of Geographical Sciences and Urban Planning at ASU, says until now, urban climate researchers were less concerned with energy-related heat waste, because cities weren’t producing much.

“We have looked at anthropogenic heat across U.S. cities, global cities, in fact. And at the city scale, typically the emissions are on the order of 10s of watts per square meter,” said Sailor.

That’s true for a city like Phoenix, which he says emits around 10 to 20 watts of heat waste per square meter.

However, when studying the heat waste impact of large scale data center projects, such as the CyrusOne complex in Chandler, Sailor and his team found that for every megawatt of energy demand, there is almost the same amount of generated waste heat.

For example, “even with very efficient data centers, if you have a 50 megawatt IT load, you’re still rejecting on the order of 60 megawatts of heat, and that heat goes somewhere,” said Sailor.

He and a team of researchers drove electric vehicles equipped with thermal sensors around a handful of large scale data centers in the valley to study the impact of this heat waste. After several rounds of testing and peer-reviewed analysis, Sailor’s team found temperatures were consistently 1 to 2 degrees warmer within a quarter-mile of these facilities.

As more data centers seek to be built in the Valley, Sailor and his team are hoping to use their research to help local leaders make more informed decisions on where to zone these facilities and what mitigation measures to consider.

They’ll do so by building a digital twin of various communities that already host data centers to model how the radius and direction of the heat waste emitted from a project changes when different interventions are made. A digital twin is a 3D computer model that urban planners often use to visualize risks or design impacts on real landscapes.

“So this could be things such as, you know, what if there were a mandatory setback between the facility and a neighborhood, or if you included green and blue infrastructure at the facility scale itself, can you produce cooling downwind that offsets the heating from the data center?” said Sailor.

Based on the facilities they have already studied, the researchers noted a slight improvement in downwind warming if there was an irrigated park between the data center and the community.

“Of course, it typically requires water to accomplish that, right, and then there’s that trade-off,” said Sailor.