Waste heat system performs well during cold snap

by Peter Boileau

The high-rise office buildings that surround the one-of-a-kind glass spheres in Seattle are part of a unique campus. While the exteriors are striking, there’s an innovative story to tell inside their central heating and cooling plants. The buildings connect to a highly-efficient waste heat recovery system that supplies heat to 2.5 million square feet of occupied space. The district energy system was put to the test when Seattle experienced its first major cold spell of the season.

UMC turned Block 14 over 11 months ago and turned Block 19 over in November for partial occupancy. The office towers take raw waste heat from the EcoDistrict and convert it into building grade heat. Five (5) megawatts of low-temperature waste heat is secured from the data center across the street. By processing the waste heat through Block 14’s district energy system, the system can generate upwards of six (6) megawatts of high-temperature water to serve 100 percent of the current campus heating needs.

This week an arctic blast from the north tested the waste heat system. Seattle experienced the coldest days yet of the season – with temperatures in the low to mid-20s. The system supplied more than enough heat for two-square blocks, without the need for auxiliary boilers. To put this into perspective, a typical central plant system heating this much space would require 24 million BTUH of gas boilers to provide the same amount of heating (equivalent to heating requirements for over 500 single family homes).

Seattle Spheres and the remaining floors of Block 19 will come online and connect to the district energy system later this year. As the campus continues to grow, we will continue to share significant performance milestones from this unique district energy system, never before seen in the Pacific Northwest.

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