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Photo: Diana Rogers, SLAC |
SLAC's water cycle
Along the Loop Road at Stanford Linear Accelerator Center, the roar of falling water and a refreshing mist filled the air after six solid weeks of California rain. But the water cascading down the inside of Campus Cooling Tower 101, and landing in a frothy pool, is hardly scenic. The corrugated metal building sprouts pipes of all sizes. The bottom section of the front façade is open except for mineral-encrusted slats, allowing Loop Road walkers to experience an industrial facsimile of the small falls that spring to life in the winter hills of California.
The perennial cooling tower is one of six at SLAC that cools vacuum systems, klystrons, magnets, and other parts that drive the accelerators. Cooling Tower 101 lowers the temperature of the chillers that cool computer components in the Computer Building.
Water flows through pipes next to hot equipment, soaking up the heat. The pipes run to nearby heat exchangers, transferring the heat to water in another set of pipes. The cooling water flows back to the cooling tower, like blood returns to the lungs for more oxygen. Spray nozzles release droplets of the cooling water– completely safe tap water–into the tower. As they fall through open air, the droplets release heat into the rush of air created by powerful fans on the cooling tower roof. On cool mornings, columns of steam rise from the cooling towers. Some loose water evaporates into mist.
To replenish one cooling tower, SLAC recycles half a million gallons of water a year. In winter, crews from Conventional & Experimental Facilities pump rainwater out of manholes with a truck called "The Dominator." After filtering the water, they top off Cooling Tower 1701, also known as "The Big One," near the downstream end of the linear accelerator. Just like its wild brethren, the Big One's waterfall carries real California rain.
Heather Rock Woods
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