Sussex building sets industry standardLocal engineers design fix for geothermal cooling system
Work to fix a geothermal system at Sussex County's Emergency Operations Center has attracted national attention and set a standard for the industry.
The center's geothermal system was not keeping the facility cool; interior temperatures reached in the high 80s and into the 90s, jeopardizing the heat-sensitive technology in the building. The ground was retaining heat through a process known as thermal retention.
When that occurs, most users abandon the underground loop geothermal system and put in a cooling tower, said Jay Egg of Egg Geothermal. However, Sussex County engineers worked with Egg to design a supplemental cooling system tied into the existing geothermal system. What the county needed was a new geothermal system to fix its existing geothermal system.
The temporary fix back in 2011 was to install a cooling tower at the cost of $50 per day, but county engineers realized quickly they needed a better, more cost-effective solution. “The cooling tower was too expensive and maintenance was intense,” Hudson said.
Because of the heat generated by computers and other high-tech equipment in dispatch and emergency centers, cooling issues are not uncommon, Egg said. He said the problem first surfaced in Florida where the temperature is constantly warm.
The county's geothermal system is supplied by 24 wells, each one a 600-foot closed loop system.
A mechanical cooler, although more widely used, was a more expensive option in the long run, said Sussex engineer Steve Hudson, costing more than $280,000 to operate over 10 years. The supplemental system cost more to install but will cost less than $30,000 in utility bills over a decade.
A supplemental pump-and-injection geothermal system turned out to be the permanent fix. The supplemental open-loop well system, which cost more than $470,000, has turned out to be state-of-the- art costing less than $4 a day in electricity to operate.
The idea for the fix came from an unlikely source. During a discussion about the problem, Councilman Sam Wilson, R-Georgetown, said driving a new well and pouring cool water over the underground system might help. “Why not use water from another well to cool the system,” Wilson said.
The water used to cool the system is then injected back into the aquifer so no water is wasted, Egg said.
The work could qualify for a $250,000 FEMA grant. If that occurs, the system will pay for itself within 10 years, he said.
“It's operating better than we could have imagined,” Egg said during a Sept. 24 presentation to county council. “This is now the model how to properly implement geothermal technology throughout the country.”
Hudson said the temperature dropped 10 degrees immediately as soon as the system went on line.
“This represents reduced costs, reduced water usage and reduced maintenance. Why not use the energy we already own under our feet?” asked Jack DiEnna Jr., executive director of Geothermal National and International Initiative.
DiEnna, who works with companies all over the country, said he was going to use the county's system to show how other emergency and critical care centers could break away from traditional, mechanical cooling systems.
Egg said the county's pump and injection system is the wave of the future and the days of closed loop systems are numbered.