Giant Ice Cube Helps Keep Community College Cool

October 07, 1990|By Donna E. Boller | Donna E. Boller,Staff writer

Howard Community College is giving new meaning to the words "chill out" with a 54-foot long, 10-foot wide, 7 -foot high ice cube.

The giant ice cube is the centerpiece of an innovative cooling system added during the summer to increase the community college's air-conditioning capacity and reduce energy costs.

Contractors, engineers and commercial building owners attended seminars at HCC last week to learn about the technology and potential cost savings in what engineers call "cool storage" or "thermal storage."

Ted A. Kluga, vice president of Jack Dale Associates Inc., energy consultant for the community college, said that expansion of the air-conditioning system had been planned in conjunction with the opening of the new science and technology and student services buildings in October 1989.

Installation work was delayed until February of this year because it took nine months to get a building permit from the county government, Kluga said.

However, David M. Hammerman, county chief of inspections, licenses and permits, said the community college's permit application was received Nov.

21, 1989, and issued Feb. 1, 1990 -- nine weeks later.

With just one summer of experience, officials at the school in Columbia aren't yet certain how much the new system saved on energy costs, although they are working on calculations. Kluga estimated that the college will save at least $30,000 a year on an energy bill that in 1989-1990 totaled about $500,000 and is budgeted for $540,000 this year.

The community college received $141,000 in federal and state grants toward the $200,000 cost of the project, Kluga said. However, HCC had its new cooling system in place too soon to benefit from a rebate that Baltimore Gas and Electric Co. began offering in July to customers that install thermal storage.

The new system is "good for the environment and our budget both," said William E. Klarner, head of plant operations at HCC. "At some point in the future, these devices are going to be commonplace."

He said thermal cooling doesn't eliminate the chlorofluorocarbons and Freon gas from air conditioners that destroy the ozone layer. It does allow BG & E's commercial customers to use power during off-peak hours, reducing peak demand and saving BG & E from having to build new generating stations.

The giant ice cube looks "very unspectacular" from the outside, Klarner said. It resembles a metal tank with a control panel. Inside, coils filled with ethylene glycol, a refrigerant, are submerged in a tank of water.

Between 11 p.m. and 7 a.m. during the summer, when BG & E has unused generating capacity, plant operations workers at the college turn on the refrigeration system to freeze the water in the tank into a block of ice.

When demand for air conditioning is high -- during the BG & E peak hours of 10 a.m. to 8 p.m. -- instead of turning on a conventional chiller to cool the buildings, college workers simply turn on a pump that runs the refrigerant through the ice to cool it, then sends it back to a heat exchanger to cool water that circulates through the buildings.

The college's savings are based on BG & E's different rates; 4.4 cents per kilowatt hour for electricity used during peak hours and 1.9 cents per kilowatt hour for electricity used at night.

Klarner said HCC is using the thermal storage unit to supplement its two conventional air-conditioning chillers. Together the units serve all campus buildings except the physical education building, a total of 270,000 square feet.

"It (thermal storage) really does reduce the need for so much refrigeration in the daytime," the plant operations chief said.

He said the system had some initial bugs, such as a tendency to shut itself off, and could not meet air-conditioning needs on a 100-degree day, which may mean the college will have to add another thermal storage unit.

The technology behind the new cooling system is nearly half a century old, but it fell out of popularity when energy costs dropped after the 1930s, reports a pamphlet published by BG & E.

John J. Murach Jr., supervisor of industrial and commercial services in BG & E's marketing and energy services department, said the utility began promoting the thermal storage concept in 1984.

Initial costs of new commercial construction can be cheaper with thermal storage rather than conventional units, Murach said, because the builder can use smaller ducts and piping, in addition to the electrical savings.

However, the technology is not applicable to residences or small businesses that can be cooled with window air conditioners, he said.

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