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Schools: In hot summer classroom, district sees cool million in savings
By Charles Swenson
The classrooms are empty, but the air conditioners continue to hum. In Room 613 at Rosemary Middle School in Andrews on the first days of summer it was a comfortable 77 degrees. It cost taxpayers $208.82 to keep it that way in the three weeks since the end of the school year.
There are no students next door in Room 614, but it isn’t quite empty. It’s also kept at 77 degrees, but only at a cost of $16.19. In one corner sits a geothermal heat pump.
“The savings are so phenomenal,” said Bill Crompton, director of facilities for the Georgetown County School District. So much so that the district went back to check the figures to make sure they were correct.
“This just went over the top,” said Tony Holcomb, the district’s energy manager.
The district energy budget, which includes electricity along with oil and gas, is $2.6 million. It was up by 1.6 percent, the first increase in seven years, but the budget was adopted the same week Santee Cooper announced a plan to raise rates an average of 7.5 percent over the next three years. The increase would begin in April.
The district has kept its energy budget stable in spite of a 25 percent rise in electric rates since 2005. The district also added Waccamaw Intermediate School, more security lights and more classroom electronics over those 10 years.
The district’s in-house energy management program has saved $2.9 million over the decade, Holcomb said. Georgetown County ranks 13 among the state’s 85 school district’s for energy efficiency, according to the S.C. Energy Office.
The geothermal heat pumps would take the district to another level of energy savings. Unlike a conventional system that transfers energy from the air to heat or cool a building, the geothermal system uses shallow ground water for the exchange. The constant temperature of the water makes the systems more efficient.
The geothermal systems are more expensive than conventional systems, so the district decided to run a test to find out what the payback would be from increased efficiency. “We had to pick two rooms that were exactly alike,” Holcomb said. Like many of the district schools, Rosemary Middle uses heat pumps mounted on the outside walls of each classroom. Room 614 was due for replacement, so it got a geothermal unit. The cost was $11,000, including the boring for the pipes that run 14 feet below the ground. The cost of a conventional replacement would be $5,000.
The district has 600 in-wall heat pumps. They account for about 40 percent of the district’s energy budget, Holcomb said.
At its current rate, the geothermal unit would pay for itself in two years. The actual cost of additional units would be less than that of the one in Room 614 because up to 10 units can share a well, Holcomb said.
With 600 geothermal systems, the district would save over $950,000 a year in electric bills at the current savings rate. That’s 37 percent of its entire energy budget.
“The project is bigger than we thought it would be,” Holcomb said. The district has had calls from the military and the Army Corps of Engineers asking about its test.
Despite the immediate evidence of savings, there are other factors that the district needs to consider. Those can’t be measured until students return to class in August. “We’ll be taking sound meters in there to test, we’ll interview teachers,” Holcomb said.
Although the geothermal unit sits inside the classroom, it has a fan that varies its speed according to demand. That makes it quieter as well as more efficient, he said.
Room 613 with its conventional heat pump “was always the cool classroom,” said LaTonya Goodson, interim principal at Rosemary Middle. When teachers were arranging classroom assignments she had one ask for 613 because the teacher always felt hot in other rooms. “I said, I think you’ll like it in 614,” Goodson said.
She has looked in a few times and had seen the comparison of the electric meters Holcomb set up. “It was interesting,” she said. “I’m going to watch it myself.”
Comfort is a key factor in all the district’s energy management programs, Holcomb said. But even when that is considered, in Room 614 “we’ll see more savings when the kids get in,” he said.
The district spends 40 to 45 percent of its $2.6 million energy budget from August through October, Holcomb said. That’s because the weather is still hot, but the hours of daylight grow shorter and the number of activities increase.
And while district officials and taxpayers will be impressed by the savings, he said the students “are not as concerned about the money as they are about the environmental issues,” Holcomb said.
In its first three weeks, the geothermal unit reduced carbon dioxide emissions by 1.5 tons. It saved 155 pounds of coal. It saved enough energy to power nearly two homes for a month. “We want the students to see this,” Holcomb said.
The district reset the meters on the two units at Rosemary Middle on Wednesday, which marked the start of the new fiscal year. It plans to run the test for a full year. If the savings hold up, the cost of replacing all the in-wall heat pumps will be included in a capital projects plan that the district is compiling. The district has maintained a consistent tax rate for its debt since 2011. Starting next year it will begin to have excess capacity for its debt service that will grow to $9 million a year by 2021.
Along with the investment in geothermal heat pumps, the district is also looking at the potential for generating its own electricity with solar panels. It has acres of roof space and its buildings are surrounded by open space.
“Our peak demand is between 7 a.m. and 3 p.m. There is no way to avoid that peak demand,” Holcomb said. But with solar panels “we would be able to drop our demand levels.”
He’s looking for a grant for a small solar panel that would test the potential savings.