The improvements in the Mineral County School District energy savings didn’t stop with the solar project. The green vocational building in the back of the high school is next for some sprucing up. “The building now has propane forced-air heat and electric air conditioning units on the roof – it’s too expensive,” Chris Schultz, Mineral County school superintendent said.
The district is installing two five-ton heat exchangers, or heat pumps for the building’s climate control. The heat pump works on a closed liquid circulatory system of several thousand feet of coiled pipe buried 5-6 feet under the ground The compressor inside the system works to change the pressure of the liquid contained therein. The higher the pressure, the more the liquid heats.
If the ground is 72 degrees in summer, the relative cool of the ground is pumped into the building. The heat inside the building is absorbed by the liquid and cooled by the ground on its journey through the system.
In winter, the 55-degree ground heat is circulated through the building at higher pressure, which raises the temperature of the liquid. The heat pump absorbs and distributes nearly all the liquid’s heat. The extremely cooled liquid circulates back to the relative warmth of the ground where it heats up again.
Schultz said the cost of the new system is approximately $45,000 with a $7,000 financing charge. “We’ll have it paid off in five years sand save $8,000 a year in energy. That $8,000 savings will help pay for the system,” Schultz said.
Schultz added that the current system maintains the entire building at a constant temperature while individual classrooms can control their own temperature settings.
Schultz also said the present system required a minimum $21,000 investment plus an energy cost of $40,000m which totals over $61,000. “Over five years, we’re already going to save over $9,000 with the new (heat pump) system,” Schultz said.
Schultz added that once the heat pump system is paid off, the $8,000 energy savings continue yearly. He doubted the propane and electricity would see a long-term downward trend in costs.
“The other great thing about the heat pump is that it’s 410 percent efficient – It puts out four times as much energy as it takes to run it,” Schultz said. He added the propane and electrical systems use more energy than they produce.
“We can use this money we save for other important projects. We’re pretty excited,” Schultz concluded.