Palatine, Ill. — An Illinois state grant has helped officials of a high school here to initiate a pilot project to heat an indoor swimming pool using solar thermal energy.
William Fremd High School received $48,600 under the state's Solar Thermal Grant Program to install a solar thermal system to heat its indoor pool throughout the year.
The Illinois Department of Commerce and Economic Opportunity administers the program, which covers up to 30% of the cost paid by state schools and small businesses to install solar thermal heating systems.
The availability of the grant prompted Fremd High School officials to embark on the school's solar thermal project, which entailed the installation of 100 solar collectors on the school's roof.
“What I think you'll find is that when there's an incentive out there, and we can match that incentive with a need, then it's worth doing,” said Steven East, Township High School District 211's director of purchasing and facilities. “I think the technology of these systems has improved. Twenty or 30 years ago you could buy solar panels, but you don't see any of them in use anywhere. Technologically, I expect that we're now getting a far superior product.”
School officials hope the solar thermal system will reduce the school's natural gas usage by approximately 7,900 therms per year, saving more than $12,000 annually.
If the system produces the intended results, East said District 211 might consider using similar systems to heat the pools at the district's other five schools. “We thought this would be a good pilot for us,” he said. “We have five swimming pools, one in each of our schools, and we thought we'd try one and see if this really works as we hope it will.”
District 211 went with local contractor Ideal Heating Co., of Brookfield, Ill., to complete the installation. The solar thermal system will act as the primary source of heat for the pool year-round, and the school's existing system will serve as a backup in the winter, according to Andy Usher, the company's vice president.
“Hopefully it will save energy costs to heat the pool year-round,” he said. “The sun's pretty good in the winter or summer in Chicago. Some people think it snows all the time, but there really is a lot of sun.”
The swimming pool's existing heating system continuously circulates water through a filter using a circulating pump. The system then bypasses part of the circulated water to a gas-fired water heater to heat the pool.
According to the school's maintenance personnel, it takes about five days to heat the pool's water from 55°F to 80°F after draining and refilling the pool with cold water.
The school's new solar thermal hot water heating system will eliminate the heat losses in the hot water piping from the existing boiler, according to Prem Mehrotra, of General Energy Corp., which designed the system. The heat available from the solar thermal system will supplement the boiler's energy needs throughout the year.
The system's 3,100-sq.-ft. collector array features flat plate solar collectors mounted on the school's roof with steel tube framing and installed in four rows of 25 collectors each.
A 1.5 HP self-priming inline circulation pump circulates fluid through a heat exchanger located in the pool's equipment room, according to Mehrotra. The pump handles the flow of fluid through the heat exchanger and up to collectors piped in parallel and connected with ½-in. insulated pipe. The loop consists of 2-in. supply and return pipe header and a 50/50 mixture of distilled water and propylene glycol to maintain a freeze point to -20°F.
The pool's current pump continuously operates year-round and is always consuming heat to compensate for evaporation and displaced water, Mehrotra said. With an average capacity of 700 Btu/sq.ft./day, the solar thermal system can meet the pool's hot water needs and eliminate the need for a boiler during the summer, he said.
Temperature and pressure sensors in the solar collector loop piping provide the inlet and outlet water temperatures, and a Btu meter calculates the total amount of heat generated through the solar thermal system. East said in addition to saving money, the system should give the high school's students a chance to learn about solar energy.
“The cost benefit is huge, but beyond that, it's certainly something our kids will be able to learn from,” he said.