Waldo County General Hospital has found a way to save nearly $1 million over the next 20 years while at the same time having a more reliable and more environmentally friendly air conditioning system.

Until May, the hospital had a large chiller unit on its roof to cool the water going through the air conditioning system. The chiller was only 12 years old, but it was very inefficient, required a high level of maintenance and used a form of Freon, R22, that is no longer being manufactured because of environmental concerns.

When Bill Jenkins, the maintenance and security manager at WCGH, went looking for a replacement, Johnson Controls Inc. did a study and found that two new smaller chillers would be more efficient, saving an estimated $47,785 in electricity costs per year. Because of that large savings in electricity use, Efficiency Maine is willing to give WCGH a rebate of $135,000 following installation and inspection of the new chillers.

The new chillers also use a new Freon, R134A, which is much more ozone-friendly, and at a capacity of 150 tons each, provide room for expansion. The old chiller had a capacity of 270 tons.

The new units have four compressors with a five-year warranty on each one. In the old unit, one of the three compressors had to be rebuilt every year at a minimum cost of $5,300. Jenkins expects the new compressors to last 12 to 15 years before there are any significant mechanical problems. He also expects with the rapid changes in the technology of chillers, it may someday be more economical to replace them than to rebuild them.

Taking into consideration the savings in electrical costs, the rebate, and the maintenance cost of the old unit, Jenkins said the new units will pay for themselves in less than four years and then will generate significant savings for the hospital.

Plus, he said, the controls on the old system never worked right and reliability was a constant worry. He said the old system started with a bang, while the new ones have variable-speed drives that will take them up to speed as needed, instead of trying to run at 100 percent all the time.

However, getting the old unit, which weighed 12 tons off the roof, and the new ones up there was quite a feat. A tractor-trailer was brought in to move the new units close to the roof and then a crane was used to do the lifting.

The process started May 19 when a small chiller, which was on the roof as an emergency unit because of concerns about the main chiller, was taken down. On May 24, one of the two new units was hoisted to the roof and the piping was done to allow the new unit to take over and the old unit to be cut off.

On June 1, the old unit was taken off the roof and the second of the new chillers was hoisted up. After that the second chiller was hooked into the piping and is currently being tested and calibrated to work in sync with the other chiller. Each unit has two compressors and they are calibrated to cycle evenly among the four.

By the end of the month, Efficiency Maine should be visiting to inspect the new chillers and to approve payment of the $135,000 rebate.