Energy-Saving Air Conditioners Could Provide Taxpayer Relief

February 26, 1998

GAINESVILLE — University of Florida researchers seeking to trim air-conditioning costs in large buildings have found new techniques they say could save taxpayers and consumers hundreds of thousands of dollars annually.

In fact, they say, measures already in place at the Alachua County jail will save more than $100,000 a year, and plans are under way to take similar measures at some UF buildings, where they estimate annual savings could approach a half-million dollars.

In many cases, finding ways to cut costs starts with a simple reality check.

“How a building functions is often different from the designer’s intentions,” said Michael West, a mechanical engineering specialist with UF’s Energy Extension Service. “We look for inefficiencies due to old technology and then retrofit new technology solutions.”

The situation at the jail arose when its architect, trying to end a humidity problem at the jail that could have led to uncontrolled mold growth, installed a hot-water reheat system that uses heat to control the humidity levels. The problem was, it caused the jail’s energy bills to nearly triple.

“We wanted to find a more efficient way to run the buildings that was less expensive,” West said.

To reduce the costs, the Energy Extension Service suggested installing heat pipes, which transfer heat inside the air system from one area to another to stabilize humidity levels.

During a further evaluation of the jail, West discovered there was more air flowing into the building than the occupants needed, making the rooms sticky. The solution: Reduce the amount of air circulating through the air system, which required the air conditioners to work less.

West also found the air-conditioning units at the jail were installed direct from the manufacturer, so the settings were not adjusted to accommodate the building. Simply re-adjusting the units was the cost-effective answer to the problem. In addition, West said, some air-conditioning units at the jail were twice the size needed. As the units age, they will be replaced with proper-sized models.

With the evaluation of the jail an apparent cost-saving success, West and the Energy Extension Service have been asked to seek ways to cut the energy costs at UF.

West evaluated buildings that house the university’s microbiology and cell science department, the entomology/nematology department and the College of Veterinary Medicine. All the buildings require 100 percent fresh air to be flushed through laboratories to remove harmful chemicals.

Supplying that much fresh air continuously not only is expensive, West said, it’s also unnecessary because the labs are not in use all the time. He developed a plan to install motion sensors and variable-speed motors in the buildings. If there is no motion in the labs, there’s no need to pump large amounts of air through the rooms. And if fume hoods are closed, indicating no use of chemicals and no need for ventilation, but motion is detected, the motors will adjust according to the situation, reducing energy costs.

“We want to make the buildings’ computer-controlled air systems smarter,” West said.

He estimated the changes could save the university nearly $500,000 a year.

West and the Energy Extension Service hope to evaluate more buildings and create a set of easy-to-follow guidelines for the university and others so energy-saving measures can be put in place before construction begins.

“It’s much more expensive to do it after construction, for public and private buildings alike,” West said.