Outdoor units were installed while the bank was in operation, providing a seamless experience for employees and customers.

VRF Zoning Yields Significant Energy Savings for Bank

April 6, 2015
Energy modeling showed three new Mitsubishi Electric variable-refrigerant-flow (VRF) zoning systems would meet each of the bank’s needs.

An independent community bank that has been in operation since 1898, Century Bank and Trust occupies a 24,000-sq-ft, three-level building in Milledgeville, Ga. About 25 years ago, the building underwent a renovation that included the installation of a water-source-heat-pump system.

“At the time, it was a state-of-the-art system,” Brian Robinson, vice president of Century Bank, said. “Now, it’s not. This is a 100-percent-on, 100-percent-off system.”

The resulting inefficiency cost the bank greatly.

“Our bill ran from $6,000 to $8,000 a month,” Robinson said. “Then there were the leaks.”

Meanwhile, employees were uncomfortable.

“We had heaters at every desk contributing to the electric-bill problem,” Robinson said.

Robinson called in Air Conditioning Specialist Inc. (ACS) of Milledgeville to study the situation and propose a solution. ACS gathered data using EnergyPro modeling software.

“We used this software to track Century Bank’s energy consumption at the time and to predict future energy consumptions in various scenarios,” Scott Reaves, ACS senior project manager, said.

Three scenarios—(1) install another water-source-heat-pump system, (2) install a variable-refrigerant-flow (VRF) zoning system, and (3) install a non-VRF zoning system—were analyzed.

When it came to the VRF zoning system, the predicted cost savings “looked good, almost too good,” Robinson said.

VRF zoning technology allows each zone to be operated at its own temperature.

The bank sought a second opinion from Georgia Power.

“Their cost savings looked even better,” Robinson said, adding a third company was called in, “and their cost savings looked even better.”

The cost-saving predictions were impossible to ignore, but the bank also was focused on improving employee and customer comfort. The previous system was outdated and aging quickly, but it did offer 20 zones.

“They didn’t want to lose that zoning capability and, in fact, hoped to have even more zones such that everyone could have their own control,” Reaves said.

Additionally, the bank wanted to stay open throughout the installation.

“We looked at the results from the EnergyPro models and the stated needs of the Century Bank employees and easily concluded that three new Mitsubishi Electric VRF zoning systems would check off every need,” Reaves said.

ACS was familiar with the systems, having completed several large-scale installations at schools, warehouses, and more.

Installation began in March 2012 and was completed within a month. The bank remained open the entire time, with the installation taking place at night.

“We did one system per floor at 20 tons per floor, installing the systems one by one,” Reaves said. “This minimized the amount of movement we had to deal with, and we used the existing ductwork.”

ACS removed the entire chilled-water system and then brought in and installed more than 60 tons of Mitsubishi Electric equipment.

“The whole installation was very professional,” Robinson said, “and not one time did it interrupt business. The (Mitsubishi Electric) equipment was so much smaller and easier to install. ACS had a harder time taking out the old, heavy units than they did installing the new ones.”

Following installation, the bank immediately saw significant reductions in energy use.

“We ran an energy model, and the results were outstanding,” Reaves said. “We saw an energy savings of more than 28 percent.”

The bank additionally saw reductions in water consumption of about $100 per month.

As impressive as the three cost-savings projections were, “The real energy savings were even better,” Robinson said.

“And this is comparing apples to apples,” Robinson added. “I’m looking at last June compared to this June, and the weather has been consistent.”

Each floor of the bank had a 10-ft-by-10-ft mechanical room that was packed with HVAC equipment.

“The Mitsubishi Electric VRF zoning systems completely eliminated the need for that,” Reaves said. “So, Century Bank picked up a storage closet—or even an additional office—on each floor.”

The bank likes what the equipment offers.

“It is quiet, efficient, and independently controlled,” Robinson said. “It’s also programmable. We are very pleased with the results.”

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