As with many aging air conditioning systems in south Florida, the Miami Court of Appeals found itself badly in need of a retrofit. In 1996, its two 60-ton chillers were on the verge of compressor failure, and replacement was inevitable.

Great Case made for TES

The building management at the court learned about the concept of thermal energy storage (TES), which was just beginning to make its mark in the hvac industry. The concept is simple: at night, ice storage tanks make and store ice, which is then used to cool a building during the day. TES is extremely efficient for large facilities that operate primarily during peak utility time, when chillers are shut down and rely on “ice mode.”

Management decided that this option was best for them. Ken Potter, court marshal, said a decision had to be made about the new system from three choices: a) buy new 60-ton chillers, b) buy one 90-ton chiller, or c) use thermal energy storage, which would greatly reduce their monthly ‘energy overhead.’ Said Potter: “Since the Court is closed on weekends and at night, we agreed TES was the best idea. We knew it would save thousands of dollars, plus FP&L (Florida Power & Light) added a sizable rebate.”

Though the environmentally friendly TES system is a revolutionary method in its capacity to save money and lower energy costs, the high initial cost of investment is often considered a major barrier to installation. An organization that decides to upgrade to TES must have a chiller that gives the building enough ice-making capacity to carry it through peak demand periods. In the court’s case, this was one 90-ton chiller. Second, a facility must purchase ice storage tanks, which tend to be costly.

However, in most cases, TES pays for itself within five to seven years, due to the drastic slashing of monthly expenses.

Luckily, the court was eligible for both state and federal energy grants. Working closely with John Nix, technical specialist from FP&L, it was able to prove to the advisory committees the benefits of the new system.

The project was broken into two parts. First, the old chillers were removed and replaced by one 90-ton, energy-efficient chiller from Thermal Concepts (Davie, FL,

Larry Maurer, president of Thermal Concepts, has been excited to take part in the growing trend toward TES installations. “I think it’s a matter of common sense. It’s like asking someone, how would you like to have $10,000-15,000 per month taken off your utility bill? The answer is obvious. Our chillers represent 50% of the resulting cost savings.”

In July of 1997, the court received enough funding to complete the second part of the upgrade to the new system — the ice storage tanks. Thermal Concepts installed the tanks and tested the new system one weekend.

Putting Costs ‘On Ice’

Looking back, the TES system has been a huge success. “The court’s cooling costs have been cut in half,” said Nix. The initial FP&L rebate, $21,000, covered almost 20 percent of the cost of adding ice storage tanks.

Since 1997, the $15,000 in annual cost savings comes from two sources. Fifty percent of the savings is from TES, 50% is from the energy-efficient chillers. In the court’s case, it may not have all been possible without the state and federal grants.

Overall, energy savings such as this can represent itself any day in court. ES