How the Dallas-Ft.Worth Airport is Using DOWTHERM SR-1

Midland, MI - September 07, 2005

At the new Terminal D at Dallas-Ft. Worth (DFW) International Airport, the high-efficiency pre-conditioned air (PCA) system is working wonders to ensure that aircraft passengers and flight crew are cool and comfortable when the aircraft is parked at the gate. The PCA system is one of many centralized, ground-based cooling systems that are being used at airports in place of traditional Auxiliary Power Units (APUs).

The PCA system is comprised of water-cooled industrial chillers and thermal energy storage (TES) tanks. The chiller system supplies thermal fluid to exchangers in air handlers that are typically mounted on passenger bridges. The air handlers are coupled to the aircraft at the gate and supply chilled air directly to the aircraft's air conditioning manifold.

The aircraft cooling system serving the planes and jet bridges in Terminal D of DFW International Airport is made up of two, 460-ton chillers, and a 20,000 gallon TES tank, pumping and control equipment, and the plumbing required to deliver and return the glycol-based heat transfer fluid to the air handlers at the individual gates.

The chillers and TES tanks are at the heart of the cooling system. The TES system is designed to build ice in the polymer balls at night during off-peak hours when power costs are lower. This ice is then "burned" during the day to supplement the capacity of the chillers.

The glycol-based fluid returning from the individual gate service points enters the thermal energy storage tanks at about 60 F, and is cooled to about 40 F before it reaches the chillers. This results in a significant reduction in the daytime load on the chillers.

The aircraft cooling system at DFW uses 240,000 gallons of a 30 percent solution of DOWTHERM* SR-1 inhibited glycol-based fluid to heat and cool the planes that dock at Terminal D every day. The working properties of the fluid are extremely suitable for these types of cooling systems, as well as heating, ventilating and air-conditioning systems. In colder temperatures, the HVAC system, with DOWTHERM SR-1, is used to heat the aircraft and jet bridges, keeping passengers warm.

Particular to cooling systems, the thermal fluid needs to offer the right level of freeze protection to keep the TES tanks and circulation lines working efficiently. A 25 percent solution of DOWTHERM SR-1 fluid provides effective freeze protection to 10 degrees F, which is below the system's design limit. Also, the long-term reliability of the corrosion inhibitor package in DOWTHERM SR-1 fluid provides good assurance that the complex piping, control valves, and pumping equipment in the system will be consistently protected from corrosion damage.

At DFW, DOWTHERM SR-1 fluid was specified to perform at an operating rate of 20-180 degrees. Additionally, Dow dyed the fluid a specific color to enable the airport to monitor their own fluid levels for internal maintenance.

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For Editorial Information:

Holly LaRose-Roenicke
The Dow Chemical Company
(989) 638-7703