AEDC tackles upgrade project to VKF compressed air system

  • Published
  • By Philip Lorenz III
  • AEDC/PA
ARNOLD AIR FORCE BASE, Tenn. --  An Energy Conservation Investment Program-funded modernization project at the von Kármán Gas Dynamics Facility at AEDC will save energy and money in the long run, according to John McInturff, ATA program manager on the project.

"The savings are estimated to be around $162,000 and [the upgrade will reduce energy demand by] 6,841 MMBTU [one million British Thermal Units] annually," he said.

The design phase of the project is funded and it will begin between late this fiscal year or in fiscal 2011 and be ready for execution by mid-year of fiscal 2011.

"This project is funded with Energy Conservation Improvement Program funds; ECIP is part of the MILCON [Military Construction] program," said Vickie Davis, Air Force energy manager at Arnold. "Getting these funds is highly competitive and had to be approved by Congress."

McInturff said it is important to understand the scope of the project.

"A part of this effort is to redo the purge air heater for the high pressure air dryer system and, instead of using high pressure air as part of that process, we are looking at adding a dedicated 300-psi system for that and the seal air," he said. "We are also replacing multiple heating, ventilation and air conditioning [HVAC] units in Building 876, the engine test facility shop building."

VKF's high pressure system brings ambient pressure air up to 3,800 to 4,000 pounds-per-square inch (psi), which is required for running testing in the facility and supplying air to high-pressure tanks on base. However, if air is needed at lower pressures for seal air, the time and expense involved negatively impacts testing and other operations.

Seal air is used primarily to inflate valve seats.

"The high pressure system is around 3,800 to 4,000 psi," McInturff said. "If they pump the compressed air through a PRV (pressure reducing valve) to reduce that pressure back down around 300 psi, we're wasting all of that energy to pump it up to around 4,000 psi and drop it back down."

The air is also cooled by this process and must be heated to return it to a usable temperature, all of which, in turn, takes more energy and time.

Adam Fanning, an ATA high pressure air mechanical systems engineer, said the high pressure air generated at VKF "is the main process air used for testing at APTU, and also T-3 testing. Other facilities such as the J cells and C-Plant use reduced pressure high pressure air for seal air and PWT uses it for heated high pressure makeup air to achieve certain test conditions. Then it's used in all the A, B and C Tunnels at VKF for model injection systems and also for some process air."

The term process refers to what is done to make the air suitable for testing and other applications. This includes the pressure, temperature and amount of moisture in the air.

Fanning said excessive moisture in the air can cause damage to the test article due to the friction of water vapor going across the surface of the article. High humidity also provides a less realistic environment for testing.

"[When we're done with the project] we'll have a compressor system that will provide air at around 400 to 500 psi, depending on what compressor we choose and what's right for our application," he said. "Three hundred is the pressure needed for seal air and 400 psi is the pressure needed for reactivation air. So, the system will have to be at least a 400 psi system, unless a design effort proves otherwise. This [system] will provide the reactivation air and the seal air. We're going to make this reactivation system a standalone system, which will also provide seal air for VKF."

Steve Pearson, deputy general manager for ATA, said a lot has changed since energy was seemingly abundant and inexpensive.

"There is no escaping the fact that we consume a tremendous amount of energy at AEDC," he said. "But that does not mean we don't have a responsibility to make all our processes as energy efficient as possible when it is practical."