For the 78th Civil Engineering Squadron at Robins Air Force Base (AFB), home to 60 military units and the largest industrial complex in Georgia, the poor lighting levels in its hangars and engine shop was a cause for concern in regards to safety and convenience.

With four buildings totaling 500,000 sq. ft., it was imperative for the AFB to not only improve conditions for the Georgia Air National Guard members who worked there, but to also reduce the cost of energy purchased by the Air Force.

Robins AFB engineers used energy modeling data to identify where it would be easiest to save energy. The Air Force then bundled the lighting upgrade with a previously planned geothermal project to increase efficiencies. Trane won the competitive bid for the combined lighting/geothermal project at Robins AFB.

Trane’s winning proposal outlined a holistic approach, which included day-lighting, dimmable fluorescent lamps and a geothermal water source heat pump system, utilizing the adjacent lake as the heat sink. The plan showed how the combined elements could enhance energy savings for the base.

Renewable Lighting Improved Workspaces

Trane employed daylight harvesting to provide up to 40-foot candles of illumination, reducing the number of lighting fixtures required for optimal illumination while lowering electricity consumption.

Now, natural sunlight from more than 300 active tracking skylights provides most of the interior lighting for the facility during the day. Active tracking skylights use a solar-powered sunlight tracking device in each dome. This tracking device consists of a mirror array that redirects three times more sunlight into the workspace below.

New Lights Saved Energy

Inside the facility, light sensors control fluorescent lighting levels based on skylight illumination. Trane installed lighting upgrades in buildings, hangars, the maintenance facility and the warehouse operated by Air Guard, Air Force Reserve, 116th ACW and Defense Logistics Agency (DLA) agencies.

More than 800 Super T8 high-bay fixtures replaced metal halide lamps to bring lighting levels up to required illumination standards — allowing the facilities to operate 24 hours, seven days a week. De-lamping and relocation of lighting and BACnet®-enabled lighting panels further improved energy savings and operator safety, and met change of mission requirements.

Geothermal System Now Heats Water

The Robins Billeting Area — four separate motel and temporary housing buildings for base officers and VIPs — utilized aging, noisy air-cooled chillers for cooling and natural gas boilers for hot water heating and showers. Trane redesigned the mechanical rooms in each building, installing efficient water source heat pumps, controls, high-efficiency boilers, hot water storage and pumps.

The completed hybrid geothermal system utilizes a local lake as its renewable energy heat source in winter and heat sink in summer. The system consists of 160-tons of geothermal heat pumps paired with specially-designed stainless steel heat exchangers in the lake. Engineers added a desuperheater to the system to utilize rejected condenser heat to preheat the domestic hot water, resulting in an 80 to 90 percent energy savings for water heating.

The system quietly and efficiently maintains comfortable indoor temperatures in the billeting facilities, while reducing energy consumption and lowering greenhouse gas emissions at Robins AFB. Trane installed a water spray fountain in the lake to cool it if necessary.

Comprehensive Results

Trane’s holistic approach with Robins AFB enhanced lighting levels, provided a substantial energy savings, maintained indoor comfort and satisfied requirements of the AF Strategic Facility Energy Plan. Building Lifecycle Cost Analysis (BLCC) showed an ROI of less than 10 years and a Savings to Investment Ratio (SIR) of over 2.0. The expected useful life of the geothermal and day-lighting systems is more than 20 years.

Whether your job involves a simple equipment upgrade, or a complex lighting and comfort system upgrade with competitive federal government bids, Trane has the expertise and solutions to get the job done.

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