Have you ever looked at the large, gray rectangular boxes on the roof of Philadelphia International Airport (PHL) and wondered what they are and what they do? These units are called air handlers and they have the essential function of circulating air evenly throughout the airport. There are more than 700 air handlers airport-wide that provide PHL with warm or cold air, depending on the time of year.
The airport’s Facilities and Maintenance Heating Ventilation & Air Conditioning (HVAC) team works tirelessly year-round, preparing the HVAC system before every season and fixing issues such as cleaning clogged coils or drains from condensation pans, adjusting valves and, twice a year, changing air filters.
In the spring, the HVAC team inspects all of the air handlers to check for clogged drains, clean air filters and ensure fan belts are working correctly. In addition to this routine maintenance, the team makes sure the coils are clean and replaces water heaters and bad motor bearings, which range from one horsepower (HP) to 50HP and weigh 900 pounds. HVAC also maintains exhaust fans and an estimated 150 air conditioning direct expansion (DX) systems, primarily for telecom rooms where cold air is critical for equipment to function.
The air handlers cannot function without three plants at PHL: the A-West Thermal Plant, the Central Utility Building (CUB), and the Satellite Thermal Plant. As its name implies, the A-West Plant provides heating and cooling to international terminal A-West, while the CUB provides the same for terminals A-East through D, and the Satellite Thermal Plant provides HVAC to terminals E and F. The A-West and Satellite plants use circulating water systems to pump heated or chilled water through pipes and coils to the air handlers. The CUB, on the other hand, provides steam for heat and chilled water cooling. Inside the air handlers, air passes through the heated or chilled coils and is then distributed throughout the terminal buildings.
Air handlers are not the only way PHL distributes heat throughout the airport. There are 140 door heaters airport-wide that also utilize circulating water systems and natural gas for heating. Door heaters are utilized primarily at pedestrian entrance doors and baggage tug doors. The HVAC team begins inspections and maintenance on the door heaters in August and continues into January. PHL turns on the large boilers in the thermal plants to begin heating the airport in October.
PHL brings in five-to-10 percent of outside air to keep the air fresh throughout the airport and uses an economizer to save energy by allowing more outside air to enter the airport during milder weather. According to the American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE), the recommended temperatures within large facilities “range from 68°F to 74°F in the winter, and from 72°F to 80°F in the summer.” PHL’s HVAC team strives to accommodate passengers and tenants with the perfect temperature; however, it’s challenging due to personal preferences. PHL currently tries to maintain an average temperature between 71-74°F in both winter and summer. When there are temperature inconsistencies and complaints that the indoor airport temperature is 80°F and too hot, the HVAC team often has to fix the problem on the roof, where it’s about 110°F. Similarly, when there are complaints that the airport is 60°F and too cold, the HVAC team is fixing the problem on the roof where it may be as low as 20°F.
"Our HVAC team works every day, sometimes even working 16- plus hour shifts in extreme conditions to maintain comfortable temperatures at PHL for guests, stakeholders, and employees," said PHL Deputy Director of Facilities Allan Moore. "Our team is one of the best out there, and we appreciate everything they’re able to accomplish despite the challenges that they face."