We’ve all responded to service calls in the dead of winter or wormed our way past a dead animal in a crawl space. We’ve all had to deal with wading through some hoarder’s junk to get to an access panel that wasn’t so easy to access, or gotten a snoot-full of dust from a filter that hasn’t been changed in years. Stripped hardware, frayed wires, and botched home repairs from over-confident DIY-ers – we’ve seen it all. Or so we’d like to think.
This is standard stuff for any tech that’s been in the field long enough to earn some stripes. We all know that part of the job is to expect some level of inconvenience… and the occasional dead rat. If it were easy, everybody would be doing it.
What we’re talking about here are the real extremes of HVAC work. The kind of places that would make most men shudder – jobs that take you to insane heights, to places with temperatures that kill, to war zones, and even low orbit.
Every installer and service tech has a good story or two, but some have seen the abyss and lived to tell the tale.
Dizzying Heights of the One World Trade Center
At 104 aboveground floors and three million square feet of office space, One World Trade Center has more climate control features than many cities.
Imagine installing the HVAC system in this behemoth.
Just to cool its transit terminal, the WTC museum, retail stores – all of which are subterranean – along with the aboveground public spaces in the skyscraper, it takes a 12,500-ton central chiller plant that circulates 30,000 gallons of Hudson River water streaming in through 66-inch pipes every minute.
That water is collected into five 200 horsepower centrifugal chillers, each weighing in at more than 85 tons. The central chiller plant also includes five 300-horsepower chilled water pumps and two heat exchangers that each provide 1,000 tons of cooling capacity.
This system produces enough air conditioning for 1.8 million square feet, and we haven’t even gotten to the HVAC system for the three million square feet of private office space.
Each floor of office space is cooled by a pair of McQuay DX units that get their cold chilling water from the central chilled water plant in the basement. That means running pipes and conduits up and down 104 floors.
It’s estimated that large office buildings use 20 kilowatt-hours (kWh) of electricity per square foot on average every year. That represents one-third of the total building electricity use dedicated solely to HVAC. When you do the math that means One World Trade Center uses around 42 gigawatt-hours of electricity for HVAC and lighting each year. That is roughly equivalent to the total power output from the Hoover Dam over a four-day period.
Deadly Cold of the Antarctic Research Station
You could probably guess that cooling is not the main issue at the Amundsen-Scott South Pole Station. With the record high here a blistering 9 °F, you’re more likely to find the average high outside this facility at -14.6 °F in the summer and -68.6 °F in the winder.
Repairs and upgrades on the station are only possible during a few of the relatively “hottest” months of the year when there is a solid 24 hours of sunlight each day. HVAC techs work on a tight schedule because if they don’t finish before the weather gets bad, the station is no longer habitable and needs to be evacuated or it’s certain death.
If you’re working on the station’s HVAC system you’ll also need to keep in mind the limited power supply. Because it’s about as remote as possible, the station generates all its own power, and that means brown-outs when demand is at its peak.
You’ll also contend with a one-of-a-kind heating system. In a place where the outside ambient air temperature is regularly dozens of degrees below freezing, obviously pumping air directly into the heater isn’t going to get you anywhere. The air first needs to be warmed by passing it over a coil that’s part of a heated glycol system. Once the air is about room temperature it will be ready to enter a more traditional hot air venting system.
If you already have some experience with refrigeration you’ll recognize this as actually being a reversed freezer.
The Black of Space
It’s crazy to think, but some outfit had to design the life-or-death HVAC system on the International Space Station before it was launched, and you can bet NASA consulted with the best in the business.
When designing the HVAC system, engineers had to keep in mind a number of things you wouldn’t normally consider:
Here’s how they pulled it off. First they started with insulation. The station is basically almost entirely wrapped with a reflective coating that keeps the sunlight from radiating heat onto the station, and the shady spots from radiating heat out.
However, now that you’ve got a thoroughly insulated space station, what are you going to do with the excess heat that is produced internally by the occupants, machinery, and computers? You guessed it: heat exchangers.
Specifically, a dual-exchange heat system that starts as an inside water-based loop driven by an inch-wide rotor that spins at 17,000 rotations per minute. This loop then goes through an ammonia-based heat exchange system. The heat must be transferred to the ammonia because, as you probably guessed, that water’s going to freeze once you get it outside the climate-controlled living quarters of the ISS.
The heated ammonia is then passed along to an aluminum honeycomb-panel radiator in the shade outside the living area of the ISS where it’s dissipated as infrared radiation. In total, there are 14 radiators that together add up to 1,680 square feet.
Servicing the War Zone
You stopped at Burger King on your way to work in the morning to pick up breakfast. You’ve got a busy day ahead that starts with checking an expansion tank with a finicky water meter. You’re excited because in the evening Toby Keith is playing a show for the servicemen, and you get to go. That night as you’re falling asleep you wake up to the sound of mortars exploding in the distance, then go back to sleep because you don’t hear any nearby return fire.
Just another day as an HVAC tech stationed at al Asad Airbase in western Iraq. Not everyone can say their place of work is so intense. In February 2015 eight ISIS fighters were repelled from an attack on the base, making international headlines and offering a sobering reminder that that there is still major conflict in Iraq.
Al Asad Air Base was originally built by Yugoslavian contractors hired by Saddam Hussein in the 1980s and was designed to accommodate 5,000 inhabitants. Captured by coalition forces in 2003, it quickly grew into the second-largest US military base in the country during Operation Iraqi Freedom, and now houses thousands of service members and civilian contractors, all making their temporary home in a place where the average daily high in June through September is above 100 °F.
The Department of Defense operates 38 major bases abroad along with many other smaller facilities, not to mention those at home. Each of these bases has unique heating and cooling demands. And this is just living quarters – not to mention aircraft, ships, tanks, or storage facilities. HVAC techs have their work cut out for them maintaining a controlled climate in extreme environments from desert facilities like al Asad to places like Eielson Air Base in Alaska.
Most branches of the military have an enlisted equivalent position for HVAC tech, but demands also require plenty of civilian HVAC contractors. As you gain experience in this field, chances are that you’ll meet plenty of colleagues who are veterans. You’ll also find that many jurisdictions that license HVAC techs allow relevant military experience to count towards training and experience requirements for licensure.