An Inside look at Wellman's HVAC
Have you ever raced to class, shuffled into a classroom with 100 other students and spent the next 15 minutes sweating in your seat wondering if you smell bad? Or have your beads of sweat turned to ice when the AC blows directly on you?
In this post, you’ll find out what goes on behind the scenes before you sit down and long after you’ve left. Let’s take a look into Wellman Hall. Whether you’ve had classes in Wellman, or taken a quick nap inside, the same type of processes occur in other buildings around campus.
Our story begins in the wee hours of the morning, when the classrooms are dark and quiet. Around 6am, the building comes to life. The fans turn on and the building uses 62° F outside air to cool the rooms. Air temperatures mix to create 70° F air in the rooms. This may seem chilly, but this temperature helps keep the rooms cool with the upcoming onslaught of students. Let’s explore in a little more detail and see what’s going on in classroom number 26.
Just after 9am the temperature is still about 70° F, but the room will quickly warm up as students trickle in for class. When class starts at 10am, the room is roughly 74° F. Since morning classes are a little smaller and the outside temperature is relatively low (in the 70s, °F), the room’s air conditioning units can maintain this temperature by simply increasing air flow.
It isn’t until people start packing the room for their 12:10pm class that things get heated. At 12:10pm, it’s about 74° F inside the classroom, and about 81° F outside. The room soon reaches its maximum occupancy, 120 people. The temperature in the room rises to 76° F in 15 minutes. The air conditioner responds by increasing air flow and brings the room temperature back down to 75° F. It’s an uphill battle though with all those warm bodies and flowing brain juices, so the temperature starts to creep back up.
At 3:45 p.m., classes have been underway for several hours and the room has consistently had about 120 people in it. The room reaches a temperature of 77° F between 3:45pm and 4:30pm. The air conditioner has been steadily supplying 62° F air, at the room’s maximum rate of about 1400 cubic feet per minute, but with outside temperatures hovering around 92° F, it’s doing everything in its power to keep the room comfortable.
By 7:30 the day’s classes are over and the room temperature drops back to 71° F. The building gets a reprieve, until tomorrow…
Let’s take a quick look back to see how the room temperature fluctuated throughout the day. As you can see, the number of people in the room, air flow, and outside temperatures all affect the temperature in the classroom.
Did you know?
If you’re sitting in the back of the room you may have a different experience than someone sitting in the front of the room, and we’re not just talking about your grade in the class.
A little tip: if you’re in a vaulted classroom and you are usually hot, sit in the front of the room where it is likely to be a little cooler. This may not always be your experience, but hot air rises…
So why does the temperature creep up when you’re in your lecture?
Temperatures in rooms on campus are controlled with a "comfort band" to avoid over-cooling or over-heating. Our office is trying to tune these comfort bands to keep you comfortable and to make sure we aren't wasting energy. You need to let us know when it’s too hot or cold though, so we can help make your learning a top priority. Remember that you can always whip out your phone and tell that good-looking bovine on TherMOOstat that your room is hot, cold or perfect.