Welcome to HVAC Tech Talk brought to you by Vital Mechanical Service. These are short trainings on different components, equipment, and systems.
Ron: With Michelle, who’s new to the industry and understands how difficult learning HVAC can be.
Michelle: And Ron, who’s a mechanical engineer and understand how these systems really work. AHU session one, level beginner, the basics.
Ron: So Michelle, an air-handler is any device used to regulate, circulate, and filter air as part of a heating, ventilating, and air conditioning system. But when you entered into the industry, what did you think an air-handler was?
Michelle: I had no idea. It was really confusing. I didn’t know where they were. I didn’t know what they were actually doing.
Ron: And in the last few years, what did you learn about an air-handler?
Michelle: Basically all it is is a machine that takes in the air, it cleans it, heats it up or cools it down for a designated space.
Ron: That’s right. And the main components of an air-handler are fans, dampers…
Michelle: What are dampers?
Ron: Dampers are air valves inside the air-handler that regulate the amount of flow that pass through any certain area. And then we have filters, then a heating section, and or a cooling section, depending if we have to heat or cool the air…
Michelle: Oh, wait, wait, wait. That brings up a really good point. When I first came in the industry, I didn’t realize that these units either had a heating section or a cooling section.
Ron: Or both.
Michelle: Or it doesn’t do any of that and it just takes the air and circulates it around the room.
Ron: Yeah, absolutely. It depends on the specific application of that air-handler.
Michelle: So they’re customized?
Ron: They’re unique for that situation.
Michelle: I got it. Okay, let’s get back on topic.
Ron: Understood. And the last component is controls.
Michelle: Wait, what are controls?
Ron: Controls are the brains that tells an air-handler what to do and when to do it.
Michelle: Kind of like me bossing you around.
Ron: Or, or a thermostat.
Michelle: Okay, got it. So what exactly do you use an air-handler for?
Ron: We use it to make a space more comfortable, functional, and sometimes even for safety.
Michelle: Okay, functional. Give me an example.
Ron: Sure. Data centers. They produce an enormous amount of heat. Think of this. If the average office is 10 foot by 12 foot and it was a data center, at the end of one working day we would have to remove enough heat energy that is equivalent to 12 gallons of gasoline, or enough gas to fill up the tank of my car.
Michelle: Holy smokes, that’s a lot. I’m thinking road trip.
Ron: I’m thinking we finish this training.
Michelle: So let’s talk about safety. Where would you apply that?
Ron: Surgery suites. Do you know why they keep them so cold?
Michelle: I have no idea.
Ron: I used to think they kept them cold to like inhibit the growth of bacteria. Not true. They keep it cold so that doctors and nurses don’t sweat in the high pressure situations.
Michelle: I appreciate that.
Ron: I also appreciate that. But what’s interesting, and has to do with bacteria and safety, is the filtration we use on those suites is so good it only lets 3 out of 10,000 particles through.
Michelle: Oh wow, that’s impressive.
Ron: I know. And we’re not talking about bird-sized particles, we’re talking about microscopic particles.
Michelle: That’s really tiny, but what’s left?
Ron: So when we think about comfort, we think of air-handlers in office spaces. And no one’s really thinking about them.
Michelle: Yes, I’m not.
Ron: But we want to keep people really comfortable. That’s what’s important.
Michelle: Well, Ron, why would they be uncomfortable in the first place?
Ron: Well, if it’s cold outside we want to heat the space, if it’s hot outside we want to cool the space. Even with the seasons, office equipment generates heat. Even people generate heat equivalent to a 100 Watt light bulb. And we want to remove that.
Michelle: And keep people from being sleepy.
Ron: Yes, we want to keep people from being sleepy. People breath out CO2.
Michelle: Wait, what’s CO2?
Ron: Carbon dioxide. Not to be confused with carbon monoxide which comes out of your car.
Michelle: Which I totally would do that.
Ron: Do not do that. That’s bad. But carbon dioxide, it actually just displaces air that’s higher in oxygen, and with the lack of oxygen we get tired.
Michelle: I learned something new.
Ron: I think everybody did. So with an air-handler we want to exchange the inside air with fresh, outside air.
Michelle: So when you’re saying comfort, you’re really talking about two things: creating the right temperature and providing fresh air.
Ron: Yes. So those are the basics. Let’s review.
Michelle: Let’s review.
Ron: An air-handler is a device used to regulate, circulate, and filter air as part of a heating, ventilating, and air conditioning system. The major components are…
Michelle: Fans, dampers, filters, heating, and cooling sections.
Ron: That’s correct. An air-handler makes a space functional, safe, and comfortable. And Michelle, how does it make it comfortable?
Michelle: By creating the right temperature and providing fresh air.
Ron: Yes, that’s correct. Yay! We’re done with this training!
Ron: The next training will be about the different air-flows that are associated with an air-handling unit. Until then…
Michelle: Thanks Ron.
Ron: And thank you Michelle.