The heating, ventilation, and air conditioning (HVAC) system in an industrial building is like a giant version of a residential furnace and air-conditioner combination. While there are significant similarities, there are also a few differences. Size is the biggest one; industrial air-handling can take up a large portion of building space, and requires many large, high-powered fans to blow air into heating ducts. (These fans consume a large amount of the buildingâ€™s total power).
Typical air-handling units work in an "H". Outside air comes into the unit via one leg and stale air is vented from the other leg. The bridge of the "H" is where the new and used air is mixed to salvage some of the heat and humidity from the exhaust, which helps save money by warming and humidifying the incoming air. The mixed air is then heated or cooled, and it leaves the unit and supplies the building. Typically, 25 percent fresh air is mixed with the recirculated air. Units that use this process are sometimes called "economizers" as opposed to just regular "air-handling units."
The IL Centre has six air-handling units. The first unit houses the enthalpy wheel, which feeds air to all of the other units. Each air-handling unit serves a specific zone of the building. Each unit must provide a certain number of â€œair exchangesâ€ per hour, and this number depends on the maximum number of people who will be using the space at any given time.
The air-handling fans on the right are sending and receiving air from each of the colour-coded zones on the map. The white zones receive no air directly; air diffuses in through vents and doorways. (The sixth unit, which is not indicated on the maps, serves Goodwin Hall).