Once the building cooling/heating load has been calculated and the VAV system has been laid out, the next step is for the engineer to select the exact sizes, models, and configurations of the terminal units that will deliver the comfort to the space. For both the single duct and fan powered terminal units, several variables must be considered including unit capacities, sound, type, heating requirements & type, and manufacturer.
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A mechanical engineer must consider several variables and equipment types when designing a VAV system. This includes the load on the space, the static pressure in the ductwork, the types of terminal units, and the occupancies in the space. The engineer must also consider how the terminal units are going to be controlled. These decisions must weigh the initial cost with the long-term energy efficiency. Using a theoretical office building, we will walk through the general design process and the decisions the engineer must work through to arrive at a final...
