When using a terminal reheat system, what aspect is primarily being controlled?

In a terminal reheat system, the primary aspect being controlled is the heating or reheating of air at terminal units. This system is designed to provide precise temperature control in specific areas or zones, allowing for comfort adjustments based on the heating needs of the space. Each terminal unit, which can be a fan-coil unit or similar device, actively reheats or conditions the air to maintain a desired temperature as dictated by the thermostat in that zone.

By focusing on the heating or reheating aspect, the system ensures that even in cases where air conditioning may be providing cool air, the terminal units can warm the air if needed, thus delivering a consistent and comfortable temperature experience for occupants. This capability is crucial in environments where maintaining exact temperatures is vital for comfort and efficiency.

The other options, while related to HVAC operations, do not represent the primary focus of a terminal reheat system. For instance, fresh air intake pertains to ventilation requirements, cooling demand relates to overall system operation rather than specific zone control, and air filtration is concerned with air quality rather than temperature management. Thus, the focus of terminal reheating is clearly on controlling the temperature of the air being delivered to individual spaces.