VAV terminal box. A room's own damper on a shared cold deck, metering its air between a minimum and a maximum and reheating at the minimum. Multi-zone VAV and terminal boxes.
One air handler makes one cold deck — a supply at, say, 13 °C — and every room has its own box on that deck: a damper that meters the room's air between a minimum and a maximum, and usually a reheat coil. A room that needs cooling opens its damper; a room that needs nothing sits at its minimum and, if that minimum is still too much cold air, reheats it. The handler's fan runs at the sum of the boxes, and the deck temperature is reset from the box that needs it coldest.
The reheat is the cost of the arrangement — cold air made by the chiller and warmed again by a coil — and the box minimum is what sets it, which is why minimums matter more than any other number on a VAV floor. HVAC Builder models the boxes on the serve links of a building run: each room's box carries its own load at the deck temperature, the critical-zone reset follows 90.1 §6.5.3.5, and the reheat is booked room by room, electric or hot-water.
Open the builder — the examples in the Design tab's sources list include a machine of this kind, and the Simulate tab runs it against a year of weather.
DOAS — dedicated outside-air system · SZVAV — single-zone variable air volume · Economiser · Waterside economiser · Demand-controlled ventilation · Face-and-bypass · Head-pressure control · Humidity ceiling and floor · Cycling and modulation · Coupling · Priority · Category · Nested system · Design point and TMY year