Catalogue

14 UV-PRC003-EN
Application Considerations
load of the classroom, the equipment operates at an optimum speed, keeping sound levels to a
minimum. Another solution for acoustically sensitive application is the option for “Low Acoustics,”
which uses the ECM technology to manage the fan speeds. However, if the room temperature rises
above the setpoint, the controller will switch to high speed for sustaining the space needs. As part
of this strategy, ventilation must also be considered. The Tracer UC400 controller will reposition
the outside air damper to confirm the minimum outside air cfm is met at both operating conditions.
This setup allows the unit ventilator to meet the space comfort condition, while providing a lower
sound level and proper ventilation.
Ventilation for Acceptable IAQ
Supplying proper ventilation to a classroom is challenging. The various rooms that make up a
school are forever changing in their proper ventilation needs. Building occupants and their
activities generate pollutants that heighten the ventilation requirements. And because of this
intermittent occupancy, the ventilation frequency of a classroom is constantly on the move.
Ventilation systems dilute and remove indoor contaminants, while mechanical heating and cooling
systems control the indoor temperature and humidity. Supplying an adequate amount of fresh air
to an occupied classroom is necessary for good indoor air quality. IAQ should be considered a top
priority in the school environment because children are still developing physically and are more
likely to suffer the consequences of indoor pollutants. For this reason, air quality in schools is of
particular concern. Proper conditioning of the indoor air is more than a quality issue; it
encompasses the safety and stewardship of our investment in the students, staff and facility.The
beauty of a classroom unit ventilator is its ability to provide heating, cooling, ventilation and
dehumidification as a single-zone system.
ASHRAE Control Cycles
There is a variety of control systems available today in unit ventilators. The exact method of
controlling the amount of outside air and heating capacity can vary. However, all systems provide
a sequence of operation designed to provide rapid classroom warm-up and increasing amount of
ventilation air to offset classroom load.
To help supply proper ventilation to these fluctuating heat gains, the Trane unit ventilator is
designed to provide rapid classroom warm-up and increasing amounts of ventilation air to offset
classroom overheating.
Figure 9. Equipment placement
Ventilation
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