Here ya go:
SYSTEM Type = UVT
SYSTEM Type = UVT
Unit Ventilator
This simulation is for a unit ventilator serving one zone. Therefore,
entering multiple zones assigned to one system is simulated as a zonal
system with one unit ventilator in each zone. This unit was used almost
entirely in school classrooms prior to the accepted practice of air
conditioning schools. The transition to air conditioning was made by adding
a cooling coil; however, this type of unit ventilator with a cooling coil is
not available. (Use SZRH or PSZ serving multiple zones of similar use for
this application.) The unit consists of an economizer damper, air filter,
fan and heating coil which may be hot-water, steam, electric coil or
furnace. Fin tube radiation is often installed on each side of the unit
ventilator to blanket the windows with warm air. The radiation is usually
controlled using an outdoor reset and is operative nights and weekends to
hold minimum night temperatures. Optionally, the radiation may be
thermostatically controlled, riding in parallel with the unit heating coil
even when the fan is on.
Figure 67 Unit ventilator
Other names and/or applications for UVT
The UVT system is seldom applied for applications other than schools. Also
note that the HVSYS system is a central ventilation system that is also a
school system.
Standard Temperature Controls
The unit ventilator control is nearly the same as that for large systems. On
a rise of temperature in the classroom, the heating coil modulates closed
but only to the point that the supply air temperature does not fall below
the minimum of approximately 55F. On a further rise of space temperature the
economizer modulates to full open with a limit of 80F to 90F, at which point
the outside damper returns to its minimum position. The outside air damper
is closed, whenever the fan is off, on nights and weekends. In very cold
climates the fan cycles on to hold the night setback; however, the fin tube
radiation normally is sufficient for this purpose.
------------------------------
Subtopic help for this Topic:
Input template for a standard UVT unit
Covered in detail by separate Topics are the
following:
