Benefits of Fan Powered Terminal Units
Fan powered terminal units can provide performance benefits and increased
flexibility for a wide range of HVAC
applications. Substantial savings in
operating costs may be realized through
efficient recovery of waste heat, enhanced
heating performance and reduced central
system HP for fan powered systems.
Examples of some of the performance
benefits of fan powered units are:
- Heat gain from plenum return reduces
the requirement for reheat;
- Redistributing excess heat from interior
zones to perimeter zones where it is
- Lower minimum air flow rates can
be selected compared to single duct
designs and can be based on ventilation
rate requirements instead of heating
- Increased air motion under low load
- Providing the capability to respond to
a thermostat demand for heat during
periods when the central fan system is
- Eliminating perimeter radiation with the
addition of a reheat coil to the terminal
unit resulting in increased usable floor
Variable Volume/Parallel Flow
Fan Powered Terminal Units
With the variable volume model, the
conditioned primary air does not pass through the fan. The primary air section
and the recirculating fan section operate
independent of each other, except that
both are under control of the same room
thermostat. They are sequenced so that
both sections generally do not operate
at the same time. The primary air section
responds to a demand for cooling, while
the recirculating fan section responds to a
demand for heating.
Benefits of Variable Volume Fan
Powered Terminal Units
The primary air valve is sized for cooling
demand similar to single duct terminal
The recirculating air section is typically
sized at 50% of the maximum primary air
valve demand which results in lower noise,
lower unit cost and reduced energy when
compared to constant volume terminals.
Constant Volume/Series Flow
Fan Powered Terminal Units
With the constant volume model, the
recirculating fan section operates
continuously. All conditioned primary air
passes through the recirculating fan. The
total discharge rate remains constant while
the proportions of cold primary air and warm
recirculated air are varied thermostatically
to satisfy the load. The recirculating fan will
mix the warm air from the ceiling plenum
with the conditioned primary air.
|Benefits of Constant Volume
Fan Powered Terminal Units
- Reductions in air quantities are avoided,
improving the performance of most supply
air diffusers by maintaining constant throws.
- Air motion in the occupied zone remains
constant, avoiding the low air motions
typical of variable volume systems
during periods of low load. Recent
ASHRAE research suggests that low air
motion in combination with higher space
temperatures is the major cause for
complaint in many recently constructed
- Supply air temperature is modified,
preventing over cooling during periods of
- Noise levels are maintained constant, less
objectionable than intermittent noise.
- Compact, durable zinc-coated steel casing
means reduced ceiling plenum space requirements and protection from
- Terminal casing is internally lined with
dual density fiberglass insulation. The insulation's high density skin
provides erosion resistance while effectively attenuating noise. Insulation
meets requirements of UL181 and NFPA-90A.
- Proven reliable primary air section with
heavy gauge damper and low leakage blade seal.
- Electrical components for the fan unit
as well as the pneumatic or electronic control components, are all mounted
on the same side of the housing. This provides for more design flexibility
and reduces design restrictions.
- PRICE terminals come standard with SCR
fan speed control for efficient, quiet adjustment of fan capacity. Electric
motors are specifically designed to operate with SCR controls ensuring
reliable maintenance free operation.
- Fan motor is isolated from the blower
housing to reduce noise.
- Energy efficient, fan motor is designed
to meet consistent torque specifications providing reliable and repeatable
- Large removable bottom access panel provides
access to the interior of the unit for cleaning, inspection and service.
- Electric reheat configuration and discharge
air flow are specifically matched to eliminate element hot spots and
maintain element life.
- Acoustical and flow performance is ARI
certified providing reassurance that design goals will be met and that
Price fan powered terminal units will provide occupant comfort and efficient
- Catalog performance data is the result
of Price laboratory testing done in accordance with industry test standards.
and minimum flows are factory set to reduce field installation costs.
- Fan speed controller, SCR minimum voltage
is factory set to optimize motor bearing life.
- Pneumatic electric switches are factory
set to reduce field installation costs.
- Price offers a variety of control options
to suit the specific demands for each application. Pneumatic, electronic
and digital controls are all available to provide the designer with
a wide choice for innovative and cost effective design solutions.
Price fan powered terminal unit receives a full operational check before
shipment and arrives factory calibrated in accordance with project specifications.
This means costly labor and setup delays are avoided.
- Units are certified in accordance with
the ARI 880 certification program.
- Units are ETL listed to meet UL1995 and
CSA No. 236.