OAFE-2000
IO&M Manual
Paragon Controls Incorporated
1
Revision Level 000
1. INTRODUCTION
1.1. Description
The
OAFE-2000
is a packaged and specifiable outdoor airflow measuring system capable of producing
an overall ±0.5% of reading accuracy and will satisfy LEED, ASHRAE 62.1, ASHRAE 189.1, ASHRAE
170 and California Title 24 requirements for verifying the required ventilation rates or air changes per
hour.
The
OAFE-2000
is designed to tackle the challenges of outside airflow measurement which is often low
velocity, loaded with particulate, and application specific. The packaged system consists of an integral
transmitter and multiple airflow elements, factory mounted and pre-piped in a casing designed for
flanged connection to ductwork, control dampers, louvers, etc. The airflow measurement station is
constructed to comply with ASHRAE Standard 111 for equal area traversing of an airflow measurement
plane.
Utilizing Paragon Controls’ full sheet metal capabilities, the
OAFE-2000
can match up with almost any
new or existing ductwork, hood, or outside air opening for a seamless engineered solution. An optional
inlet bell is available for plenum applications. Application specific materials such as 316 Stainless Steel
are available where salt-air may be a concern.
The integral (Multi-Trans Smart Ecosystem)
MTSE
Transmitter is a flow and pressure transmitter that
has been engineered to provide a cost-effective solution for accurate airflow measurement of up to
three systems; perfect for air handling or rooftop units requiring ventilation rate monitoring at the
outside air intake and supply and return fan/fan array airflow monitoring. The MTSE can connect to
each fan’s existing piezometer-ring airflow sensors or to field installed airflow stations; up to five flow
sensing points. The MTSE can simultaneously measure up to four additional differential pressure
sensing points such as pressure drop across filters or coils, duct static pressure, and plenum pressure.
The total (summed) airflow rate for the individual flow systems differential pressure points is indicated
on a 3.5-inch HMI touch screen.
The total airflow rate of each system is available to the BMS or local controller via dedicated field
selectable 0-10 VDC or 4-20 mA analog outputs and via field selectable BACnet®-MS/TP Master or
Modbus® RTU Slave network communications. Independent flow and pressure values for each of the
nine sensing points is also available to the BMS or local controller via network communication.
1.2. Basic
Operation
The airflow measuring station produces pneumatic output signals referred to as total (high) and static
(low) pressure. These two pressure signals are piped to the MTSE where the static pressure is
subtracted from the total and the result indicated as velocity pressure (differential pressure). This
measured differential pressure is equal to the average velocity of the air stream moving through the
plane that the airflow measuring station is located in. This signal can be converted to air velocity and
flow using the following equations:
a
a
T
460
921
.
29
325
.
1
a
V
P
V
7
.
1096
A
V
Q
Where:
a
Actual density of air, in lb/ft
3
(0.075 lb/ft
3
at sea level and 68°F)
a
T
= Actual temperature, in °F (default value is 68°F)
P
V
= Velocity pressure, in inches H
2
O
V = Velocity, in fpm
Q = Flow, in cfm
A = Area, in ft
2
