Economizer Operation; Temperature Comparison Economizer (Default); Temperature Comparison With Oa Enthalpy Setpoint Economizer (Optional); Temperature Comparison With Enthalpy Comparison Economizer (Optional) - Daikin MicroTech Operation And Maintenance

Unit ventilator controls for applied classroom unit ventilators
Table of Contents

Advertisement

Economizer Operation

The economizer function is used by the UVC to determine if
the OA is adequate for economizer (primary) cooling. When
both the economizer and mechanical cooling are available,
the economizer is used as primary cooling and the UVC adds
mechanical cooling only if the economizer is not adequate to
meet the current cooling load (e.g., the OA damper reaches
100% and cooling is still required).
The UVC supports three economizer functions:
• Basic (default)—Temperature Comparison Economizer
• Expanded (optional)—Temperature Comparison with OA
Enthalpy Setpoint Economizer
• Leading Edge (optional)—Temperature Comparison with
Enthalpy Comparison Economizer
Temperature Comparison Economizer
(default)
If the default Basic economizer function is selected, the unit
ventilator ships with an optional IA and OA humidity sensors.
In this case, the UVC is factory set for the Basic Economizer
Strategy—the UVC automatically detects that no OA humidity
sensor is present and adjusts to use the Temperature
Comparison Economizer function.
Table 19: Economizer Enable/Disable Tests Defined
Economizer Enable/
Tests
Disable Tests
A
OA temp setpoint
B
IA/OA differential temp
C
OA enthalpy setpoint
IA/OA differential
D
enthalpy
Table 20: How Economizer Enable/Disable Tests are Selected
Economizer
Control Temp Sensor
Strategy
Unreliable
All
Ignored
Reliable
Basic
Reliable
Expanded
Reliable
Reliable
Reliable
Leading Edge
Reliable
Reliable
NOTE: The hard-wired sensor and the equivalent input must both be unreliable for the value to be considered unreliable.
OM 1280-2 • MICROTECH UNIT CONTROLLER
Enable Test
Effective OA Temp < (Econ OA Temp Setpt – Econ Temp Diff)
Effective OA Temp = < (Effective Space Temp - EconOASetpt)
Effective OA Enthalpy = < (Econ OA Enthalpy Setpt – Econ Enthalpy Diff)
Effective OA Enthalpy < (Effective Space Enthalpy – Econ Enthalpy Diff)
OA Temp Sensor
Ignored
Unreliable
Reliable
Reliable
Reliable
Reliable
Reliable
Reliable
Reliable
Temperature Comparison with OA
Enthalpy Setpoint Economizer (optional)
If the optional Expanded economizer function is selected, the
unit ventilator ships with an optional OA humidity sensor, which
is used along with the OA temperature sensor to calculate OA
enthalpy. In this case, the UVC is configured for the Expanded
Economizer Strategy and uses the Temperature Comparison
with OA Enthalpy Setpoint Economizer function. Refer to
19
and
Table
20.
NOTE: Temperature Comparison with OA Enthalpy Setpoint
Economizer requires an optional OA humidity sensor.
Temperature Comparison with Enthalpy
Comparison Economizer (optional)
If the optional Leading Edge economizer function is selected, the
unit ventilator ships with an optional IA humidity and OA humidity
sensor, which are used along with the IA temperature and OA
temperature sensors to calculate IA enthalpy and OA enthalpy. In
this case, the UVC is factory set for the Leading Edge Economizer
Strategy and uses the Temperature Comparison with Enthalpy
Comparison Economizer function. Refer to
20.
NOTE: Temperature Comparison with Enthalpy Comparison
requires both an optional OA humidity sensor and an
optional IA humidity sensor.
Space Humidity Sensor
OA Humidity Sensor
Ignored
Ignored
Ignored
Ignored
Ignored
Reliable
Reliable
Unreliable
Unreliable
36
Description of Operation
Table 19
Disable Test
Effective OA Temp >= Econ OA Temp Setpt
Effective OA Temp > (Effective Space Temp –
EconOASetpt - EconDBDiff)
Effective OA Enthalpy >= Econ OA Enthalpy Setpt
Effective OA Enthalpy >= Effective Space Enthalpy
Economizer Enable/
Disable Tests
Ignored
OA damper closed
Ignored
OA damper closed
Unreliable
Test B
Reliable
Test C
Reliable
Test C and Either Test B or Test A
Reliable
Test D and Test B
Unreliable
Test B
Unreliable
Test B
Unreliable
Test B
www.DaikinApplied.com
Table
and
Table

Hide quick links:

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the MicroTech and is the answer not in the manual?

Questions and answers

Table of Contents

Save PDF