Attributes (Heat Recovery Enthalpy Suitability Determination) - Johnson Controls - Metasys - LIT-12011147 - Software Application - Controller Configuration Tool - 16.0

Controller Tool Help

Brand
Johnson Controls
Metasys
Product name
Controller Configuration Tool
Document type
User Guide
Document number
LIT-12011147
Version
16.0
Revision date
2023-10-02
Language
English

The following table describes the attributes used by the Heat Recovery Enthalpy Suitability Determination modules.

Table 1. Heat Recovery Enthalpy Suitability Determination Attributes

Name

Type 1

Description

Default Value

Deadband

 

Provides an input to make sure the return air and outdoor air conditions are different so that heat recovery operations are possible.

5 °C, 10 °F

Elevation

 

Indicates the distance above or below sea level and is used for psychrometric calculations.

0 ft, 0 m

Display Precision: 1s

Exhaust Air Temperature

 

Exhaust air temperature.

25 °C, 77 °F

Heat Recovery Diff

 

Heat recovery temperature suitability differential. Once heat recovery is suitable, the difference between Exhaust Air Temperature and OA Temperature must decrease by the Heat Recovery Diff value below the setpoint to make heat recovery unsuitable.

1 °C, 2 °F

Heat Recovery isAllowed

 

Contains a network input that can be used to make heat recovery suitable or not suitable. True means heat recovery may be suitable and False means not suitable.

True

HR-AVAILABLE (Heat Recovery Suitability)

G, V

Used to determine whether the heat recovery is used for cooling control or heating control, or if the heat recovery is unsuitable for either control.

Set Name: AHU HR Suit

HRT-SP (Heat Recovery Setpoint)

 

Contains the heat recovery temperature suitability setpoint. If the OA Temperature minus the Exhaust Air Temperature is greater than the Setpoint, Heat Recovery is suitable for cooling. If the Exhaust Air Temperature minus the OA Temperature is greater than the Setpoint, Heat Recovery is suitable for heating; otherwise, heat recovery is not suitable.

6 °C, 11 °F

Low Limit Process Variable

 

Contains the low limit process variable that may be the glycol temperature in a glycol loop or the exhaust air leaving air temperature for an enthalpy wheel. The low limit process variable must be reliable for heat recovery to be suitable.

7 °C, 45 °F

OA Humidity

 

Indicates the outdoor air humidity.

45.0% RH

OA Temperature

 

Contains the outdoor air temperature. If the temperature difference between the exhaust air temperature and the outdoor air temperature is large enough, heat recovery may be suitable.

25 °C, 77 °F

Return Air Humidity

 

Indicates the return air humidity.

30.0% RH

Return Air Temperature

 

Return air temperature.

25 °C, 77 °F

Supply Fan Status

 

Indicates the operating status of the AHU supply fan, where Running equals True and Off equals False.

True

Unit Set

 

Indicates the units of measurement used at the site.

SI, IP

Set Name: Unit Set

1 C - Configuration Mode Only, G - Default Element (Generated State, if applicable), SC - Simulation and Commissioning Modes Only, V - Calculated Value (Outputs)