OutsideAirOptimization is available in the kitControl Energy folder. The OutsideAirOptimization component is used to support applications that need to allow for enthalpy based free cooling.
This object is typically used during occupancy periods.
The freeCooling output is set to false if outside >= inside and set to true if
outside <= inside - (abs) thresholdSpan. You can select temperature or enthalpy comparisons. There is also a low temperature check to protect against freezing.
Setup of the object involves the following properties (also see Example 13), as follows:
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Temperature Facets
This is used to set the units and number precision of the Outside Temp, Inside Temp, and Low Temperature Limit properties.
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Humidity Facets
This is used to set the units and number precision of the Outside Humidity and Inside Humidity properties.
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Outside Temp
Input for the current outside air temperature. This input must be valid for this object to function.
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Outside Humidity
Input for the current outside air humidity. This input must be valid for this object to function.
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Inside Temp
Input for the current inside air temperature. This input must be valid for this object to function.
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Inside Humidity
Input for the current inside air humidity. This input must be valid for this object to function.
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Low Temperature Limit
This property is used to provide freeze protection.
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Outside Enthalpy
This is the calculated outside air enthalpy.
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Outside Enthalpy String
This provides the outside enthalpy value as a string or possible status/error message.
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Inside Enthalpy
This is the calculated inside air enthalpy.
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Inside Enthalpy String
This provides the inside enthalpy value as a string or possible status/error message.
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Free Cooling
This boolean output value is set to the value of the Free Cooling Command when it is determined that free cooling should be used. Otherwise, the value is set to null.
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Current Mode
This indicates what mode this object is currently in.
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Input out of range
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Free Cooling
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No Free Cooling
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Low temperature
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Input error
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Threshold Span
The difference between the inside enthalpy and the outside enthalpy must be greater than this value before free cooling will be enabled.
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Use Enthalpy
Setting this property to true will enable the use of enthalpy for determining if free cooling is available. Otherwise, it will just use outside and inside temperature to decide.
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Free Cooling Command
If it is determined that free cooling is available, this is the boolean value that will be set in the Free Cooling property.
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Use Null Output
If this property is true, then the null flag will also be set on the Free Cooling output when free cooling is NOT available.
Example 13. Using OutsideAirOptimization
An example OutsideAirOptimization component usage is shown in Figure 39.
