Outside Air Optimizer OAO - Economizer Control

The 75F Outside Air Optimizer, OAO is a replacement for existing economizer controls. No longer is your economizer at the mercy of a cooling call. The 75F OAO harnesses the power of your building to make load based decisions on when to bring in outside air. Your building data plus real time data analytics makes this one intelligent economizer. 

The 75F OAO is similar in many respects to a traditional economizer with a few tweaks that make it far superior. 

1. No more relying on an outdoor enthalpy sensor. These sensors are exposed to every extreme weather event and are known to fail prematurely. 75F uses real time weather data averaged from multiple sources in the cloud to deliver a consistent feed for outdoor enthalpy. 
2. Your economizer now has the data of your building to work with. Unlike a traditional economizer that only receives a call for cooling to make decisions. Combined with a zoning system the OAO can make true load based decisions for when and how much to open the economizer.
3.  Use the power of trending data to see that your economizer is working. Traditional economizers do not feed their data to the cloud even if you have a "smart" thermostat installed. With traditional economizers, if they break or stop working, there is nothing but a blinking light inside a sealed RTU to warn you. On top of that the Dx will pick up the slack so you would never notice. Real time trend data alerting makes sure your economizer never has any down time. 

Cooling

When the system requires cooling the OAD will open for two reason. 

1. The RA CO2 level is high. When this is the case the the OA Damper will open 10% for every 100ppm over the threshold (adjustable). 
2. The outdoor enthalpy is lower than the indoor enthalpy. In this case the OA damper will open according to the load in the space. The damper will continue opening further if the load does not decrease or continues increasing. The damper will shut completely if the MAT drops below 44deg. 

Image 1 - Unit in Full economizing mode. 

Image 2 - Unit in full economizing with Dx cooling.

Image 3 - Unit 50% economizing 

Heating

When the system requires heating the OA damper will open for only one reason. 

1. The RA CO2 level is high. When this is the case the the OA Damper will open 10% for every 100ppm over the threshold (adjustable). 

Image 4 - Unit no economizing heat. 

Image 5 - Unit 50% economizing during heating call due to high CO2 Levels. 

Building Pressure

In small buildings the OA damper of an RTU can have a large impact on the building pressure. 75F offers a Differential pressure adder that will factor in the building pressure when opening the OA damper.

Exhaust Fans - If your economizer has a powered exhaust you can use the Exhaust Fan relay on the OAO Smart Node. This relay will energize when the economizer damper position breaches a threshold. The default is 50%. 

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