Economizer function in A/C units

[delimashare]

Hi
Please I need an explanation on how ECONOMIZERS work to save energy in A/C wall mount units.My second question is how would using an Economizer in A/C unit affect the pressure inside a building?
Thanks

 

[MintJulep]

http://www.bacharach-training.com/norm/econ.htm

 

[ChrisConley]

Economizers use 100% outdoor air, when conditions permit, to provide 'free cooling'.

Depending on the economzier this will create a positive pressure in the building.

 

[nuhvac]

Depending on your controls the economizer will not affect your pressure in the building. If you are mixing return and outside air when cooling is running, and then when the economizer function kicks in (if your controls function this way) the unit should decrease the amount of outside air it is suppling.

 

[Waramanga]

unless your unit is shoving 1000 l/s plus extra into a room your pressure wont do much unless it is exceptionaly well sealed and the fans can pump some kind of pressure

 

[EEJaime]

Most of the systems that our MechNecks specify have a damper system that when it goes to 100% outside air the return becomes 100% exhaust. Pressure is not affected. It saves energy because the compressor is OFF.

 

[KiwiMace]

To add:
Economizers usually work with an enthalpy sensor - comparing the heat energy of the outdoor air with that of the return air, and deciding which airstream uses less energy to cool.

Using temperature alone would not account for energy to remove humidity.

 

[tys90]

Generally, you began economizing below a predetermined outdoor air enthalpy and continue to raise the amount of outdoor air mixed into the system until you are at 100% OA then you begin to reduce it as the enthalpy continues to drop until you reach a point where you being heating and you are back at minimum outdoor air.