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# Revision history [back]

### Modify effectiveness in rotational HeatExchanger:AirToAir:SensibleAndLatent

I have a project where I would like to change the effectiveness of my heat wheel. I am using Supply Air Outlet Temperature Control and in summer months when the outdoor temperature rises the effectiveness of the wheel drops ( in reality the RPM of the wheel would be changed to reduce effectiveness and thus provide lower temperature) I need some help with two problems: 1) How to change the effectiveness as the rotational speed changes. 2) For a given rotational speed, how to make the effectiveness a parabolic, rather than a (presumably) linear, function of airflow.

Can I access the rpm as a variable controllable by EMS ? ( how ? in that case) Can I change the effectiveness as a function of airflows in stead of defining effectiveness at 100 and 75 % airflow rates( on my experience the effectiveness is not a linear function) thanks for any help!

 2 retagged Aaron Boranian 12565 ●49 ●20 http://bigladdersoftware.com/

### Modify effectiveness in rotational HeatExchanger:AirToAir:SensibleAndLatent

I have a project where I would like to change the effectiveness of my heat wheel. I am using Supply Air Outlet Temperature Control and in summer months when the outdoor temperature rises the effectiveness of the wheel drops ( in reality the RPM of the wheel would be changed to reduce effectiveness and thus provide lower temperature) I need some help with two problems: 1) How to change the effectiveness as the rotational speed changes. 2) For a given rotational speed, how to make the effectiveness a parabolic, rather than a (presumably) linear, function of airflow.

Can I access the rpm as a variable controllable by EMS ? ( how ? in that case) Can I change the effectiveness as a function of airflows in stead of defining effectiveness at 100 and 75 % airflow rates( on my experience the effectiveness is not a linear function) thanks for any help!