Ask Rick: Should I use a bypass damper on an Energy Recovery Wheel?

Q.  Should I use a bypass damper on an Energy Recovery Wheel?

A.  We typically use a bypass damper around a energy recovery device for frost control and economizer.  That is typical for Heat Pipes and plate exchangers.  In the case of an Energy Recovery Wheel we typically slow the wheel down to minimum speeds to allow for both frost control and economizer.

Bypassing the wheel in economizer would be less pressure drop and could create savings.  The problem is that the unit casing has to grow to accomplish this.  After careful study we have found that it is not cost effective to make the Energy Recovery Unit casing larger just to install a bypass for the wheel.