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Dear Forum, One of my commissioning projects uses an enthalpy wheel on several AHUs. These AHUs have a bypass for the wheel or just shut the wheel off when conditions are more favorable to use straight outdoor air (or a mix of OA and return air.)

The sequence of operation mentions the bypass, but doesn't describe how it becomes active. I have not previously thought about the best control scheme for de-energizing the wheel or bypassing, so I'm reaching out to folk who may have thought it over .... (or tested it in a model)

I have some manufacturer literature which suggests a dry bulb economizer-like changeover. I've done a mockup in Excel using TMY weather data and a DB-based changeover looks sloppy compared to a logic-based approach - but I may be missing something.

Can you share any insights?

Dear Forum, One of my commissioning projects uses an enthalpy wheel on several AHUs. These AHUs have a bypass for the wheel or just shut the wheel off when conditions are more favorable to use straight outdoor air (or a mix of OA and return air.)

The sequence of operation mentions the bypass, but doesn't describe how it becomes active. I have not previously thought about the best control scheme for de-energizing the wheel or bypassing, so I'm reaching out to folk who may have thought it over .... (or tested it in a model)

I have some manufacturer literature which suggests a dry bulb economizer-like changeover. I've done a mockup in Excel using TMY weather data and a DB-based changeover looks sloppy compared to a logic-based approach - but I may be missing something.

Can you share any insights?

Dear Forum, One of my commissioning projects uses an enthalpy wheel on several AHUs. These AHUs have a bypass for the wheel or just shut the wheel off when conditions are more favorable to use straight outdoor air (or a mix of OA and return air.)

The sequence of operation mentions the bypass, but doesn't describe how it becomes active. I have not previously thought about the best control scheme for de-energizing the wheel or bypassing, so I'm reaching out to folk who may have thought it over .... (or tested it in a model)

I have some manufacturer literature which suggests a dry bulb economizer-like changeover. I've done a mockup in Excel using TMY weather data and a DB-based changeover looks sloppy compared to a logic-based approach - but I may be missing something.

Can you share any insights?

Dear Forum, One of my commissioning projects uses an enthalpy wheel on several AHUs. These AHUs have a bypass for the wheel or just shut the wheel off when conditions are more favorable to use straight outdoor air (or a mix of OA and return air.)

The sequence of operation mentions the bypass, but doesn't describe how it becomes active. I have not previously thought about the best control scheme for de-energizing the wheel or bypassing, so I'm reaching out to folk who may have thought it over .... over... (or tested it in a model)

I have some manufacturer literature which suggests a dry bulb economizer-like changeover. I've done a mockup in Excel using TMY weather data and a DB-based changeover looks sloppy compared to a logic-based approach - but I may be missing something.

Can you share any insights?

One of my commissioning projects uses an enthalpy wheel on several AHUs. These AHUs have a bypass for the wheel or just shut the wheel off when conditions are more favorable to use straight outdoor air (or a mix of OA and return air.)

The sequence of operation mentions the bypass, but doesn't describe how it becomes active. I have not previously thought about the best control scheme for de-energizing the wheel or bypassing, so I'm reaching out to folk who may have thought it over... (or tested it in a model)

I have some manufacturer literature which suggests a dry bulb economizer-like changeover. I've done a mockup in Excel using TMY weather data and a DB-based changeover looks sloppy compared to a logic-based approach - but I may be missing something.

Can you share any insights?