De-Humidifier in ACRP Units

BillP · ‎2021-06-26

Dear Folks,

A very simple question. Does apc ACRP's units have "DE-HUMIDIFIER" in it??? As I know ACRP units have 'Electric Rehaeat' and 'Humidifier' in it but does they have a "Dehumidifer"???

Because I read dehumidification rates in ACRP catalog but I have heard many times that it doesn't have this tool. We have to buy a third party dehumidifier for DC.

BillP · ‎2021-06-26

Hello Warifir,

The InRow RP does support Dehumidification Control. However, there is no dehumidifier. I have elaborated on how this feature works below.

Since humidity control is based on the return air dewpoint. Dehumidification is under discrete control (a unit’s dehumidification output is either 0% or 100%). A unit enters dehumidification when the dewpoint rises above the dehumidification setpoint plus dead band. The cooling demand must be satisfied and the fan speed must be below 80% to provide headroom for cooling. When dehumidification is active the fan speed is constant at 40%. The unit leaves dehumidification if the dewpoint drop below the dehumidification setpoint - the maximum rack inlet temperature rises excessively (In-Row mode), or the return air temperature rises excessively (RACS or HACS mode).

Reheat is used during dehumidification (CW and DX) to increase the unit’s ability to dehumidify.

Dehumidification – heat assist function disabled ... The supply temperature controller setpoint is reduced to 62°F or the supply air dewpoint + 3.6°F, whichever is higher.

Dehumidification – heat assist function enabled ... Reheat output is gradually increased until the supply temperature controller is near its maximum output. As more heat is added, the supply temperature controller will compensate by opening the valve (RP-CW) or increasing the compressor speed (RP-DX) in order to maintain the supply temperature setpoint configuration setting. This results in the air temperature leaving the coil being as cold as possible while still maintaining the unit’s supply temperature at the supply temperature setpoint setting. Reheat output is gradually decreased if the supply temperature controller‘s output gets to close to it’s maximum.

See Answer In Context

BillP · ‎2021-06-26

Hello Warifir,

The InRow RP does support Dehumidification Control. However, there is no dehumidifier. I have elaborated on how this feature works below.

Since humidity control is based on the return air dewpoint. Dehumidification is under discrete control (a unit’s dehumidification output is either 0% or 100%). A unit enters dehumidification when the dewpoint rises above the dehumidification setpoint plus dead band. The cooling demand must be satisfied and the fan speed must be below 80% to provide headroom for cooling. When dehumidification is active the fan speed is constant at 40%. The unit leaves dehumidification if the dewpoint drop below the dehumidification setpoint - the maximum rack inlet temperature rises excessively (In-Row mode), or the return air temperature rises excessively (RACS or HACS mode).

Reheat is used during dehumidification (CW and DX) to increase the unit’s ability to dehumidify.

Dehumidification – heat assist function disabled ... The supply temperature controller setpoint is reduced to 62°F or the supply air dewpoint + 3.6°F, whichever is higher.

Dehumidification – heat assist function enabled ... Reheat output is gradually increased until the supply temperature controller is near its maximum output. As more heat is added, the supply temperature controller will compensate by opening the valve (RP-CW) or increasing the compressor speed (RP-DX) in order to maintain the supply temperature setpoint configuration setting. This results in the air temperature leaving the coil being as cold as possible while still maintaining the unit’s supply temperature at the supply temperature setpoint setting. Reheat output is gradually decreased if the supply temperature controller‘s output gets to close to it’s maximum.