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Latent heat ,coil sizing, wheel Vs reheat

Latent heat ,coil sizing, wheel Vs reheat

Latent heat ,coil sizing, wheel Vs reheat

(OP)
Dear gents,

I have unsuccessfully posted this topic few minutes ago so apology if a topic with the same subject shows up twice.

I would like to know if the latent heat load is always taken into account when sizing a cooling coil.
I am talking about situation where a cooling below dew point followed by the reheat is required in order to get the required relative humidity and dry bulb temperature.

Another question..
Why the typical system that does the above is usually set  as: cooling below DP + reheat.  Would it not be more economically viable to dehumidify first ( i.e. with desiccant wheel)  and then to cool the air but this time ( as humidity ratio is lower ) the desired relative humidity will be reached before the dew point is hit.
This would eliminate the need for reheat coil and condensate pipework.
Does the desiccant wheel work with large air volumes ( 500-600 AcH/Hr)?

Many Thanks

RE: Latent heat ,coil sizing, wheel Vs reheat

Manufacturer's data includes latent load.

If cooling below dew point is required then latent load must be taken into account.

Desecants are economical only in over saturated or high RH flows.

If the desired RH was reached (and final absolute moisture content) with the desecant only, there is no need for the cooling/reheat you will only need cooling XOR reheat depending on the final temperature.

It is only prudent not to save on reheat and condensate pipework unless you are absolutely sure that the desired conditions are met by the use of diseccant only in all wheather all year round conditions.



 

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