DX PAU & Air-cooled condensing unit

[watana]

would seek for help of how to design an appropriate A/C system for DX PAU & Aic-cooled condensing unit, air flow rate: 920L/s and on-coil 33C/65%rh max to 18C/65%rh min. supply air temp at 18C.

[Lc_shi]

what's PAU?

[Snowman123]

Might mean packaged airhandling unit ????????

[watana]

it means primary air handling unit(fresh air handling unit), the cooling capacity is 15 R.T.

[Lc_shi]

OK. Understand.
you can apply DX coil or water coil to deal with the fresh air and you'd better use heat recovery tech to save energy.
May you sepecify:
OA (temp and humidity)
SA (temp and humidity)
RA (same as above)
the ratio of fresh air etc.

i'd like to offer my suggestions

rgds
lichuan

[abbasi]

CFM = 1980
Capacity = 15TR
Entering (DB/WB) = 91.4/81.3 (Fahrenheit) 65% RH
Leaving (DB/WB) = 64.4/57.35 (Fahrenheit) 65% RH

I am sorry nobody can design DX coil on these parameters as critical point cant be achieved however if leaving conditions are changed
Say
Amended Data
CFM = 1980
Capacity = 15TR
Entering (DB/WB) = 91.4/81.3 (Fahrenheit)
Leaving (DB/WB) = 58/57.35 (Fahrenheit)


Then DX coil data will be

5.57 Sq. ft, 8 rows (@350 FPM)

I do a lot of designing for these DX coils and AHU’s and find it difficult to understand how u can get 65% RH at leaving conditions

[frank]

I do a lot of designing for these DX coils and AHU’s and find it difficult to understand how u can get 65% RH at leaving conditions

Hi Abbasi

Perhaps he's looking for the DX coil for temperature control and then a humidifier to raise the RH back up