For our friends down under...

20 TAS=(110-32)/1.8'spec outdoor temp (C)
30 RHS=10'spec outdoor RH (%)
40 DTS=32/1.8'spec temp diff (C)
50 PAO=RHS/100*EXP(18.761-5248/(273+TAS))'spec outdoor vapor pressure (kPa)
60 PWO=EXP(18.761-5248/(273+(TAS-DTS)))'spec cooler vapor pressure (kPa)
70 CS=2000/2119'spec airflow (m^3/s)
80 QS=1200*CS*DTS'spec cooling power (watts)
90 PS=QS/2450000!'spec water evaporation rate (kg/s)
100 WO=.62198/(101.325/PAO-1)'spec outdoor humidity ratio
110 TI=(80-32)/1.8'indoor temp setpoint (C)
120 PWI=EXP(18.761-5248/(273+TI))'indoor cooler vapor pressure (kPa)
130 WI=.012'indoor humidity ratio setpoint
140 PAI=101.325/(1+.62198/WI)'cooler air vapor pressure (kPa)
150 P=PS*(PWI-PAI)/(PWO-PAO)'indoor water evaporation rate (kg/s)
160 C=P/(1.2*(WI-WO))'outdoor airflow with remote exhaust (m^3/s)
170 TA=(90-32)/1.8'outdoor temp (C)
180 Q=2450000!*P-1200*(TA-TI)*C'sensible cooling with Ta (C) (watts)
190 PRINT C,P,Q

ext airflow water flow cooling
(m^3/s) (kg/s) (watts)

.6835968 5.391054E-03 8650.772

With an 8651/420 = 20.6 COP and a 70.3 EER. I'd skip the special box and
put the cooler near a window with a 1-way plastic film intake damper, with
the exhaust fan and its film damper on the other side of the room. The box
only adds capacity vs efficiency.

Nick