| 
Outdoor air design condition: 1% dry-bulb/mean coincident
wet-bulb, 1977 ASHRAE Handbook.
EER = (Energy Efficient Ratio) BTU cooling output per watt of electrical input.Comparison
base to conventional system 60° S.A.; 25°delta T.
EUC = energy use comparison to conventional system with an EER of 8.
SA = Supply air temperature leaving I/D unit at 1% design condition.
I/D efficiency: indirect = 60%(DB - WB x .6); direct = 90% (DB -WB x .9).
Note: Sea level psychrometric chart used 5000 ft. elev. will increase S.A. temperature 3
to 4%.
City |
Elev.
Ft. |
(1) O.A.
Design
Temp.
DB/WB |
I/D PERFORMANCE
.733 Watts per CFM(SA) |
|
(2) |
(3)SA |
EER |
EUC |
| Los
Angles |
312 |
93/70 |
79.2/65.8 |
67.1 |
26.4 |
30% |
| San
Francisco |
8 |
82/64 |
71.2/60.2 |
61.3 |
34.9 |
23% |
| Seattle |
14 |
85/68 |
74.8/64.5 |
68.6 |
24.2 |
33% |
| Albuquerque |
5310 |
96/61 |
75.0/52.9 |
55.1 |
44.0 |
18% |
| Denver |
5283 |
93/59 |
72.6/50.5 |
52.7 |
47.6 |
17% |
| Salt
lake city |
4220 |
97/62 |
76.0/54.0 |
56.2 |
42.4 |
19% |
| Phoenix |
1117 |
109/71 |
86.2/64.0 |
66.2 |
27.7 |
29% |
| El
Paso |
3918 |
100/64 |
78.4/57.2 |
59.3 |
37.8 |
21% |
| Santa
Rosa |
167 |
99/68 |
80.4/61.6 |
63.5 |
31.7 |
25% |
| Spokane |
2357 |
93/64 |
75.6/57.8 |
59.6 |
37.4 |
21% |
| Boise |
2842 |
96/65 |
77.4/58.5 |
60.4 |
36.2 |
22% |
| Billings |
3567 |
94/64 |
76.0/57.5 |
59.4 |
37.7 |
21% |
| Portland,
Or. |
57 |
90/68 |
76.8/63.5 |
64.8 |
29.7 |
27% |
| Sacramento |
17 |
101/70 |
82.4/64.0 |
65.8 |
28.3 |
28% |
| Fresno |
326 |
102/70 |
82.8/63.8 |
65.7 |
28.4 |
28% |
| Austin |
597 |
100/74 |
84.4/69.5 |
71.0 |
20.6 |
39%
|
The
VARI - COOL Modular I/D System
 |
Screened intake cowl |
 |
Indirect evaporative cooler |
 |
Damper section (optional) |
 |
Return air connection & damper
sections (optional) |
 |
Filter
section (optional) |
 |
Direct evaporative cooler |
 |
Supply air fan section (optional) |
 |
Conventional heating section, hot
water coil, etc. (optional) |
 |
Supply Air |
 |
Secondary fan & plenum |
 |
Conventional chilled water or
direct expansion cooling coil (optional) |
The VARI-COOL modular equipment design consists of matching
components to provide single I/D two and three stage system from 2000 CFM to 8000 CFM of
supply air (nominal capacity of 4 to 20 tons). These systems allow the design engineer
many selection options to tailor the equipment to meet desired criteria. In addition,
factory assembled parallel units can be selected to provide single station units to
nominal 20,000 CFM.
The Indirect Unit
The modular 60 series indirect unit is available in seven
nominal sizes in 1000 CFM increments; the model 2S (2000 CFM) to the model 8S (8000 CFM).
The indirect unit includes the water pump and accessories, factory mounted float valve,
water distribution and filtering system, water make-up, drain and overflow fittings. The
water bleed assembly is piped to the overflow fitting. Duct connections are provided on
the inlet and outlet of the primary (dry) side an d secondary (wet) sides.
The nominal heat exchange efficiency (sensible cooling) at
1000 CFM per core primary air and 800 CFM per core secondary air is 60% of the wet bulb
depression.
The Direct Unit
The direct unit is furnished in six
matching sizes to the indirect unit. As with the indirect unit they are in 1000 CFM
increments. Sizing is from 2000 CFM to 8000 CFM. The duct connections match the equivalent
size indirect unit. The cabinetry construction and corrosion resistant protective coating
are to the same specification and high standards of the indirect unit. |
