Basic Calculations
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Transcript of Basic Calculations
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Air Change Method
To choose the right size Evaporative Cooler for your place, you need to determine the air volume in the bulding orhow many cubic feet of air per minute (CFM) required:
Find the total volume of the space to be cooled:
V = L x W x H (1 cubic meter = 35.315 cubic feet)Note: In work spaces with high ceilings, consider only the worker environs, normally up to 3.5 or 4.0 meter above the floor (If large volumes of space are occupied by machinery or stored goodes, these volumes need not be included).Determine the required cubic feet of air per minute (CFM) by multiply the volume in cubic feet by theappropriate Air Changes Frequency Factor:
Required CFM = Building Volume (ft³) X Air Changes Frequency FactorConsulate local cods for air change requirements or in absence of code refer to the next list.
Air Quality Method
REMEMBER: Arrange for Exhausting System, fans or openings. Exhausting the air on at least 90% of the Cooler's rate is very important to get a proper cooling.
Other Calculations Methods
Normal Place
Hot workhouse
Hot and smelly workhouse
Frequency Factor
0.5
BASIC CALCULATIONS
CFM = People x Outdoor Air Requirement (CFM/person)
When temperature of area is higher than the ambient outdoor temperature, general ventilation may beutilized to provide "free cooling". Knowing the desired indoor and design outdoor dry bulb temperatures,and the amount of heat removal required (BTU/Hr):
CFM = Heat Removal (BTU/Hr) / ( 1.10 x Temperature difference )
Determine number of people occupying the respective building spaces. Find CFM/person requirements inVentilation Rates for Acceptable Indoor Air Quality. Calculate required outdoor air volume as follows:
People = Occupancy/1000 x Floor Area (ft²)
Heat Removal Method
Suggested Air Changes Frequency Factor
Select from the Engineering Data page the nearest Unit size that deliver's the required CFM.
NOTE: This sizing method can be used for general sizing only. Use more accurate methods for more appropriate sizing. For the indirect/direct ducted systems refer to the Certified Air Delivery at Various External Static Pressures schedule and select the proper Unit size that deliver's the required CFM at the calculated static pressure of your duct system.
Spinnery, electric, machine
Dying, plastic, shoes, print, metallurgy
Office, resturant, hospital, station
hall, shopping mall, bazaar 0.50 - 0.75
0.75 - 1.0
1.0
Normal Place
People gathering places
Example
5.03 5.14 5.25 5.36 5.4845 4.47 4.58 4.69 4.8 4.924.37 4.47 4.57 4.67 4.77 4.87
3.91 4 4.08 4.17 4.2640 3.97 4.07 4.17 4.2735 3.48 3.56 3.65 3.74 3.82
3.28 3.35 3.43 3.5 3.58 3.652.79 2.86 2.92 2.98 3.04
30 2.98 3.05 3.13 3.225 2.48 2.55 2.61 2.67 2.73
2.19 2.23 2.28 2.33 2.38 2.431.68 1.71 1.75 1.79 1.83
20 1.99 2.04 2.09 2.1415 1.49 1.53 1.56 1.6 1.64
1.09 1.12 1.14 1.17 1.19 1.220.56 0.57 0.58 0.6 0.61
10 0.99 1.02 1.04 1.07
0.92 0.94 0.96 0.985 0.5 0.51 0.52 0.53 0.55
99%
EVAPORATION RATE
Wbd(f)Gallons Per Hour evaporated per 1000 CFM with a Saturation Efficiency of:
0.8 0.82 0.84 0.86 0.88 0.9
700 55% 69% 79% 91% 94%
99%600 57% 70% 80% 91% 95% 99%500 59% 72% 82% 92% 96%
99%400 62% 77% 85% 94% 97% 99%300 67% 81% 88% 96% 98%
12" 16" 24"200 71% 86% 91% 98% 99% 99%
Dry Cleaners 30 30Adapted from ASHRAE Standard 62-1989 "Ventilation for Acceptable Indoor Air quality"
MEDIA EFFICIENCY
Air Face Velocity (fpm)Media Efficiency Percent
4" 6" 8"
Ballrooms / Wedding Halls 25 100Hospital Operating Rooms 30 20
Beauty Shops 25 25Game Rooms 25 70
Conference Rooms 20 50Hospital Patient Rooms 25 10
Laboratories 20 30Restaurant Dining Area 20 70
Auditoriums, Sporting Spectator Areas, Theaters 15 150Office Spaces 20 7
Retail Facilities, Libraries, Dormitory Sleeping Rooms, Pharmacies 15 20Classrooms 15 50
Supermarkets, Hardware Stores 15 8Photo Studios 15 10
BASIC CALCULATIONS
Ventilation Rates for Acceptable Indoor Air Quality
AreaAir Requied Occupancy
CFM/person person/1000 ft²
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Du
280 kg
Operation Mass 460 kg
Air outlet size 800x800 mm
Unit Dimensions 2300x1400x1530 mm
4- Fan is 25x25 Inch, heavy-duty centrifugal type, made of hot-dipheavy gauge galvanized steel, Accurately balanced, with a solidstrong shaft, and a heavy-duty cast iron pillow block Bearings.Water inlet 1/2 Inch
Noise ≤ 72 dB ≤ 75 dB 5- Evaporative Media is made of specially corrugated cellulosematerial with high cooling efficiency and long life, speciallydesigned to minimize scaling and colgging of the inlet fromatmospheric dust, the total thickness of the media is 20 cm.The dimensions of the Media are properly selected to maintainan Air Face Velocity less than 2.6 m/s (500 fpm).
Shipping Mass
Motor Current 22.4/13.2 A 22.4/13.2 A
Pump Current 1.0 Amps
Water Reservoir 2 x 100 Liter
2- Motor is continues duty 5 HP, 220/380 V, 3-Phase, 1-Speed,Frame 184 T, Enclosure ODP, Insulation Class B, Rating 40degree C ambient condition, with auto reset overload protection.
Airflow 16500 CFM28000 m³/h
18500 CFM31400 m³/h
Suitable area 240 m² 260 m² 3- Water Pump is selected to insure the delivery of 1.5 gallons perminute of water per square foot of horizontal (top) pad surfacearea for proper wetting, with Flow Rate 2800 L/H At 2.8 m Head(10.2 GPM At 9' Head), with auto reset overload protection.
TECHNICAL DATA Technical specifications:
Model AJ-1605C AJ-1875C 1- Cooler body made of hot-dip galvanized steel 1.2 mm thicknessfor a strong structure, long life & durability.Power 5 HP 7.5 HP
CENTRAL EVAPORATIVE COOLER - 5 / 7.5 HP
New futuresNO more rust & corrosion ..New plastic inner frame is wholly casing the wet mediaand will avoid any contacts between the water and theUnit metallic body.Low cost media replacement ..New split layer ( 2 cm-thik ) protects the cooling mediafrom salts & dust, this thin layer only shall be replaced,which cost's so less.NO more dust ..New added aluminum filters prevent dust to get insidethe Unit, this protect the cooling media and the cooledarea from dust. This is offered as an option.