RESIDENTIAL EVAPORATIVE
COOLING
 Team 11
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Joe Campbell
Matt Doiron
Adam Dowling
Ewan Fraser
Steve Seeley
 Supervisor, Client
– Dr. Basu
DESIGN CONDITIONS
 Problem
– Design & construct a residential
evaporative cooling device
 Performance
– Max operating Temp 35°C
– Max ΔT = 5 – 6 °C
BACKGROUND + THEORY
 As water evaporates it absorbs energy from
the surroundings
 Nozzles 
Surface Area
Cooling
DESIGN GOALS
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Environmentally Friendly
Compact & Light weight
Simple Design
Easy to Operate & Maintain
Quiet
Safe
Reliable
How It Works
Construction
 Frame
– 1-1/4” Angled Aluminum
– 1/4 “ Plate
– Mounting for Fan,
Nozzles, Pump and
Reservoir
Construction
 Chamber
– Polystyrene (0.06 in)
– Allows for most water to
be contained within
device
– Water-tight
– Allows for mounting of
Nozzles, Reservoir, and
Louvres
– Mounts directly to Fan
Construction
 Louvers
– Aluminum sheet metal
– Removes majority of
water droplets leaving
the system
– Mounts directly inside
the chamber
Construction
 Reservoir
– Polystyrene pieces
– Water-tight
– Acts as a catch for
excess water in the
system and containment
for our feed water
– Mechanical water level
control
Construction
 Water System
– 1.5 gpm 1300 psi
Pressure Washer
– High pressure hosing
and fittings
– High pressure nozzles
– Water enters reservoir,
is pumped through
nozzles and excess
water collects in
reservoir
Construction
 Completed Cooler
Testing
 Wet and dry bulb
temperatures
 Air velocity leaving
device
 Flow of water through
pump
 Electrical load of fan
and pump
Results for Water Evaporation Test
Average values of
Water Evaporation
Directly in front of outlet
5 ft from outlet
10 ft from outlet
38 ft from outlet
9 ft from inlet
(30 minutes after running)
Initial
Temperature
Trial 1
Trial 2
Wet Bulb Dry Bulb
Relative
Water
Energy required to
Specific
Tons of
Temp
Temp
Humdiity evaporated
evaporate water
Humidity (ω1)
Cooling
(°C)
(°C)
(Φ)
(kg/min)
(kW)
13.83
15.50
0.0091283
84.31%
0.18
6.80
1.93
15.17
15.25
0.0102792
96.24%
0.25
9.49
2.70
15.67
15.92
0.0109454
97.39%
0.29
11.04
3.14
16.50
16.67
0.0116442
98.35%
0.34
12.67
3.60
16.00
20.33
0.0095140
64.56%
14.00
14.00
23.00
23.00
0.0062108
0.0062108
35.74%
35.74%
0.20
7.70
2.19
Results of Air Velocity Test
 Anemometer
 Average air flow
rate 1650 cfm
 Gradient ranged
from 0 m/s at the
centre of flow to
9.8 m/s at the
edges
 Compared to the
rated 2000 cfm
Results of Water Flow Test
 High flow nozzle rate
– 1 gpm
 Low flow nozzle rate
– 0.5 gpm
 Therefore the total
flow from the pump
was 1.5 gpm
 Compared to the
rated 1.5 gpm
Results of Electrical Load
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Fan start up load = 500 W
Fan idle load = 300 W
Pump start up load = 1700 W
Pump idle load = 1000 W
Budget
Original Budget
$ 1000
Actual Cost
$ 1300
 Reasons we went over budget:
– Frame
– Pipes, nuts, bolts, fixtures, nozzles
– Unexpected changes
 Metal louvers
 Electrical system to handle large loads
Difference
$ 300 (30 %)
Prototype vs. Commercial
 This device is a prototype
 Differences:
– Mass production
 Lower cost per unit
 Everything is made specifically for the application
– Manufacturing methods
 Molded pieces, so less assembly
Prototype vs. Commercial
(continued)
 Changes to make:
– Fan: Right flow rate, could be quieter
– Electrical: Oversized pump = oversized load
– Material: Too much material for required load
– Pump: Right pressure, too much flow
 Most important item to change
 Huge power consumption (14 Amps)
 Too much flow (1.5 gpm, 5.67 L/min)
Prototype vs. Commercial
(continued)
 Pump scaling laws
– No characteristic curves for
our pump
 Compared to other pumps
– Fit goals better, but much
more expensive
– MarchPump Model 320
 Up to 40ft head, can be less
than 1.5gpm
 1.3Amps, 150W
 Similar pumps can cost
$900 US
http://www.marchpump.com/320.htm
A/C Evaporation Comparison
 A/C units remove heat
– Cooling rate
– Larger temperature and humidity control
 Evaporative cooler
– Evaporation rate
– Speeds up chemical process
A/C System
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http://www.sears.ca
Kenmore A/C Unit
$930
2.2 kW
1000 Watts
Use of Refrigerants
Evaporative Cooler
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$1,300
Latent cooling rate 5.3 kW
Energy Required 1.3 kW
2.4 g/s evaporation
Conclusion
 Goal
– To design and build a prototype evaporative
cooler
 Testing
– Promising results for conditions tested
 Areas of improvement
– Noise level
– Component sizes
– Cost
Questions?