This document presents a project on misting technology. It discusses how misting systems work using evaporative cooling to lower air temperatures by up to 15°C. Misting nozzles atomize water into micron-sized droplets to maximize evaporative cooling effect. The project describes system components like high pressure pumps, mist lines, and nozzles. It provides various misting application areas and benefits. Performance parameters, equations, and sample data from a test installation are also included to evaluate system efficiency.

1. A
Project
Presentation On
.By:
ARPIT KUMAR MISHRA (CT-1670/09) MD. SALMAN (CT-1676/09)
KAUSHAL KISHOR (CT-1672/09) SUNIL KUMAR YADAV (CT-1692/09)
SHAILESH SHUKLA (CT-1674/09) ABHISHEK TRIPATHI (CT-1707/09)

2.  Misting technology is based on the principle of
evaporative cooling.
 Evaporative cooling is the process of removing heat
from the air by using water vapour.
 Misting system lower the temperature of the
surrounding area upto 15 0C.
 The evaporation of 1kg of water gives the same
cooling effect as the melting of 7 kg of ice.

3.  The Misting Nozzles converts ordinary water into billions
of micron-sized water particles.
 As heat is taken for evaporation, temperature of that
particular area drops immediately.
 More the heat absorbed more the cooling effect in that
area.
 Any time an outdoor environment is faced with rising
temperatures, using outdoor cooling solutions such as
misting systems is beneficial.

4.  Misting system work so effectively because of the high
pressure pump.
 The pump pushes the water through ¼” nylon/steel lines
to brass mist nozzles, producing microscopic droplets of
water.
 The fine mist of water droplets hits the hot air and flash
evaporates to cool the surrounding space upto 15
degrees.
 When evaporation occurs, temperature drops.

5.  The outdoor heat, necessary to cause evaporation,
actually draws from the air temperature and cools the
surrounding area within seconds.
 Our misting system do this by atomizing high-pressure
water via specialized misting nozzles that produce a fine
mist/fog that is perfectly sized for evaporation.
 The lower the relative humidity, the better the evaporative
cooling effect.

6. HIGH PRESSURE PUMP
¼” MISTLINE
PUSH LOCK CONNECTORS
MISTING NOZZLES

7.  The nozzles are made of high-grade stainless steel or
brass.
 It is also known as impaction-pin nozzles.
 These nozzles have orifice diameters of 6 thousands of
an inch and produce droplets in the 4 to 40 micron range,
ideal for outdoor air cooling.

9.  High-pressure fogging represents a significant advance
in evaporative cooling technology.
 Fog systems create a large evaporative surface area by
atomizing the supply water into billions of super-small
spherical droplets.
 The size of the droplet plays an important role in the
amount of cooling that takes place.
 Water droplets less than 40 microns in diameter is called
fog and over that it’s called a mist.
 The speed of evaporation of water droplets depends on
the surface area of water droplets exposed to the air.

11. High pressure fogging systems are very effective in
controlling industrial waste odors.
BENEFITS
 Lowers chemical & operating costs
 Proven fast, broad range effectiveness
 Easy installation & operation
 No hazardous waste
 Reduces capital expenditures

12.  Humidity control is very important in a number of
industries.
 Stabilizing moisture in wood products prevents warping,
joint separation and shrinkage while reducing dust in
working environment.
 In the textile industry & printing industry, it is also an
important factor.
BENEFITS
 Controls plant humidity within + 3%
 Uses pressurized water, no compressed air
 Produces micro mist, which is quickly absorbed into the
atmosphere
 Economical, low maintenance operation

13.  Don’t get wet using an outdoor mist cooling system
 Surrounding surfaces don’t get wet
 Maintenance on a misting system
 Water used in a standard misting system &
environmental impact
 A climatic Emergency - Outdoor cooling systems

14.  Open areas like Terrace, Balcony, Lawns
 Outdoor eating areas
 Recreational areas
 Odor control, Lumber processing
 Motels, Restaurants, Hotels, Resorts or Amusement
Parks
 For humidification in businesses such as Woodworking,
Textiles, Plant Propagation and Cold Storage etc.
 Pool and Patio, Greenhouse, Vegetable gardens, Flower
gardens & will keep away also small flying insects, dusts

15. HIGH PRESSURE PUMP
LOW PRESSURE PUMP
When pressure needs for the system are below 800 psi,
LOW PRESSURE PUMPS are used.
When pressure needs for the system are above 800 psi,
HIGH PRESSURE PUMPS are used.

16.  A high pressure pump is broadly defined as any pump
that can generate high discharge pressure, generally in
excess of 800 psi.
 High-Pressure Misting Systems operate between 800
and 1200 psi (pounds per square inch) of water pressure.
 A High- Pressure Pump is the heart of the misting
system and is utilized to increase the pressure of the
water flow.
 As the micron water droplets “flash evaporate” they pick
up heat from the air, which significantly drops the
temperature upto 15 0C, without making you wet.

17.  High pressure systems are chosen for applications where
maximum cooling is needed.
 These applications would include residential areas,
restaurants, amusement parks, sports stadium, hotels
and resorts.
 Other benefits include they can control odors, dust and
used to add humidity to a green house or other
environments.
 High pressure systems are also used for fire and smoke
control, frost protection and visual effects in a pool,
garden or other areas.

18.  Discharge(water flow)-Q [gallons per minute(GPM), litre
per minute(LPM)], Approx-[1LPM-50LPM]
 Pressure-P [pounds per Square inch(PSI), bar], Approx-
[1000PSI-2200PSI]
 Speed-RPM
 Power-[KW,HP] by Single phase motor-[220V-9amp]
OTHER APPROXIMATIONS
 15.24 meter long mist line with 2-Filteration System
 Nozzles of 40 micron orifice [5~20 micron] droplet size

19.  H[ft]={2.31*p[PSI]}/SG
 P[HP]={H[ft]*Q[GPM]*SG}/3956
 P[HP]={p[PSI]*Q[GPM]}/1714
 T[in.lbs.]={P[HP]*63025}/N[RPM]
 d[in3/rev.]={6.2822*T[in.lbs.]}/p[PSI]
 N[RPM]={231*Q[GPM]}/d[in3/rev.]
 Q[GPM]={T[in.lbs.]*N[RPM]}/{p[PSI]*36.77}
 p[PSI]={6.2822*T[in.lbs.]}/d[in3/rev.]
 Bhp={T[in.lbs.]*N[RPM]}/5250
 W/min={6.2822*T[in.lbs.]*N[RPM]}
 n=P[HP]/Bhp
 Q[GPM]={N[RPM]*d[in3/rev.]}/231

20.  Specific Gravity of water SG=1 (8.34 lbs/gal)
 1 PSI=2.31ft of water=0.06895 bar
 1 GPM=3.78 LPM
 1 HP=0.7456 KW
 1 kilo pounds(1kip)=1000 lbs

21. Equation For Fog Cooling- The following equation can be
used to work out how much water needs to be evaporated
into a known area and how much air movement or
ventilation is required in order to reduce the temperature
inside a growing structure to the required levels.
STEP-1
T1=Outside Temperature
T2=Required Inside Temperature
Ro=Outside Relative Humidity
Ri=Required Inside Relative Humidity

22. STEP-2
Calculating X-the saturation temperature and H-the specific
enthalpy (the energy contained in 1 kg of air):
X0=R0*[0.0212T1
2+0.2435T1+4.278]/1000
Xi=Ri*[0.0212T2
2+0.2435T2+4.278]/1000
H0=(1.006T1+Xo*1.84T1+2502)*1000
Hi=(1.006T2+Xi*1.84T2+2502)*1000
STEP-3
D=air density
U=heat transmission coefficient of outdoor(values from 4 to
10W/m2.OC)
I=incoming solar radiation(moles/m2.s)
a=inside evaporation coefficient(values from 0.5 to 0.7)
r=radiation transmission coefficient of outdoor(values from
0.1 to 0.5,the average for a polythene covered structure is
0.75)

23. STEP-4
Calculating the required air flow rate (ventilation rate) out of the outdoor
AFR=[Ira-U(T2-T1)]/(Hi-Ho)
STEP-5
Converting air flow rate to cubic meters per minute
AFR=[(AFR*3600*D)/60]*35.3ft/min
STEP-6
Calculating the water flow rate for fogging:
EFR=AFR*(Xi-Xo)
STEP-7
Converting EFR to gram of water per m2 per hour (1 g of water = 1 ml):
EFR=EFR*3.6*106

24. STEP-8
Divide the number obtained in the last step by 46546 to get
your final answer in gallons per ft2 per hour.
EFFICIENCY OF THE NOZZLE IN A
MISTING/FOGGING SYSTEM
 The efficiency of a misting or fogging system depends on
the number of nozzles used in the system and the rate of
water sprayed out of each nozzle.
 An equation to estimate the efficiency (b) of nozzles used
for misting (large droplets because of low pressure or
large holes in the nozzle) or fogging (small droplets
because of high pressure and small holes in the nozzle),
with respect to water pressure (P, in kPa) is listed below-
b = 0.124 + 1.35 * 10-4*P

25.  The poles are used in our
project to give the support
to the roof frame structure.
 Proper height should be
maintained for best
performance of our
outdoor mist/fog cooling
system.
 The height of each pole is
7.5 feet.

26.  The roof frame is a
structure which gives
support to the mistline.
 Intermediate supports are
given to strengthen the
whole roof structure.
 The roof is covered with
white sheet to avoid sun
light to enter in the
enclosed area where
localized cooling is needed.

27. Constructed hut from side
view
Constructed hut from
front view

28.  We use nylon mistline of
15.24 metre length with
1 threaded tee.
 We use 12 threaded
brass connectors with
this mist line in which
nozzle stems are
inserted.

29.  We use anti drip brass
nozzles to create mist/fog.
 The diameter of the
nozzle is 0.15 mm with
ceramic orifice.
 Since the nozzle orifice is
too fine so clean water is
desired to avoid clogging.

30.  The mist/fog machine is a
combination of pressure
pump and motor.
 Both connected through
belt drive.
 The base of the machine
is made such that it can
resist vibration produced
by the machine.

31. Company - Nature Gold
H.S. Overseas Pvt. Ltd.
Power Sprayer - NG-18A
Pressure - 2.1-4.5 Mpa
Operation - 800-1200rpm
Capacity - 10-16litre
Required Power- 0.6-1.0
H.P.
Pressure Gauge - With Bar
and Mpa Indicators

32. Company - Everest
Induction Motor
H.P. - 1.5
RPM - 1440
Phase - 1
Volts - 220
AMP - 9
Rating - Const.
INSU.- ‘A’
CYC - 50

33.  Filters as mean itself it
filters the water and
remove dust particles to
avoid clogging in the
mistline.
 An air relief valve is also
provided at the top of the
cylindrical filter to extract
air from the filter.

34.  Water lifting pump to
provide efficient gravity
head to the pressure
pump.
 Water lifting pump
provide a gravity head of
about 3.5 feet.

35.  There is no single method of reducing heat stress in
outdoor areas.
 The longer side of the frame should have an east-west
orientation.
 This reduces the amount of direct sunlight shining on the
side walls or entering the house.
 Painting the roof white may increase the level of sunlight
reflected, thus reducing the amount of absorbed solar
energy.

37.  Outdoor areas should be shielded from direct sunlight as
much as possible by means of side curtains.
 Side curtains are the cheapest way of preventing sunlight
from entering the house.
 The west side of the hut can also be fitted with side and
vertical curtains.

39.  TRY SQUARE
 HAND HACK-SAW
 FILE
 METRE SCALE
 DIGITAL THERMOMETER
 HYGROMETER

41.  How much moisture is already present in the air?
The maximum theoretical cooling potential typically ranges
around 15 to17oC when air temperature are in 32 to 38oC
range. This corresponds to a relative humidity of about
50%.
 How efficient the Cooling system is?
This determines the practical achievable cooling.
Efficiencies of current systems range in practice from
around 50% to 76%
To lower air temperature 17 oC requires evaporating about
0.125 gallons (0.5 liters) of water per hour for every
thousand cubic feet of air going through the hut.

42. The wet bulb temperature and the dry bulb temperature are
identified, the cooling performance or leaving air
temperature of the outdoor cooling system may be
determined:
TLA = TDB – ((TDB – TWB) x E)
TLA = Leaving Air Temp
TDB = Dry Bulb Temp
TWB = Wet Bulb Temp
E = Efficiency of the evaporative media.
Sensors are provided to measure relative humidity and dry
bulb temperature.

43. Time Outside
Temperature(0
C)
Outside
Relative
Humidity(%)
Inside
Temperature(0
C)
Inside Relative
Humidity(%)
10:00AM 44.9 50 34.7 37
10:30AM 45.9 47 35.3 35
10:55AM 46.5 45 35.0 36
11:25AM 46.3 45 36.1 33
11:45AM 47.0 45 35.5 35
12:05PM 45.0 47 34.7 37
12:30PM 46.3 45 36.3 33
01:00PM 45.5 49 38.5 31
01:15PM 45.9 47 38.3 31
01:30PM 46.3 45 37.1 32
01:45PM 47.3 43 37.0 32
02:00PM 42.5 50 35.5 34
02:15PM 41.5 53 34.5 35
02:30PM 42.3 51 33.1 39
02:45PM 44.7 47 33.5 39
02:59PM 42.7 49 33.9 37

44. We take readings on the date June 3, 2013 from
morning 10 AM to 3 PM. From the readings we plotted
four graphs which are:
 Outside Temperature Graph
 Outside Relative Humidity Graph
 Inside Temperature Graph
 Inside Relative Humidity Graph

49. WIND SPEED
 Stronger the wind, more rapid the evaporation.
TEMPERATURE OF AIR
 Higher the air temperature, more rapid the evaporation.
 The amount of water vapour the air can hold depends on
temperature.
 The amount of water vapour that may be evaporated into
air is directly proportional to the air temperature.
 That is, higher the temperature, more water vapour the
air can hold.

50. If the inlet and outlet are equal in size and there is no wind,
airflow can be estimated by the equation listed below.
V = 2 * A * (C/0.65) * [g * h * (Ti – To)/Ti]1/2
where V is in m3/5, g is the gravitational constant, A is the area of
one of the openings, C is the coefficient of discharge of each
opening, h is the distance, m, between the two openings, and Ti
and To are indoor and outdoor air temperature, K, respectively. If
the two openings are not equal, the smaller of the two is used in
the above equation. V is adjusted by multiplying (1 + % increase
in flow). The % increase in flow can be calculated using the
regression equation shown in Fig.
y=-0.1687xd+3.1542x3-22.294x2+72.098x-52.75
R2=0.9997

51. Ratio of outlet to inlet area

52.  The nozzle is made of 316
stainless steel (SS) and
consists of a small orifice
from five to seven
thousands of an inch for
outdoor cooling.
 It can be seen that 85% of
the droplets generated are
below 10 microns in size
and almost none are
greater than 20 microns.
 As higher atomization
pressure is used, droplet
size decreases.

53.  The water used should be pure and free from dust to
avoid clogging in the mist line as well as in nozzle.
 The lubrication oil should be checked timely to avoid over
heating of the pressure pump and its proper working.
 The pressure should be maintained to produce best
cooling effect relative to the environment conditions with
the help of pressure gauge and pressure controller.
 The base of the machine is made such that it can resist
vibration produced by the misting/fogging machine.
 All connections should be tightened properly to avoid
leakage.

54. An attempt has been made in developing an outdoor mist/fog
cooling system and utilizing it to produce best cooling effect:
 We reduced the outdoor temperature upto 15 0C with respect
to the outdoor temperature in peak summer condition by using
our cooling system.
 To produce more cooling effect, we used pure white sheet on
roof frame for pure reflectivity of sun light because white sheet
is totally reflective (equal to one) theoretically.
 We controlled the odor of surrounding by mixing scented liquid
in the water.

55.  We can produce more cooling effect by increasing no. of
nozzles.
 We can also produce more cooling effect by using very
high pressure and high capacity pump.
 We can increase the efficiency of our outdoor mist/fog
cooling system by using fans in a proper orientation to
provide a swirl effect within the hut for best evaporation
and rapid cooling.
 By maintaining proper orientation of hut (east – west
orientation) to avoid sun radiation enter into the enclosed
area where localized cooling is desired.
 Maintaining the proper height of the hut structure, we can
increase the evaporation rate.