Outdoor Mist Cooling System By Shailesh Shukla

Sunday, April 9, 2023

STUDY & FABRICATION ON OUTDOOR MIST/FOG COOLING

SYSTEM THROUGH HIGH PRESSURE PUMP, TUBES &

NOZZLES

A Project

Presentation On

.

By: SHAILESH SHUKLA


INTRODUCTION 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.


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.


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.

WORKING OF MISTING SYSTEM


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.


HIGH PRESSURE PUMP

¼” MISTLINE

PUSH LOCK CONNECTORS

MISTING NOZZLES

COMPONENTS OF A OUTDOOR MIST COOLING SYSTEM


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.

NOZZLES



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.

HIGH-PRESSURE FOG



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

WASTE WATER ODOUR CONTROL


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

HUMIDITY CONTROL SYSTEM


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

FACTORS OF AN OUTDOOR MIST COOLING SYSTEM


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

TYPICAL APPLICATIONS


HIGH PRESSURE PUMPLOW 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.

PRESSURE PUMP


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.

HIGH PRESSURE PUMP


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.

ADVANTAGES


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

REQUIRED QUANTITIES


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

REQUIRED FORMULAS FOR DESIGNING HIGH PRESSURE PUMP


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

TAKE


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-1T1=Outside Temperature

T2=Required Inside Temperature

Ro=Outside Relative Humidity

Ri=Required Inside Relative Humidity

CALCULATING THE COOLING POTENTIAL OF EVAPORATION


STEP-2Calculating X-the saturation temperature and H-the specific enthalpy (the energy contained in 1 kg of air):

X0=R0*[0.0212T12+0.2435T1+4.278]/1000

Xi=Ri*[0.0212T22+0.2435T2+4.278]/1000

H0=(1.006T1+Xo*1.84T1+2502)*1000

Hi=(1.006T2+Xi*1.84T2+2502)*1000

STEP-3D=air densityU=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)


STEP-4Calculating the required air flow rate (ventilation rate) out of the outdoor

AFR=[Ira-U(T2-T1)]/(Hi-Ho)

STEP-5Converting air flow rate to cubic meters per minute

AFR=[(AFR*3600*D)/60]*35.3ft/min

STEP-6Calculating the water flow rate for fogging:

EFR=AFR*(Xi-Xo)

STEP-7Converting EFR to gram of water per m2 per hour (1 g of water = 1 ml):

EFR=EFR*3.6*106


STEP-8Divide 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


POLES 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.


ROOF FRAME & SHEET 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.


Constructed hut from side view

HUT CONSTRUCTIONConstructed hut from

front view


NYLON MIST LINE / BLACK PE PIPE 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.


NOZZLES 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.


MIST/FOG MACHINE 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.


SPECIFICATION OF PRESSURE PUMP WITH PRESSURE GAUGE

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


SPECIFICATION OF HP STARTING MOTOR

Company - Everest Induction Motor

H.P. - 1.5

RPM - 1440

Phase - 1

Volts - 220

AMP - 9

Rating - Const.

INSU.- ‘A’

CYC - 50


FILTER 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.


WATER LIFTING PUMP Water lifting pump to

provide efficient gravity head to the pressure pump.

Water lifting pump provide a gravity head of about 3.5 feet.


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.

HUT ORIENTATION


TALLER SHEDS ALLOW MORE DIRECT SUNLIGHT TO ENTER

THE HOUSE


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.

SIDE CURTAINS


SIDE CURTAINS


TRY SQUARE

HAND HACK-SAW

FILE

METRE SCALE

DIGITAL THERMOMETER

HYGROMETER

MEASURING TOOLS & INSTRUMENTS


TABLE-1


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.

FACTORS OF COOLING


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.

COOLING PERFORMANCE OF OUTDOOR MISTING SYSTEM


READINGS OF JUNE 3, 2013 WITH OR WITHOUT INSTALLED SYSTEM

Time Outside Temperature(0C)

Outside Relative

Humidity(%)

Inside Temperature(0C)

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


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


OUTSIDE TEMPERATURE GRAPH


OUTSIDE RELATIVE HUMIDITY GRAPH


INSIDE TEMPERATURE GRAPH


INSIDE RELATIVE HUMIDITY GRAPH


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.

WHAT AFFECTS EVAPORATION RATE?


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-52.75R2=0.9997

FLOW ESTIMATION


Percentage Increase In Flow Relative To Ratio Of Outlet-To-Inlet Area

Ratio of outlet to inlet area


DROPLET SIZE DISTRIBUTION 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.


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.

PRECAUTIONS


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.

CONCLUSION


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.

FUTURE SCOPE



THANK YOU

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Outdoor Mist Cooling System By Shailesh Shukla