T E A M : J E F F P H I L I P PA RT , T E A M M E M B E R N A M E S R E M OV E D

WHIRLPOOL CAPSTONE STEAM GENERATION

PROJECT

INITIAL DESIGN CONCEPTS

• Ultrasonic Humidifier• Uses piezoelectric transducer to vibrate water droplets

into vapor.• Produces “Cool Mist” immediately with no warm up time.

• Boiler • Steam exits boiler after it reaches vaporization point.

• Impeller Humidifier • Fan pulls water droplets through diffuser and into

atmosphere. • “Invisible Mist” exits fan after water moves through

diffuser

TESTING METHOD

• Gauze attached to thermocouple as wet bulb

• The end of the gauze was placed in a measuring cup of water

• Second thermocouple used as dry bulb

• The convection fan was run continuously

PERFORMANCE AT 350° F

• The boiler performed the best at 350 degrees Fahrenheit

2 4 6 8 10 12 14 160.000

0.500

1.000

1.500

2.000

2.500

3.000Relative Humidity versus Time at 350F

no added humidity

boiler

humidifier

Time(mins)

Rela

tive H

um

idit

y(%

)

PERFORMANCE AT 450° F

2 4 6 8 10 12 14 160.000

0.200

0.400

0.600

0.800

1.000

1.200

Relative humidity vs. time at 450F

no added humid-ity

boiler

humidifier

time(min)

Rela

tive H

um

idit

y(%

)

• The humidifier performed the best at 450 degrees Fahrenheit

FMEA

Product Funtion Potentional Failure Mode Severity Potention Root Cause Occurance Rating Corrective Actions

Ultrasonic Humidifier Provide Steam To Oven Cavity

Tranducer Fail 10 Hard Water 5 Customer Instructions: Deionized Water

10 System Flood 4 Use Corrosion Resistant Material

Tubing Leak 10 Material Wear 5 Use Stronger Heat Resistant Tubing

Cloged Transducer 10 Hard Water 5 Customer Instructions: Deionized Water

Steam Boiler Provide Steam To Oven Cavity

Boiler Reserve Leak10 Material Corrosion 5 Use Corrosion Resistant Material

10 Resevoir Scaling 5 Heating Element in Water Resevoir

Tubing Leak 10 Material Wear 5 Use Stronger Heat Resistant Tubing

Overflow 10 Customer Error 6 Add Failure Valve

Drain Valve Drain Customer Getting Burnt 10 Hot Water Draining 5 Auto Valve Drains When Cooled

BOILER CONSTRUCTION CONSIDERATIONS

• Recycles no parts from the steam generator used in performance testing.

• Water reservoir will maximize the surface area that will be exposed to the external heating plate constructed from welded aluminum .

• Heating plate will be constructed from scrap range top element received after the oven breakdown

• Electric coils will be removed and set in a non-conductive base plate

• Coil path will be milled into the base plate. • Glass plate will be cut to size and attached

to the base plate with an adhesive.• Steel brackets will be bent to mount the

prototype behind the oven cavity. • Rubber top will be purchased and hole for

nozzle drilled • Boiler construction considered

“reasonable” and scores middle value of 2 on Pugh matrix.

HUMIDIFIER CONSTRUCTION CONSIDERATIONS

• Many recycled parts from the ultrasonic humidifier used during the performance testing

• Wires on the humidity level switch and led light will be stripped and extended

• Switch and LED light will be mounted below stove knobs

• Re-designed body will be 3-D printed and contain humidifier components.

• Mounting brackets will be made from bent steel to secure body behind oven cavity

• Humidifier construction is considered “good” and scores best score of 1 on Pugh matrix

COST

BoilerHumidifier

Boiler Design Cost

part size/type/quantiy Cost

nichrome wire 5 ft $5

aluminum body 1 $7

switch 1 $2

rubber top 1 $3

heat resistant tubing 1 $1

water resevoir 1 $2

drain valve 1 $1

water sensor 1 $1

led light 1 $2

lock 1 $1

TOTAL $25

Humidifier Design Cost

part size/type/quantiy Cost

transformer 1 $6

transducer 1 $4

small fan 1 $2

wiring 3 ft $1

circuit board 1 $4

water sensor 1 $1

led light 1 $2

switch 1 $2

water resevoir 1 $2

body 1 $5

drain valve 1 $1

TOTAL $30

RELIABILITY   Ultrasonic Humidifier Steam Generator ComparisonQuality of Steam

Impure water mist could be directly injected into the oven cavity if water in the reservoir is contaminated. Customer Introduction is needed.

As the water goes through the boiling process, there is less possibility of impure steam being injected to the oven cavity.

Steam generator has less possibility of having contamination issues.

Warm-up Time

Water mist is formed as soon as the system is turned on. Users can find out whether the humidity feature is properly working or not immediately.

It takes about 12 minutes for boiling water. But the oven also needs time for pre-heating.

Ultrasonic humidifier works much faster than steam generator. Ultrasonic humidifier requires no warm up time.

Quality of Food Cold mist injected into the oven cavity could cause a temperature fluctuation which affects the quality of food.

As the heated steam is injected into the oven cavity, there are less food quality issues due to temperature.

Ultrasonic humidifier is expected to have a higher possibility of food quality issue. But further testing is required to verify it.

Control The flow rate can be easily controlled by adjusting the vibration speed of the unit. Users can easily adjust the flow rate with a knob.

The flow rate can be easily controlled by adjusting the electric current with a knob.

Flow rates of both systems can be easily controlled by users.

Maintenance As fewer components are required for installing a mist generating unit into the oven, there are less maintenance issues. Components such as a transducer and a fan are easily replaceable. There are also scaling issues.

Additional Heating components are required for boiling water. Same as an ultrasonic humidifier, there are scaling issues. (run vinegar through it to clean it)

Ultrasonic humidifier requires less effort for maintenance. But both systems has common scaling issues which affects the life time of each system greatly.

PUGH MATRIX

Pugh Matrix

Design FMEA Cost Performance Application Construction Reliability Usability TOTALHumidifier 1 3 2 1 1 2 1 10Boiler 3 1 2 2 2 2 1 11

1-good2-reasonable3-poor

Water Entrance

Vapor Exit

3-D DESIGN

Water Drain

Fan Entrance

Circuit Board

Transducer

Water Sensor

Flow onto Transducer

PlungerPath for fan flow

Water Entrance

Switch

Low Water LED

Vapor CAVITY Entrance

Body

Transformer

Regulator

DESIGN MODIFICATIONS

Vapor Exit Ramp

Angled Vapor Exit Extended

Roof

DESIGN MODIFICATIONS

Floating Magnet

Altered Dimensions

COMPLETE PROTOTYPE

• Oven front (above)• Prototype and connection

mounted on the oven back (right)

LED SwitchPrototype Water Inlet Prototype Water Reservoir

TESTING RESULTS AT 350°F

2 4 6 8 10 12 14 160.0

10.0

20.0

30.0

% Moisture by volume vs. time at 350F

Time(min)

% M

ois

ture

by v

olu

me

TESTING RESULTS AT 400°F

2 4 6 8 10 12 14 160.0

15.0

30.0

45.0

60.0

75.0

% moisture by volume vs. time at 400F

Time(min)

% M

ois

ture

by v

olu

me

TESTING RESULTS AT 450°F

2 4 6 8 10 12 14 160.0

15.0

30.0

45.0

60.0

75.0

% moisture by volume vs. time at 450F

Time(min)

% m

ois

ture

by v

olu

me

BREAD TESTING METHOD

• Oven pre-heated to 350 °F• Thermocouple placed

approximately 2 inches into dough• Desired Thermocouple

reading of 93° C (200 °F)

BREAD TESTING RESULTS

With Prototype

Normal Oven Conditions

MODIFICATIONS AND SUGGESTIONS FOR FUTURE IMPROVEMENTS

• Design permanent water reservoir and water inlet • CNC Machine components from heat resistant plastic • Design smaller fan and scale down body size to accommodate limited

space at oven back• A larger piezoelectric plate could increase the water vapor production• Add required circuitry to central board to eliminate humidifier board,

transformer, and regulator• Move LED and switch for better physical appearance

Product Funtion Potentional Failure Mode Severity Potention Root Cause Occurance Rating Corrective Actions

Humidifier Prototype Provide Steam To Oven Cavity

Tranducer Fail 10 Hard Water 5 Customer Instructions: Deionized Water

10 System Flood 4 Use Corrosion Resistant Material

Tubing Leak 10 Material Wear 5 Use Stronger Heat Resistant Tubing

Cloged Transducer 10 Hard Water 5 Customer Instructions: Deionized Water

10 Material Corrosion 5 Use Corrosion Resistant Material