Cordless Garment Steamer
Explore a steamer concept that simplifies on-the-go steaming by removing barriers to set-up, and optimizes size and power for one garment of steaming
Role: Lead R&D Engineer
Time: 3 months
Outcome: Proof-of-Concept Prototype
Define
Based on Consumer Experience, What are the Specifications?
How much do steamers weigh?
How long does it take to steam an outfit?
Understanding the Consumer Experience
What MUST this product do?
What do we WANT to optimize?
Steam at 10 g/min
Weigh less than 2.5 lb
Steam an outfit on 1 charge
Steam in horizontal and vertical orientations
Effectively remove wrinkles
No water leaks
Provide enough energy in a small portable package
Factors that could impact total energy required:
Mass of Boiler
Initial Temperature of Water
How long the heater needs to be on in order to maintain a steaming temperature
Biggest Challenge
Minimize footprint
Maximize steam time
Minimize time at the outlet
Minimize steps to store
Measure
Let's see what the numbers look like!
If we lived in an ideal world and our heat transfer was perfect, how much energy is needed to steam water? Enthalpy Balance!
(Total Enthalpy) X (Water Mass) = ENERGY
(Total Enthalpy) X (Flow Rate) = Power
Let's make sure our model is valid!
What is the minimum power that a battery needs to provide to a heater with “No mass”?
In the real world, a "no-mass" heater does not exist.
To get as close as possible, I dripped water onto this steamer and varied the wattage to see what the minimum power to maintain steam and not pool water.
Result: ~480W
Conclusion: Our model is valid!
Design an Experiment to test the different factors that impact energy required.
Testing Setup
IntlLab dosing Pump, Scale, and Stopwatch
Flow Rate
InkBird Temp Control + Kettle
Temperature of Water
LabView/hioki
Temperature of boiler at different locations over time
Wattage, Voltage, Current over time
1/4 Factorial Testing Matrix
Analyze
With data collected and calculations performed, What are the possible solutions?
What are the results from the experiment?
Outlet Only
Battery Only
Hybrid
Tradeoff Discussion
None of the configurations meet the exact needs of Marketing
Marketing
Lowest Energy:
Big Mass
70C Water
450 W
Usage 3
Highest SNR:
Small
70C Water
600 W
Usage 3
Design
"Steaming" out the details of the possible configurations
Battery Optimization
Hybrid Configuration Optimization: EES Model
Inputs: # of Batteries in Pack, Capacity of Battery Pack
Outputs: Thermal Mass Required, Mass of Batteries, Power Provided by battery pack, Continuous Discharge Current, Metal & Battery Cost
Approximately 1 lb of mass stores the same energy as 0.33 lb of battery
For the same amount of weight, a battery costs ~8x as much money as aluminum
Optimized: ~2 lb thermal mass with 3 batteries with a capacity of 2800 mAh
What Optimized Configuration is best path forward?
Pugh Matrix
Low Score Wins:
Move forward with the Battery only configuration.
Test
Created a Proof-of-Concept Prototype
Water Tank Connector and Trigger barrowed from existing product
3D Printed Housing
3D Printed Water Tank
Custom Machined Boiler with 500W Cartridge
Dosing Pump to provide 10g/min
Inverter to allow for DC supply to heater
3D Printed Battery Pack with sourced batteries and pins