Assignment 5.2 – Practicing the C2B Spiral
Sarah Hashiguchi
Design Concept
Thermo Capture Jacket
About
This jacket was design for summer hiking conditions where while it's usually sunny, but the temperature may change drastically throughout the hike. Often time hikes gain significant elevation where the top of the hike is much cooler than the start. At this point, it is also common to take a break and as vigorous movement comes to a pause, the body can feel cold especially if it's sweaty and there is any sort of wind factor. This jacket was primarily inspired by the shape Green Birdwing Butterfly wing scales, the adaptable properties of Numbat fur, the lightweight structure of Dragonfly wings, and the solar capturing cells of Oriental Hornets. While the final lap around the spiral was a fun exploration, it brought the design farther from a sustainable solution, so the final jacket is most closely based on the first two laps.
Process
Round 1
Identify
I want to design a jacket for hiking. I've noticed current jackets are good for certain conditions, but each have their draw backs.
It needs to:
be lightweight + easily packable
really breathable during the hike when energy is being expended
protect skin from sun damage
keep the body warm when stopping for breaks
quick dry from sweat
The overall purpose is to keep the hiker as comfortable as possible so they can focus on enjoying their natural surroundings rather than their thermoregulation.
Interpret
The jacket needs to manage thermal energy. This will be done by inhibiting heat transfer to the ambient air, and rather storing the energy to reuse in a cyclic process. The operating parameters include a dynamic climate where the weather may be dry, hot or cold, windy, and sunny. The object would start in a nutrient rich area (a city) and be used in both nutrient and non-nutrient rich area (depending on location of the hike).
Discover
Natural models / nature's strategies + observations:
Wing Scales Aid Thermoregulation → Green Birdwing Butterfly has honeycomb scales that maximize light absorption and regulate body temp
Thinner Fur Keeps Numbat Warmer → Numbat's maximize solar radiation absorbed by their skin. Piloerection, when hair stands on end, also creates an insulating layer of air around its body.
Fur Dries by Shaking → Animals shake at a frequency to dislodge largest droplets and let the smaller droplets air dry (not worth the energy to remove). Loose skin allows for high forces on droplets.
Light weight structures → Dandelion seeds use discs of radiating threads, while dragonfly wings are adaptive materials with calculated microstructures
Abstract
Strategies + Observations
shape helps absorb sun radiation
air is trapped and used as warm "blanket"
ability to move/change direction of hair aids heat control
movement physically dries fur while conserving as much energy as possible
structure + material can make for light weight yet robust properties
Emulate
Conceptual Design
this jacket will capture heat
it will release unused heat through vents (flaps?)
it will store heat until needed later in the hike (when their is a break and movement temporarily ceases)
energy will heat up reserves that are protected away from the body
can be reversed for opposite effect
Evaluate
Against Design Brief
The design was based on the assumption that this would be for summer hiking and the jacket would not have to protect against rain. Would it be helpful or advantageous to make it waterproof or water resistant?
The design was based on the assumption that someone would wear the jacket for the whole hike. Maybe it stores energy until the person begins to overheat, and then they take the jacket off until they get chilly, at which point they can access the heat reserves?
Against Nature's Design Principles
Optimize rather than maximize → one versatile jacket is better than owning many that each only serve one purpose (for one climate/set of conditions)
Locally attuned + responsive → changes based on dynamic environment
Resilient → increases rate of adaptation to climate
Cyclical → uses heat already generated (free energy) and reuses it when it's needed again
Benign manufacturing → I don't think this would be achievable based on the types of materials to make this function
Round 2
Identify
How could the jacket store energy?
Interpret
Same as round 1: The jacket needs to manage thermal energy. This will be done by inhibiting heat transfer to the ambient air, and rather storing the energy to reuse in a cyclic process. The operating parameters include a dynamic climate where the weather may be dry, hot or cold, windy, and sunny. The object would start in a nutrient rich area (a city) and be used in both nutrient and non-nutrient rich area (depending on location of the hike).
Discover
Energy-Storing Tendons Give Wallabies Their Bounce → they use elastic recoil to boost energy efficiency. The cost of locomotion can be unchanged regardless of speed or load (pregnant mother).
Pigments Absorb Solar Energy → Oriental hornets turn solar energy into electrical energy that they then use for physical activity, temperature regulation, and metabolic functions (like a liver would perform). Oval bumps on the solar-sensitive bands increase the surface area for absorption.
Abstract
Strategies + Observations
kinetic energy + potential energy turn into elastic strain energy of stretching tendons
90% of energy can be stored for re-use
muscle attached to tendon is stiff and doesn't change length so that the force stays concentrated rather than being dissipated and lost
pigment absorbs solar energy
energy can be directed to different functions as needed
surface texture maximizes absorbent area for sunlight
Emulate
Conceptual Design
The jacket will have a textured surface with "cells"
These will capture both sun energy and radiant body heat
This energy will be stored until it is needed
There will be a trigger to release energy in the form of heat from the "cells" to warm the hiker's body when needed
Evaluate
Against Design Brief
The design was based on the assumption that at some point during the hike, there will always be sun. Maybe there are certain cells to capture sun energy, and more to capture radiant body heat, since that is more constant and predictable.
Against Nature's Design Principles
Optimization → Uses available energy
Systems based → Converts sunlight to storable energy, and rereleases as heat
Benign manufacturing → I don't think this would be achievable based on the types of materials to make this function
Round 3
Identify
How could this work in colder conditions? Hiking late fall or early spring? Higher elevations?
Interpret
Similar to previous rounds, the jacket needs to manage thermal energy. This will be done by inhibiting heat transfer to the ambient air, and rather storing the energy to reuse in a cyclic process. The operating parameters have changed slightly to include a colder climate, that still experiences a fair amount of both wind and sun. The object would start in a nutrient rich area (a city) and be used in both nutrient and non-nutrient rich area (depending on location of the hike). It would also need to be thin an flexible, opposed to the classic bulky winter coat.
Discover
Blood Vessel Network Prevents Heat Loss at Body Surface → The gray whale's tongue has no blubber to keep it warm like the rest of its body, so it must cool its tongue down to minimize heat loss to the cold ocean water. It does this by acting as a counter current heat exchanger where the thin wide network of blood vessels slow down the flow of blood allowing the heat to disperse within its body and cool down before reaching the end of the tongue.
Vascular Lining Helps Maintain Body Temperature → The leatherback sea turtle has a vascular lining that helps warm air as it is breathed in and cool air before it is fully breathed out. This retains heat within the body and minimizes heat lost to the turtle's surroundings
Abstract
Strategies + Observations
a network of small branches distribute heat
vessels keep body warm near surface of skin to prevent it from getting too cold
conserve heat lost to environment by pre-cooling (to retain heat)
Emulate
Conceptual Design
This jacket will essentially function as a heated blanket
In addition to storing energy as previously mentioned, it could also be plugged in and charged at home before a hike
A network/lattice of thin copper wire would run throughout the jacket like the web of a vascular system, and heat up to keep the hiker warm
Temperature of the copper wire could be adjusted up or down to achieve the ideal temperature throughout the hike
Evaluate
Against Design Brief
The design was based on the assumption that the hiker would not be wearing a backpack or anything else that might come into contact with the jacket so all heat would be directed towards the person's body rather than absorbed by an object
Could still explore water resistance, quick dry, and SPF attributes
Against Nature's Design Principles
Resilient → This design is more resilient in harsher conditions that previous versions
Optimization → While this design uses some available energy, it would still rely on traditional electricity as well making less aligned with this principle
Benign manufacturing → I don't think this would be achievable based on the types of materials to make this function