Hand Warmers
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Basics
- This page aims to go over the various forms of Hand Warmers, Existing Off The Shelf Options, and potential for OSE Improvements/Development
Disposable
- These are a bit wasteful
- Essentially Iron Powder and Charcoal/Some other materials to Moderate the Redox Reaction (Slow Hot Rust, rather than a Metal Fire etc)
- POTENTIALLY could be collected+reprocessed
- Also potentially could be made from or reprocessed with DRI as that process yields itself well to Powderization
- Alternative Chemistries would be interesting to pursue, but Disposable Devices (Short of Emergency/Expeditionary Use) don’t really fit OSE Specifications
Reusable
Rechargeable
Electric
- Essentially just a battery, resistive heating element, and control circuitry cleverly packaged together
- Main concern is Battery Life (long term, Charge/Discharge Cycles, ESPECIALLY thermal management)
- They do have the advantage of being easily recharged, and typically having long run times (10+ Hours)
Phase Change Materials
- Pretty Neat
- Also if clear they have a neat visual of the Supercooled solution recrystallizing
- Main downside is short runtime
- For better or for worse they are recharged via Boiling
- If you currently have Electricity etc this is a bit of a pain vs Battery Rechargeable Units
- If Camping or currently Without Electricity, it is neat as even a Pot over a Campfire could work as long as you have water
- Typically Sodium Acetate in a Solution of Water (also potentially a Dye Added)
- Could Paraffin Wax either in a mixture, or in a “heat spreader” outer layer extend the release of the heat?
Fueled Versions
- Disadvantage over Rechargeable is that you have a Fuel Cost to consider, not just the (comparatively low) Cost of Electricity etc
- Also in Combustible Atmospheres / Some Locations they probably aren’t allowed either
- Although if Intrinsically Safe Battery Electric Hand Warmers exist is the REAL question
- Can have long(er) runtime, no issues with Cold Weather Operation, etc
Solid Fuel
- Insulated Box you put smoldering charcoal “sticks” in
Liquid Fuel
- Zippo Style Catalytic Hand Warmers
- Run on Lighter Fluid tests on other materials would be neat
Internal Links
External Links
- A Video by the YouTube Channel “Technology Connections” Titled “Reusable handwarmers that get hot by freezing” ( ‘’’~18 Minute Watch’’’ )
- It goes over both the Phase Change Reusable ones, and the Disposable Iron Based Ones