- 1 Physical mechanics of cooling
- 2 Transport
- 3 On efficiency
- 4 Using the effects - practice and products
- 4.1 When passive cooling works
- 4.2 Device cooling
- 4.3 Personal cooling
- 4.4 Some small tricks
- 4.5 Swamp coolers
- 4.6 Mini dehumidifier
- 4.7 Those small personal ACs
- 4.8 Air conditioning
- 4.9 "Eco coolers"
- 5 Passive effects
- 6 Parts of designs
- 7 Unsorted
Physical mechanics of cooling
Passive cooling tends to mean 'what happens with no moving parts'.
...so whatever amount of conduction, radiation, or convection would happen anyway.
Sometimes includes adding a fan. While technically that's active cooling (because you're adding work, and using energy), the same amount of convection would happen anyway, but now a little faster because you're stirring the air better. (If you're stirring in air that is colder essentially for free (e.g. if outside air is), great)
On the technical side
This tends to mean
- conduction - a good conductor spreading heat throughout
- radiation - thermal radiation means movement of charges in materials (anything above 0 K) is radiated as EM at the surface
- (black-body radiation can be seen as a "thermal radiation's real-world math becomes easier if we make some assumptions like that it's not really interacting in other ways")
- convection - fluid flow, in this context often
- flow caused by heat changing temperatures and densities
- that flow assisting better heat interchange with that fluid, because warmer air moving up tends to draws in colder air from the sides (which technically is an effect that needs gravity)
In practice there's more than one of these happening, but often one that counts for most exchange.