Re: 70 to 25 in 48 hours, moving air, water
- To: perennials@mallorn.com
- Subject: Re: 70 to 25 in 48 hours, moving air, water
- From: A* R* <a*@austx.tandem.com>
- Date: Thu, 12 Mar 1998 13:48:39 -0600 (CST)
> Well.. sort of. The principle here is that a lot of energy is gained or
> lost when water changes phases between liquid and solid (any younger brains
> remember just how many joules or Kcals it is?) You need to add a bunch of
> energy (or is that a Kbunch) to turn 32F ice into 32F water. Similarly, you
> have to remove a bunch of energy from 32Fwater to make 32F ice.
Isn't this what's called sublimation/
At any rate, you intuitively know this. Take a glass of water that's
been in the fridge and is below 40F. Take a glass of water that's been
sitting on the counter at 70F. Put in freezer. It takes a *heck* of a
long time to freeze the 40F water -- much longer than bringing the 70F
down to 40F. Same goes from moving the Thanksgiving turkey into the
fridge from the freezer -- takes *forever* to thaw.
And you know how much energy fridge/freezers use.
--
Amy Moseley Rupp (amyr@austx.tandem.com) Austin, TX, USDA z8b, Sunset z30
Amy Moseley (amy@ece.utexas.edu) Graduate Student in Software Engineering
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