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Comment by kintamanimatt | Hacker News Reader

I hope the fridge was off.

A fridge will act as a fantastic acoustic shield but probably not a functioning Faraday cage. I think this blog post has taken a few artistic liberties in suggesting its use was as a Faraday cage, especially as the article she links to doesn't mention the fridge's purpose as a Faraday cage.

Assuming this story isn't stretched and exaggerated (I have a hard time believing it isn't) and the fridge was on, this could be a fast way to trigger condensation to form inside the phone when the device is removed back into a warmer environment, depending on the ambient humidity. I just wouldn't dream of putting my phone in a cold fridge for anything other than the briefest time for this reason.

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Maybe phones are not so sensitive to condensation. At least here in Finland phones seem to work fine, despite outside temperatures being similar or below to what is found in a fridge most of the year. People move phones in and out of buildings all the time with large temperature differences between. I don't think I have heard anyone breaking a phone because of condensation here.

Why not on? Wouldn't the compressor improve the situation by adding background noise? Also if condensation is a concern you can put the phones in a plastic bag.

When a fridge is on it usually means it's cold! If it's off (and has been for a while) it could be expected to be around room temperature, eliminating the issue of condensation.

The compressor isn't on all the time. It turns on intermittently when the temperature inside the fridge exceeds a certain threshold. It would be unlikely of much use most of the time.

Putting the phones in a bag does nothing to solve the issue of condensation. What happens is the phones would cool down substantially in the fridge. When they're removed, the cold surfaces (inside and out) would cause moisture in the warmer air to condense into water droplets, possibly causing issues with the battery and the other circuitry. Hong Kong is quite a humid place and it appears that he was at an acquaintance's home at the time of the frigid phone incident. It's unclear how well air conditioned this acquaintance's home was, which could lead to some especially nasty condensation issues. It's also unlikely this acquaintance's fridge would have been brought up to room temperature just for the sole purpose of storing phones for a couple of hours. This is why I'm inclined to believe the anecdote is BS.

"The compressor isn't on all the time. It turns on intermittently when the temperature inside the fridge exceeds a certain threshold."

Modern, high-efficiency fridges have compressors that operate continuously. It's more efficient than cycling. My fridge draws about 60 watts continuously.

It's still thermostatically controlled, of course, so if the doors are left open, it will kick up higher.

I'm not exactly a fridge nerd but I had no idea such fridges existed and I'm somewhat curious as to why it's more efficient than cycling. Perhaps it's the ease of which to maintain a constant temperature, rather than a fluctuating one?

What fridge do you have out of interest?

I have an Electrolux.

Here's a report about variable-power compressors:

http://www.panasonic.com/industrial/includes/pdf/invertercom...

I was introduced to refrigeration nerdery by talking with a friend who designs the cryocoolers for JWST (http://www.jwst.nasa.gov/cryocooler.html) who nodded sagely and said "more efficient that way" when I mentioned my new fridge did not cycle on/off. Now that's a fridge nerd!

The problem with cycling is that powering up is the least efficient part of the cycle. So a fridge (or an air conditioner for that matter) that cycles frequently is spending more time running in its least efficient mode.

I'm not a fridge nerd either, but my understanding is that adding thermal mass to the fridge will reduce the heating spikes from things like opening the door which will reduce the frequency at which it cycles up. So you can make your fridge more efficient if you have the space to put big jugs of water in the fridge and big blocks of solid ice in the freezer.

You might only save a buck that way, but if the space isn't being used for anything else you have nothing to lose.

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