[Request] Cost of Refrigeration of Foodstuffs theydidthemath

Question

Assuming a modern household refrigerator of average cost and electrical efficiency, how long can you store an item of food inside the freezer before the cost of the energy consumed keeping it at -4°C exceeds the cost of the item itself?

(x-post from /r/askscience)

Unimportant Unscientific Backstory

So. My family has a pretty lax approach to food safety, and we're generally okay with consuming things past the listed expiry date on the package, within reasonable means.

What I found not reasonable, though, is a half-eaten 400g packet of seaweed which has been sitting in the freezer for a decade that the parents refuse to let me toss out, having expired in 2008 (oh, they'll eat it, they claim. Eventually. 🙄)

Apart from bringing it out annually to celebrate its birthday, I also regularly mention that the cost of refrigeration might very well have exceeded how much the item is worth in the first place.

I tried doing some research, but my Google-fu was way too weak, so appreciate the subreddit's help in ballparking this figure. 🔬 Physicists, Electrical Engineers, Food Scientists - anyone with an expert opinion on this; over to you, please.

Variables

I would immediately assume the answer to this question might depend on many factors like those listed below, so I've attempted to put in brackets what I think would be sufficiently generic options for calculation, but feel free to substitute your local equivalents if it helps

• heat capacity of food (1kg deboned chicken breast)
• price of food item (New York grocery store)
• storage temperature (-4°C)
• room temperature (25°C, 1atm)
• unit cost of electricity (New York 2007-17 utility rates)
• efficiency of freezer (EPA Energy Star, 2007 models)

Very importantly, would the cost of freezing that quantity of chicken breast be significantly greater than freezing the same volume of air?

Thanks in advance to anyone who can solve this long-ongoing bugbear of mine!

Submitted June 09, 2017 at 11:26PM by Cymcune http://ift.tt/2s5zKtD theydidthemath