Friday, July 1, 2016

Refrigeration and air conditioning

Seems like a good time to give a nod of appreciation to the
refrigerator and its companion, the air conditioner. I was surprised
to read in the Wikipedia that artificial refrigeration dates back to
1750. That is well before we were a nation.

We have a refrigerator and a freezer. One keeps foods below 40° F
(4.4 C) and the other cools down to below 0° F (-17.78 C). There are
many foods we don't want to freeze, often for convenience and
palatability rather than food safety. I often think it odd that we
have these little boxes in the house, compartments in larger boxes
really, that are arranged to have heat pumped out of them until the
desired temperature is reached. It seems surprising that we so often
want to chill or freeze our food. Lynn's lasagna or soup can sit in
the freezer usually on a paper plate inside a zip plastic bag for
immediate use in the microwave for months or more. Then, zap! Ready
to eat. I was surprised when our daughter visited us and zapped
frozen chicken breasts into delicious servings so quickly and with no
time spent on thawing. We do have a pantry of canned foods and dry
foods like crackers and cookies. But with milk, vegetables and
fruits, we almost never have a meal that doesn't have one or more
ingredients from the refrigerator or the freezer.

The idea of pumping heat out of something fascinates me. I enjoyed
the parts of "Where Good Ideas Come From: the Natural History of
Innovation" by Steven Johnson that discussed the invention of air
conditioning. Again, we get the idea of heating with unwanted heat
and then cooling somewhere else so that the interior of the house or
school or theater gets cooled. If the earth is going to heat up, we
will be happy to have the techniques and the machinery to make use of
our knowledge and cool things down.

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