You could take a certain quantity of ice, figure out how long it takes to melt under a fan in hot weather, then calculate the energy required to get that quantity of water into ice (heat capacity equations), and you'd have a rough figure for energy spent per unit time.
Then compare that with the energy consumption of an air-con unit.
Re:How to Sleep Comfortably on a Hot Night
by derobert on Tuesday August 18, 2009 @03:12PM
(#771215)
An experiment is easy to run. Obtain a Kill-a-Watt or other power meter, then measure (a) how much power the freezer uses over a day w/o freezing extra ice for fan-ice cooling, repeating several times; (b) how much power the freezer uses over a day with freezing extra ice for fan-ice cooling, repeating several times; (c) how much power the fan uses blowing over the ice; (d) how much power an AC uses to keep the room comfortable, repeated several times; (e) [bonus] how much power an AC set to a higher temp. + a fan blowing on you uses to keep the room comfortable, repeated several times.
You can then compare (b)-(a)+(c) vs. (d) or (e).
Ideally, you'd do these experiments in identical conditions (temp., sunlight, wind, humidity, etc.), of course.
Any ideas on how to be more rigorous about thinking this through or running an experiment?