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That last paragraph is me. Your ideas are intriguing to me, and I wish to subscribe to your newsletter. I discovered the ceiling fan was a powerful knob. While

That last paragraph is me. Your ideas are intriguing to me, and I wish to subscribe to your newsletter. I discovered the ceiling fan was a powerful knob. While "storing" heat (early daytime, colder in than out) it helped to keep the air as still as possible to extend the battery. As the heat starts to get uncomfortable at ~1pm, ramped up the ceiling fan. Later after the air-cooling switchover at ~5pm (cooler out than in), switched the ceiling fan to blow up at the gable ceiling. The surface airflow greatly reduced the radiant "chicken broiler" effect. Overnight the operation wasn't as critical, but switching direction every couple hours would best chill all available mass. YMMV Running AC for a couple hours in the morning is good to remove humidity from night cooling. The morning air is relatively cool, so AC is still quite efficient. A small application of (and modification on top of) night-swing cooling, but critical to efficiently maintain humidity. On extreme days it could even help to mist water on the roof. In theory this can be automated with an oscillating sprinkler and a valve. Even just a valve indoors turned manually could make a great benchtop experimental setup. The aim is for the water to instantly evaporate and not soak the roof, perhaps 30 seconds (one "swipe") every 15 minutes or so. It's almost like a "force field" barrier keeping the heat out, but once the battery is drained it doesn't help much. Eagerly watching NightHawkInLight's PCM project[1] with interest too. Personal cooling seems like the ultimate sustainability frontier. Japan was a big innovator after the Fukishima shortage, with fan-jackets worn in hot offices.[2] Fans work until dew point = body temperature, but above that it seems (for now) phase change wins over a battery-powered compressor. Maybe something to chew on among all that. Sorry it got long. Cheers [1] https://www.youtube.com/watch?v=Nqxjfp4Gi0k https://www.youtube.com/watch?v=Nqxjfp4Gi0k [2] https://abcnews.go.com/Business/japan-disaster-sparks-demand-air-conditioned-clothes/story?id=14210492 https://abcnews.go.com/Business/japan-disaster-sparks-demand...

fuzzfactor 2y ago
Ceiling fans usually have larger motors than portable fans and unless there is enough ventilation to allow the heat released by the motor itself to escape, heat will gradually build up in a room with closed doors and windows, just from the heat of the motor alone. Fans are really best only while you are feeling the breeze directly, and for the best effect ceiling fans are more ideal for outdoor use because their excess heat can be more than you expect. After running it for a while, turn it off, wait for it to stop spinning, and feel how hot the motor is. Yup. Not always a problem if you keep the windows open, or are willing to pay for the A/C to remove this excess heat.
- schiffern 2y ago
  > Fans are really best only while you are feeling the breeze directly Indeed! I use them thusly. This is kinda the genius of those Japanese fan-jackets. It's essentially a fan connected to a flexible person-shaped "shroud" (AKA a jacket) which makes sure all the airflow is actually directed over a person's skin. I was gonna invent something to solve exactly that problem you raise, only to realize Japanese inventors beat me to it. :-) P.S. The biggest noticeable effect of having the fan on during the day was to accelerate heat transfer through the hot gable ceiling to the indoor air. Predictably, forced fluid movement accelerates heat transfer, so the "heat battery" of stored up nighttime coldness would rapidly deplete in only an hour or so. During cloudy weather this effect was a lot less, because the ceiling wasn't baking hot.

fuzzfactor 2y ago

Ceiling fans usually have larger motors than portable fans and unless there is enough ventilation to allow the heat released by the motor itself to escape, heat will gradually build up in a room with closed doors and windows, just from the heat of the motor alone. Fans are really best only while you are feeling the breeze directly, and for the best effect ceiling fans are more ideal for outdoor use because their excess heat can be more than you expect. After running it for a while, turn it off, wait for it to stop spinning, and feel how hot the motor is. Yup. Not always a problem if you keep the windows open, or are willing to pay for the A/C to remove this excess heat.

schiffern 2y ago
> Fans are really best only while you are feeling the breeze directly Indeed! I use them thusly. This is kinda the genius of those Japanese fan-jackets. It's essentially a fan connected to a flexible person-shaped "shroud" (AKA a jacket) which makes sure all the airflow is actually directed over a person's skin. I was gonna invent something to solve exactly that problem you raise, only to realize Japanese inventors beat me to it. :-) P.S. The biggest noticeable effect of having the fan on during the day was to accelerate heat transfer through the hot gable ceiling to the indoor air. Predictably, forced fluid movement accelerates heat transfer, so the "heat battery" of stored up nighttime coldness would rapidly deplete in only an hour or so. During cloudy weather this effect was a lot less, because the ceiling wasn't baking hot.