I worked in a building with an archaic HVAC system and where the sun would shine right in my room in the afternoon in April. Four of us worked in a small room and we were all software devs whose bodies generate about 100W of waste heat, I had Windows desktop and a Linux desktop and a Windows laptop and a Sun SPARC workstation and a Sun Ray terminal each of which wasted another 100W and the other devs had the same.
Temps got over 100F in April when the building as a whole was in heating mode and could not supply aircon. I’d be wearing a tank top and drinking a lot of water and people would ask me how I bore it and I said it was no problem because the humidity was low.
One hot summer I covered the windows of my house with space blankets that I bought because I was doing a presentation in space solar geoengineering and turned my hue lights to green on the theory that you get more visibility illumination for less energy (and heat felt on my bare skin) that way. Opened the windows manually and ran fans all night to equilibriate to night temperature and enjoy the heat soak all day.
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
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.
> 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.
How can I prevent my work computers turning my home into an oven?
Powered ceiling vents that pull air into the attic, then powered fans at the front/rear of the home relative to the normal air currents during summer. Fans use far less power than HVAC and will keep the attic dry, free of mold. Some fans also have adjustable though not super accurate high/low temperature controls to automate this process.
If the ambient temperature outside is very hot then another modification would be to have vents in the floor that connect to 300 to 500 feet of corrugated pipe that runs underground over a large area then has a tall intake pipe with a screen. The constant low temperature under ground will bring the ambient temperature to a difference between the outdoor ambient air and the constant 50F/9.9C underground. This would also need some low powered push-pull fans.
> tie the heat pump into Home Assistant via bluetooth to keep it set above indoor ambient
To avoid condensation it only needs to be above the indoor dew point temperature[1], so there's actually some thermal headroom in this system for additional performance.
The auxiliary transmission-fluid-cooling radiator often seen as an option for pickup trucks intended for towing trailers or other heavy-duty use can probably withstand the elements a lot better than some alternatives.
Found in many different sizes, capacities, and connections with a few affordable possibilities like these:
Temps got over 100F in April when the building as a whole was in heating mode and could not supply aircon. I’d be wearing a tank top and drinking a lot of water and people would ask me how I bore it and I said it was no problem because the humidity was low.
One hot summer I covered the windows of my house with space blankets that I bought because I was doing a presentation in space solar geoengineering and turned my hue lights to green on the theory that you get more visibility illumination for less energy (and heat felt on my bare skin) that way. Opened the windows manually and ran fans all night to equilibriate to night temperature and enjoy the heat soak all day.