Sorted by New

Wiki Contributions


Air Conditioner Test Results & Discussion

Measuring energy consumption is cheap and easy with a $30 Kill-a-Watt:

I propose a follow-up experiment to measure daily energy consumption alternating hose configuration with the same set temperature.  The previous experiment tried to answer "how much does maximum cooling power change between configurations," while here we would answer "how much does efficiency changes between configurations."

Potential issues:

  1. If this causes your unit to run at different power levels, you would also capture any efficiency change based on the power level, but I would guess your unit regulates simply as on/off (check the (instantaneous) power consumption with the Kill-a-Watt to be sure).
  2. If one configuration works faster, it may not do as much work on the other side of the room before the unit senses "cool," and turns off.  Fans in the room increasing circulation will mitigate this.
  3. I don't know how many days you would need for good statistics to smooth over all the day-to-day environmental changes.
  4. You should also analyze weekend vs. weekday, and possibly exclude one.
  5. You will need to monitor that both configurations actually are up to the task.

I'm not sure I want to register an advance prediction, but if OP agrees to do this, I will at least put some thought in towards one.

Ceiling Fan Air Filter

I'm not so sure a central air system wouldn't be up to the task.  I calculate this purifier at 150 CFM from the product page and assuming 8 ft. ceilings, and this implies 1,500 CFM would be a fairly typical residential HVAC system, so that seems roughly adequate to me.

Also, that product page suggests you should cycle air 5 times per hour, but that seems excessive to me.  I use that unit in a much larger room on a low setting and it does just fine getting rid of any smoke smell from wildfires.

Ceiling Fan Air Filter

Though I love the idea of a filtered ceiling fan that's out of my way and can therefore be larger and quieter, I don't think a jury-rigged solution would work at all.  Fans tradeoff flow for static pressure (, and I'd bet ceiling fans are optimized for flow.  The filters will up the impedance considerably compared to basically open air, and the flow would drop dramatically.


Also, some (most? all?) central air systems can run fan-only (no heat or AC), making additional filters unnecessary.

When Can You Use a Travel Adapter?

I would not have predicted that.  I don't think I've ever seen a power brick not rated for multiple voltages.  If I ever find one, the first thing I would do the next time I'm in a 240V country is plug it in and see what happens, but please don't do that yourself unless you know what you're doing.

When Can You Use a Travel Adapter?

One of my TVs is rated to work anywhere, and another is not.  All my computer monitors are rated for multiple voltages.  For my TV that's rated 120V only, I think it's intentionally not certified for 240V because it's an NTSC model.  There might be a fuse set to blow if you plug it in to 240V, but if not, I would be only mildly surprised if it just worked.

When Can You Use a Travel Adapter?

Your heuristic is accurate, but I think understanding why it is accurate is as easy as remembering the heuristic.

The near-universal switched-mode power supply works efficiently for a broad range of input voltages and frequencies.  If your device runs on DC, with very rare exceptions (some high-end audiophile gear, specialized equipment), it has one of these AC/DC converters (power brick, wall wart) and can run on the mains power anywhere in the world.

All electronics run on DC.  Anything with a large motor (not the motor for your optical drive tray) uses AC.  Things like light bulbs and resistive heaters in principle work with both AC and DC, but are designed for specific inputs.  Getting it wrong  be dangerous, but in almost all cases will result in non-operation or a blown fuse.  (If you're fooling around, or using devices that have a non-standard plug, all bets are off.)

Russia has Invaded Ukraine

Russia attacking the rest of Ukraine may be a tactic to keep Ukraine from concentrating it's forces in the east, rather than an attempt to take significant territory.  It's still possible Russia will stop and consolidate gains after taking a chunk of the east (like in Georgia and Crimea).

Occupying Kiev is the kind of thing where cheap weapons (missiles) can destroy expensive weapons (tanks), and is probably very undesirable, depending on how many of those cheap weapons have gotten and will get to Ukrainians.  It might be possible to install a puppet government with minimal losses, though.

New edition of "Rationality: From AI to Zombies"

I would love an elaborate collector's edition box set for my coffee table when all six books are revised. The version on my phone is the one I'm actually going to read, but this is the kind of thing I want friends to see in my apartment when they visit.