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Cake day: June 10th, 2023

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  • MetaCubed@lemmy.worldtoMemes@lemmy.mlThe worst place in the galaxy
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    27 days ago

    Well… “They’re all” is kinda rhetorical shorthand, but the vast, vast majority of Israeli citizens are colonizers definitionally, just like how “all” north Americans are colonizers (obviously except indigenous people). The difference is that the USA/Canadian settler colonial projects have already “”“succeeded”“”.



  • A. Care to provide any evidence for your “gender is a mental disorder” point? Even a little?

    B. No one actually cuts a penis off, just FYI

    C. Its not uncommom for Cis teenage girls get breast reduction surgery, or even implants. Do you have issue with this? Or do you only have an issue when it’s trans men getting a mastectomy?

    D. Why you gotta be weird dude? I guarantee you’ve interacted with at least a handful of trans people in your life and were genuinely clueless about it. (I’m pre-empting the “we can always tell”)

    Edit: didnt notice he’s banned. Leaving it anyway.













  • Sorry, my notifications have been messed up because of the lemmy.world issues! Some other people have already answered but I’ll still reply :)

    A heat pump’s efficiency is measured differently than that of a gas furnace.

    The actual unit for heat pumps is the Coefficient of Performance (CoP). This measures the power input (electricity) VS the power output (heat). A “400% efficiency” as I put it, is a CoP of 4, meaning that for every watt of power used, 4 watts of heat energy are moved. As some other people pointed out, depending on the quality and technology of the heat pump and the interior/exterior temperature, the actual range of a heat pump is a CoP of anywhere from 2-5.5 (the theoretical, perfect maximum is 8.8). The efficiency of the heat pump does dip as the temperature of the region it’s pulling heat energy from lowers, there’s less energy available to move, so it has to work harder. This is why heat pumps in regions with especially cold winters have what’s usually called “emergency heat” which brings us to…

    Electrical heating. This works by pushing electricity through a wire to heat it up. Directly turning electricity into heat. Electrical heating always has a CoP of 1 (terms and conditions apply). For each watt of electrical power consumed, 1 Watt of heat energy is produced.

    Finally we have gas heating, which is still the only option for some areas for various reasons. Gas heating efficiency is not measured with CoP but instead with Annual Fuel Utilization Efficiency, simply a number that represents what % of the fuel burned is actually turned into useful heat energy. I’m finding AFUE ranges of 76-97% as a general range for modern furnaces. If a furnace has an AFUE of 90%, that means that when it burns an amount of fuel representing 100 units of heat potential (I’m not using a unit, BTUs confuse and terrify me) then 90 of those units will be turned into usable heat, and 10 of them will be waste, whether that is heat that leaves via the chimney or is simply unburnt fuel.

    TLDR: 400% means 4x more energy is moved than is used, I apologize for the wordiness, I find this stuff rather interesting


  • Sorry my point wasn’t that we shouldn’t explore other options to use instead of/in tandem with A/C. I was entirely pointing out that the use of an AC/heatpump is by itself, in absence of the context of what is used to power it, a non issue as its one of the most efficient electric heating/cooling technologies we have.

    Wind catchers could be, and likely are a great technology to adapt for wider use, though I can’t speak to that, I’m not an HVAC engineer.


  • I agree with you that we should be exploring alternatives, but aircon is extremely energy efficient for how much thermal energy it moves (reaching 400% efficiency in some cases) . The problem isn’t aircon itself, but what is being used to power it (coal/natural gas power plants)

    In fact the technology behind aircon can be expanded into a heat pump to both heat and cool, being more efficient than electro-resistive or gas heating. There’s even water heaters that will actually cool the area they’re in and use the heat they gather from the space to heat the water.

    Technology Connections has a great series of videos that go in depth on both heat pumps and aircon.