- cross-posted to:
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- hackernews@derp.foo
- cross-posted to:
- technews@radiation.party
- hackernews@derp.foo
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Huh, go figure. Anytime I’ve ever mentioned anything about this online, I got downvoted into oblivion with everyone basically saying ‘this is a non-issue’.
I knew I wasn’t crazy. Take my upvote.
I never understood how people couldn’t see that this is the logical result of moving heat from inside to outside.
Like seriously, do people think the heat just goes away?I always figured it was a flea’s fart compared to the whole outside
Sure, individually. But in cities you’ve got tens of hundreds of thousands of buildings, if not millions, doing the exact same thing. Combine that with all the heat absorbed from asphalt, concrete, etc. We’ve known for a long time that cities are usually a few degrees F hotter than the surrounding area.
Poof into the ether!
If only, right?
People are not smart.
It’s pretty logical really… Ac units consume a lot of energy to do their job, that energy will eventually end up as heat. They’re not magic, even if some people think they are.
They also take heat from inside and move it outside. It’s kind of an air conditioner’s while thing.
Yeah, but that’s not relevant. That heat came from the outside in the first place. Heat pumps are very effective at moving heat, i.e. a 2kw unit kan move 8kw worth of energy. It’s not that 8kw that’s the problem. That’s just the heat that’s being moved. That’s a net-zero operation. It’s that 2kw that’s used to move the heat which is a problem. That 2kw is effectively being added to the system, and it comes from whatever your local power grid energy mixture is.
The heat absolutely did not (all) come from outside. Some of it did, varying amounts depending on your insulation. But everything in your house using electricity is adding heat, any gas powered anything is adding heat, and you are adding heat.
A rule if thumb for spaceship design is one person = 100 W
The 8kw of heat may have originally come from outside, but now it’s been put back and concentrated around the AC unit.
So the area around the AC unit has 10kw of extra heat that it would not have otherwise had.
Have you actually ever stood next to an air conditioner exhaust fan? Have you ever worked on air conditioners to even understand how they work?
Sure some of the heat they generate comes from the electrical energy they use, but the whole thing is designed as a heat pump.
An air conditioner moves the heat inside the home or building to the outside. That heat doesn’t magically just disappear, you’re literally moving the heat outside of the convenience of your facility, only to heat up the environment around it.
For every action there is an equal and opposite reaction.
That heat doesn’t magically just disappear
It doesn’t just magically appear either.
True that. We should figure a way to harness the exhaust heat from air conditioners. Easier said than done though, as I’m not aware of any source of energy that doesn’t itself generate heat…
The 8kw you moved are. It irrelevant. The problem is that you consider the system as a whole, but that’s not how it works. If you consider the transfers like that, interior and exterior are 2 different systems, and the exterior system does get this 8kw time tens of thousands to units in the city. You modify the air flow and amplify the heat. The 2kw of energy used is added to city, sure, and that’s also significant, but “simply moving the heat” also has an effect.
What are you suggesting, that we not cool ourselves down? This is the natural result of moving heat out of a room and into the atmosphere. Of course there is waste heat put into the atmosphere too, but much of that heat, if it was produced from renewables, was itself extracted out of the atmosphere to start (solar, wind…).
It really is a non issue. Or at least, this is not an issue we can solve, because these are just the laws of thermodynamics.
The real problems lie where we ignore the natural laws of thermodynamics. Like using fossil fuels for power at large scale.
No shit, you don’t say huh?
Looks like we’re soon to figure out why they dug so many tunnels underneath the country we currently call Turkey that could house like 20,000 people.
Right now, humans are gradually destroying them(our)selves living in matchboxes on the land and burning all the fuel we can find.
Edit: Environmental air temperature tends to be way more stable and more comfortable underground.
Building underground isn’t an option everywhere.
Mostly because hot air rises. The entropy equation seems pretty silly when you consider the volume of outside
Hot air can only rise so far homie. Upper layers of the atmosphere are actually rather cold. Ever seen the tops of mountains and wonder why so many of them are covered in snow?
The Earth doesn’t have a heatsink to transfer extra heat into outer space, so we’re stuck with this conundrum of how to manage our own planet and the heat we generate.
But the collisions between the atoms cause them to rise. If you get to less dense collisions, your temperature goes down. That’s just ideal gas law. I don’t get it actually
This is kind of a non-starter. Hell the example used even says 1400 people died from the heatwave. Oh but they have some recommendations that might cool things a few degrees…at night! AC will become more and more of a necessity as we move further into global warming.
prisoner’s dilemma. you need the whole city to not be selfish and buy air conditioners in order to make the difference, but once some people cave in and purchase it, eventually everyone will need it.
I mean 2-3 degrees C is probably not a significant difference when temperatures are already in the upper 30s when talking about not using them.
That’s the things, 2-3°C of average difference disturbs the current climate and creates big variations, so in daily life it might be closer to ±5-10°C, depending on the season.
This is the best summary I could come up with:
A study found that waste heat generated by a city’s worth of air conditioners during a heatwave can raise the outside temperature by more than 2 degrees Celsius.
As Europe faces more frequent and more intense heatwaves, you might have considered taking the plunge and buying an air conditioning unit.
It comes from a study published in 2020 that was based on a scenario in which air conditioners are used in all buildings of a city like Paris to maintain an interior temperature of 23 degrees Celsius during a heatwave.
Temperature increases due to air conditioning (AC) use “depend on the time of day and the characteristics of the heatwave, mainly its intensity”, according to the study.
They found that, after “Nine days of a heat wave similar to the one of 2003,” the systematic use of AC during that time would increase air temperature “by up to 2.4°C”.
And as cities are only likely to grow hotter as a result of climate change, that means that citizens are likely to demand more indoor air conditioning.
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