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submitted 6 months ago* (last edited 6 months ago) by wabafee@lemmy.world to c/showerthoughts@lemmy.world
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[-] tunetardis@lemmy.ca 52 points 6 months ago

That's why we need passive daytime radiative cooling. In theory, it could completely eliminate the urban heat island, but it still seems to be mostly at the pilot project stage so far. I did read somewhere that you can DIY with some packaging tape (which somehow has the right properties?) over a reflective backing. Maybe I'll experiment a bit this summer.

[-] BastingChemina@slrpnk.net 26 points 6 months ago* (last edited 6 months ago)

There is a lot of passive system to prevent heat to come in, in the first place.

  • Brise soleil (sun-breaker) - these systems prevent direct sun to go through the window in summer, but let it in to heat up the habitation in winter.

A illustration of a "Brise-soleil"

  • Trees ! - Trees have a cooling effect in summer and a keep the warmth in winter. They also improve air quality, physical and mental health. Increasing the areas covered by trees in city could bring down there temperature by several degrees.

Increasing tree coverage to 30% in European cities could reduce deaths linked to urban heat island effect

A street in Brooklyn with cars park on both side and a full tree canopee

  • proper thermal insulation.
[-] tunetardis@lemmy.ca 8 points 6 months ago

Yeah, I'm a big believer in shade trees! The one in our front yard has grown tall enough to provide blessed relief from a blazing afternoon sun. The only problem is the dude next door, who's heavy into solar, is worried it'll block his panels. And I'm a believer in solar too, so I don't know what to say. Maybe we can come to some sort of compromise…

[-] azertyfun@sh.itjust.works 7 points 6 months ago

proper thermal insulation

what an understatement. it's very unsexy but also incredibly effective. if your house is over 20 years old, you don't need fancy-ass blinds, you need to get your house insulated ASAP. everything else must wait.

insulation is the number one most effective thing anyone can do to improve the energy use of their living space. only when your house is properly insulated can you think of shade management, greenery, passive ventilation, heat pumps, etc. in an insulated house, those either won't work at all or will be wildly inefficient.

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[-] mojo_raisin@lemmy.world 5 points 6 months ago* (last edited 6 months ago)

You totally can.

I'm planning on making some panels to help cool my garden in an attempt to help plants survive extreme heat and sun by shooting some of that heat into space! The combination of partial shading with cooling mass vs heating mass should help a bit. People think it doesn't work, but I'd imagine growing a garden on a asphalt blacktop vs white cement would make a few degrees difference. This technology does the same thing, it just pushes the boundaries further to cool below atmospheric temperature.

https://www.youtube.com/watch?v=dNs_kNilSjk

https://www.youtube.com/watch?v=N3bJnKmeNJY

You're the first person I've seen bring this up, not sure why it's not more popular, just new I guess. Also, usually when I bring it up people say it's' bad because it will encourage more fossil fuel growth and they totally miss the point.

[-] PipedLinkBot@feddit.rocks 3 points 6 months ago

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[-] Deconceptualist@lemm.ee 46 points 6 months ago

Infinite environmental destruction glitch

FTFY

[-] muntedcrocodile@lemm.ee 38 points 6 months ago

Smart enough to understand heat pumps dumb enough to think it's has that large of an effect.

[-] agressivelyPassive@feddit.de 35 points 6 months ago

In cities it actually does have an effect, especially in crowded ones. Millions of people in a relatively small area blasting AC "exhaust" out of their windows heat up the crammed air and in turn the buildings, streets, etc. which increases the heat island effect of cities.

Granted, it's not a huge effect, but it's measurable. First source I could find: https://www.euronews.com/green/2023/08/30/fact-check-is-air-conditioning-making-cities-hotter

[-] captain_aggravated@sh.itjust.works 6 points 6 months ago

see I've been wondering if a heat pump system could heat an oven hot enough to bake bread. use environmental heat to manufacture Wonder Bread or something.

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[-] CosmoNova@lemmy.world 34 points 6 months ago

I remember a statistic claiming that at the peak of the Iraq war, the annually power consumption of US military ACs alone exceeded that of the African continent.

[-] Knuschberkeks@feddit.de 23 points 6 months ago

turns out running AC to cool tents is super inefficient. Who could have known?

[-] buzz86us@lemmy.world 33 points 6 months ago

If only there were these things that grew out of the ground that cooled you home with their shade.. What were they called again?

[-] intensely_human@lemm.ee 14 points 6 months ago

If only people who lived in houses understood that not everyone lives in a house.

[-] Scolding7300@lemmy.world 13 points 6 months ago

+1 although trees can shade the ground around the building and cool the area that way too

[-] Fedizen@lemmy.world 7 points 6 months ago

they also convert some of the sunlight turning air into sugar instead of getting warmer

[-] Croquette@sh.itjust.works 12 points 6 months ago

It is still highly beneficial in term of heat when there is a lot of shade in a city.

The tarmac gets really hot and release that heat for a long time.

[-] buzz86us@lemmy.world 4 points 6 months ago

That is an urban planning problem

[-] Harbinger01173430@lemmy.world 8 points 6 months ago

Lamp posts? Radio towers?

[-] MNByChoice@midwest.social 26 points 6 months ago

Then heat pumps in winter will lower winter temperatures.

[-] wabafee@lemmy.world 2 points 6 months ago* (last edited 6 months ago)
[-] Turun@feddit.de 2 points 6 months ago

Unfortunately it does not work that way :(

[-] aubertlone@lemmy.world 2 points 6 months ago
[-] Turun@feddit.de 4 points 6 months ago

Ah, I was afraid that might happen. Oh well.

[-] Aurenkin@sh.itjust.works 13 points 6 months ago

It's fine, just remember to open your window when you run your AC

[-] Strobelt@lemmy.world 3 points 6 months ago

If everyone had ACs and did this we could revert global warming!

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[-] Alto@kbin.social 5 points 6 months ago

Already happens in a very round a bout tangential way. At least in America, most homes have far more heating capacity than they will ever actually use.

[-] someguy3@lemmy.world 3 points 6 months ago* (last edited 6 months ago)

This doesn't follow the meme or make any actual valid criticism. Furnace use doesn't feed into itself. And furnaces kick on and off based on the thermostat, so sizing with a factor of safety doesn't matter.

[-] dcoe@lemmy.world 5 points 6 months ago

Nope. An AC just moves temperatures around. If it heats one area, it cools another.

[-] pm_me_your_titties@lemmy.world 51 points 6 months ago* (last edited 6 months ago)

Except it is not 100% efficient. It will have losses, which will add extra heat to the surrounding area over what was removed from the target area. Thus contributing to the increase of entropy in the universe. And bringing us one step closer to the heat death.

[-] kakes@sh.itjust.works 13 points 6 months ago

The real trick is to reverse-cycle your AC, and pump the heat into your home. Because of math and algorithms, this one trick will decrease entropy and take us further away from the heat death.

[-] NoneOfUrBusiness@kbin.social 6 points 6 months ago

Man's forgetting the second law of thermodynamics: The ~~house~~ entropy always wins.

[-] algorithmae@lemmy.sdf.org 2 points 6 months ago

That's legitimately how heat pumps work, except without decreasing entropy unfortunately

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[-] hperrin@lemmy.world 17 points 6 months ago

ACs also generate heat as a waste product (they’re not 100% efficient), but I’m not sure that actually heats up the surrounding area to a noticeable degree.

[-] Silentiea@lemmy.blahaj.zone 2 points 6 months ago

They're more than 100% efficient (they move more watts of heat than they produce), but they're less than ∞% efficient (they use Watts of energy still, so they still produce Watts of heat)

[-] hperrin@lemmy.world 2 points 6 months ago

100% efficient would mean they do their job without any waste heat. They create waste heat, therefore they are not 100% efficient.

The only thing that is 100% efficient is an electric heater, because its job is to create heat, so it doesn’t create “waste heat”.

[-] Silentiea@lemmy.blahaj.zone 2 points 6 months ago

A heat pump can heat a home by more than the energy in the electricity it uses. It's more than 100% efficient at "converting electricity into heat in your home". It does that by not actually covering electricity but by moving heat, and it is less than 100% efficient at converting electricity into motion, and introduces some waste heat

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[-] wabafee@lemmy.world 3 points 6 months ago* (last edited 6 months ago)

Yes your right should have been more clear. If AC moves hot air from a house. This hot air goes out then imagine hundreds of AC doing that. Would that in turn heat up the area around it.

[-] teegus@sh.itjust.works 6 points 6 months ago

As long as the temperature inside remains constant, as much cold leaks out as is transported inside. So the only residual heating outside would be from inefficiensies in the system, not the moving process itself.

[-] Coreidan@lemmy.world 4 points 6 months ago

You need some lessons in thermal dynamics my man.

[-] Thorry84@feddit.nl 4 points 6 months ago

To be extra clear: An AC transports the heat, not the hot air. It removes heat from the air and transfers that heat to the outside air.

There's also heat pumps that work with water instead of air. So they remove heat from the air and push it into water. This water can be a closed loop, or be open where the water is lost. It can also work the other way around where the heat pump takes heat from outside and pumps it into water, heating up the water to then be used for heating a home or taking a shower. There are also water-water pumps that work on water on both ends.

Because heat pumps pump the actual thermal energy, the medium doesn't really matter much.

[-] TrickDacy@lemmy.world 4 points 6 months ago

I don't think that's how anything works

[-] bunkyprewster@startrek.website 6 points 6 months ago

It does and in two ways

  1. running a refrigerator with an open door in a closed room makes the room warmer not cooler. The fridge just moves heat around but there is inefficiency too that comes out as excess hear

  2. using energy to cool your personal space, increases global warming leading to a need for more air conditioning

[-] covert_czar@lemmy.dbzer0.com 3 points 6 months ago* (last edited 6 months ago)

I've thought about the same shit and that's true lol
Covid lockdown was the best days with climate Hope everyone will understand what's causing global warming

[-] cyberpunk007@lemmy.ca 3 points 6 months ago

Global warming lockdown, let's do it 🤣

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this post was submitted on 28 Apr 2024
211 points (88.9% liked)

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