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.
this post was submitted on 28 Apr 2024
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Showerthoughts
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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.
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- 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.
- proper thermal insulation.
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…
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.
I've added it at the end because it seemed obvious to me but yeah, insulation is the first thing to do. Especially under the roof.
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.
Infinite environmental destruction glitch
FTFY
Smart enough to understand heat pumps dumb enough to think it's has that large of an effect.
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
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.
I don't know the answer, but it this did work it would both make the outside of the oven super cold and be so slow to warm up that it would be pointless. Keep in mind that you have to get stuff in and out so air exchange is inevitable, every time you open the door you'd be reducing the heat substantially and it would take a long time to rise back up.
Also my gut feeling is that any practical implementation wouldn't be as energy efficient as you'd hope.
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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.
turns out running AC to cool tents is super inefficient. Who could have known?
If only there were these things that grew out of the ground that cooled you home with their shade.. What were they called again?
If only people who lived in houses understood that not everyone lives in a house.
+1 although trees can shade the ground around the building and cool the area that way too
they also convert some of the sunlight turning air into sugar instead of getting warmer
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.
That is an urban planning problem
Lamp posts? Radio towers?
Gazebo!
Then heat pumps in winter will lower winter temperatures.
Who knew!
Unfortunately it does not work that way :(
Whoosh
Ah, I was afraid that might happen. Oh well.
It's fine, just remember to open your window when you run your AC
If everyone had ACs and did this we could revert global warming!
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Nope. An AC just moves temperatures around. If it heats one area, it cools another.
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.
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.
Man's forgetting the second law of thermodynamics: The ~~house~~ entropy always wins.
That's legitimately how heat pumps work, except without decreasing entropy unfortunately
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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.
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)
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”.
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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.
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.
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.
You need some lessons in thermal dynamics my man.
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.
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.
I don't think that's how anything works
It does and in two ways
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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
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using energy to cool your personal space, increases global warming leading to a need for more air conditioning
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
Global warming lockdown, let's do it 🤣
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