I am completly opposed to Air-conditions propagandized as a solution to climate change. What is the wright approach to combating this state of temporary relief except from old-fashioned fans? Don’t get me wrong. They do the job for me. I am reffering to finding a solution for people more with health issues or large facilities that are in need of something more drastic.
Oh, I just remembered this video I watched. There is this guy on youtube that does a lot of material-sciency kind of stuff using common household ingredients. One of his videos he makes a salt-based change change material, which basically works as an icepack that freezes at around 18 degrees Celsius.
The idea is that it takes a long time for the material to melt from 18 degrees to 19 degrees so it can keep you comfortably cool if you put it in a plastic bag and wear it in a vest to keep yourself cool. If you have a cool basement, then it can pretty much re-freeze by putting it on the cold floor.
DIY Supermaterial Could Save You From Heatstroke: Salt based PCMs
Its an interesting watch.
There’s plenty we can do, but all interventions are somewhat limited in effect. With the trend of increasingly intense heat waves, we’re likely going to have to do all of the non-AC interventions and install AC in lots and lots of places.
- Awnings to block sunlight from heating up spaces through windows
- Better ventilation systems which can more effectively pump in colder air from outside during the night
- Heat-reflecting paint to minimize heat gain from solar radiation
- More trees to provide local cooling/shade
- Ceiling fans to provide reduced perceived heat
- District cooling, when appropriate, to provide cooling at a higher energy efficiency
All help, but when the temperatures start hitting 40 C with high humidity, you’re basically out of luck without an AC, that can pump out the heat and lower the humidity.
Extremely good insulation, possibly building things underground, and then air conditioning. You said people with health issues. If you need to make sure something is a a specific temperature because of health concerns, you need air conditioning to be certain. Really making sure you’ve got incredible insulation is really all you can do. Tall trees that block the sun around the building can help. Using blinds and curtains as well instead of letting the sun in.
@JackbyDev @turip Problem with insulation is that there isn’t a good way to retrofit old buildings with it without mold building up, as old buildings were designed to breathe.
You can ventilate periodically, air doesn’t hold that much thermal energy. You can also use heat recovery ventilation, should work in reverse to keep the heat out too.
There is not a magic solution that is perfect in every scenario. Air conditioners decrease humidity as a side effect, though.
Building anything underground is extremely expensive and energy intensive, as you have to constantly pump ground water and pour concrete to keep walls from breaking under pressure of tons of soil.
So yeah, underground could work, but better used sparingly when benefit outweighs the costs, like maybe in areas that could go literally uninhabitable on the surface. Otherwise not worth it.
Most of North America built bungalows after WW2. All your dramatic concerns were addressed 50 years ago, and no, they were not extremely expensive and 8" concrete walls with French drains and sump pumps work well.
If you can come up with an alternative way to cool the air indoors that’s less energy demanding and environmentally friendly that could be a revolutionary invention on a global scale
Not gonna debate A/Cs merits as a fix for climate change but the ability to chill and cool a place at will is one of the overall more important human innovations ever. Food storage and preservation as well as tons of medical/scientific research and development is dependent on refrigeration.
It’s also really gonna depend on where you live in the world to be able to rely on standard fans, which still rely on electricity and if the humidity gets too high for your sweat to evaporate may not even cool you down properly enough to prevent wet bulb heat deaths. Bangladesh for example will cook in the coming years without something to break the heat and muggy air.
First thing is to avoid air conditioner entirely so that your body climatizes. If you’re sitting in AC at work than that’s part of the problem.
-
Block the sun from hitting your house. Outside the window not inside.
-
Use evaporation to cool your body / the air. Swamp coolers for the house but also neck coolers for your body.
-
If/when it drops below 20°C get as much airflow as possible. If you can use thermodynamics to your advantage by forcing hot air upstairs out while cool air from lower comes in.
Swamp coolers do nothing in humid summers.
Almost no one mentioned roller shutter. They need to be installed outside to actually work, but they are very good at reducing temperature inside (I had them installed on my southwest facing windows). Air conditioning is ok, but it’s also such a lazy solution and it seemingly prevents people from even trying to come up with different ideas.
-
@turip youtu.be/stvTwCY-8IU Here is an option, but you will need a powerful dehumidifier, which might use the same amount of energy as a good heat pump. Or we can go with the China option of treating cooling as a public utility that saves up to 50% of the energy that AC uses. youtu.be/AAz5D3TnQ_k
Back to the caves. Literally.
The alternative is architecture designed to keep a building cool.
Or modifying what you have already.
Take a south or west facing window with a balcony & railing in front. By installing planter boxes on the railings and growing black eyed susans / morning glory / any climbing flowers, letting them grow up bamboo poles space 4" apart, you can create a heat absorbing barrier. The plants block and use the energy that would have been absorbed by your house. Unlike shades/screens they won’t heat up until they begin radiating heat themselves.
Female Hops are another great planting option. They cannot reproduce without a male plant, and every year they will grow back stronger. Train them underneath your building eaves and they will reduce the amount of heat energy your house absorbs.
…
Also insulation. In Canada we need lots of insulation under our roofs for the winter. So while during the summer our black top roofs absorb a lot of heat, not as much of that heat is transferred to the indoor air as a roof with less insulation.
I second that! I am not too sure about hops tbh, in the sense that they don’t seem to thrive/survive where I live, but the idea of using vegetation is helping greatly to cool the microclimate. The downside is that you will need at least a balcony, the bigger it is, the more vegetation you can have, and the more you have, the cooler it will be. If you have a garden, it’s a whole other level, in the best possible way.
This approach is also great because you can plant eatibles, and have your own veggies and fruits.
Hops need LOTS of dirt for roots, water, and something to climb. I live in Zone 6a but our summers peak at 35°C so they might be more viable than you think.
If you do them in raised bed you 100% cannot have a sealed bottom.
Its important to mention that this does require some maintenance and to be sure that the outside of the building is structurally sound (ie. gaps, rotted wood, crumbling morter,etc.)
building is structurally sound
Especially if you go with permanent plants. Like I suggest against Virginia Creeper cuz it will obscure any developing issues.
There is only so much you can do to achieve that. If temperatures are in the upper 30s for an entire week. You can’t keep the heat out forever
Yeah, if you build with conventional stick and fibreglass.
Thermal mass and earth-cooled air and shading can achieve a lot.
Planting trees and bushes and plants around the property helps cool down the air around it too
Best I can do is clear cutting to build a neighborhood and then an HOA that won’t let you plant trees.
I don’t think I’ve ever heard of an HOA in Canada, yet.
At least not in Québec.
Native trees mostly, but external shade in any form you can get it.
Most solutions require engineering the building for little to no use of AC and relying on better ventilation.
One example that can be applied to a house is a central shaft with a fan on the bottom, which will pull in air closer to the ground and blow it upwards - remember, cold air tends to stay down while hot air tends to go upwards. The house will need to have a small elevation, or the central shaft will need some ducts for the air to come in.
There’s also the Persian Windcatchers, which they have used for centuries, towers that receive hot air from one side, bring it down to an underground channel and blow off cold air from another side.
Green roofs can also help significantly.
Green as in the color? Or green as in environmentally conscious?
I am having to replace my black shingle roof very soon and planned to do a white one.
Green roofs as in actually having plant life growing on top of them
Even better! But sadly not something my current home could support.
I’ve seen green roofs on bus stops and favelas in Rio, Brazil, where their roofs have terrible infrastructure. From what I understood, they basically partnered with a local university to try to reduce the heat island effect in favelas, as most of them had no greenery at all
They came up with a cheap solution involving a plastic liner, similar (perhaps the same) to those used in ponds; a geotextile layer of bidim, which is a lightweight material; and plants that don’t need soil to grow, like those found growing on rocks or trunk of trees. Which means it is super light and still provide the same benefits as a green roof with soil in it
I have a pitched roof on a mobile home.
Sounds cool. Did you DIY? Do you have to move often?
I don’t think pitch is a problem as those plants cling to trees at 90° and the layers are glued, but I understand it is not a solution that can be installed anywhere :)
You might want to look at metal roofing. White helps and makes sense from a visual standpoint where the base material can only be dyed/painted and not changed, but even painted metal reflects infrared better, which is where the heating energy really exists.
@XeroxCool @nocturne There are special nano-materials they have that blocks all IR heat from entering the building. We shall see how this scales.
A white tin roof is the plan.
Eeeexcellent, I’m excited for you.
Insulated attics make roof material irrelevant. Heat comes in from walls.
Those roofs are for architectural projects or custom homes for Hollywood celebrities. Nightmare in costs and they don’t last.
Look up succulent roofs sometimes and you might change your preconceived and mostly false opinion about green roofs 🤷
Those are cheap, low maintenance and last forever.
I’ve been fascinated by this concept of passive radiative cooling, where you have some material that radiates heat to space in an infrared window where the atmosphere is transparent. Apparently, a sheet of such material can be a fair bit cooler than the ambient temperature without any consumption of energy? It would not necessarily be an alternative to air-conditioning, but it could potentially reduce the energy costs quite a bit, while lowering the heat island effect in urban areas.
There are some interesting applications where a radiative surface that is shielded from radiation coming back the other way can emit radiation to cool itself by a few degrees below ambient temperatures. There’s one paper from a few years ago that describes being able to cool to 5°C below ambient temperature even in direct sunlight with some exotic materials.
Interesting stuff.
Looks like this paper on the topic was only released yesterday. It’s more focused on the practical issues of deploying PRC panels, where other papers I’ve read seem to discuss the tech in a lab setting that may or may not be scalable?
Window awnings can help a lot in summer and are relatively easy to retrofit on an existing building.
I’ll answer your question first, but I have some issues with the framing you’re using around that question. The two other main methods of practical temperature management available to us are evaporative cooling and geothermal. Your body has a built-in evaporative cooling mechanism called sweat. Fans take advantage of this. But not everyone has equally effective bodies for this, not all climates are particularly effective for it (high humidity makes it extremely ineffective) and not everyone finds it comfortable for their situation. Swamp coolers are a different form of evaporative cooling that move the evaporation process onto a substrate which then cools things down with a fan. You can also find natural evaporative cooling working for you in many places, for example around large bodies of water. There is an externalized cost here if you’re trying to make evaporative cooling work in an environment that’s unsuitable for it, and the cost of fresh water is a significant line item on the energy budget too. Don’t neglect that by assuming evaporative cooling is a clear win that is automatically preferable to an air conditioner. All these evaporative solutions share the reality that they’re going to add (often very significant amounts of) humidity to the air. Air conditioning on the other hand can actually remove humidity from the air, and is one of the few practical methods of doing that. It’s solving the issue in a different way, but it’s a significant and important difference.
The other option is geothermal. This is genuinely underutilized today and I think we can certainly save a lot of energy budget by accessing stable and susprisingly comfortable temperatures underground basically year-round. Geothermal heat pumps (which use air conditioning technology) are by far the most practical way of doing this in our current situation, but older solutions involving buildings that are deeper in the ground or that have airflow going through the ground can provide access to this temperature too – with the caveat that you’ll often run into problems with water, flooding, or condensation/mold unless you’re in a particular sort of environment where this is not a concern.
As for the framing: You have to look at it systemically I think. We do a lot of things that seem dumb on the surface, and sometimes they are dumb, but more often they are making tradeoffs for particular reasons and a lot of times those turn out to be the right tradeoffs, there’s just a lot of complexity to the system that you’re glossing over. You can certainly argue those reasons, and try a different path, as long as you understand them first. Some of the reasons might be invalid or the tradeoff might not be the right trade, but I don’t see the benefit in making blanket value judgements without understanding what they are and why they’re happening. But I think you’ll find it more challenging than it seems to come up with a better solution in the long run.
What is your specific objection to air conditioners? Temperature is a huge line item on any energy budget, and it has to be managed somehow. There are few places on the planet where humans can live year-round without some form of temperature management, and quite often that requires energy. Firewood is not always a given and not perfectly sustainable at least the way we use it. An air conditioner is not propaganda it is a tool, and you have to figure out if it’s the right tool for the job but that’s never going to be a binary true/false. I think saying you’re “completely opposed” to them and calling them propaganda might be blinding yourself to what the actual goal is and what tools you can use to get there.
Using an air conditioner to live in a hot place is, at least as I understand it, still more energy efficient than using any kind of heater or even a heat pump (which is just an air conditioner in reverse) to live in a cold place, and hot places also have more readily available sources of other energy, typically, so this is not necessarily the wrong choice as transmitting energy long distances is not always a good call either. But you have to understand the tradeoffs you are making. This is why it might seem like propaganda, but it might just be that someone’s done the math and come out to this answer. If you are looking at different numbers, or missing some of those numbers, you might come to a different conclusion, but the air conditioner itself is not the problem, the disagreement in the numbers and the context you are putting those numbers is going to be the root cause you need to figure out.
Afternoon siesta. There is a reason most hot climates have a culture of an afternoon nap in the shade.
Don’t forget to drink lots of water. Not soda or coffee, simple water. Carry a water bottle with you everywhere and make sure you empty and refill it regularly. As the scout camp I was at last week constantly says “Hydrate - or die!”
There are all sorts of alternatives. But they are all really expensive, difficult to deploy and tend to be viable only in certain locations. Earthships are one.
https://en.wikipedia.org/wiki/EarthshipI’ve seen some people do closed-loop earth tube systems. But they collect mold and have drainage issues.
Older homes and barns use to have Cupolas or widow’s walks, also historically called a roof walk or captain’s walk. The hot air rises and is vented out the top of the house.
https://www.architerms.com/cupola
https://en.wikipedia.org/wiki/Widow’s_walkYou may hate AC but for some locations and situations it’s the best solution. If not the only solution.
Earth tubes could pump water instead of air and then pass it through a car radiator or similar kind of heat exchanger.
I find the idea interesting but haven’t actually tried it. Could cost a bit and not sure how effective it would be.
That’s a buried coil closed heat pump system. Very expensive.
Yup. But my answer was getting kind of long. There are tons of solution from all over the world. You could write a book on this.
Ground source heat pump operate like earth tubes.
