New technology could reduce the amount of energy for air conditioning
wired.com
wired.com
1. Air conditioning consumes 10% of global energy and 20% of energy used in buildings.
2. Demand for cooling is expected to increase significantly, with 2/3 of world households projected to have air conditioning by 2050.
3. Dehumidification accounts for over half of energy consumption in air conditioners in humid conditions.
4. New technologies are being developed to improve air conditioning efficiency:
a. AirJoule by Montana Technologies:
- Uses metal-organic framework material for dehumidification
- Claims to reduce energy for dehumidification by up to 90%
- Still in prototype and testing stages
b. Blue Frontier:
- Uses liquid desiccant for dehumidification
- Being installed in various locations in the US
c. IceBrick by Nostromo Energy:
- Energy storage system for large-scale cooling
- Can reduce annual cooling costs by 30% and associated emissions by up to 80%
- Only suitable for centralized cooling systems
d. Gradient:
- Window-based heat pumps with larger external units for better efficiency
- Currently costs $3,800, aiming to reduce to $1,000
6. Passive cooling measures (e.g., window shutters) should not be overlooked as they cost nothing to run.
7. Current non-centralized air conditioners operate at only about 20% of their theoretical maximum efficiency.
Technology Connections just did a video on awnings. I'm not quite as puppy eyed about them as TC, but they are pretty darn effective.
What about insulation? In my experience the insulation in most hot places is abysmal, compared to cold places. I’m not even a layman, but shouldn’t the physics work the same? Or does the air flow from AC change the equation?
Insulation works great in hot climates, but only when the building is also well air-sealed and air-conditioned. Otherwise, insulation alone will just make a house work like an oven after it heats up (through radiant and convective heat gain).
I have one, and it helps keep my house a lot more comfortable in summer, reducing the need for a/c to maybe a couple of weeks a year.
MOFs are super interesting!
https://en.wikipedia.org/wiki/Metal%E2%80%93organic_framewor...
they are one of the most complex non-biological structures I know of
Edit to add: just in case, you should never use water out of a dehumidifier for anything but grey water use cases unless you sanitize and purify it - it can make you very sick!
So Florida is known as the sunshine state, but it's also the rainy state. It rains 2.5x more by inches than it does in Rainy Seattle.
I often wonder why hot water systems aren't linked into the HVAC as well. I know you can get heat pump water heaters, but it seems like integrating it into the HVAC system would potentially allow for system scale optimizations. I would assume the cost/complexity is too much for residential systems. For that matter, refrigeration in homes falls into the same category as they are a heat pump that's dumping waste heat into your living space.
Modern cars are already doing this with heat pumps to manage batteries and the cabin temperatures.
It's pretty easy to see where building technologies will go by looking at car technologies...
Adding different systems to the mix, to where we now need the HVAC guy, plumber, etc. to all set up a working system together seems like a recipe for disaster.
Assuming these were the prior positions of a non heat pump system, you've gone from creating heat to transferring heat; while both radiate heat, the heat pump is much closer to net 0.
One reason don't see combined systems is that refrigerator and water heater don't move that much heat. Refrigerator is fine dumping the heat into the kitchen, and water heater pulling heat from the basement. The air inside the house turns into the working fluid.
Best part is, you can supply heat to the tank in multiple ways, even concurrently. Think heat pumps, solar water heaters, or even a fireplace if you're so inclined.
I wonder if there is another way to connect things?
One interesting thing he pointed out was that HVAC system load calculations are predicated on a max exterior temperature of something like 92 or 94 degrees (I forget the exact number). If the exterior temperature exceeds that, the system's ability to cool faster than the space heats is compromised. And if you think, oh, just oversize the system then, you'd be making a mistake as well. Over-sized systems don't run enough for proper dehumidification and most houses I've been in do not have a dedicated dehumidification loop. My friend has one in his house, but it uses dedicated vent lines and everything, so it's a sizeable investment. That's actually where things like this system start to become interesting.
The framing (at least as I understood it) was more on the psychometric side - 24C@65% relatuve humidity _feels_ worse than 27C@45%RH, but the energy savings aspect is also non-trivial.
As an aside - a fairly large number of central AC systems in the US do not have a humidity censor, so they only go by the temperature set point. Upgrading to control system which does measure humidity, while energy inefficient (because AC would be used to dehumidify the air _below_ the target set point), is an option, though not as good as having a stand-alone humidity control system. Sadly, I am unaware of Nest and/or Ecobee's support for this sort of a setup. Probably not cost effective for them. :\
It's complicated to quantify, but in a sense 24C@65% is warmer than 27C@45%RH. Or rather, maintaining your body temperature is more difficult in the former than in the latter.
The human body produces ~100W of heat, and the primary way to get rid of it in warm weather is evaporative cooling: at below 100% relative humidity water slowly evaporates, this takes energy and thus cools down the surface the water was sitting on. We use that by coating us in sweat and letting it evaporate. This is more efficient the lower the relative humidity is.
The attempt to quantify this in a nice metric is the wet bulb temperature (what would a thermometer with a wet cloth around it show). 24C@65% is a wet bulb temp of 19.3C, 27C@45% is a wet bulb temp of 18.8C
I've got both of these. Nest has a setting for 'cool to dry', but my climate is usually not humid and hot at the same time. I don't see a similar feature on the Ecobee, but the Ecobee app is perhaps more confusing. It does send alerts when the detected humidity is above set points. Where I do have issues with humidity is in my basement; typically the basement stays around 5-10 F less than the first floor, and if the first floor is 50% relative humidity, moving the air into the basement results in a much higher relative humidity. If the a/c is running for the first floor, there's a good chance of significant condensation on the vents right after the air handler.
Ecobee has a setting to enable this: https://support.ecobee.com/s/articles/How-to-use-AC-Overcool...
They also have a setting to adjust the temperature for humidity: https://support.ecobee.com/s/articles/Adjust-the-Temperature...
Same, and the worst part is that Nest already includes a hygrometer to show humidity in the app. All they need to give the user is a toggle: setpoint in regular dry bulb temperature, or setpoint in calculated wet bulb temperature (or heat index or "feels like" or whatever user-friendly calculation). Although their remote temperature sensors don't have a hygrometer, only the main unit.
A dedicated central dehumidifier is nice, but I've found them to be kind of noisy, especially when installed in the attic. Its got its own compressor, so the vibrations will transfer into the structure.
It's basically half of a closed cycle heat pump, in which the hot side is an externality.
https://youtu.be/hc_HcT4pIOE?si=0Nn1HwY-rpvhny9H&t=922
in the next video we're going to
show you how to improve the efficiency
of air conditioners and not by a small
amount it's estimated that approximately
$200 billion a year is used worldwide to
generate the electricity that drives air
conditioning so even a few per reduction
in the cost of running an air
conditioner would make a huge difference
and could save billions of dollars and
what we're going to show you isn't going
to improve the efficiency by a small
amount but by a huge amount so stay tunedWired (and other news sites), what the hell are you doing to computers? Stop it. People on newer phones may not notice it, but they're still burning just as many cycles on whatever stupid bullshit you decided to add to your site.
Maybe we wouldn't need so many air conditioners if sites like yours didn't exist.
“when you scrolled the page 2 pixels just now, it triggered 500 network requests to various tracking sites. additionally, it forced redrawing the site 3 times, and consumed 400ms of GPU time.”
But if I’m not at work, I frankly don’t care enough. A single button “take trade for 1 second and send it to GPT4” is the level of effort I’m willing to freedom dedicate to these folks’ crap.
We have district heating in New York [1]. Fascinating to think of district cooling, too.
- living in MODERN, so air-tight, well insulated buildings, designed to get the Sun when needed in winter, but not get it in summer with simple design choices etc;
-living in places where nights are fresh and having p.v. to cool with no energy consumption from grid during the day.
Now the above points are a bit bold but try reasoning why we live where we live. In the past places where circadian thermal delta was/is lower was very good places because it was less hot than now and there was no cheap heating. Similarly living in some places very deep in a valley was nice because floods was a thing anyway, but having clean water was invaluable and homes back then have had much less things who can be damaged by floods. Climate have change but technology, human living is changed much more. In the present world many inhabited parts of the world that back than was nice places, today they are not and others back than not so nice today are nice places.
In the past being many in a single places means:
- being able to defend against enemies
- having access to all professions and services
- having trade and learning opportunities
- be more exposed to illness, BUT being able to get help much easier
now? It means that
- 9/11 alike attacks or simple drone attacks are much more easy and deadly
- you get more dysfunctional services because we are too dense for them in too many place (as an example packages delivery in large condo complex vs single family homes)
- be more exposed to illness, with sometimes even LESS chances of a quick aid
- being mostly limited by nearby activities instead of having plenty of space for build a new one and remote work
Try to weight this, in terms of opportunities, disasters and who win vs who loose.
Right now we build giant boxes to live/move around in that suck up the sun's heat, then we insulate the box, then build another box to remove moisture in the box, cool the air in the box, blow it around, and then we have to power it...
....or we could live and move around in an open, shaded area, where wind can pass easily, fans blow on us to cool us (your skin is designed for cooling with wind, unlike most other animals on the planet), and cool mists can assist.
The latter is how I stay comfortable while camping in 90% humidity and 90F temperature. There are other solutions too, like staying underground during the peak of the heat, taking a dip in a pool of water, drinking cold liquids. All these and more don't require an exponential increase in energy generation, advanced engineering, or boxes designed to create an artificial environment.
No need to by hyper-efficient when energy is almost free.
Installed cost, I mean. Assume, like in most houses, none of the supporting electrical work has been done for solar already.
Where’s the dirt cheap home solar?
Energy is only free at times when we don't actually need it.