this post was submitted on 06 Aug 2024
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Cooling represents 20% of global electricity demand in buildings, a share that’s expected to rise as the planet warms and more of the world turns to cooling technology. During peak demand hours, air conditioners can account for over half the total demand on the grid in some parts of the world today.

New cooling technologies that incorporate energy storage could help by charging themselves when renewable electricity is available and demand is low, and still providing cooling services when the grid is stressed.

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[–] DrunkenPirate 12 points 3 months ago (3 children)

Call me naive but I thought that one needs cooling when its hot and the sun burns outside. At that time there‘s plenty of PV energy available. No need for storage, just take it directly.

[–] beeng@discuss.tchncs.de 7 points 3 months ago (1 children)

Brick and concrete holds heat for hours.

[–] DrunkenPirate 1 points 3 months ago

Oh, that‘s it. I remember my good old tile stove.

[–] evasive_chimpanzee@lemmy.world 2 points 3 months ago

In plenty of places, the wet bulb temperature is high 24 hours a day. At night, the temperature goes down, but relative humidity goes up, so you feel cooler, but also worse. You still need AC during that time, but mainly to dehumidify.

Also, in many places, peak demand is actually in the early evenings because people let their houses get hot while they are at work, but turn the AC on when they get home.

Any way you can store energy for even a few hours is really nice, and these kind of solutions could help adjust the daily demand curve to meet the supply curve.

[–] activistPnk@slrpnk.net 1 points 3 months ago* (last edited 3 months ago) (1 children)

Consider this excerpt:

When the grid is extremely stressed, utility companies are sometimes forced to shut off electricity supply to some areas, leaving people there without power when they need it most. Technologies that can adjust to meet the grid’s needs could help reduce reliance on these rolling blackouts.

So grid-powered a/c can give the grid relief at peak times with this tech.

But indeed this tech on a PV-powered compressor seems sketchy. There are probably moments when the sun is hitting hard but the temp has not climbed up yet (sunrise) in which case it would be useful to store the energy. But I’m struggling to understand how the complexity of the system would be justified considering the overall efficiency is reduced as well. I wonder what proportion of time this system would be working in storage mode. If sunrise is 9am and peak heat is 2pm, maybe there’s ~2—4 hours of storage time potential.

OTOH, consider someone with a slightly underpowered PV. Maybe the energy storage can compensate for peak heat times when the PV output may be insufficient. Perhaps it would enable homeowners to spend less on PV panels.

[–] DrunkenPirate 1 points 3 months ago (1 children)

If you have a PV upon your house, the most effective power storage option will be a general power storage, not storing power within the aircon. Doing so, it‘s just accessible by one single device. Instead of all electric devices in the house.

I assume this aircon is targeting apartments in a residential block. But even here, I assume it makes more sense to run a small battery storage such as a camping storage for your apartment and offer power for all your devices, not just a single one.

[–] activistPnk@slrpnk.net 1 points 3 months ago* (last edited 3 months ago)

Well that depends on how equipped you are. One cool thing about compressors is you can straight up connect a PV directly to a compressor with no voltage regulators or anything. So if you have a simple setup like that, I can see up front cost effectiveness in storing ice. But if you already have batteries, and thus voltage regulators and all the costly intermediate components to make that possible, then I would agree.. I might rather store it in lead acid batteries as that would be more versatile.

[–] evasive_chimpanzee@lemmy.world 6 points 3 months ago (1 children)

Current air conditioners can act like a battery, too. A house has a lot of thermal mass, and you can intentionally use it to your advantage. Smart thermostats are commonly integrated with electric utilities such that they can bump the set temp up during times of high cooling demand. Something they could and should set up is additional pre-chilling, so you could preemptively cool your house down a few extra degrees when demand is low, then when demand is high, you wouldn't pass your set point by much.

[–] Fiivemacs@lemmy.ca 4 points 3 months ago (2 children)

Better be a sealed device. I ain't adding moisture to my air in a bad attempt to cool it.

[–] SteveKLord@slrpnk.net 6 points 3 months ago (2 children)

While it uses water for cooling, it says nothing about adding moisture to the air. It does mention removing moisture from the air, though

Blue Frontier’s cooling units pass a stream of air over a thin layer of the desiccant, which pulls moisture out of the air. That dry air is then used in an evaporative cooling process (similar to the way sweat cools your skin).

[–] evasive_chimpanzee@lemmy.world 1 points 3 months ago (1 children)

The "used in an evaporative cooling process" is the part where it sounds like it adds moisture to the air. I think it happens outside, though. It sounds like their whole thing is to run moist outside air over the dessicant, then run that dry air over water that is on a heat exchanger. This would cool the heat exchanger that would be tied to ductwork or whatever to cool the house. Evaporative coolers already exist (both as in-house "swamp coolers" and external chillers usually used on bigger buildings). They don't work if the humidity is already high, though, so this system would enable them to function better in high humidity areas, and it could take advantage of only doing the energy intensive step of drying out the dessicant when there is surplus energy.

[–] activistPnk@slrpnk.net 1 points 3 months ago (1 children)

Sounds like they would do well in Arizona, where the air is dry. IIUC swamp coolers were very popular in Arizona until ~20 years ago when temps increased so much that swamp coolers could not make enough difference (this is largely because more and more land became concrete, which reduced the effect of evaporative cooling the land mass). So a/c became more popular in AZ IIUC. But the dry air would still be dry.

[–] evasive_chimpanzee@lemmy.world 1 points 3 months ago

They still use the same principle a lot with those misters they put everywhere for like outdoor restaurant seating and whatnot. Humidifiers placed inline with your AC ducts will also boost the cooling performance of your system, too.

[–] Fiivemacs@lemmy.ca 1 points 3 months ago* (last edited 3 months ago)

It should mention removing moisture. A standard air conditioner is moreso a giant dehumidifier then an air 'cooler'. Without seeing the actual design the first impression is some trays that hold water and freeze during nor.al operation. After electrical demand exceeds a set limit, or companies want to because they will most likely have the ability, they shut off the 'cooling' and just blow the room air across the frozen stuff giving the impression of cooling.

I'm hoping the frozen stuff is contained, but then you have the issue of expansion when it freezes. So who knows.

[–] activistPnk@slrpnk.net 3 points 3 months ago* (last edited 3 months ago)

Great basic concept but I think I would benefit more for the stored cooling going toward ice cubes for mojitos.

I don’t imagine that a single family dwelling would benefit from the extra complexity of adding cold water pipes in all the floors of the house. Probably makes more sense for apartment buildings (or perhaps homes that already have hydrothermal floors for heating).