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Improving air conditioner efficiency could reduce worldwide temps

nytimes.com

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Re: Improving air conditioner efficiency could reduce worldwide temps

#121

Post by athenot »

axelfontaine wrote: post #64

American air conditioners running at full power, chilling the interior and dripping on the sidewalk below on a hot day always deeply trouble me. Maybe it's my european view on things, but for contrast here in Munich we aren't just building out a city-wide heat network, but we also have a cold network! Cold river water flows through the pipe network that traverses the city and large office building can get connected t…

The dripping is from condensation. Right now in Atlanta, the dew point is 24°C. That means if I cool my house to reach that temperature, the humidity inside will be 100%… perfect for mold and terrible for everything else.

Using an open water cooling mechanism would work in hot and dry climates, but then again those are the areas where water is a lot more precious and you don't want to waste it through evaporation. (In a highly humid environment, evaporative cooling does not work because the water has nowhere to go.)

A heat pump is the only mechanism that works for this kind of climate. The exchange could be improved by using water or the ground to absorb the heat, but those solutions are way more expensive to install and can have environmental concerns of their own.

I'm generally impressed with the energy initiatives in Germany and have been following the Passive House movement for a while, but some technologies only work for specific climates or only in one direction.

Re: Improving air conditioner efficiency could reduce worldwide temps

#122

Post by grogenaut »

LeifCarrotson wrote: post #60
RcouF1uZ4gsC wrote: post #39

Earlier quoted context omitted.

The issue in cooling preferences is that if it is too cold, people can wear sweaters or even bring space heaters. If it is too hot, there is not much you can do. I think this problem is exacerbated by open office plans. If you have private/semi-private offices, you can probably do a much better job of controlling local temperature.

We have private offices, but central HVAC. Multi-zone cooling (independent of having lots of little, less efficient window/through-wall units) is relatively uncommon. It's exacerbated (good word) by the fact that the large front office has mostly women sitting at low-power PCs, the offices are mostly men at powerful workstations (aka space heaters), and the HVAC ducts run though the office drop ceilings, meaning anyo…

doesn't that mean you use less power though?

Re: Improving air conditioner efficiency could reduce worldwide temps

#123

Post by dmritard96 »

dv_dt wrote: post #98
dmritard96 wrote: post #79

One thing missing from this article is demand response: "It matters, researchers say, because cooling has a direct relationship with the building of coal-fired power plants to meet peak demand. If more air-conditioners are humming in more homes and offices, then more capacity will be required to meet the demand. So 1.6 billion new air-conditioners by 2050 means thousands of new power plants will have to come on line…

> "So 1.6 billion new air-conditioners by 2050 means thousands of new power plants will have to come on line to support them." Or not, where California has brought enough solar power online to the point that during peak times it has to pay to offload power to other states because some natural gas operators can't (won't?) shutdown...

A big part is also demand response in California, for instance, why PG&E was subsidizing smart thermostats. They can adjust all the setpoints and in aggregate reduce the compressor cycling. to 'chop' the peak down on really hot days.

Re: Improving air conditioner efficiency could reduce worldwide temps

#124

Post by EGreg »

lostapathy wrote: post #26
maxerickson wrote: post #22

Earlier quoted context omitted.

The slightly warmer planet cools off faster (Newton's law of cooling). The heat doesn't just statically build up over time. As long as we still have cold seasons, it is safe to assume that solar inputs are dominating our own.

Right. When we generate electricity via solar or wind, the heat involved has (essentially) been shifted from elsewhere. That energy was going to reach our planet either way. Whether we use a solar panel to shift it somewhere we can use it, or if it just heats the whatever it would have otherwise ran into, we aren't adding energy to the system by shifting it around. The waste heat from solar panels is just the energy…

So then, isn't fossil fuel energy "just" stored sun energy too? If it hadn't wound up underground, our planet would have been slightly hotter already.

Re: Improving air conditioner efficiency could reduce worldwide temps

#125

Post by grogenaut »

emodendroket wrote: post #85
RcouF1uZ4gsC wrote: post #39

Earlier quoted context omitted.

The issue in cooling preferences is that if it is too cold, people can wear sweaters or even bring space heaters. If it is too hot, there is not much you can do. I think this problem is exacerbated by open office plans. If you have private/semi-private offices, you can probably do a much better job of controlling local temperature.

I'm not sure such a thing would work here, but Japan famously ran their "Cool Biz" campaign to encourage people to dress lighter in the summer. https://en.wikipedia.org/wiki/Cool_Biz_campaign

I'm down with anything that gives me a reason to wear shorts and a tshirt at work!

Re: Improving air conditioner efficiency could reduce worldwide temps

#127

Post by pdelbarba »

cannonpr wrote: post #107

I hate to say it but AC always felt like thoughtless engineering and consumerism, especially the electric varieties. It's ironic that in a sunny, energy rich environment, you spend extra energy on a heat pump. In a lot of environments some better architecture will take care of the problem via passive methods, additionally evaporative methods work pretty well in dry environments and polute considerably less ? Failing…

Currently live in Colorado where the highs are regularly in the 90s. Turn the house fan on at night for a couple hours, cool everything off, then close all the doors and windows during the day and everything is perfectly comfortable. When I lived in Philly however... 90% humidity and 80 degrees AT NIGHT is no joke.

Re: Improving air conditioner efficiency could reduce worldwide temps

#128

Post by grogenaut »

21 wrote: post #89
klodolph wrote: post #24

Earlier quoted context omitted.

Off the top of my head, * A lot of home conditioners are fighting the weather in conditions with poor insulation, running when nobody is home, or running in rooms when people are in different parts of the house. * Office air conditioners are often set too cold, subjectively speaking, sometimes resulting in workers bringing sweaters or even space heaters to their desks. This is shockingly common. Multi-zone cooling ca…

A lot of offices don't even bother to turn the AC, or the lights off at night. A lot of people just leave their computers on (with sleep disabled), just because they don't want to wait 30 sec for the boot or to start their apps.

I leave my pc on because if there is an issue I need to be able to remote into it and there's no "wake on lan" type enterprise thing setup (don't even know if that exists). I could drive in but the gas cost and time costs of that are higher (my guess) than leaving the pc in idle 24/7.

Re: Improving air conditioner efficiency could reduce worldwide temps

#129

Post by rplst8 »

mjfern wrote: post #90
rplst8 wrote: post #46

Earlier quoted context omitted.

There are standardized efficiency measurements that all A/C manufacturers must conduct and publish in the US. You'll see terms like COP, EER, and SEER. Those allow you to compare pretty easily. Currently the minimum is a SEER of 13, but I've seen units as high as 22 advertised.

A SEER 13-14 system can run $5-6K, while a SEER 22 system can cost upwards of $15K (as a guesstimate). In theory, a SEER 22 system can pay for itself over the long-term due to reduced electric/gas expenses. The issue is that higher SEER systems, above 16 I believe, rely on variable speed motors. My understanding is that they are inherently less reliable. A SEER 13-16 system might last 15-20 years (if you're lucky), w…

I've said elsewhere in the thread, but insulation does little to help in the summer months. Fiberglass insulation mostly protects from convective cooling/heating (i.e. airflow). Heat in the summer is mostly through conduction and even more-so radiative (near infrared). Windows treatments could definitely help there, but unless you want everyone's windows to be mirrors, it likely won't help that much.

Re: Improving air conditioner efficiency could reduce worldwide temps

#130

Post by muninn_ »

rplst8 wrote: post #111
QuarterReptile wrote: post #94

Earlier quoted context omitted.

I agree with most of what you've said, but I'd also argue that having large groups living out in the desert is such an absurd configuration for humans that it presupposes an indifference for any sort of sustainability.

Having large groups living in mega city heat islands is also an absurd configuration but pretty much the entire world is guilty of that one.

Eh, not really. Cities are better for Co2
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