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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

#281

Post by astrodust »

rplst8 wrote: post #106
maxxxxx wrote: post #71

Just insulate the houses in the US. I am always shocked how badly built US houses that cost 600k are.

Good insulation is pretty standard here in the US for everything built in the last two decades or so. That said, fiberglass insulation mostly only helps against convection cooling/heating. I.e. through the movement of air. Summertime heat is mostly conductive and radiative i.e. near infrared. Insulation doesn't do much to stop that. Shade trees however help this big time. A large tree placed in the right spot to shad…

If anything they're over-insulated which can create other problems like a lack of fresh air, mold and fungus problems, and poor air quality in general.

The more you insulate the more you need to ensure you have proper ventilation, which is a sort of paradox.

Re: Improving air conditioner efficiency could reduce worldwide temps

#282

Post by cestith »

davidw wrote: post #43

People in the US consume way too much air conditioning. It's pretty common where I work for people to have sweaters to put on inside due to the AC. Outside it's in the 80ies, with something like 10% humidity in the summer - absolutely perfect unless you're doing hard labor in direct sunlight.

Meanwhile in Houston, we're having a nicely cool and dry day for July ... After a high of 93, at just before 6 PM it's 89 degrees and 57% humidity. By 4 AM, it'll be 78 F and 90% humidity, with a high tomorrow of 90 at 2 PM with 58%.

Re: Improving air conditioner efficiency could reduce worldwide temps

#283

Post by toomuchtodo »

astrodust wrote: post #279
toomuchtodo wrote: post #176

Earlier quoted context omitted.

> That's because your house is designed with active cooling as a presumption. No, it isn't. I have an enormous oak tree that overhangs the southern roof. My windows have a very low level of solar radiation they allow through. The ambient air temp at night is almost 80F. The house is built of concrete block, and stores heat during the day, releasing it at night. We're routinely at 60-80% humidity. Just waiting for som…

As good as those features might be, you're still dependent on active cooling to make it liveable. There are other measures that have been used for millenia in desert and jungle environments where the house itself encourages particular paths of air flow that bring in cooler, fresh air and vent hot, stale air. We've got the technology now to evolve this even further by doing computer simulations to come up with better…

At high humidity, you're still going to be hot and drenched in sweat. The only solution is energy efficient thermal transfer (AC, heat pump, etc) and dehumidification.

Re: Improving air conditioner efficiency could reduce worldwide temps

#284

Post by chewyland »

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…

It was 45 in Bulgaria. Without my Daikin, I doubt I would have survived.

Re: Improving air conditioner efficiency could reduce worldwide temps

#285

Post by Zarath »

Open a damn window. I'm sure in some places AC is necessary, but way too often I hear/see people running it when there is absolutely no reason other than they are even mildly uncomfortable.

Seriously, this problem isn't going to be fixed until people actually pay the true cost of what they are doing: Electricity + Global Warming externalities.

Re: Improving air conditioner efficiency could reduce worldwide temps

#286

Post by [deleted] »

illegalsmile wrote: post #245
losvedir wrote: post #118

Earlier quoted context omitted.

> My bedroom in Tampa, FL reaches 90F at night without air conditioning. There is no way I could live without AC here. You obviously could live there... it would just be unpleasant. I lived a year in Singapore where temperatures were in the 80-90 range. I stayed on-campus at NUS and was lucky to have a room with A/C, but it wasn't common. The majority of students make do with big fans and windows. I remember working…

Turns out that the GP could adapt to sleeping in 90F temperatures as the human body is adaptable. After a few weeks you'd be used to it and it wouldn't matter. The Creek/Seminole did it in the southeast.

[deleted]

Re: Improving air conditioner efficiency could reduce worldwide temps

#287

Post by astrodust »

toomuchtodo wrote: post #283
astrodust wrote: post #279

Earlier quoted context omitted.

As good as those features might be, you're still dependent on active cooling to make it liveable. There are other measures that have been used for millenia in desert and jungle environments where the house itself encourages particular paths of air flow that bring in cooler, fresh air and vent hot, stale air. We've got the technology now to evolve this even further by doing computer simulations to come up with better…

At high humidity, you're still going to be hot and drenched in sweat. The only solution is energy efficient thermal transfer (AC, heat pump, etc) and dehumidification.

There are ways of doing this that don't involve expending energy, but it requires re-thinking the very concept of the modern house.

A thousand years ago you had to build things this way, you had no alternative, but now it's taken for granted that air-conditioning will solve all problems.

Re: Improving air conditioner efficiency could reduce worldwide temps

#288

Post by cestith »

EGreg wrote: post #124
lostapathy wrote: post #26

Earlier quoted context omitted.

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.

Fossil fuel is stored chemical energy. Burning it releases the energy. Photovoltaic solar power is converting one type of energy (light) into another (electricity), with the waste heat being the same waste heat the light would've created by shining on something else. Solar thermal energy is using the heat from the sun to do work (which may include heating oils, air, or water to drive a turbine to generate electricity) or to generate electricity (using, say, thermal-piezo conversion).

The only effective ways we have to store solar power are batteries, supercapacitors (once they're viable), large heat masses (such as stone or water), growing plants, or putting energy into chemicals for later storage (electrolysis and storing the hydrogen, forming artificial hydrocarbons, recycling aluminum for aluminum/air power cells, pumping water uphill to power a turbine later, pressurizing gases to later drive a turbine, stuff like that).

Not all of the things I mentioned work at every scale. Some of them are more efficient than others. They may all have advantages and drawbacks.

Re: Improving air conditioner efficiency could reduce worldwide temps

#289

Post by joeyo »

esrauch wrote: post #228
Berobero wrote: post #178

Earlier quoted context omitted.

You realize the world's birth rate has already been on the decline for decades, correct? And in general, the bulk of this occurred not because of coercion, but because of economic development and the ensuing shifts in optimum family strategy.

When you say "birth rate is falling" its effectively the second derivative on "number of people" right? As in, if we have go from 2 children born per person to 1.5 children born per person, we are still growing the number of people. Even if "children per person" falls slow enough you could even indefinitely increase the rate that new people are added right?

That's right, but note that the replacement rate depends on mortality rates and any gender-bias for either birth or mortality. Generally birth rates below 2.1 are consider "sub-replacement", but it can be much higher in some locales (due to disease, war, etc). Here are some per-continent population projections:

https://commons.wikimedia.org/wiki/File:World_population_(UN...

(Interestingly, the above chart was created about 10 years ago; I do wonder how accurate it's been.)

Re: Improving air conditioner efficiency could reduce worldwide temps

#290

Post by WalterBright »

sjg007 wrote: post #276
WalterBright wrote: post #174

Earlier quoted context omitted.

Simply using a white coating on the roof can reduce the A/C bill by about 3%. It's so simple, I do not know why this isn't part of the building code in hot places. People may not like it for their homes, but for commercial buildings with flat roofs, it's a no-brainer.

It is in Arizona. White or silver.

https://www.google.com/maps/place/Phoenix,+AZ/@33.4437866,-1...

Looks like good progress. Less penetration into the residential areas, but progress.

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