Live data from Hacker News

Improving air conditioner efficiency could reduce worldwide temps

nytimes.com

31–40 of 349 posts

Re: Improving air conditioner efficiency could reduce worldwide temps

#31
post #18

> The Lawrence Berkeley study argues that even a 30 percent improvement in efficiency could avoid the peak load equivalent of about 1,500 power plants by 2030. Okay, but where is this 30% jump in efficiency going to come from? That seems like a pretty big leap!

It's already available. In the USA there's a efficiency rating called SEER which the federal government mandates new ACs must be at least rated at SEER 13. But if you want to spend the money you can buy ACs with SEER ratings above 25.

Re: Improving air conditioner efficiency could reduce worldwide temps

#32

Earlier quoted context omitted.

I hear ammonia and propane: http://www.drawdown.org/solutions/materials/refrigerant-mana...

Isn't there a big fire/explosion risk as these are very flammable?

Most RV's use this combo for the fridge. They don't seem to explode but there does seem to be a number of fires.

Re: Improving air conditioner efficiency could reduce worldwide temps

#33
post #13

Not for nothing, but ain't greenhouse gases only the short term problem? The Earth radiates a fixed amount of energy into space every year. But when we produce electricity etc. no matter how we do it, more than half of the energy escapes as heat - a byproduct of boiling the water or whatever! This isn't sustainable in the long run either! We are basically raising the temperature of the atmosphere even without greenho…

Yes, constantly increasing energy consumption by a fixed percentage per year projects out to physical absurdities like boiling the oceans or needing to expand colonies throughout the universe faster-than-light. But Tom Murphy is employing a straw-economist ("Note: because I have a better retention of my own thoughts than those of my conversational companion, this recreation is lopsided to represent my own points/words.") to make a point. I thought that was one of his weaker blog entries and I was a regular reader of his blog.

The Earth radiates a finite but not fixed amount of energy into space every year. Radiated power goes up with the 4th power of absolute temperature (modulated by greenhouse effect). The effects of increasing the greenhouse effect from fossil combustion are much greater than the direct waste heat from fossil combustion, because the greenhouse effect slightly amplifies the warming effects of the ~10^17 watts of sunlight reaching Earth's surface. Fossil combustion directly accounts for ~10^13 watts of terrestrial heating. Note the 4 orders of magnitude difference.

Re: Improving air conditioner efficiency could reduce worldwide temps

#34
post #18

> The Lawrence Berkeley study argues that even a 30 percent improvement in efficiency could avoid the peak load equivalent of about 1,500 power plants by 2030. Okay, but where is this 30% jump in efficiency going to come from? That seems like a pretty big leap!

Most home AC units in the US are single-stage, where they're all the way on, or all the way off. You can pay more for a two-stage unit, which has low & high operation. But in other countries, VRF systems are more popular (variable refrigerant flow) - they operate their fans & compressors at speeds which match the demand, and so use less electricity. And are quieter.

Re: Improving air conditioner efficiency could reduce worldwide temps

#35
post #18

> The Lawrence Berkeley study argues that even a 30 percent improvement in efficiency could avoid the peak load equivalent of about 1,500 power plants by 2030. Okay, but where is this 30% jump in efficiency going to come from? That seems like a pretty big leap!

Some of it can come from social engineering instead of HVAC technical breakthroughs -- automated thermostats like the Nest, hand-held body-coolers like

http://news.mit.edu/2013/madmec-design-competition-1017

Better summer clothes will help too. I've been pretty impressed by advances in cooling undergarments that are designed to wick away moisture and encourage air flow.

Anyway, all of these seemingly unrelated things contribute to improved AC efficiency.

Re: Improving air conditioner efficiency could reduce worldwide temps

#36
post #18

> The Lawrence Berkeley study argues that even a 30 percent improvement in efficiency could avoid the peak load equivalent of about 1,500 power plants by 2030. Okay, but where is this 30% jump in efficiency going to come from? That seems like a pretty big leap!

It's been mentioned elsewhere in this thread, but if you run your refrigerant loop through the ground instead of cooling it using the hot ambient air, you can absolutely achieve that improvement in efficiency. The concept is described here:

https://energy.gov/energysaver/geothermal-heat-pumps

The amount of efficiency increase you get depends on the ground temp, which varies by latitude, but I've seen 70% reductions in electricity usage quoted for systems installed in North America.

A side benefit is you no longer have a big, loud heat exchanger running on the side or top of your house. The pump unit for a ground loop can sit inside your garage, it's about the size of two mini-fridges and only emits a quiet hum.

Sidenote: When I bring up ground loop air conditioning in conversation with people, no one has ever heard of it. The technology has a marketing problem. That makes sense in states where electricity is cheap, but in places like California I'm surprised the state hasn't mandated them for new installations and offered tax breaks to give it some momentum.

Re: Improving air conditioner efficiency could reduce worldwide temps

#37
We need a corresponding article telling us how many power plants we can avoid building by not mining Bitcoin. I love the general idea of cyber currency / bitcoin / block chain, but I hate that the implementation requires so much energy.

Re: Improving air conditioner efficiency could reduce worldwide temps

#38
post #18

> The Lawrence Berkeley study argues that even a 30 percent improvement in efficiency could avoid the peak load equivalent of about 1,500 power plants by 2030. Okay, but where is this 30% jump in efficiency going to come from? That seems like a pretty big leap!

If you're in the US, you can likely save much more than 30% today by replacing a central air system with a ductless mini-split style system. These are already dominant in the rest of the world, however.

Re: Improving air conditioner efficiency could reduce worldwide temps

#39
post #18

> The Lawrence Berkeley study argues that even a 30 percent improvement in efficiency could avoid the peak load equivalent of about 1,500 power plants by 2030. Okay, but where is this 30% jump in efficiency going to come from? That seems like a pretty big leap!

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…

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.

Re: Improving air conditioner efficiency could reduce worldwide temps

#40
post #18

> The Lawrence Berkeley study argues that even a 30 percent improvement in efficiency could avoid the peak load equivalent of about 1,500 power plants by 2030. Okay, but where is this 30% jump in efficiency going to come from? That seems like a pretty big leap!

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…

> Gender is supposedly a huge factor in temperature preferences

Source?

Post reply on HN