Improving air conditioner efficiency could reduce worldwide temps • Hacker News Board

Re: Improving air conditioner efficiency could reduce worldwide temps

#61

Post by rplst8 » Thu, Jul 13, 2017, 8:32 PM UTC

Scramblejams wrote: post #36

bradlys wrote: 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 i…

The challenge for these is the cost. First, you either have to drill wells that are ~500 feet deep or lay coils of tubing under your yard (if you have one) below the frost line. Doing either is expensive, though the wells are much more so. The downside of the cheaper option (the coils under yard) is that earth shifts, and the coils will too. I've had two separate friends install these (usually 4-6 separate coils) only to have the earth move and rip open a coil or kink it. Usually you have a valve for each one to shut it off so the unit can sill operate on the remaining working coils, however with each lost coil the efficiency goes down.

Also, the ground-source heat-pumps aren't cheap. They are in the $7-10k range - just for the unit - and not many people know how to repair them as they are a bit of a specialty item in the HVAC industry.

Re: Improving air conditioner efficiency could reduce worldwide temps

#62

Post by maxerickson » Thu, Jul 13, 2017, 8:32 PM UTC

tasty_freeze wrote: post #59

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.

Obviously solar input dominate over whatever energy we add through burning fossil fuels. Nobody contests that. You must have heard of the greenhouse effect. THAT is the issue. By changing the composition of the atmosphere, a fractionally greater percentage of the astounding amount of energy is reflected back to the earth instead of escaping into the atmosphere, raising the temperature of the atmosphere and oceans. Im…

The post I replied to literally says "Not for nothing, but ain't greenhouse gases only the short term problem?"

Do I still have to go through the imagination exercise?

Re: Improving air conditioner efficiency could reduce worldwide temps

#63

Post by maxerickson » Thu, Jul 13, 2017, 8:33 PM UTC

comicjk wrote: post #56

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.

Newton's law is for convection of heat into the air. The cooling of the earth happens by radiation into vacuum, so it's actually much MORE temperature-sensitive: the heat radiated is proportional to the fourth power of the temperature. https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law

Thanks for the correction.

Re: Improving air conditioner efficiency could reduce worldwide temps

#64

Post by axelfontaine » Thu, Jul 13, 2017, 8:33 PM UTC

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 to it. This way they can save massively on electricity for air conditioning by having the water do the cooling instead. And then once the water has traversed all pipes, it simply gets released back into its stream on the other end of town, just as clean as when it entered, and only slightly warmer.

Re: Improving air conditioner efficiency could reduce worldwide temps

#65

Post by 24gttghh » Thu, Jul 13, 2017, 8:33 PM UTC

thehardsphere wrote: post #53

24gttghh wrote: post #50

Earlier quoted context omitted.

Fortunately? Congress is a bit of a double-edged sword in that regard...

Quite true. But if you are concerned about the EnergyStar cuts, it is fortunate because they are not likely to happen.

I wish I could share in your confidence. Have there been a number of bi-partisan congresspeople who have express support for EnergyStar and other efficiency programs?

Re: Improving air conditioner efficiency could reduce worldwide temps

#66

Post by DannyBee » Thu, Jul 13, 2017, 8:34 PM UTC

rplst8 wrote: post #46

clumsysmurf wrote: post #23

Trump's 2018 budget zeroes funding for Energy Star, which among other things, helps consumers pick the most efficient devices, save money in the long run. What other ways can consumers compare the efficiency of A/C units? I would think some standardized testing and labels would be required.

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.

Depends on the type of A/C

You can get ground source heat pumps that are 50 SEER, 5.3 COP (and they'll provide all your hot water, too)

There used to be a federal tax incentive of 30% of the cost, no max, but it expired at the end of 2016.

Re: Improving air conditioner efficiency could reduce worldwide temps

#67

Post by LeifCarrotson » Thu, Jul 13, 2017, 8:34 PM UTC

mperham wrote: post #52

JumpCrisscross wrote: post #40

Earlier quoted context omitted.

> Gender is supposedly a huge factor in temperature preferences Source?

Every (hetero) marriage.

This is one case where the plural of anecdote is, indeed, data. But I am grateful to see a sibling comment cite a proper study confirming what we already knew.

Re: Improving air conditioner efficiency could reduce worldwide temps

#68

Post by rplst8 » Thu, Jul 13, 2017, 8:34 PM UTC

DiabloD3 wrote: post #55

Nition wrote: post #49

Earlier quoted context omitted.

Also, people who set their home heat pump to "auto" instead of "heat" in winter and "cool" in summer. No-one should mind if they have it on 18 in winter and the sun heats the room to 20 in the afternoon, but a heat pump on auto will start cooling to maintain the room at 18.

I also agree, if you have a heat pump do not use auto mode, it will never do what you actually want.

While it's not the best thing to do, it doesn't matter much as the efficiency of the systems go way way up when the outside temp is near the same as the inside temp.

Re: Improving air conditioner efficiency could reduce worldwide temps

#69

Post by Eric_WVGG » Thu, Jul 13, 2017, 8:35 PM UTC

JumpCrisscross wrote: post #40

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…

> Gender is supposedly a huge factor in temperature preferences Source?

http://www.newyorker.com/tech/elements/is-your-thermostat-se...

The biological reasoning, as I understand it, is that men have a higher ratio of heat-generating muscle than women.

When I first moved to NYC, I was bewildered by all the women walking around with scarves and summer dresses; it was explained to me that this was a strategy to optimize being comfortable in the outdoor heat, and then having something to withstand the frigid offices.

(Personally, I'm of the opinion that one should acclimate to their climate, and folks who hate the heat wouldn't mind it so much if they didn't coddle themselves with AC all the time.)

Re: Improving air conditioner efficiency could reduce worldwide temps

#70

Post by MacsHeadroom » Thu, Jul 13, 2017, 8:36 PM UTC

JumpCrisscross wrote: post #40

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…

> Gender is supposedly a huge factor in temperature preferences Source?

"Researchers found the women’s average metabolic rate was 20 to 32 percent lower than rates in the standard chart used to set building temperature. ... Dr. Kingma said a woman might prefer a 75-degree room, while a man might prefer about 70 degrees, which Dr. Kingma said is a common current office temperature."

https://www.nytimes.com/2015/08/04/science/chilly-at-work-a-...