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Heat Pumps – The Well-Tempered Future of A/Cs

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Re: Heat Pumps – The Well-Tempered Future of A/Cs

#101

Post by triceratops »

Maxburn wrote: post #81
kevin_thibedeau wrote: post #38

Earlier quoted context omitted.

It's not just buzz. It's more efficient than resistive heating and modern units have better performance in cold temps. Hence the push to promote them. The downside is that you have added complexity driving up installation costs and reliability down.

Walk around in the American Heating and Refrigeration conference for a while to get a feel of these trends, this was specifically called out by many manufacturers as driven by the green movement.

That doesn't make them a buzz word.

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#102

Post by triceratops »

Maxburn wrote: post #89
jondwillis wrote: post #39

Earlier quoted context omitted.

Why put renewable in quotes? Because it isn’t 100%?

Basically yes. Renewable is more of a supplement to current grids for most of us. There might be a couple rare few areas that currently claim 100%.

Vs the alternative, natural gas, which is famously 100% renewable?

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#103

Post by chickenpotpie »

addisonl wrote: post #99
chickenpotpie wrote: post #78

Earlier quoted context omitted.

I haven't formed an opinion on the matter yet, but I do think there's a large difference between it being too cold and too hot. If I'm too cold and my power goes out I have a lot of options to survive. I can put on more clothes, get under a blanket, light my furniture on fire, etc If I'm too hot and my power goes out, I die. Once the wet bulb temperature gets above a certain level in shade, there's nothing that can b…

Wet bulb isn’t an issue in notoriously dry Phoenix. If your power goes out in Phoenix you jump in a pool.

What? That doesn't make any sense at all. The whole point of wet bulb temperature is to adjust for humidity. Also only 33% of Phoenix homes have a pool. Using a pool as a solution to prevent people from dying is a "let them eat cake" idea

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#104

Post by CarVac »

chickenpotpie wrote: post #103
addisonl wrote: post #99

Earlier quoted context omitted.

Wet bulb isn’t an issue in notoriously dry Phoenix. If your power goes out in Phoenix you jump in a pool.

What? That doesn't make any sense at all. The whole point of wet bulb temperature is to adjust for humidity. Also only 33% of Phoenix homes have a pool. Using a pool as a solution to prevent people from dying is a "let them eat cake" idea

It's not an issue because Phoenix is always dry, so the wet bulb temperature is always low.

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#105

Post by samtho »

Schweigi wrote: post #88
itzworm wrote: post #70

Earlier quoted context omitted.

There are ceiling cassettes for mini-split systems that aren't nearly as much of an eyesore as the wall mount ones are.

Mini split systems can be used with ducts. All big venders sell heads which are specifically made to be connected to ducts. That way you get the best of both worlds and its also easy to retrofit to an existing (ducted) house.

This is a little known fact outside of the HVAC trades as everyone associates mini-split systems with the infamous wall-mounted indoor unit. I bought this LG unit[0] which I used some duct-foam board to build an adapter for and fanned out ductwork for that zone. People are amazed when I tell them this is a ducted mini split.

[0]: https://www.supplyhouse.com/LG-LDN127HV4-12000-BTU-Multi-F-C...

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#106

Post by sigilis »

londons_explore wrote: post #63
digdugdirk wrote: post #2

Well this was an oddly terrifying introductory paragraph for an IEEE article: "... half of Phoenix residents are at risk of an emergency room visit or worse if their electricity fails during a future heat wave, according to a recent study. Air conditioning is what keeps people there comfortable—and alive—a growing fraction of the year. The extreme heat already kills hundreds of Phoenix-area residents every year, a nu…

It raises the question of if we should deploy 'emergency coolers' - perhaps single-use barrels of some chemical that gets cold when a pull-tab is pulled. To be a workable solution, it needs to be more reliable/cheaper/more effective than just a regular gasoline generator powering a regular aircon unit. After a flood/hurricane/nuclear strike, they would provide enough coolness to keep people alive for a few days.

Water can be used for this purpose, and swamp coolers are something that can be pretty trivially implemented by people in relatively dry areas. For very humid places you generally need energy input for cooling.

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#107

Post by Maxburn »

triceratops wrote: post #102
Maxburn wrote: post #89

Earlier quoted context omitted.

Basically yes. Renewable is more of a supplement to current grids for most of us. There might be a couple rare few areas that currently claim 100%.

Vs the alternative, natural gas, which is famously 100% renewable?

Master-Blaster rules Bartertown!

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#108

Post by chickenpotpie »

CarVac wrote: post #104
chickenpotpie wrote: post #103

Earlier quoted context omitted.

What? That doesn't make any sense at all. The whole point of wet bulb temperature is to adjust for humidity. Also only 33% of Phoenix homes have a pool. Using a pool as a solution to prevent people from dying is a "let them eat cake" idea

It's not an issue because Phoenix is always dry, so the wet bulb temperature is always low.

The wet bulb temperature of Phoenix still gets very high. Last July, there was an average wet bulb temperature of 73 degrees Fahrenheit. 95 degrees will kill a healthy human, it takes much less to kill a vulnerable person or someone performing manual labor. Climate change is only going to raise that number.

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#109

Post by addisonl »

chickenpotpie wrote: post #103
addisonl wrote: post #99

Earlier quoted context omitted.

Wet bulb isn’t an issue in notoriously dry Phoenix. If your power goes out in Phoenix you jump in a pool.

What? That doesn't make any sense at all. The whole point of wet bulb temperature is to adjust for humidity. Also only 33% of Phoenix homes have a pool. Using a pool as a solution to prevent people from dying is a "let them eat cake" idea

Like the other commenter who already corrected you, it makes perfect sense if you actually understand how wet bulb works, here’s a calculator for you: https://www.omnicalculator.com/physics/wet-bulb

Hint: Phoenix is at 17% humidity today, even their all time high of 122 doesn’t push the wet bulb temp out of the safe range.

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#110

Post by chickenpotpie »

addisonl wrote: post #109
chickenpotpie wrote: post #103

Earlier quoted context omitted.

What? That doesn't make any sense at all. The whole point of wet bulb temperature is to adjust for humidity. Also only 33% of Phoenix homes have a pool. Using a pool as a solution to prevent people from dying is a "let them eat cake" idea

Like the other commenter who already corrected you, it makes perfect sense if you actually understand how wet bulb works, here’s a calculator for you: https://www.omnicalculator.com/physics/wet-bulb Hint: Phoenix is at 17% humidity today, even their all time high of 122 doesn’t push the wet bulb temp out of the safe range.

I understand how wet bulb temperature works just fine. You didn't need to write a snarky response to engage in this discussion.

Now include climate change raising the temperature and changing the length and severity of monsoon season, continued development raising the heat island effect.

It doesn't matter what the average wet bulb temperature over the entire coty over a long period of time. It matters what the peak wet bulb temperature is for significant number of vulnerable people. The wet bulb temperature only has to get very high once to kill a large swath of people.

I understand just fine the wet bulb temperature has been within safe levels for the vast majority of people so far. My concern is about the future.

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