7 ms·

It might be a "waste" but it doesn't have to be damaging. Air conditioners (a special case of heat pumps) are extremely efficient and could easily be powered fr

It might be a "waste" but it doesn't have to be damaging. Air conditioners (a special case of heat pumps) are extremely efficient and could easily be powered from a solar array. The hottest places in the world tend not to be short of sunlight. Where they get the water from is another matter though. I always wondered how much you could scale up Air Well technology, which condenses water out of the air. I suspect the places that have lots of sunlight also don't have a lot of humidity. https://en.wikipedia.org/wiki/Air_well_(condenser) https://en.wikipedia.org/wiki/Air_well_(condenser)

thomasahle 5y ago
According to [1] Air conditioners use about 6% of all the electricity produced in the United States. I guess that's less than I had imagined. And apparently it's not just because northern houses don't have AC, since apparently [2] 87% of houses do. Edit: Then again a lot of energy is used by industry, so maybe 6% used by residential air conditioning is a lot. [3] suggest 17% of residential energy is AC. [1]: https://www.energy.gov/energysaver/home-cooling-systems/air-conditioning https://www.energy.gov/energysaver/home-cooling-systems/air-... [2]: https://www.eia.gov/consumption/residential/reports/2009/air-conditioning.php https://www.eia.gov/consumption/residential/reports/2009/air... [3]: https://www.eia.gov/energyexplained/use-of-energy/electricity-use-in-homes.php https://www.eia.gov/energyexplained/use-of-energy/electricit...
- LeoPanthera 5y ago
  Heat pumps are amazing things, they are more than 100% efficient, since they use only n watt-hours to move >n watt-hours of energy from one place to another. Under ideal conditions they can move 3n while consuming only n. It's far more efficient to use a heat pump in reverse to heat a space than it is to use a traditional electric heater, which is "only" 100% efficient. (Perhaps I should have said joules, not Wh? Units are confusing.)
  - hunter2_ 5y ago
    When cooling a dwelling, the trick is figuring out where to move the heat. Typically we dump it outside (waste) but we should be heating our hot water tanks, swimming pools, or anything else that needs concentrated heat at the same time that we're removing it from the indoor air. Alec from Technology Connections recently made some videos about heat pumps on YouTube that touch on this sort of thing.
    - mikepurvis 5y ago
      This has always made me super grouchy— I even have my house plumbed for hydronics! I wish I could tie the AC units into that, put all the rads in bypass during the summer, and use the hydronic water to preheat shower water before it hits the gas-powered on demand system.
    - amluto 5y ago
      In very hot climates, swimming pools get too hot, and you might prefer to chill the pool water.
      - asdfasgasdgasdg 5y ago
        I'm sure this might happen somewhere, but I grew up in Florida and it never happened in Orlando. I would always have been happy for the pool to be warmer.
    - nfriedly 5y ago
      > Typically we dump it outside (waste) but we should be heating our hot water tanks, swimming pools, or anything else that needs concentrated heat at the same time that we're removing it from the indoor air. My house actually does that! I had never heard of the idea before moving here, but we have a geothermal system and in addition to the ground loop, it also dumps heat into the hot water heater when cooling the house. (Until the water reaches some maximum temperature.)
      - rstupek 5y ago
- rootusrootus 5y ago
  The comparison I'd like to see is how much energy is consumed in a hot climate to keep a house cool vs keeping a house warm in a cold climate.
  - LeoPanthera 5y ago
    Unless you're using a heat pump for heating (we should be, but it's extremely rare), heating almost always uses more energy than cooling. This can be an unexpected problem with electric vehicles in cold climates, which have to waste a lot of power on heating the interior. Only recently have EVs started to use heat pumps for this purpose rather than resistive heating.
    - tejohnso 5y ago
      Can you explain why it is extremely rare if we should be using it? Is it politics? Branding?
      - stormbrew 5y ago
        There's a lot of inertia against heat pumps for reasons that are not at all clear. Where I live, in a pretty northern climate where until recently almost no one owned an AC but climate change is very visibly changing that, it's very difficult to get HVAC people to take you seriously if you say you want a heat pump even if you're getting an AC anyways. A lot of it seems to stem from the fact that most heat pumps operate poorly or inefficiently below about -10C (some higher than that). The fallacy that lies behind the inertia seems to be that "if you can't use it exclusively, you shouldn't bother at all". Since there's a non-trivial number of days below -10C where I live (about 1078 hours spread across 89 days here last year), it's considered frivolous. Of course, because we build our houses to hold in as much heat as possible for winter, now that it's getting over 20 and 30 a lot more a lot more people are buying AC, which is all of a heat pump other than a reversing valve, so to me it seems silly to NOT get a heat pump for the like 200+ days in between peak heat and peak cool seasons.
        5y ago
- njarboe 5y ago
  Heating takes a lot more energy generally than air conditioning (citation needed) in the US. Which makes sense when you think of the difference in temperatures from the inside of the house and the outside in winter compared to summer. Many people complain about the rise of air conditioning and how much energy it wastes, but actually it allows people to not live in the cold parts of the country, and is probably a net positive energy saver. Here is a great chart on home energy use [1]. [1] https://www.eia.gov/energyexplained/use-of-energy/homes.php https://www.eia.gov/energyexplained/use-of-energy/homes.php
einpoklum 5y ago
Solar arrays you install in such an area can power useful activity elsewhere - and its not like we're at 100% renewable energy everywhere to obviate this. So The waste of energy _is_ damaging.

thomasahle 5y ago

According to [1] Air conditioners use about 6% of all the electricity produced in the United States. I guess that's less than I had imagined. And apparently it's not just because northern houses don't have AC, since apparently [2] 87% of houses do. Edit: Then again a lot of energy is used by industry, so maybe 6% used by residential air conditioning is a lot. [3] suggest 17% of residential energy is AC. [1]: https://www.energy.gov/energysaver/home-cooling-systems/air-conditioning https://www.energy.gov/energysaver/home-cooling-systems/air-... [2]: https://www.eia.gov/consumption/residential/reports/2009/air-conditioning.php https://www.eia.gov/consumption/residential/reports/2009/air... [3]: https://www.eia.gov/energyexplained/use-of-energy/electricity-use-in-homes.php https://www.eia.gov/energyexplained/use-of-energy/electricit...

LeoPanthera 5y ago
Heat pumps are amazing things, they are more than 100% efficient, since they use only n watt-hours to move >n watt-hours of energy from one place to another. Under ideal conditions they can move 3n while consuming only n. It's far more efficient to use a heat pump in reverse to heat a space than it is to use a traditional electric heater, which is "only" 100% efficient. (Perhaps I should have said joules, not Wh? Units are confusing.)
- hunter2_ 5y ago
  When cooling a dwelling, the trick is figuring out where to move the heat. Typically we dump it outside (waste) but we should be heating our hot water tanks, swimming pools, or anything else that needs concentrated heat at the same time that we're removing it from the indoor air. Alec from Technology Connections recently made some videos about heat pumps on YouTube that touch on this sort of thing.
  - mikepurvis 5y ago
    This has always made me super grouchy— I even have my house plumbed for hydronics! I wish I could tie the AC units into that, put all the rads in bypass during the summer, and use the hydronic water to preheat shower water before it hits the gas-powered on demand system.
  - amluto 5y ago
    In very hot climates, swimming pools get too hot, and you might prefer to chill the pool water.
    - asdfasgasdgasdg 5y ago
      I'm sure this might happen somewhere, but I grew up in Florida and it never happened in Orlando. I would always have been happy for the pool to be warmer.
  - nfriedly 5y ago
    > Typically we dump it outside (waste) but we should be heating our hot water tanks, swimming pools, or anything else that needs concentrated heat at the same time that we're removing it from the indoor air. My house actually does that! I had never heard of the idea before moving here, but we have a geothermal system and in addition to the ground loop, it also dumps heat into the hot water heater when cooling the house. (Until the water reaches some maximum temperature.)
    - rstupek 5y ago
rootusrootus 5y ago
The comparison I'd like to see is how much energy is consumed in a hot climate to keep a house cool vs keeping a house warm in a cold climate.
- LeoPanthera 5y ago
  Unless you're using a heat pump for heating (we should be, but it's extremely rare), heating almost always uses more energy than cooling. This can be an unexpected problem with electric vehicles in cold climates, which have to waste a lot of power on heating the interior. Only recently have EVs started to use heat pumps for this purpose rather than resistive heating.
  - tejohnso 5y ago
    Can you explain why it is extremely rare if we should be using it? Is it politics? Branding?
    - stormbrew 5y ago
      There's a lot of inertia against heat pumps for reasons that are not at all clear. Where I live, in a pretty northern climate where until recently almost no one owned an AC but climate change is very visibly changing that, it's very difficult to get HVAC people to take you seriously if you say you want a heat pump even if you're getting an AC anyways. A lot of it seems to stem from the fact that most heat pumps operate poorly or inefficiently below about -10C (some higher than that). The fallacy that lies behind the inertia seems to be that "if you can't use it exclusively, you shouldn't bother at all". Since there's a non-trivial number of days below -10C where I live (about 1078 hours spread across 89 days here last year), it's considered frivolous. Of course, because we build our houses to hold in as much heat as possible for winter, now that it's getting over 20 and 30 a lot more a lot more people are buying AC, which is all of a heat pump other than a reversing valve, so to me it seems silly to NOT get a heat pump for the like 200+ days in between peak heat and peak cool seasons.
      - 5y ago
njarboe 5y ago
Heating takes a lot more energy generally than air conditioning (citation needed) in the US. Which makes sense when you think of the difference in temperatures from the inside of the house and the outside in winter compared to summer. Many people complain about the rise of air conditioning and how much energy it wastes, but actually it allows people to not live in the cold parts of the country, and is probably a net positive energy saver. Here is a great chart on home energy use [1]. [1] https://www.eia.gov/energyexplained/use-of-energy/homes.php https://www.eia.gov/energyexplained/use-of-energy/homes.php

einpoklum 5y ago

Solar arrays you install in such an area can power useful activity elsewhere - and its not like we're at 100% renewable energy everywhere to obviate this. So The waste of energy _is_ damaging.