5 ms·

> Air conditioning is anti-social. It buys its owner comfort at the cost of shifting the surplus heat somewhere else You could make the same argument for heati

by usaphp 8y ago

> Air conditioning is anti-social. It buys its owner comfort at the cost of shifting the surplus heat somewhere else You could make the same argument for heating, no?

thaumasiotes 8y ago
You don't usually do heating in cases where you're worried about surplus heat. You could make the same argument for every productive activity except heating...
- rconti 8y ago
  You could argue we should all be worried about surplus heat, all the time. I heard an interesting argument about the efficiency of air conditioning the other day. It pointed out that, while removing heat from a room is of course not 100% efficient, it is merely shifting heat from one place to another (plus some waste). Whereas heating is ALL "waste". So more waste heat should be generated from, and more energy used in, heating vs air conditioning. We definitely have a bias to accept that the New Englander is virtuous in heating his or her home in the winter, but the Arizonan is wasteful in cooling their "inhospitable" house in the summer. Maybe we should rethink this.
  - writinghawk 8y ago
    Heating need not be 'all waste'. An air (or ground) source heat pump heats a room, counterintuitively, by pumping heat from the colder air outside. It uses less energy than the amount it releases into the room.
    - MrStonedOne 8y ago
      (also known as an ac in reverse)
      - rootusrootus 8y ago
        I've heard this term twice in this thread. Do most people not just call them heat pumps? Certainly that's what they're known as here in the PNW.
        thaumasiotes 8y ago
        I don't know that I've encountered a space heater based on a heat pump, but in my mind... "air conditioner" - a machine which keeps one or more rooms in a house cool, powered by a heat pump. "heater" - a machine which keeps one or more rooms in a house warm, usually not powered by a heat pump. "refrigerator" - a machine which keeps its own interior cool, powered by a heat pump. "freezer" - a machine which keeps its own interior below freezing, powered by a heat pump and usually attached to a refrigerator. All of which is to say, a heat pump is a machine that moves heat. It's named after its effect. But "heaters", "refrigerators", and "air conditioners" are named after their purpose, not their mechanics, and include heat pumps--if they do--incidentally, as the mechanism by which they achieve their purpose. If somebody came up with a refrigerator that still kept your food cold but didn't use a heat pump, I wouldn't hesitate to call it a "refrigerator".
  - thaumasiotes 8y ago
    > while removing heat from a room is of course not 100% efficient, it is merely shifting heat from one place to another (plus some waste). > Whereas heating is ALL "waste". > So more waste heat should be generated from, and more energy used in, heating vs air conditioning. This is a logical mistake. It doesn't matter whether you think the heat produced in heating is metaphysically "wasted" or not; the energy used in heating vs air conditioning is a function of the temperature differential you want to maintain. Air conditioning means you're doing work to keep a certain volume of space at an artificially low temperature, and heating means you're doing work to keep a volume of space at an artificially high temperature. The amount of energy you use in order to achieve that goal depends on the amount of work you need to do, not on whether you're doing the work in order to lower or raise the temperature.
    - rconti 8y ago
      Both result in "waste" heat (eg, added entropy) but in the case of combustion or resistive heating (covered above in the thread), the entire purpose is to generate waste heat. Whereas in air conditioning (or, as mentioned, heat pumps), the waste heat is only a side effect.
      - thaumasiotes 8y ago
        Who cares? Both processes involve doing work by consuming energy. In one case, the work is moving heat, and in the other case, the work is producing heat. The term "waste" is pretty meaningless in this context; what you really have is the question "how much energy does this process consume?" The answer to that question won't change depending on how you label the products.
        rconti 8y ago
        Waste heat is 1% of global warming, and is thought to affect the jet stream and .. other things. https://blogs.agu.org/geospace/2016/06/17/study-waste-heat-major-source-national-warming/ https://blogs.agu.org/geospace/2016/06/17/study-waste-heat-m... http://www.climatecentral.org/news/waste-heat-from-cities-may-be-altering-weather-patterns-says-new-study-1552 http://www.climatecentral.org/news/waste-heat-from-cities-ma...
  - kevin_thibedeau 8y ago
    The Arizonan should be using an evaporative cooler.
  - photojosh 8y ago
    If we're talking about electrical heating, this is only true for resistive heating, which is indeed all "waste heat". But many air conditioners can run in "reverse cycle" [0], where you're transferring outside heat back in, and is much more efficient, apparently 50% cheaper to run in electricity costs. When you run one of these systems, your New Englander and Arizonan are virtuous to the degree of the difference between inside and outside temperatures. ;) There's even now some combined cycle AC systems which use the extracted heat to generate your hot water [1], sadly not yet available/cost-effective for small residential installations, but they're only off by a factor of 2 now (8kW is the smallest system I've seen, my central air is 4kW). [0] https://en.wikipedia.org/wiki/Heat_pump https://en.wikipedia.org/wiki/Heat_pump [1] http://www.mitsubishielectric.com.au/air-to-water-hot-water-heat-pumps.html http://www.mitsubishielectric.com.au/air-to-water-hot-water-...
    - jdmichal 8y ago
      I actually just replaced a 20-year-old AC system that had a link to the hot water system. Installers just removed the water heater link entirely. Said that the extra resistance and energy involved in the exchange cost more than just venting the heat in modern systems with high SEER ratings. No idea if that's accurate; just what I heard.
    - rconti 8y ago
      Sorry, I meant both resistive AND combustion (eg, "gas"). Now, obviously, natural gas is far cheaper than electric for heat in most of the US at least, but it's all 'generated' heat, with all of the waste heat and CO2 emissions that entails.

by usaphp 8y ago

> Air conditioning is anti-social. It buys its owner comfort at the cost of shifting the surplus heat somewhere else You could make the same argument for heating, no?

thaumasiotes 8y ago

You don't usually do heating in cases where you're worried about surplus heat. You could make the same argument for every productive activity except heating...

rconti 8y ago
You could argue we should all be worried about surplus heat, all the time. I heard an interesting argument about the efficiency of air conditioning the other day. It pointed out that, while removing heat from a room is of course not 100% efficient, it is merely shifting heat from one place to another (plus some waste). Whereas heating is ALL "waste". So more waste heat should be generated from, and more energy used in, heating vs air conditioning. We definitely have a bias to accept that the New Englander is virtuous in heating his or her home in the winter, but the Arizonan is wasteful in cooling their "inhospitable" house in the summer. Maybe we should rethink this.
- writinghawk 8y ago
  Heating need not be 'all waste'. An air (or ground) source heat pump heats a room, counterintuitively, by pumping heat from the colder air outside. It uses less energy than the amount it releases into the room.
  - MrStonedOne 8y ago
    (also known as an ac in reverse)
    - rootusrootus 8y ago
      I've heard this term twice in this thread. Do most people not just call them heat pumps? Certainly that's what they're known as here in the PNW.
      - thaumasiotes 8y ago
        I don't know that I've encountered a space heater based on a heat pump, but in my mind... "air conditioner" - a machine which keeps one or more rooms in a house cool, powered by a heat pump. "heater" - a machine which keeps one or more rooms in a house warm, usually not powered by a heat pump. "refrigerator" - a machine which keeps its own interior cool, powered by a heat pump. "freezer" - a machine which keeps its own interior below freezing, powered by a heat pump and usually attached to a refrigerator. All of which is to say, a heat pump is a machine that moves heat. It's named after its effect. But "heaters", "refrigerators", and "air conditioners" are named after their purpose, not their mechanics, and include heat pumps--if they do--incidentally, as the mechanism by which they achieve their purpose. If somebody came up with a refrigerator that still kept your food cold but didn't use a heat pump, I wouldn't hesitate to call it a "refrigerator".
- thaumasiotes 8y ago
  > while removing heat from a room is of course not 100% efficient, it is merely shifting heat from one place to another (plus some waste). > Whereas heating is ALL "waste". > So more waste heat should be generated from, and more energy used in, heating vs air conditioning. This is a logical mistake. It doesn't matter whether you think the heat produced in heating is metaphysically "wasted" or not; the energy used in heating vs air conditioning is a function of the temperature differential you want to maintain. Air conditioning means you're doing work to keep a certain volume of space at an artificially low temperature, and heating means you're doing work to keep a volume of space at an artificially high temperature. The amount of energy you use in order to achieve that goal depends on the amount of work you need to do, not on whether you're doing the work in order to lower or raise the temperature.
  - rconti 8y ago
    Both result in "waste" heat (eg, added entropy) but in the case of combustion or resistive heating (covered above in the thread), the entire purpose is to generate waste heat. Whereas in air conditioning (or, as mentioned, heat pumps), the waste heat is only a side effect.
    - thaumasiotes 8y ago
      Who cares? Both processes involve doing work by consuming energy. In one case, the work is moving heat, and in the other case, the work is producing heat. The term "waste" is pretty meaningless in this context; what you really have is the question "how much energy does this process consume?" The answer to that question won't change depending on how you label the products.
      - rconti 8y ago
        Waste heat is 1% of global warming, and is thought to affect the jet stream and .. other things. https://blogs.agu.org/geospace/2016/06/17/study-waste-heat-major-source-national-warming/ https://blogs.agu.org/geospace/2016/06/17/study-waste-heat-m... http://www.climatecentral.org/news/waste-heat-from-cities-may-be-altering-weather-patterns-says-new-study-1552 http://www.climatecentral.org/news/waste-heat-from-cities-ma...
- kevin_thibedeau 8y ago
  The Arizonan should be using an evaporative cooler.
- photojosh 8y ago
  If we're talking about electrical heating, this is only true for resistive heating, which is indeed all "waste heat". But many air conditioners can run in "reverse cycle" [0], where you're transferring outside heat back in, and is much more efficient, apparently 50% cheaper to run in electricity costs. When you run one of these systems, your New Englander and Arizonan are virtuous to the degree of the difference between inside and outside temperatures. ;) There's even now some combined cycle AC systems which use the extracted heat to generate your hot water [1], sadly not yet available/cost-effective for small residential installations, but they're only off by a factor of 2 now (8kW is the smallest system I've seen, my central air is 4kW). [0] https://en.wikipedia.org/wiki/Heat_pump https://en.wikipedia.org/wiki/Heat_pump [1] http://www.mitsubishielectric.com.au/air-to-water-hot-water-heat-pumps.html http://www.mitsubishielectric.com.au/air-to-water-hot-water-...
  - jdmichal 8y ago
    I actually just replaced a 20-year-old AC system that had a link to the hot water system. Installers just removed the water heater link entirely. Said that the extra resistance and energy involved in the exchange cost more than just venting the heat in modern systems with high SEER ratings. No idea if that's accurate; just what I heard.
  - rconti 8y ago
    Sorry, I meant both resistive AND combustion (eg, "gas"). Now, obviously, natural gas is far cheaper than electric for heat in most of the US at least, but it's all 'generated' heat, with all of the waste heat and CO2 emissions that entails.