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Could farmers in cold climate pump CO2 into a greenhouse, raising it to ~1000ppm, to meaningfully reduce the need to heat during the winter? Is the heat trappi

by cwkoss 7y ago

Could farmers in cold climate pump CO2 into a greenhouse, raising it to ~1000ppm, to meaningfully reduce the need to heat during the winter? Is the heat trapping effect of CO2 measurable at building scale? Would double paned windows containing pure CO2 between the panes function as measurably better insulators?

eesmith 7y ago
As https://en.wikipedia.org/wiki/Greenhouse_effect https://en.wikipedia.org/wiki/Greenhouse_effect points out: > The term "greenhouse effect" continues to see use in scientific circles and the media despite being a slight misnomer, as an atmosphere reduces radiative heat loss[8] while a greenhouse blocks convective heat loss. A simplified model is at https://en.wikipedia.org/wiki/Idealized_greenhouse_model https://en.wikipedia.org/wiki/Idealized_greenhouse_model . A quick look suggests ε - the emissivity of the atmosphere - is the key parameter answering your question. The Δε must be high enough to affect the calculation. Simply filling a greenhouse with CO2 isn't enough to get there. (Plus, greenhouses aren't primarily cooled by radiative heat loss.) FWIW, CO2 was used in double paned windows, going back to at least the 1930s. https://patentimages.storage.googleapis.com/1f/67/5c/7a7917dd451732/US2094381.pdf https://patentimages.storage.googleapis.com/1f/67/5c/7a7917d... says: > Carbon dioxide is found to give good results and, as compared with air, materially increases the effectiveness of the article as a heat insulator. However, as https://www.rbaofqc.com/windows/argon-as-gas-fill-for-double-pane-windows/ https://www.rbaofqc.com/windows/argon-as-gas-fill-for-double... points out, under "Early Gas Fills": > Air as a fill wasn't effective in providing insulation, so some manufacturers started looking for alternatives. The 1970s saw the use of carbon dioxide and Freon. Although they helped increase the insulation value of windows, they were proven to be sensitive to seal failure and cause discoloration. Argon and krypton are more effective than CO2, but they are not greenhouse gasses because convective heat loss is different from radiative heat loss.
- cwkoss 7y ago
  Awesome answer, thank you!

by cwkoss 7y ago

eesmith 7y ago

As https://en.wikipedia.org/wiki/Greenhouse_effect https://en.wikipedia.org/wiki/Greenhouse_effect points out: > The term "greenhouse effect" continues to see use in scientific circles and the media despite being a slight misnomer, as an atmosphere reduces radiative heat loss[8] while a greenhouse blocks convective heat loss. A simplified model is at https://en.wikipedia.org/wiki/Idealized_greenhouse_model https://en.wikipedia.org/wiki/Idealized_greenhouse_model . A quick look suggests ε - the emissivity of the atmosphere - is the key parameter answering your question. The Δε must be high enough to affect the calculation. Simply filling a greenhouse with CO2 isn't enough to get there. (Plus, greenhouses aren't primarily cooled by radiative heat loss.) FWIW, CO2 was used in double paned windows, going back to at least the 1930s. https://patentimages.storage.googleapis.com/1f/67/5c/7a7917dd451732/US2094381.pdf https://patentimages.storage.googleapis.com/1f/67/5c/7a7917d... says: > Carbon dioxide is found to give good results and, as compared with air, materially increases the effectiveness of the article as a heat insulator. However, as https://www.rbaofqc.com/windows/argon-as-gas-fill-for-double-pane-windows/ https://www.rbaofqc.com/windows/argon-as-gas-fill-for-double... points out, under "Early Gas Fills": > Air as a fill wasn't effective in providing insulation, so some manufacturers started looking for alternatives. The 1970s saw the use of carbon dioxide and Freon. Although they helped increase the insulation value of windows, they were proven to be sensitive to seal failure and cause discoloration. Argon and krypton are more effective than CO2, but they are not greenhouse gasses because convective heat loss is different from radiative heat loss.

cwkoss 7y ago
Awesome answer, thank you!