4 ms·

> going into cellar. The air will get cooler but the humidity will rise. You are going to die, unless you can cool the air DRY BULB temperature below 35C. Don'

by jefftk 5y ago

> going into cellar. The air will get cooler but the humidity will rise. You are going to die, unless you can cool the air DRY BULB temperature below 35C. Don't you mean wet bulb temperature? Why would you need a dry bulb temperature below 35C? > It will be shitty, wet, 100% humid, hot place, to sit half a day in with your family, kids and neighbors that don't have an expansive cellar like you, but at least you will survive If we do start seeing this kind of temperature around the world, I expect people will start building underground refugees or repurposing existing structures.

lmilcin 5y ago
I mean DRY BULB temperature. Reducing dry bulb temperature == removing heat. Reducing wet bulb temperature == removing humidity. But it doesn't matter a lot, because at 100% humidity (required to spontaneously dew humidity out of air) dry bulb temperature equals wet bulb temperature. Dry bulb changes indpendently of wet bulb temperature but cannot be lower than wet bulb temperature. Because when air temperature (dry bulb) reaches wet bulb temperature you are at dew point and when you cool down further all that moisture is going to either cause mist or dew or snow or rime. In fact, lowering DRY BULB temperature under dew point (WET BULB temperature) is the leading way to remove humidity in nature -- the water precipitates in the form of mist high up in the atmosphere, the mist coalesces into droplets and falls down on air as rain. Alternatively, if the temperature is below zero, it causes snow by sublimation (both wet and dry bulb temperatures are equal.
- bumby 5y ago
  >Reducing dry bulb temperature == removing heat. Reducing wet bulb temperature == removing humidity. This isn't the best interpretation. Both reducing humidity and reducing dry-bulb temperature can reduce the amount of energy in the air. Take a look at a psychrometric chart [1]. If you hold the humidity constant and reduce dry bulb temperature, you indeed reduce the enthalpy (what I interpret you mean by 'heat'). Likewise, if you keep the dry-bulb temperature constant and reduce the humidity you also reduce the enthalpy To your point, this is why fixed dry-bulb economizers aren't recommended in humid climates as a means of conserving air-conditioning energy by bringing in outside air but enthalpy controllers are allowed across all zones. [1] https://www.engineeringtoolbox.com/docs/documents/816/psychrometric_chart_29inHg.pdf https://www.engineeringtoolbox.com/docs/documents/816/psychr...

by jefftk 5y ago

lmilcin 5y ago

I mean DRY BULB temperature. Reducing dry bulb temperature == removing heat. Reducing wet bulb temperature == removing humidity. But it doesn't matter a lot, because at 100% humidity (required to spontaneously dew humidity out of air) dry bulb temperature equals wet bulb temperature. Dry bulb changes indpendently of wet bulb temperature but cannot be lower than wet bulb temperature. Because when air temperature (dry bulb) reaches wet bulb temperature you are at dew point and when you cool down further all that moisture is going to either cause mist or dew or snow or rime. In fact, lowering DRY BULB temperature under dew point (WET BULB temperature) is the leading way to remove humidity in nature -- the water precipitates in the form of mist high up in the atmosphere, the mist coalesces into droplets and falls down on air as rain. Alternatively, if the temperature is below zero, it causes snow by sublimation (both wet and dry bulb temperatures are equal.

bumby 5y ago
>Reducing dry bulb temperature == removing heat. Reducing wet bulb temperature == removing humidity. This isn't the best interpretation. Both reducing humidity and reducing dry-bulb temperature can reduce the amount of energy in the air. Take a look at a psychrometric chart [1]. If you hold the humidity constant and reduce dry bulb temperature, you indeed reduce the enthalpy (what I interpret you mean by 'heat'). Likewise, if you keep the dry-bulb temperature constant and reduce the humidity you also reduce the enthalpy To your point, this is why fixed dry-bulb economizers aren't recommended in humid climates as a means of conserving air-conditioning energy by bringing in outside air but enthalpy controllers are allowed across all zones. [1] https://www.engineeringtoolbox.com/docs/documents/816/psychrometric_chart_29inHg.pdf https://www.engineeringtoolbox.com/docs/documents/816/psychr...