3 ms·
This is all fascinating stuff to me, I'd never really heard of wet bulb before. Quick question though: how does the pressure difference play into this in a base
by f154hfds 5y ago
This is all fascinating stuff to me, I'd never really heard of wet bulb before. Quick question though: how does the pressure difference play into this in a basement? As far as I'm aware below ground pressure and voids under basements tend to cause pressure differentials in even non-AC basements (causing radon issues where I'm from)? I assume this would help a cellar situation in the event of power outage as air even slightly below ground tends to be much cooler than above ground air?
- lmilcin 5y agoThe pressure difference between your backyard and your basement is for all practical purposes null. It is also orders of magnitude smaller than those caused by gusts of wind and changing weather.
- f154hfds 5y agoI'm not sure this is so simple. Clearly your answer is correct with a largely uninsulated house with a basement only partially below ground (perhaps most of the developing world to be fair). Any semi-sealed home will have heat naturally accumulate (and dissipate) at the top. Apparently the movement of air upward - known as the stack effect - creates a (slight) vacuum pull at the bottom. Of course it's a small effect in normal temperatures but in extreme reverse stack-effect scenarios like you're describing the ground temperature below 3 - 5 feet should result in a basement being lower temperature than the backyard as available air gets sucked through the cooler ground to get into the basement? I'm sure this varies widely by region (ground temps vary in 3 - 5 ft depths) but everywhere this temperature will be cooler than the outside in such weather extremes.