Physics Question Time!

[penk]

So I'm running a dehumidifier in my basement due to the ridiculous humidity levels in the last week or so. In an hour of running, it extracted about a half gallon of water from the air.

Which got me thinking.

Given:
1) Basement air volume of approximately 4500 cubic feet (20x30 basement with an 7.5' ceiling)
2) A relative humidity of between 50 and 60% (based on current forecasts. It's occasonally spiking up to 80%)
3) Ambient temperature at the start of this process at 84 degrees fahrenheit. Current indoor temperature is 76 degrees.

How much water is actually IN the air now?

If I cool down to 72 degrees, how much water will be extracted - ie, how often do I have to change the tank out?

I've been S'ingTFW, and have gotten a lot of physics chattering, but haven't been able to suss out the actual values.

Any ideas?

Comments

[frobzwiththingz.livejournal.com]

At the humidity level we are currently dealing with, I'd suspect that you can forget about thinking about "how much water is in the air" at all, and assume that your limiting factor is actually "How much heat can the compressor move from the cooling coils". So you need to know how "efficient" the your dehumidifier is, or its COP value; the ration of much heat it moves from the cold side to the hot side, divided by the power input from the AC outlet. The manufacturer may tell you this on the spec sheet of the unit. From there, you use the heat of vaporization of water, 540 cal/g, and directly calculate the amount of condensed water produced per unit time, given the power the unit takes in from the wall.