Ice blocks in humidifier

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JDS74
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Re: Ice blocks in humidifier

Post by JDS74 » Thu Jul 31, 2014 6:56 pm

englandsf wrote:Finally tried 6-7 fake reusable ice cubes in my S9/H5i set up last night with humidity on 2 and Climate Line/Heat off. The slightly cooler air was nice but it was also significantly drier - so caused some extra congestion. Overall, not worth it as the congestion was more unpleasant than the cooler air was pleasant. Net fail.
I read a study on the humidity levels reached at the mask for several heated humidifier systems. The net was the humidity level didn't get to the specified setting until about one hour after the start.

So, if you placed some actual frozen distilled water cubes in the chamber you might be able to get 20 or 30 minutes of cool air before the humidifier overcame the lower temperature. I suspect that it wouldn't take much to give the effect but also melt in time to give you the level of humidity you need.

Alternatively, you could keep your distilled water in the fridge and try mixing some with room temperature to get various temperatures to see how long the cool effect would last.

Just a thought about how to design an experiment.

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Ontario CPAP
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Re: Ice blocks in humidifier

Post by Ontario CPAP » Thu Jul 31, 2014 8:36 pm

Cooling the air reduces the amount of water vapor it can carry.

At 15C, air can hold a maximum of 11g of water vapor per kg of dry air.
At 20C, air can hold a maximum of 15g of water vapor per kg of dry air.
At 25C, air can hold a maximum of 20g of water vapor per kg of dry air.

(I used this psychrometric chart to obtain these values http://www.fao.org/docrep/s1250e/S1250EEV.GIF)

This is why humidity is expressed as "relative humidity" -- the amount of water vapor in the air relative to the maximum amount of water vapor the air can hold at that temperature. In all three cases, above, the air is holding 100% of the water vapor it can for that temperature, thus the relative humidity is 100%, BUT the amount of water vapor in 25C air is almost twice as much as for 15C air.

If you cool the air, it holds less water. The relative humidity is still 100%, but actual amount of water vapor in the air is less, and thus it feels drier.

This is also why rainout occurs. If you have 100% relative humidity air at 25C but it cools down to 20C in the hose, 20g - 15g = 5g of water vapor must condense back in to liquid water -- 20C air cannot hold more than 15g of water vapor. Hence we use hose heaters to keep the air temperature high to avoid the water vapor in the air from condensing back in to liquid form.

deuelpm
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Re: Ice blocks in humidifier

Post by deuelpm » Sun Aug 03, 2014 4:27 am

I was thinking hose-cooling too if not for the rainout factor. You'd almost need something like one of those ultrasonic humidifiers... not sure how that would work...

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palerider
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Re: Ice blocks in humidifier

Post by palerider » Sun Aug 03, 2014 10:14 am

deuelpm wrote:I was thinking hose-cooling too if not for the rainout factor. You'd almost need something like one of those ultrasonic humidifiers... not sure how that would work...
you could plumb a nebulizer inline, or I guess you could put one of the little ultrasonic pucks in a container of water and put that inline, one of those external humidifier would work, with some tinkering.

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Tatooed Lady
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Re: Ice blocks in humidifier

Post by Tatooed Lady » Sun Aug 03, 2014 7:40 pm

palerider wrote:
deuelpm wrote:I was thinking hose-cooling too if not for the rainout factor. You'd almost need something like one of those ultrasonic humidifiers... not sure how that would work...
you could plumb a nebulizer inline, or I guess you could put one of the little ultrasonic pucks in a container of water and put that inline, one of those external humidifier would work, with some tinkering.
Sounds a lot like work. Could one then shout, "PUCK YOU!" ?

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palerider
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Re: Ice blocks in humidifier

Post by palerider » Sun Aug 03, 2014 7:48 pm

Tatooed Lady wrote:
palerider wrote:
deuelpm wrote:I was thinking hose-cooling too if not for the rainout factor. You'd almost need something like one of those ultrasonic humidifiers... not sure how that would work...
you could plumb a nebulizer inline, or I guess you could put one of the little ultrasonic pucks in a container of water and put that inline, one of those external humidifier would work, with some tinkering.
Sounds a lot like work. Could one then shout, "PUCK YOU!" ?
I think it might be mandatory

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