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System one humidifier
#11
(09-16-2014, 11:57 AM)Galactus Wrote: I know that the water needs to be heated to get the vapor in the air to maintain the humidity, but I never found the air to be "heated", the air always seems to me to be about the rooms temperature heat. In the winter if the bedroom is cold the air is cold and when hot in the summer it seems hot. I find when I turn up the humidifier it gets moister but not really hotter. Am I missing the boat there? Can only describe how it feels to me. But if my info is incorrect please feel free to correct me so no one gets wrong info.

From the laws of physics and what little ASHRAE info I have been exposed to down through the years, when you add specific heat energy to water and it causes the water to evaporate, the heat you applied is contained in the water vapor as latent heat. That means it cannot be measured with a thermometer and will not feel any warmer when breathed. It just increases the total energy contained in the air without increasing its specific temperature.

As a side note, people with lung deficiency problems will not like moisture laden air since it contains less O2 per unit volume.

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#12
(09-18-2014, 03:45 PM)surferdude2 Wrote: From the laws of physics and what little ASHRAE info I have been exposed to down through the years, when you add specific heat energy to water and it causes the water to evaporate, the heat you applied is contained in the water vapor as latent heat. That means it cannot be measured with a thermometer and will not feel any warmer when breathed. It just increases the total energy contained in the air without increasing its specific temperature.

That may make sense in some situations, but I think it's not right in this particular scenario. Suppose the room air is 70F. If you run that air over water at 80F, it will get warmer and pick up some humidity. If you heat the water to 100F, the air will come out of the humidifier warmer in thermometer temperature and also more humidity. It's not just water vapor going into the air from the water, there is also conductive heat transfer from the water to the air. Imagine if the water was at 100F and the air was flowing really slowly. The air temperature would get close to 100F.
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#13
Soooooooo does the 1-5 setting = heat or = humidity?

I was under the impression from what I recall of my far away school days on this subject that forcing air over water at any temperature would allow the air to pick up moisture. I don't recall if heating the water and keeping the forcing of the air at the same constant = more humidity in the air or not though I think it does. But above is the real question, is 1-5 a heat the air setting or a humidity setting?

And while we're on the subject and the winter looms in the background is there a way to heat the air coming through the pap beyond heating the entire room?
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#14
Actually there are 2 things going on simultaneously. First, heat is increasing the evaporation rate of the water in the tank. Second, air is being passed over heated water and there is some heat transfer going on.

Let's take the 100 degree faherenheit example. If we replace the water surface with a heated plate and pass air over it, obviously it will heat the air. If it was water, it speeds up evaporation and heats the air. How much it heats the air depends a lot on the velocity of the air traveling over the water surface.

With a nasal pillow mask and a low pressure like 8 cm/H20, the air will be heated more than with a full face mask and a pressure of 20 cm/H2O.

I think that the 1-5 setting depends on whether one has a heated hose attached or not and how it is set up.

Best Regards,

PaytonA
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#15
Ok, I understand what you are saying. But the unit has a 1-5 setting, are they intending that to be humidity or heat? I think they are intending that to be level of humidity with some heat as a side effect. Is that accurate?
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#16
The numbers 1 through 5 are only arbitrary numbers to imply that a higher setting will give you higher humidity in the air being passed through the humidifier.

The coefficient of heat transfer between the small surface of water in the humidifier and a rapidly moving stream of air is quite low as compared to the latent heat that is being transferred via the law of positive pressures as is taking place due to a change of state of the liquid water into a vapor. What little specific heat that will be added to the air in the process we are analyzing will not be be easily measurable without a lab instrument that can split a single degree. A high coefficient heat exchanger requires a large surface area in order to achieve a high deltaT when the air is moving rapidly. The major part of the electrical energy we are inputting into the water is being given off as latent heat of vaporization and does so largely independent of the surface area size.

You could prove all that by placing a common thermometer at the outlet of the air hose and let it blow until it stabilizes and then read the temperature. Then turn on the humidifier to its maximum setting and wait to see if the thermometer reading changes. Not very likely and not likely very much.
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#17
Doesnt say which System one you have. If its the 60 series with heated hose and the heated hose option is turned on then System one humidity doesnt show in the menu unless the hose is unhooked. You can turn heated hose off or on in clinical settings.

If running in system one humidity mode the 1-5 knob settings are humidity levels. In that mode the air will feel about room temperature no matter what setting. Cold room moist cold air.

With the heated hose option on and running heated hose the knob settings 1-5 are hose temp settings. Higher number warmer air.

Humidity settings are set in set up in the heated hose mode with settings 1-3. Hope that helped

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#18
Ok then, so have we established to everyones agreement that;

#1; The 1-5 settings are humidity settings?
#2; (just added by ghost) That if you add the heated hose option it will heat the air by adding new settings for heat?

I was just trying to clarify that the 1-5 settings are for humidification and not for heat (even though there may be incidental heat). Just so anyone else reading this thread will know.
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#19
Heating the air is not really the intent of the hose heater. The real intent of a hose heater is to raise the temperature of the interior of the hose to above the dew point of the air passing through it so that liquid water doesn't condense on the hose and cause a rain out problem.

Whatever amount of heat it transfers into the air is unintentional and generally very small.
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#20
Ok, so then it's all about the humidification. Ok, got it.
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