Hi, does anyone tried or has an idea if how can we do a dehumidification in flow simulation? I mean I want to test the dehumidification capacity of a dehumidifier in a space or room, thank you for anyone who can point me to a direction.
It depends what you want to simulate ; Flow can deal with humidity level or other type of values linked to it (mass of water....)
So, what do you want to test ? What do you expect from the solver ?
Hi thanks for the reply, im actually planning to simulate a dehumidifier, like I want to test in a particular room size on how long can I achieve a Relative Humidity of 60% if the room was Initially filled with 80% of relative humidity. I mean it would be best if I can know the performance of a humidifier depending on space size and the time needed to achieve lets say a relative humidity of 60% if the room was filled with 80% RH.
So, if you want to test something like you said, you can do it with two boundary conditions which would be
- an air outlet, like a volumic outlet flow rate, to simulate the replacement of the air in the local ;
- an environnement pressure condition, to simulate the deshumidifier (you could for instance put a 60% relative humidity boundary condition)
Those two taken together, would simulate the dehumidifier.
I think you have to have two separate boundary conditions cause you can't define a specific relative humidity when defining a "forced" outlet (like a volumic outlet flow rate).
Maybe other configurations would work, but more tests would be needed.
Thanks for the response, yeah i would love to try that, but I want to test a dehumidifier performance of 300ml/day, how could I convert that into a volumetric flow rate, because I bought a humidifier with a performance of 300ml/day, I want to test that in my room so I can see if it is good or not good in my room size, thanks Sylvain.
Considering you can have from the simulation the specific humidity in kg water/kg air, for instance if you simulate a room of a certain volum which contains a certain volume of air, which goes from 80% relative humidity to 60% relative humidity in a period of time, you can deduce the quantity of water which was absorbed by the dehumidifier.
To be more precise : you have to show (for instance, with global goal) the specific humidity at the beginning, and at the end of the period of time, and soustract them to get the mass of water that disappeared thanks to the dehumidifer (considering you introduce the same amount of air in the local than the amount you evacuate, so the total volume of air won't change)
What I've said would be to know what quantity of water you would remove from the local, for a period of time, so you can compare this with the value of the efficiency of the dehumidifier you have.
Thanks for the response, actually I am confused but anyway I will try to do what you told me, I I just want to know how much % of RH can my humidifier remove vs. time like after 8hours, lets say the room was at 80% RH then after running my humidifier with 300ml/day performance after 8hours I just want to know the RH % , like before and after, thanks Sylvain.
How do you compute the amount of water in air if for example lets say there is 80% RH so how much water or vapor is that in air?, I mean how do you measure the water in air if it is 80% RH?, thanks Sylvain.
You don't actually to compute it on your own, Flow will do it, when you can get the specific humidity in kg water/kg air.
Without Flow Sim, it would be with this : (in english, search for Psychometric Chart)
You have the curves of relative humidity vs temperature and enthalpy of the air ; but you don't have to use this, Flow Sim will do the computation. (You have also the Specific humidty on the right).
Like I've said before, you have to get the Specific Humidity of air before and after. It will be equal to the mass of water divided by the mass of air in the local, so you can easily find the mass of water.
Hope it's clearer.
I don't think you can directly test the efficency of the dehumidifier, for instance the one you want that perform 300 mL/day, but you can simulate the mass of water that would be removed.
Thanks Slyvain, it is now clear to me, thanks for the info, at least now I have an idea how to do this, thanks again..
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