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Thread: Humidity up in Dry Cabinet when air on is on

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    Default Humidity up in Dry Cabinet when air on is on

    I brought a Digi-cabi DHC-040 2 weeks back, and humidity was stable at 50% where I set. I didn't quite believe as it seems too good to be truth, so I got a digital meter from DIY shop to double check the reading.

    The reading stays at 50% on both the meter until I on my air conditioning, the humidity reads between 55%-57% on the second meter I placed in the cabinet, while the cabinet meter still reading 50%. Everything will return to normal about 30minute after I off my aircon. These happened for the pass 3 night.

    Anyone encounter similar situation before? Anyone can explain why is this happening? I do however believe that both meter are not faulty because I did see both meter display 70% humidity when measuring outside air.

  2. #2

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    The key word is "relative".
    Alpha

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    Moderator ed9119's Avatar
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    Default Re: Humidity up in Dry Cabinet when air on is on

    air con + a warm running peltier unit might have caused a little bit of condensation when you opened the cabinet door

    these measurements need to be taken a few hours apart ....

    its hard to comment further without understanding your room environment
    Last edited by ed9119; 10th November 2012 at 01:39 AM.
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    Moderator Octarine's Avatar
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    Default Re: Humidity up in Dry Cabinet when air on is on

    Both meters are not calibrated. Just because they display the results in a digital way does not mean they are accurate.
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    Default Re: Humidity up in Dry Cabinet when air on is on

    Quote Originally Posted by Rashkae View Post
    The key word is "relative".
    Quote Originally Posted by ed9119 View Post
    air con + a warm running peltier unit might have caused a little bit of condensation when you opened the cabinet door

    these measurements need to be taken a few hours apart ....

    its hard to comment further without understanding your room environment
    I do think it is about "relative", but don't know how to explain further.

    I do not think it is condensation since the air in the room should get drier when the room is cooling down ( typical air conditioning in HDB flat ). I also take extra precaution on the second night by doing nothing and not opening the door, but just take reading through the glass door. I realize the reading remain high at around 56% until i turn off my aircon the next morning ( I check the reading first thing when I wake up ).

    Theoretically, the humidity in the cabinet should remain unchanged at 50%, since there the are no air exchange. So I start to think if it is possible that one of the meter is setup to measure relative and not actual humidity, thus causing this difference.

    Seriously, I am not complaining but just curious and these tickles me since I am in engineering but can't explain it. On the other hand, if our cabinet meter is set up to display relative humidity, then will this cause error to most cabinet that were place in rooms where air condition varies day and night?

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    Default Re: Humidity up in Dry Cabinet when air on is on

    Quote Originally Posted by Octarine View Post
    Both meters are not calibrated. Just because they display the results in a digital way does not mean they are accurate.
    I am thinking if both meter are not calibrated, then they may not be be accurate and the reading may be slightly different but shouldn't be 5-6% apart. Well, I may be wrong and one of the meter may be faulty.

    By the way, shouldn't the cabinet's meter be calibrated before delivery?

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    Default Re: Humidity up in Dry Cabinet when air on is on

    One more interesting fact is the reading in both meter remain constantly at the same valve throughout the whole day.

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    Default Re: Humidity up in Dry Cabinet when air on is on

    Quote Originally Posted by bomia View Post
    I am thinking if both meter are not calibrated, then they may not be be accurate and the reading may be slightly different but shouldn't be 5-6% apart. Well, I may be wrong and one of the meter may be faulty.
    By the way, shouldn't the cabinet's meter be calibrated before delivery?
    Not required. For the storage of consumer electronics the inaccuracy of a 5% can be tolerated. So these meters are produced with standard settings and some lose batch testing - in the same fashion as the consumer articles. Calibrated meters are checked individually, that's the reason for the higher price.
    EOS

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    Moderator Octarine's Avatar
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    Default Re: Humidity up in Dry Cabinet when air on is on

    Quote Originally Posted by bomia View Post
    The reading stays at 50% on both the meter until I on my air conditioning, the humidity reads between 55%-57% on the second meter I placed in the cabinet, while the cabinet meter still reading 50%. Everything will return to normal about 30minute after I off my aircon. These happened for the pass 3 night.
    I suspect: When you turn on the air-con, it's cooling and drying the air in the room. If the door of the dry cab is closed, the inside air is "trapped" with it's content of absolute humidity. Due to the metal of the cabinet it's getting cooled but not dried. With constant absolute amount of humidity and decreasing temperature the Relative Humidity goes up. Easy to observe in daily weather in the evening and night, mainly in the (remaining small) areas with open greenery and trees: dew and mist.
    EOS

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    Default Re: Humidity up in Dry Cabinet when air on is on

    Quote Originally Posted by Octarine View Post
    I suspect: When you turn on the air-con, it's cooling and drying the air in the room. If the door of the dry cab is closed, the inside air is "trapped" with it's content of absolute humidity. Due to the metal of the cabinet it's getting cooled but not dried. With constant absolute amount of humidity and decreasing temperature the Relative Humidity goes up. Easy to observe in daily weather in the evening and night, mainly in the (remaining small) areas with open greenery and trees: dew and mist.
    Good explanation, this is surely the more logical reason.

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    Default Re: Humidity up in Dry Cabinet when air on is on

    Quote Originally Posted by bomia View Post
    I do think it is about "relative", but don't know how to explain further.

    I do not think it is condensation since the air in the room should get drier when the room is cooling down ( typical air conditioning in HDB flat ). I also take extra precaution on the second night by doing nothing and not opening the door, but just take reading through the glass door. I realize the reading remain high at around 56% until i turn off my aircon the next morning ( I check the reading first thing when I wake up ).

    Theoretically, the humidity in the cabinet should remain unchanged at 50%, since there the are no air exchange. So I start to think if it is possible that one of the meter is setup to measure relative and not actual humidity, thus causing this difference.

    Seriously, I am not complaining but just curious and these tickles me since I am in engineering but can't explain it. On the other hand, if our cabinet meter is set up to display relative humidity, then will this cause error to most cabinet that were place in rooms where air condition varies day and night?
    Actually, I see the reverse when I turn on the airconditioning. Whenever my AC is turned on, the RH will drop around 10-20%.

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    Default Re: Humidity up in Dry Cabinet when air on is on

    Quote Originally Posted by Octarine View Post
    I suspect: When you turn on the air-con, it's cooling and drying the air in the room. If the door of the dry cab is closed, the inside air is "trapped" with it's content of absolute humidity. Due to the metal of the cabinet it's getting cooled but not dried. With constant absolute amount of humidity and decreasing temperature the Relative Humidity goes up. Easy to observe in daily weather in the evening and night, mainly in the (remaining small) areas with open greenery and trees: dew and mist.

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    Default Re: Humidity up in Dry Cabinet when air on is on

    Quote Originally Posted by Octarine View Post
    I suspect: When you turn on the air-con, it's cooling and drying the air in the room. If the door of the dry cab is closed, the inside air is "trapped" with it's content of absolute humidity. Due to the metal of the cabinet it's getting cooled but not dried. With constant absolute amount of humidity and decreasing temperature the Relative Humidity goes up. Easy to observe in daily weather in the evening and night, mainly in the (remaining small) areas with open greenery and trees: dew and mist.

    Eureka !!
    Nikomi Canpen Zenten :eek:
    Not exactly 100% Natural but definitely the closest you can get to it

  14. #14

    Default Re: Humidity up in Dry Cabinet when air on is on

    Jus set ur dry cabin at 40%-50% then live it as it is, so even if it fluctuate it wont do too much damage.
    Next is bring ur came out and worry more bout how to shoot a better picture rather then worrying bout tt extra fluctuation.
    Everybody is entitled to their own opinion, if you don't like mine pls ignore and move on.

  15. #15

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    Quote Originally Posted by daredevil123

    Actually, I see the reverse when I turn on the airconditioning. Whenever my AC is turned on, the RH will drop around 10-20%.
    Same here.. My dry cabi's RH will drop when my aircon is on.

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