Keeping your cool

[samuttodd]

Afternoon folks, I just thought I'd check to see if anybody else here is running a dehumidifier in conjunction with their home air-conditioning unit?

 

We've got a couple of AC units at our place and I know that they suck the moisture out of the air in addition to cooling it.

 

I've brought a dehumidifier from the US with me and plugged it into my 110 V step down unit. It seems to really make a big difference in cooling the place versus running both AC units. And Now I'm just running one AC in conjunction with the dehumidifier seems to work much better. Is anybody else doing this?

 

I reckon I could run the collected water through my Berkey water filtration unit and essentially make water out of thin, er thick, air so to speak.

[jacko45k]

Won't a dehumidifier take more water out of the air?

[samuttodd]

Just now, jacko45k said:

Won't a dehumidifier take more water out of the air?

Yes,  that is why it is easier to cool yourself down in dry air.   More evaporative cooling happens from your skin,  so it is easier for your body to cool itself in drier air than wetter air.

[jacko45k]

I thought a dehumidifier added heat to the room and would up the need for AC a little? Just seems to contradict what you are experiencing.

[samuttodd]

You are also correct that the dehumidification process involves a compressor which adds some heat to the air being dehumidified.   I am getting better feeling air in the house with the dehumidifier running.  It is just way more comfortable.    I am curious how much my electric bill will be running the dehumidifier and 1 of the 2 ac's vs running both ac's.   Last month our electrical was about $60.

[jacko45k]

I suspect your ACs were not really removing much water, after all that is not their primary function, more of an incidental one. The dehumidifier is getting more water out and you are in a dryer environment, feels cooler and better to breath, Do you live in a very humid area? Or perhaps had the ACs set warm?

[samuttodd]

We live right on the water.   It is soaking wet air here in Mahachai.   The AC'S  do remove a fair amout of water,  as there is a stream of effluvium from the units outdoors.    There is a word you don't get to use very much... "Effluvium"   I got about 1/2 a gallon of water after running the dehumidifier on full tilt for 3 hrs.

 

 

We are all very much relieved that the effluvium is not miasmic.   Everybody knows that miasmic effluvium is far worse than just regular old effluvium.

[scubascuba3]

How big is the unit you have? there seems to be many mini dehumidifiers available for under 1000 baht / circ 500ml water. Maybe ok for a bedroom I'm not sure

 

 

[samuttodd]

The place we are at is pretty tight.   It is just 1 room I'd guesstimate that it is 400 Sq ft.  It only draws 2.8Amps at 110v.   It says it is a 30 pint machine,  but I don't think there is any way it could hold 30 pints befre you have to dump the water out.    It looks like there is a hose connection if I want to plumb it in to a drain.

[utalkin2me]

It seems like if this was actually effective, we would see more ac units with an attached or separate dehumidifier. Because, wouldn't ac companies want their units to be the most effective and coolest. 

 

Since they do not do that, I am betting the humidifier in concert with the ac is not worth the extra cost. 

 

 

[samuttodd]

I brought it from the states,  because the air here is so remarkably humid.   I thought it might be helpful.

 

Back home the air is about 15-25% humidity.    I sure miss southern oregon climate.    (When it isn't smokey from forest fires)

[kokesaat]

My Daikin inverters do a good job of removing moisture when set on dehumidify mode.  As well, they remove lots, but less, water when in cooling mode.

Might one of the more knowledgeable sparkies be able to tell me the pluses/minuses of using dehumidify mode for longer periods than cooling mode?  Electric usage/wear and tear on the air conditioner, etc.

Thanks

 

[steven2018]

Keep the dehumidifier clean, don't want mold buildup.

[KittenKong]

17 hours ago, jacko45k said:

I suspect your ACs were not really removing much water, after all that is not their primary function, more of an incidental one.

My air-con produces more than a big bucket of water a day. I know because I collect it and use it for watering my plants and rinsing my balcony.

 

Removing humidity is the primary function of my air-con as I have the temperature set to 27 degrees, which in Jomtien is not much lower than the outdoor temperature a lot of the time. It's the humidity reduction I am after, and that's where the comfort is.

[samuttodd]

We try and run our ac's in fan mode only  once a week for 2 hours.   Hopefully that will dry them out enough to keep mold from growing in there.

[Jeffrey346]

The ideal relative humidity for health and comfort is about 40–50%.

I keep a hygrometer in my bedroom and it reads 50-55% with my Daikin Inverter set to 24. Seems to be doing a perfect job..

[Puccini]

Some years ago I used a test device to graph the temperature and relative humidity in an air-conditioned room.
 

Phase 1: Before the A/C was switched on, humidity was 90%
 

Phase 2: Within 10 minutes after switching the A/C on, the humidity dropped to 60%

 

Phase 3: Within 10 minutes after the preset temperature was reached and the compressor automatically switched off and only the fan kept running, the humidity was back up at 90%

 

Note: This airconditioner allowed a setting of DRY. This overrode the thermostat, the compressor never switched off, humidity remained at a constant 60%, and I woke up shivering at 20 °C or less.

 

I read that some A/C units, in COOL mode, reverse the air flow for a few seconds when the thermostat switches off. This sucks the water drops caught between the lamellae back out into the water drain and thus slows down the rise in humidity during the phase when only the fan is running.

 

[Lacessit]

20 hours ago, samuttodd said:

We live right on the water.   It is soaking wet air here in Mahachai.   The AC'S  do remove a fair amout of water,  as there is a stream of effluvium from the units outdoors.    There is a word you don't get to use very much... "Effluvium"   I got about 1/2 a gallon of water after running the dehumidifier on full tilt for 3 hrs.

 

 

We are all very much relieved that the effluvium is not miasmic.   Everybody knows that miasmic effluvium is far worse than just regular old effluvium.

You've been watching Ghostbusters too many times.

[AgMech Cowboy]

22 hours ago, samuttodd said:

"Effluvium"  miasmic.   miasmic effluvium

Good English lesson. I wonder how many people had to look up miasmic. Effluvium was easy, but not an every day word.

[thaipara]

A dehumidifer _is_ an air conditioner, or, better to say, a dehumidifier wraps up all the components of an aircon in one package. Being a single package, as noted above, it raises the temperature in the room it dehumidifies, just as a refrigerator does. It's quite a complex analysis to determine whether or not your particular unit is the most cost-efficient way to go or not. The electric bill will tell the tale.

 

I had a friend in the US many years ago who did commercial and domestic HVAC. His big selling point for central air was the inclusion of adjustable ducting that allowed the user to make the choices we have here with split unit air cons - "cool" or "dry". He called it the "desert breeze" setting and after trying it there were few users who would go back to the "cool" option.

[Lacessit]

2 hours ago, AgMech Cowboy said:

Good English lesson. I wonder how many people had to look up miasmic. Effluvium was easy, but not an every day word.

Hermeneutics and semiotics are a couple I like. I can apply them occasionally to TV posts.

[samuttodd]

3 minutes ago, Lacessit said:

Hermeneutics and semiotics are a couple I like. I can apply them occasionally to TV posts.

I will admit that I had to look those up.   I've learned a lot of words in the last 50 or so years,  and these 2 are new,   so thank you for adding to my knowledge base.    I'll kick some serious ass when we play trivial pursuit next time.

[seancbk]

On 6/1/2019 at 2:12 PM, jacko45k said:

I thought a dehumidifier added heat to the room and would up the need for AC a little? Just seems to contradict what you are experiencing.

 

In Hong Kong we always ran dehumidifiers, and by doing so we were able to use the AC less.   I'm actually surprised that decent sized dehumidifiers are not common here.

They sell many different ones in HK

https://www.fortress.com.hk/en/shop/home-appliances/dehumidifiers/c/52?q=%3Anew%3AsupplierFormCategory%3ADehumidifier

 

[tifino]

On 6/1/2019 at 6:15 PM, kokesaat said:

My Daikin inverters do a good job of removing moisture when set on dehumidify mode.  As well, they remove lots, but less, water when in cooling mode.

Might one of the more knowledgeable sparkies be able to tell me the pluses/minuses of using dehumidify mode for longer periods than cooling mode?  Electric usage/wear and tear on the air conditioner, etc.

Thanks

 

the only real complication, with running the dehumidier prolonged; is if you're room is well sealed, with lots of potplants.

The plants can become overly dehydrated.

 

[Lacessit]

17 minutes ago, samuttodd said:

 

 

17 minutes ago, samuttodd said:

I will admit that I had to look those up.   I've learned a lot of words in the last 50 or so years,  and these 2 are new,   so thank you for adding to my knowledge base.    I'll kick some serious ass when we play trivial pursuit next time.

I must admit I am addicted to obscure words. You can kick more ass with orts and gralloch.

[The Fugitive]

6 hours ago, Puccini said:

Some years ago I used a test device to graph the temperature and relative humidity in an air-conditioned room.
 

Phase 1: Before the A/C was switched on, humidity was 90%
 

Phase 2: Within 10 minutes after switching the A/C on, the humidity dropped to 60%

 

Phase 3: Within 10 minutes after the preset temperature was reached and the compressor automatically switched off and only the fan kept running, the humidity was back up at 90%

 

Note: This airconditioner allowed a setting of DRY. This overrode the thermostat, the compressor never switched off, humidity remained at a constant 60%, and I woke up shivering at 20 °C or less.

 

I read that some A/C units, in COOL mode, reverse the air flow for a few seconds when the thermostat switches off. This sucks the water drops caught between the lamellae back out into the water drain and thus slows down the rise in humidity during the phase when only the fan is running.

 

Many thanks for taking the trouble both to do those tests and to share your acquired knowledge with us. Explains why when I set 27 dry I feel perfect overnight. Unfortunately, my Thai Mrs believes 27 not cool enough and every night changes to 25. She then complains how cold it becomes. Solution, hide or remove batteries from remote control.

[Puccini]

7 hours ago, The Fugitive said:

Many thanks for taking the trouble both to do those tests and to share your acquired knowledge with us. Explains why when I set 27 dry I feel perfect overnight. Unfortunately, my Thai Mrs believes 27 not cool enough and every night changes to 25. She then complains how cold it becomes. Solution, hide or remove batteries from remote control.

It looks like the DRY mode on your airconditioner works differently from what I described about mine or – more likely – I remember it wrong.

 

From your description of the DRY mode, when the thermostat relay interrupts the current to the compressor it does so simultaneously with the fan. Then, when the temperature rises and the thermostat kicks in again, the relay simultaneously supplies current again to the fan and compressor.

 

I now remember how, eons ago, when air-conditioners had no DRY mode, I got so frustrated that I rewired a Westinghouse split system myself that way. 

[Puccini]

I found the manual for my current aircon in my cloud and see that I did remember it wrong. It works as I described it for your situation.

 

I can't copy a text snippet from this particular PDF file, so I made a JPG image of the relevant paragraph and link to it below.

 

https://drive.google.com/file/d/10VJVe9X3XhhgalCMhm3G8i_o97LFC5Uz/view?usp=drivesdk

[Puccini]

It is true that with the fan off during the compressor-off phase, the air feels warmer because the windchill factor is missing. My wife and I feel it too, so we installed a super-quiet and super-slow ceiling fan, which we run together with the aircon in DRY mode.

 

During the cool season, the ceiling fan is enough by itself most of the time and during daytime we switch the aircon on for a short period when the air starts to feel sticky (humid)

[The Fugitive]

It is true that with the fan off during the compressor-off phase, the air feels warmer because the windchill factor is missing. My wife and I feel it too, so we installed a super-quiet and super-slow ceiling fan, which we run together with the aircon in DRY mode.
 
During the cool season, the ceiling fan is enough by itself most of the time and during daytime we switch the aircon on for a short period when the air starts to feel sticky (humid)

Thanks for the link and further information! My Mrs refuses to use our ceiling fan saying "Thai people not like". But fortunately she does consent to use of pedestal fans.

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