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PEA advises on cost-effective air conditioners amid Thai heat


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1 hour ago, Dellboy218 said:

FALSE

I believe I was talking about me.  Did I mention any one else?

 

What you did say was that the airdry function found on just about every aircon is meaningless.

Now perhaps you can bring graphs and reviews to to prove your hypothesis.

 

 

Sorry.

A much better and more appropriate term would have been....

REDUNDANT

 

REDUNDANT is what the "Dry Mode" button is.

Waste of space on the remote control.

 

Dehumidifiers work well when dehumidification is needed because they draw in ambient room air, pass the humid air over cold coils to condense the water vapor, then past the resulting dry air toward the back of the machine where it passes over hot coils to reheat the air, and then the air exits out the back of the dehumidifier at slightly higher temperature than when it entered the machine.

 

A dehumidifier is very useful in Chiang Mai during the humid months, such as during the raining season, and also the cool season, to avoid problems such as black mold in the house, or green mold growing on leather products such as belts, shoes, etc.

 

UNFORTUNATELY;  The AC Dry Mode does not work as well because the room air is cooled as it passes over the evaporator coils, thus providing dehumidification, but it is never re-heated.

 

When the room air reaches lower temps, then the dehumidification process does not work very well, and the room air becomes damp and uncomfortable.

 

This is why, in the past, I have often used a dehumidifier and the AC  simultaneously for best results.

 

Hope this information will be helpful to you when you next become bothered by excessive humidity in the Cool Season or the Wet Season, a condition which often leads to Black Mold, as you can learn by searching this Forum.

 

 

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Interesting topic for me as I'm about to have to specify aircons for a new-build house any day now.

 

Does anyone have any reliable data on how much more economical inverters are (for the same room volume, of course)? Everyone here seems to agree they are better, but where's the point of recouping the extra initial outlay? A year or two? 10 years? Or almost immediate?

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8 hours ago, Dellboy218 said:

nduction motor as in the compressor can take around 7 times its running energy to start.

For how long? A few seconds?

My 12000 BTU Mitsu Normal usually takes just over a kilowatt when running. Does that mean SEVEN kilowatts to start up without tripping a 20 amp breaker.

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3 hours ago, VocalNeal said:

 

Just realized I made a gaff in my explanation. The controls obviously TRANSFORM the AC to DC to power the control circuits and then the INVERTER converts the DC back to AC to run the compressor. 

 

My wife just showed me a new thing where the air conditioner runs on solar. I said good except we only use ours at night. She looked a bit confused. 

Most çontrol circuits' run on DC, as in your telly, computer  etc etc. The 'power'part is still AC as you say. I doubt whether the DC is çonverted back' to AC to run the compressor.

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2 minutes ago, KannikaP said:

I doubt whether the DC is çonverted back' to AC to run the compressor.

 

Yes, could be a pulse-width modulated DC motor. I have heard model trains use those.

I think a brushless DC motor would be too expensive but I don't know for sure.  

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17 minutes ago, KannikaP said:

For how long? A few seconds?

My 12000 BTU Mitsu Normal usually takes just over a kilowatt when running. Does that mean SEVEN kilowatts to start up without tripping a 20 amp breaker.

If it is an inverter model then no. If a direct on line non inverter model then it will take considerably more.  Standard Indiction motor theory.  If you do not believe me then this might help.  Just a quick copy paste.  I did say up to 7 they day 5 or 6. It depends on the startup load and how quickly it gets up to speed

 

 

The starting current of the induction motor is about 5 or 6 times the motor full load current. An induction motor of rating 11 KW,22 Amps,440 volts takes a high starting current of about 132 Amps. The current reduces as the motor accelerates towards its base speed or synchronous speed.Feb 25, 2564 BE
Edited by Dellboy218
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23 minutes ago, KannikaP said:

For how long? A few seconds?

My 12000 BTU Mitsu Normal usually takes just over a kilowatt when running. Does that mean SEVEN kilowatts to start up without tripping a 20 amp breaker.

A circuit breaker operates on current and time.  The attached graph might help explain.  You would have to investigate your own particular breaker to confirm.

Screenshot_20240425_181921_Firefox.jpg

Edited by Dellboy218
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1 hour ago, GammaGlobulin said:

 

Sorry.

A much better and more appropriate term would have been....

REDUNDANT

 

REDUNDANT is what the "Dry Mode" button is.

Waste of space on the remote control.

 

Dehumidifiers work well when dehumidification is needed because they draw in ambient room air, pass the humid air over cold coils to condense the water vapor, then past the resulting dry air toward the back of the machine where it passes over hot coils to reheat the air, and then the air exits out the back of the dehumidifier at slightly higher temperature than when it entered the machine.

 

A dehumidifier is very useful in Chiang Mai during the humid months, such as during the raining season, and also the cool season, to avoid problems such as black mold in the house, or green mold growing on leather products such as belts, shoes, etc.

 

UNFORTUNATELY;  The AC Dry Mode does not work as well because the room air is cooled as it passes over the evaporator coils, thus providing dehumidification, but it is never re-heated.

 

When the room air reaches lower temps, then the dehumidification process does not work very well, and the room air becomes damp and uncomfortable.

 

This is why, in the past, I have often used a dehumidifier and the AC  simultaneously for best results.

 

Hope this information will be helpful to you when you next become bothered by excessive humidity in the Cool Season or the Wet Season, a condition which often leads to Black Mold, as you can learn by searching this Forum.

 

 

I think redundant refers to your posts.

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7 minutes ago, isaanistical said:

Interesting topic for me as I'm about to have to specify aircons for a new-build house any day now.

 

Does anyone have any reliable data on how much more economical inverters are (for the same room volume, of course)? Everyone here seems to agree they are better, but where's the point of recouping the extra initial outlay? A year or two? 10 years? Or almost immediate?

 

a.  First you need to determine how many hours you will use ACs in each room.

b. And, you need to calculate (approximately) what size AC you need, in terms of Cooling Capacity, for each room  You will need to consider how cold (what your desired room temperature is) your require it to be, both in the day and at night.

d. The smallest size AC I buy is the 18,000 BTU Panasonic machine.  This has an EER/SEER above 23. But, I definitely prefer the Panasonic 20,000BTU units, due to the increasing temperatures we are experience now, and will be looking forward to in the near future.  For me, in a typical 22 square-meter room, I need 20,000BTU, or more.  

image.png.6f47129b29ceb4801641620428146d9c.png

This is the minimum I need for a 22 square-meter room. It has an SEER over 23.   I would prefer this machine had been manufactured in Japan where QC might be better.  But, still, I need high efficiency, and I get this from the machine pictured here.

 

c. You will not be able to calculate actual BT. savings unless you first know how many hours, total, you will run them.

 

d. It might be better to judge from your AC usage in the past. While living in other houses of similar size, what was your cost of power to run the ACs.

 

Then, check the efficiency of the old machines.  From this you should easily be able to estimate your savings if you increase the efficiency by 30 percent, for example.  You will be able to estimate the electric power savings per month.

 

There are also calculators offered by AC companies on line.

 

e.  For the example above, a 22 square-meter room:  IF I use the 18,000BTU unit to cool this room 16 hours per day, and average power usage of the unit is approx 1000 watts, then I would be using 16 kWh per day, or 496 kWh per month. If my machine is ten percent more efficient than another machine, I would save approx Bt.250 per month. Or, if 20 percent more efficient, then Bt.500 per month.

 

In reality, the power used by this machine is not even close to 1kW per hour.

 

f. For a comparison, look at Mitsubishi

image.png.ae2561df3f6fc174d5b19b519f28d4b7.png

image.png.ea08b37dad6711d90c6a88c85bc147f8.png

 

Panasonic SEER is 23

Mitsubishi SEER is 18

Panasonic is 27 percent more efficient.

 

If in the past, you paid Bt.4000 per month for the power used to run your ACs...as an example...

AND if those old machines had average SEER ratios of 18, ...

 

Then, theoretically, by switching to Panasonic, you might expect to save Bt.1100 per month.

 

 

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A problem with buying an aircon is that you can never try it out in a store. They usually just have the plastic housing on display .

I have an expensive on/off Daikin 24BTU and while it cools well , the lowest fan speed is still way too much noise. I absolutely hate it. 

Big aircon are much noisier than small ones.

So oversizing is not always good.

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2 minutes ago, FlorC said:

A problem with buying an aircon is that you can never try it out in a store. They usually just have the plastic housing on display .

I have an expensive on/off Daikin 24BTU and while it cools well , the lowest fan speed is still way too much noise. I absolutely hate it. 

Big aircon are much noisier than small ones.

So oversizing is not always good.

 

As I previously stated, the Panasonic machines that I buy are very quiet.

I first check the dB ratings before I buy, of course.

 

If you do not like Panasonic, then why not look at Hitachi?

 

Just as quiet.

Also, high efficiency.

Daikin, in this market, seems not to offer ACs with very high EERs....of above 20.

maybe they do now, IDK

 

 

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4 minutes ago, FlorC said:

A problem with buying an aircon is that you can never try it out in a store. They usually just have the plastic housing on display .

I have an expensive on/off Daikin 24BTU and while it cools well , the lowest fan speed is still way too much noise. I absolutely hate it. 

Big aircon are much noisier than small ones.

So oversizing is not always good.

 

The AC I have is a very big machine.

It is big because a larger casing and larger coils are needed to achieve higher efficiencies.

However, as I say, the Panasonic is a very quiet machine.

The problem I had in the past was a unbalanced fan on the compressor unit.

But, the indoor evaporator unit is quiet.

 

 

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44 minutes ago, Dellboy218 said:

If it is an inverter model then no. If a direct on line non inverter model then it will take considerably more.  Standard Indiction motor theory.  If you do not believe me then this might help.  Just a quick copy paste.  I did say up to 7 they day 5 or 6. It depends on the startup load and how quickly it gets up to speed

 

 

The starting current of the induction motor is about 5 or 6 times the motor full load current. An induction motor of rating 11 KW,22 Amps,440 volts takes a high starting current of about 132 Amps. The current reduces as the motor accelerates towards its base speed or synchronous speed.Feb 25, 2564 BE

How many homes run on 440 volts?

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38 minutes ago, Dellboy218 said:

A circuit breaker operates on current and time.  The attached graph might help explain.  You would have to investigate your own particular breaker to confirm.

Screenshot_20240425_181921_Firefox.jpg

 

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Just now, KannikaP said:

 

 

Just now, KannikaP said:

You would have to investigate your own particular breaker to confirm.

How would I do that please. How can I pass say 20 amps constantly for a time thru my breaker?

And what would I then know?

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Government should grant decent subsidies to all property owners no matter how big or small, no matter if Thai or foreigner, regarding a purchase and maintenance of solar generated installation.

Edited by Sigmund
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1 hour ago, KannikaP said:

 

How would I do that please. How can I pass say 20 amps constantly for a time thru my breaker?

And what would I then know?

Do you still have the paperwork with your breaker?  Buy one in the box and it often comes with a graph.  You would have to know what your liading is to see if it's the correct breaker.  If it hasn't tripped then it's obviously big enough.  Pm me with make and model No. And I will see if I can find anything.

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1 hour ago, KannikaP said:

How many homes run on 440 volts?

Its not 440V it's is 380V.  220 x Sq root of 3.  As an induction motor is 3 phase and most will only be supplying a single phase then obviously you have to generate a 3rd pase.  This is done with a capacitor, the uF value is set to give the 120 degree variation between phases to give the best torque.  The capacitor is normally the first thing to breakdown.  You hear any motor making humming noises but going nowhere then the chances are it's the capacitor.  Applies to a lot of washing machines pumps etc.  It's the capacitor wots failed!

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On 4/25/2024 at 5:57 PM, KannikaP said:

For how long? A few seconds?

My 12000 BTU Mitsu Normal usually takes just over a kilowatt when running. Does that mean SEVEN kilowatts to start up without tripping a 20 amp breaker.

 

I just noticed your comment that your 12000BTU Mitsu uses just over 1000 watts while on and running.

 

So, this means that the EER on this machine is less than or equal to....

 

EER = 12 

 

And, you are paying about Bt.5 per hour to run this machine.

 

By way of comparison, the machines that I suggest buying have EER ratios of 23, or higher.

 

And this means that the ACs that I have suggested buying have efficiencies of...

 

About 91% higher than your Mitsu machine.

 

This is why I have never purchased a Mitsu machine, I guess.

 

 

Edited by GammaGlobulin
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