Aircon Astiquer - Condensation and humidity

Singapore is definitely one of the very humid places on earth, as such it affects the way your air conditioner performs
(rather, under performs). The following table on DEW point will give you an idea why it affects your air conditioner
adversely.

How to interpret the above table?

It means that when hot air (~32'C) collides with a cold object, you may not necessarily see condensation (dew), it
depends on how humid is the air.

Meaning to say, if hot air with a humidity of 31% collides with an object of 18'C, there will be NO condensation.
But, when hot air with humidity higher than 62% collides with an object of 24'C, there will be condensation.

What is Humidity and what makes a place humid?

As we are all aware, water evaporates. As it evaporates, the water vapour which is transparent to the eye, "hides" in the
air. There will be a limit to how much water vapour can "hide" in the air. The maximum is of course is 100% humidity.

Most sources of humidity in our air comes from evaporation of sea water, reservoirs water, lake water, swimming pool
water, rivers. The very reason why Singapore is so humid is because Singapore is a very small island country, a tiny red
dot on the world map, surrounded by sea. The tropical sunshine helps to evaporate lots and lots of surrounding sea
water, reservoir water, rivers and swimming pool water; making us one of the most humid place on earth!

How cold is our fan coil?

It varies from models to models and depends largely on the cooling capacity of the air conditioner. But typically, a small
9000BTU air conditioner will measure an average of ~16-18'C when the room is hot, and measures ~13-16'C when the
room has cooled down to ~25'C. Thus, if your air conditioner is not over-sized, it will achieve a nice comfortable humidity.

This is the relative humidity taken from my room after i turned on my 9000 BTU Daikin air conditioner.

However, if you put in a huge 24,000BTU air conditioner in a small room, the fan coil can be as cold as 5-7'C, making
the air really dry.

What is DRY mode and how does it work?

Having explained humidity above, it becomes really easy to explain the DRY mode. The DRY mode is to make the air
dry, not to prevent water dripping. On the contrary, if your pipe is choked, setting the remote controller to a dry mode will
cause more water dripping because it is removing more water moisture from the air.

The method to make the air dry is simple; make the fan coil cooler. This can be achieved by occasionally stopping the
fan motor while the compressor is still running, the fan coil will be very cold because the coldness is not blown off by the
fan. That's why you don't feel cold in dry mode, the wind speed is always on low and occasionally it will stop (while
compressor is still running).

When your fan coil is very dirty and choked, it affects the air flow. The wind speed will be very slow and somewhat similar
to a DRY mode. You will feel that the air is uncomfortably chilling cold, but at times it will feel very stuffy.

So you reckon that you should start putting in humidifier, applying lots of body lotion and probably burn some essential
oil. But what that you are doing is only going to make things worst. Theses are things people do to sabotage their air
conditioners.

So how humid is SIngapore?

RELATIVE HUMIDITY: " Diurnal range in the high 90's in the early morning to around 60 % in the mid-afternoon. Mean
value is 84%, During prolonged heavy rain, relative humidity often reaches 100 %" .! Source: Climatology of Singapore
(National Environmental Agency)

So what does 100% humidity mean? It means that the air is so stuffed with water moisture that any drop in temperature,
the water moisture will be "squeezed" out, forming dew. It further meant that a common HDB sized bedroom, with the air
conditioner tuned on will produce 5-10 litres of water in a given night!

The above picture is water collected from a room with relative humidity of 74%. Persistent water dripping from a badly
installed water pipe that's hidden in the wall had made the owner so fed up that he decided to collect condensate water
in a bucket and use it to flush the toilet daily (good idea!)

So why will it affect the air conditioner adversely?

Modern air conditioners are built smaller and smaller, the aluminium fins are so tightly packed; when dismantled, we
shine a torch light from the back of the 1" thick aluminium fin (fan coil), and we see no light in front. Thus, when it is so
humid; the fan coil (which is cold), will be very wet. We've observed certain high efficiency fan coil models behaving
more like a choked fan coil during very humid days. The dew is filling up the gaps of the fan coil so much so that it is
choking it!

While air is made to pass through these tightly packed fan coil so that it cools down more effectively, a very wet fan coil
ends up attracting dust and oil particles. It only takes a small amount of petroleum based chemical to be released into
the air conditioned room to start reacting with the chilled condensate water to produce lots of jelly liked substance that
will start to choke your condensate water pipe and fan coil. For more details on what else you should avoid using please
refer to What people do to sabotage their air conditioner?

Therefore, if you are a foreigner who had just came to stay in Singapore, some of the usual habits and things you use in
an air conditioned room no longer works here. Taking up a maintenance contract will not put an end to your water
dripping and cooling inefficiency problems.