0

I live in a high humidity (75%) climate.

I wanted to know what happens when you combine a light humidifier with a normal AC set on "dry" mode.

The AC is activity reducing humidity, which helps me "feel" cool since water evaporates better off your body.

However, I wonder if I can reduce my energy bill by running evaporative cooling using "cold" new water ( not the water collected by the AC ).

In dries climate you use swamp cooler to reduce the temperature.

The idea here is ( if laws of thermo is obeyed ) is the water leaving the air con unit has some residual heat.

As the air gets dries it gets less efficient for the AC to reduce the temperature.

Each watt of energy gets rid of fewer BTU as the air gets drier.

It's important to note that as you add normal water mist to your room, it evaporates and absorbs heat itself.

As this vapor moves to the AC, you need very little energy ( dew point ) to turn it back to water.

The water contains extra heat that gets removed through the drain pipe.

Without this extra mist humidity, the AC would pump the heat through its internal refrigerant.

The idea here is not to replace a normal AC - a swamp cooler doesn't help in 80% humidity.

The idea here it to enhance the efficiency of a normal AC, even if it helps by 5% thats huge energy saving.

  • Hello, and welcome to Home Improvement. This won't work; using colder water is insignificant compared to the heat of vaporization of the water. You'll just end up making the A/C work harder to remove the added moisture. And, you should probably take our tour so you'll know how best to participate here. – Daniel Griscom Aug 24 at 12:20
  • 1
    Swamp coolers work by evaporation, not because they’re cold. Being cold helps, but only in rate. As dan notes, adding cold water will do little in high humidity. – Maury Markowitz Aug 24 at 13:05
0

As the air gets dries it gets less efficient for the AC to reduce the temperature.

Each watt of energy gets rid of fewer BTU as the air gets drier.

This sounds erroneous to me.

As this vapor moves to the AC, you need very little energy ( dew point ) to turn it back to water.

That doesn't sound right either.

Without this extra mist humidity, the AC would pump the heat through its internal refrigerant.

Likewise.

I think this theory is built on a faulty assumption. Also, if it were this easy to do, they'd be doing it.

0

It sounds like lots of half baked theory with no experience. If you run water over the coils of a standard unit it will do 1 of 2 things depending on the water. Condensate will end up etching the aluminum fins and causing leaks in the system. Using house hold water source will build up on the fins reducing the heat exchangers ability to reject heat in the system both are bad and limit the life of the coils.

Large chillers use falling water to keep the condensers cool but this is buffered and treated water to prevent legionnaires (the original source of the disease) These are large systems and designed to take advantage of evaporation the cooling tubing. the ones I have worked on have no aluminum some are copper and some are steel. The water has a glycol and other buffers to prevent freezing and the ph is stabilized and controlled to prevent organically from growing.

0

Heat pumps don't easily drop humidity below 40% rh. In my experience living in a humid area, it's more like 55%. Swamp coolers put out air around 95% rh, much higher than typical outdoor humidity even in humid areas. So while the air may indeed be even cooler, your sweat won't evaporate as well (same as if you were outdoors), and so you would feel hotter than only in the AC - if you've ever been in dry heat, you know what I mean. Even in a room successfully cooled to 65°F, 95%rh would be uncomfortable to work in because you just wouldn't stop sweating.

Not to mention the interior surfaces of your AC will probably have condensation develop on them, as well as other nearby metals, leading to corrosion and other moisture problems, and an increased general risk of mold and mildew.

The best way to boost the efficiency of an AC in my experience is to circulate the air in the cooled space using a high velocity fan - move the cooled air away from the AC and the hotter air towards it.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.