hair conditioner sucks and blows

[jasong]

I really don't know what kind of response I hope to get from this. On the one hand, it'd be nice to find out whether my air conditioner is actually broken. But on the other hand, if it is broken, I've been wasting years of my life dealing with temperatures I haven't actually needed to tolerate.

Basically, what happens is I will set my air conditioner to the desired temperature and there will be no discernible effect to me. I know it isn't instantaneous, but shouldn't an air conditioner at least try to adhere to the setting you put it at? It goes on, it goes off, and yet at random times it'll be way too hot, and at other times it'll cool my room down to multiple degrees less than what I want.

So, do I simply not understand air conditioners, or did it break in a way where it follows laws I can't control?

Btw, it's a window air conditioner. My distributed computing stuff happens in my room, so I got the air conditioner to cool my room down from the computer's heat.

[kladner]

Is the temperature control on the unit analog (rotary knob, etc) or digital (numeric readout). If it is the former, such things are not the most precise critters out there. Depending on the air circulation in the room it could conceivably allow some fairly wide swings. Or it could be defective. EDIT: With a rotary or other mechanical control, you can usually feel a click when you cross the turn-on point. Experiment with this with the unit Turned Off! It is not good for the compressor or your electric bill to cycle it rapidly on and off. If it has been recently stopped, it will not be able to restart for a few minutes -until the refrigerant pressures equalize somewhat.

If the control is digital, there may be a delay built in to the control circuits for the compressor and the fan. I suspect this is done to avoid unwanted cycling, especially for the compressor, on transient settings changes.

To address the general question of A/C unit effects on the ambient- When you turn the thermostat to a lower temperature, and cross the threshold for cooling to start, you should be able (in most window units I've dealt with) to hear/feel the sound of the compressor coming on. If this happens there should be a fairly immediate change in the air coming out the cooling vent.

However, overall room cooling will depend on the humidity. If a great deal of humidity has to be extracted then cooling will be slower until the room and furnishings have dried out.

EDIT2: It is important to remember that an A/C unit is either cooling or not cooling. Once it is cooling, turning the thermostat lower will not accelerate the cooling process. It can result in a cold room eventually, though. I suggest finding the setting at which the compressor first comes on, and leaving it there until the compressor cycles off. At that point evaluate the room conditions. If you want it cooler then turn the control just enough to get the compressor running. Make small changes and wait for the system to respond.

Originally Posted by jasong

I really don't know what kind of response I hope to get from this. On the one hand, it'd be nice to find out whether my air conditioner is actually broken. But on the other hand, if it is broken, I've been wasting years of my life dealing with temperatures I haven't actually needed to tolerate.

Basically, what happens is I will set my air conditioner to the desired temperature and there will be no discernible effect to me. I know it isn't instantaneous, but shouldn't an air conditioner at least try to adhere to the setting you put it at? It goes on, it goes off, and yet at random times it'll be way too hot, and at other times it'll cool my room down to multiple degrees less than what I want.

So, do I simply not understand air conditioners, or did it break in a way where it follows laws I can't control?

Btw, it's a window air conditioner. My distributed computing stuff happens in my room, so I got the air conditioner to cool my room down from the computer's heat.

[Uncwilly]

Make sure that the fans stays on (there are some units that have the fan go on and off with the compressor). Also make sure that any "fresh air" or "vent" setting is "off" or "closed", this makes the most efficient use of the unit.
Most units should be able to make a 20 F difference between the inlet air and the outlet. Make sure that any filter is clean and in place. Set the louvers to maximise the circulation pattern in the room.

Living where you do humidity is likely an issue. Be sure that the unit sets level or just a little (2mm differential) tipped to the outside. Be sure that the drain hole is not plugged. Ensure that the fins on the outside are not flattened.

Report back.

[chalsall]

Originally Posted by Uncwilly

Living where you do humidity is likely an issue. Be sure that the unit sets level or just a little (2mm differential) tipped to the outside. Be sure that the drain hole is not plugged.

Indeed.

Human perception of ambient temperature is as much a function of humidity as actual temperature. Why? Because we humans use water cooling; we sweat -- and the sweat then (hopefully) evaporates.

jasong... I would suggest you collect empirical data from your systems as to what your air conditioning is doing, rather than relying on subjective observations.

Under Linux, lm_sensor et al and cacti are your friends.

[kladner]

With a rotary or other mechanical control, you can usually feel a click when you cross the turn-on point. Experiment with this with the unit Turned Off!

Actually, this is better done in "Fan Only" mode. This keeps your result closer to operating conditions. Once you find a "click point" you can switch the machine into cooling mode.

EDIT: In a hot and humid climate getting the conditioned climate down to 78-80 F with reduced humidity and moving air can be heavenly. Just getting in the shade with a breeze is really nice.

[chalsall]

Originally Posted by kladner

However, overall room cooling will depend on the humidity. If a great deal of humidity has to be extracted then cooling will be slower until the room and furnishings have dried out.

Further to kladner's above, it is important to remember that all of this assumes a closed system.

If the system has leaks, then you might be spending a great deal of money and/or energy trying to de-humidify and/or cool what cannot be done beyond certain limits.

[pinhodecarlos]

I suggest studying the psychrometric chart if you are talking about an AC.

[jasong]

Thanks for all the awesome advice.

Because I haven't thought about my AC in forever, the reason I was reminded to post this was my parents asking me to turn it off for the winter months. But I will bookmark this thread so that I will be reminded every month or so of your ideas.

Thank you very much for all the responses, I'll be sure to try them in 4-6 months, I promise.

Edit: Kudos to the gerbils for the new title, it's much better.