Air Con, How does it work?

[skippy]

Just wondering anyone know how AC works?

I am asking because it was hot as hell last week and this thought has bugged me for some time.

When I turn on my AC I put the Fan on 2, say this uses 5 KW (wild geuss)

How much power do I use if I put it on 4 to cool the car down quicker (7 KW?)
Is it more power to run the AC or just move power to a fan thus negeligible?


Basically my questions is, is it more energy effiecent to blast the AC then off, or slow and steady?

[JynX]

Bascially the following:

A refrigerant (freon for example) is compressed causing it to become hot high pressure gas. This hot gas runs through the condenser and becomes a liquid. The liquid passes through an expansion valve which evaporates the liquid to form cold low pressure gas which is passed through the air stream which blows into the car and the cycle repeats.

Power loss should only be perceived when AC is on or off as the compressor is run off the motor through the belt system. The fan on different levels will only increase the current draw on the battery and unless you have a crappy small battery/alternator it shouldnt have much effect.


http://www.familycar.com/Classroom/ac1.htm

[Cosmo Dude]

How stuff works to the rescue again.
The climate controls in your car are a combination of four components:
1. Fan - Blows the air around
2. Vents - Air blown through these to where you want it
3. Heater core - Has engine coolant running through it, as the blower blows air through it the air is heated.
4. Air conditioner - This is a refigerated panel, as the blower blows air through it the air is cooled.
The major difference between having the fan on 1,2,3 or 4 is the amount of current the fan draws which is minimal compared to the power drain from the air conditioning compressor which is either on or off.

Basicly the answer is set it to the most comfortable level for you and your passengers their isn't a significant difference. Unless you have an A/C and A/C Econ switch.

If your A/C evaporator gets too cold it will turn off the compressor until it warms a little. This will happen less with the fan on high but I wouldn't worry about that.

[twilightprotege]

in terms of most efficient - going off home air cond systems - slow and steady is best because it takes a lot of power to cool something down, but not much to keep it cool.

but like jynx said, it doesnt use any more or less power when you turn the air cond up, it'll just make the compressor run for longer to achieve the same result.

in other words - use the air cond when you're hot. turn if off when you want every bit of power from the engine

[Cloudland]

is there any filter (which can be cleaned from time to time) in SP20's a/c system? had a look in the P5 service manual but nothing mentioned about a/c.

[twilightprotege]

not in australia nor america. in japan yes. you can modify your system to accept the air filter, but it's not easy

[Cosmo Dude]

The high and low taps on the pic that Jynx provided are for filling and testing by an A/C specialist. You also have a pressure switch which will disable the A/C system when you don't have enough gas to operate safely.

Your A/C system is one of those things that from time to time need to be serviced, now (before summer) would be a good time to have that servicing done. I wouldn't recommend doing this your self as the gasses can be damaging to the ozone, flammable, poisonous or really expensive.

I am in the middle of a big change to my A/C (to accommodate other changes) and coming into summer it was good to fix it but in the next few weeks I’m going to have the gas removed, change the compressor and re-gas the system.

[JynX]

Originally Posted by Cosmo Dude

The high and low taps on the pic that Jynx provided are for filling and testing by an A/C specialist. You also have a pressure switch which will disable the A/C system when you don't have enough gas to operate safely.

Your A/C system is one of those things that from time to time need to be serviced, now (before summer) would be a good time to have that servicing done. I wouldn't recommend doing this your self as the gasses can be damaging to the ozone, flammable, poisonous or really expensive.

I am in the middle of a big change to my A/C (to accommodate other changes) and coming into summer it was good to fix it but in the next few weeks I’m going to have the gas removed, change the compressor and re-gas the system.

Do you know what the go is with the 'new' gas they use and if the Astina systems have to be "upgraded" to accept the new gas?

I havent had AC for 2 years and after last weeks temps, thought i better get it all hooked up again. The mechanic mentioned I might need to get it upgraded for the "new" gas but couldnt digress any further. Just want to understand what it involves so some prick doesnt try and replace the whole AC system at my cost.

[Nate]

Originally Posted by JynX

Do you know what the go is with the 'new' gas they use and if the Astina systems have to be "upgraded" to accept the new gas?

I havent had AC for 2 years and after last weeks temps, thought i better get it all hooked up again. The mechanic mentioned I might need to get it upgraded for the "new" gas but couldnt digress any further. Just want to understand what it involves so some prick doesnt try and replace the whole AC system at my cost.

what he said ^^^ havent had working AC since i bought the car!

*edited so it makes sense!*

[Cosmo Dude]

I'd hope that all they need to do is remove any gas remaining in the system, replace the receiver dryer and the oil in the compressor to stop any cross contamination before re-gassing with new gas.
The receiver dryer is to the A/C what the oil filter is to the engine.
I was quoted about $150 to re-gas the 929 and that's an '86 model so I'd hope the newer Astina systems would be much the same. (Also quoted $0 to recover the gas before I start swapping out some of the pieces).

If you ring around all you should need to say is that it's a 199? Mazda and they should know off the top of their head what gas was originally in it.

[skippy]

Might help, might not help,

I was looking into getting a import a while ago and one new condition is that the Air con had to be drained before shipping then re gassed in Australia.
This was going to cost around $150-200 as I recall, and was due to a differnet gas we now use over here,



FYI,
A Mechanic mate of mine told me to use my AC atleast once a month, becuase the car vibrates the hoses need to be rubber and as such do not take to kindly to having gas sitting still in them for long periods of time.



And thanks for the responses,

My new AC method:
Blast it, then back to 1 or 2,

[Cosmo Dude]

In the Astina I didn't turn the AC off.
In the morning it de-frosted the inside of the windows and you just turn the heater up a little to compensate. Yeah you need to run the AC or it'll fail and could cost heaps to fix.

I need to have a hose re-built and it's gonna set me back $60 for a one meter hose :shock:
Plus $150 for re-gassing.