Air Conditioners power consumption?

Theres alot of bogus talk going around in market regarding the actual current consumption of AC's. Every dealer and shop keeper has a different story to tell and mostly they promote the brands which leave them with highest margin on sale. All this leads to confusion. All 1.5 ton AC's in market have clearly pasted a sticker on their indoor units which states consumption of around 8amps, the notorious Mr. Slim also has same power consumption stated on it (8amps) but dealers + pakistani awam keep saying they consume 6 amps.

I met a dealer who was selling SHARP ac's, they are new in market and he was telling me, they are even more efficient then Mr Slim and 1.5 ton SHRAP only consumes 4amps! Well all this honestly sound like biggest load of BS to me because for one, if they consume less, why the hell would manufacturer gona write something else on their products, secondly, does this even make any frigging sense? How can some AC consume 4amps, do they have some mechanism to run on air instead of electricity.

Can some educated person shed some light on this?

Thankyou

http://en.wikipedia.org/wiki/Air_conditioner_inverter

1 ton Sanyo inverter AC run for 3 hours on our friends ups with 4 batteries, consuming 3-4 amps AC max..

1.5 ton Acson AC wun on 3 amps on Econo, 5 amps on normal, and 6-7 amps on turbo mode.

[quote=“farhan_ds, post:3, topic:19587”]

1.5 ton Acson AC wun on 3 amps on Econo, 5 amps on normal, and 6-7 amps on turbo mode.

[/quote]

Farhan, where did these readings come from ?

Actually it is does not make sense. If an air conditioner is running, the compressor is running at full speed and power, no matter it is in econo mode or normal or turbo. There is no mechanism in standard AC to reduce the instantaneous power consumption of the compressor.

However if above data is correct, can any one explain the difference in current readings on Econo, Normal and Trubo modes ? May be I am missing something ATM.

The amount of current has only one implication in airconditioning terms and that is whether THE UNIT WILL COOL OR OTHERWISE. Let me elaborate in simple terms.

A unit taking 2 amps is using 230x2=460 watts of power. Now the room where this unit is installed is getting heat input at a rate more than 460 watts then the temp will not come down but will GO UP! An adult human body is like a 500 watt heater. So in a room with 2 adults the ac must be more than 1000 watts to just MAINTAIN THE TEMPERATURE.

In practical terms for PK ANYTHING LESS THAN 1.5 tons of ac power equivalent to a heat absorbing capacity of 18000 British Thermal Units(BTUs) per hour is useless. This is because of the heat ingress through the roof walls windows etc. not to speak of about 4 people or more occupying the same room. Now 1 btu/hr is equal to 3.4 watts. So 18000 btu/hr calculates to 18000/3.4=5294 watts which is equal to 5.2 kw. Divide 5294 by 230 and you get 23 amps.

Please understand that the above numbers assume 100% efficiency of operation which is not possible in the real world. In practical terms don't touch an AC which claims to consume less than 15 amps of current unless you want to install it inside a cupboard where the cat has made herself an abode.

Aurangzeb

[quote=“farhan_ds, post:3, topic:19587”]

1 ton Sanyo inverter AC run for 3 hours on our friends ups with 4 batteries, consuming 3-4 amps AC max..

1.5 ton Acson AC wun on 3 amps on Econo, 5 amps on normal, and 6-7 amps on turbo mode.

[/quote]

Thanks for the reply. But that was the exact nature of my question. How do they consume less and produce same results? What is the mechanism behind this? Because realistically, an AC consuming less will also cool down slower then one consuming more power, therefore, its likely to take longer time to trip and there won't be any savings? Apart from that, why do manufacturers write false specifications on their products if they are consuming less or more power??? Makes no sense.

[quote=", post:4, topic:19587"]

Farhan, where did these readings come from ?

Actually it is does not make sense. If an air conditioner is running, the compressor is running at full speed and power, no matter it is in econo mode or normal or turbo. There is no mechanism in standard AC to reduce the instantaneous power consumption of the compressor.

However if above data is correct, can any one explain the difference in current readings on Econo, Normal and Trubo modes ? May be I am missing something ATM.

[/quote]

Thanks for your question, its answer will help me understand the situation more.

[quote="aurangzebhaque, post:5, topic:19587"]

The amount of current has only one implication in airconditioning terms and that is whether THE UNIT WILL COOL OR OTHERWISE. Let me elaborate in simple terms.

A unit taking 2 amps is using 230x2=460 watts of power. Now the room where this unit is installed is getting heat input at a rate more than 460 watts then the temp will not come down but will GO UP! An adult human body is like a 500 watt heater. So in a room with 2 adults the ac must be more than 1000 watts to just MAINTAIN THE TEMPERATURE.

In practical terms for PK ANYTHING LESS THAN 1.5 tons of ac power equivalent to a heat absorbing capacity of 18000 British Thermal Units(BTUs) per hour is useless. This is because of the heat ingress through the roof walls windows etc. not to speak of about 4 people or more occupying the same room. Now 1 btu/hr is equal to 3.4 watts. So 18000 btu/hr calculates to 18000/3.4=5294 watts which is equal to 5.2 kw. Divide 5294 by 230 and you get 23 amps.

Please understand that the above numbers assume 100% efficiency of operation which is not possible in the real world. In practical terms don't touch an AC which claims to consume less than 15 amps of current unless you want to install it inside a cupboard where the cat has made herself an abode.

Aurangzeb

[/quote]

That was a wonderful explanation :) I now understand why 1 ton ACs are usually useless, thankfully all ACs at my home at 1.5 (18,000 BTUs). But the main issue here is, how can they consume less then what the manufacturer states on their products? And how can a 18000 BTU AC can consume 4 amps to run and still produce same type of cooling in same amount of time??

PS : Thanks asad for the link :)

[quote=“aurangzebhaque, post:5, topic:19587”]

An adult human body is like a 500 watt heater. So in a room with 2 adults the ac must be more than 1000 watts to just MAINTAIN THE TEMPERATURE.

[/quote]

Are you sure about 500W figure ? That means if there are 4 adults in a room, then the room needs at least a 2KW AC just to maintain the temperature.

May be it's 50W / adult ?

[quote=“aurangzebhaque, post:5, topic:19587”]

The amount of current has only one implication in airconditioning terms and that is whether THE UNIT WILL COOL OR OTHERWISE. Let me elaborate in simple terms.

A unit taking 2 amps is using 230x2=460 watts of power. Now the room where this unit is installed is getting heat input at a rate more than 460 watts then the temp will not come down but will GO UP!

[/quote]

@ aurangzeb - Nice explanation, let me add my two cents in some other words.

The power consumption will increase with the difference of inside-outside temperature. So a same AC will consume less power when the outdoor unit is colder (morning time, shade etc) and it will consume more power when outdoor unit is facing sunlight at peak hot times.

The current will also vary with line voltage value, it also depends how much gas is inside etc. If an AC has less gas, the current consumption will be less.

The values stated on the product labels are for extreme operational conditions - absolute maximum values.

U mean, with 90% efficiency, it will be more than 23amps? Then how come my pel 1.5 ton consumes around 1800-1850 watts (8 amps)???

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My Uncle got the Dawlance 1.5 ton ac and at peak it runs on 8 amps and when on low 2amps and its super cool

i will update you with the model when i post next

I'll let the good doctors on this forum respond to this. Let 'em dig out their old physiology textbooks. Google of course is a good alternative to old textbook these days.

Aurangzeb

Ijaz,

Use the poverty line figure of 2200 kcal per day to work out your heat dissipation.

Aurangzeb

[quote=“aurangzebhaque, post:11, topic:19587”]

Are you sure about 500W figure ? That means if there are 4 adults in a room, then the room needs at least a 2KW AC just to maintain the temperature.

May be it’s 50W / adult ?

I’ll let the good doctors on this forum respond to this. Let 'em dig out their old physiology textbooks. Google of course is a good alternative to old textbook these days.
Aurangzeb

[/quote]
Guyton. Will check

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http://books.google.com.pk/books?id=XcRPQcc0vU0C&pg=PA22&lpg=PA22&dq=human+heat+watts+exercise&hl=en#v=onepage&q&f=false

Varies between 70-300watts depends on activity and other variables.

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^ Guyton has chapters on respiratory system and metabolism .. even endocrinology chapter doesnot tell about heat dissipation in watts.. the conversion of calories to watts is not purely relateable.. also the wierd graph in there about the rate of production of heat is not practical..

@ ijaz

have measured those readings ourselves using Unitee digital meters.... ran the ac on ups with APC 3000 XL and 4x 200AH AGS batteries for almost 3 hours.

Acson has 3 power saving modes.. almost all acs have 2-3 modes of operation.. econo just runs at almost fan level cooling and very little compressor activity.... turbo is nonstop full compressor cooling activity...consider them as mehran mode, civic mode , ferrari mode.

@Aurangzeb

Heat production is totally different from heat dissipation.. your body may produce say 500 watts of heats but doesnot dissipate it all.. 90% is kept inside for normal functioning and temperature maintenance.. that is why warm blooded are at 98.6 F temp. also muscles and internal systems also require energy.. all voluntary TURBO activity needs lots of energy..even involuntary functions NORMAL need energy, so even while you are asleep, your organs keep functioning in ECONOMY mode, and thats why the heat produced is mostly consumed, some of it is dissipated, that is why we sweat and exhale heat and urinate hot urine..

@ OP

[quote=", post:, topic:"]

Thanks for the reply. But that was the exact nature of my question. How do they consume less and produce same results? What is the mechanism behind this?
[/quote]

if you read the wiki link asad posted till the end, you would understand.. that is written in quite simple words.. easy to understand..my explanation may become a bit techy.. please do ask questions if you need any more info after reading that..

[quote=“farhan_ds, post:15, topic:19587”]

^ Guyton has chapters on respiratory system and metabolism … even endocrinology chapter doesnot tell about heat dissipation in watts… the conversion of calories to watts is not purely relateable… also the wierd graph in there about the rate of production of heat is not practical…

@ ijaz

have measured those readings ourselves using Unitee digital meters… ran the ac on ups with APC 3000 XL and 4x 200AH AGS batteries for almost 3 hours.

Acson has 3 power saving modes… almost all acs have 2-3 modes of operation… econo just runs at almost fan level cooling and very little compressor activity… turbo is nonstop full compressor cooling activity…consider them as mehran mode, civic mode , ferrari mode.

@Aurangzeb

Heat production is totally different from heat dissipation… your body may produce say 500 watts of heats but doesnot dissipate it all… 90% is kept inside for normal functioning and temperature maintenance… that is why warm blooded are at 98.6 F temp. also muscles and internal systems also require energy… all voluntary TURBO activity needs lots of energy…even involuntary functions NORMAL need energy, so even while you are asleep, your organs keep functioning in ECONOMY mode, and thats why the heat produced is mostly consumed, some of it is dissipated, that is why we sweat and exhale heat and urinate hot urine…

@ OP

Thanks for the reply. But that was the exact nature of my question. How do they consume less and produce same results? What is the mechanism behind this?

if you read the wiki link asad posted till the end, you would understand… that is written in quite simple words… easy to understand…my explanation may become a bit techy… please do ask questions if you need any more info after reading that…

[/quote]
Yes I checked it before searching on net. 70-300W with Google books reference.

Which edition you checked ?

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[quote=“farhan_ds, post:15, topic:19587”]

f you read the wiki link asad posted till the end, you would understand.. that is written in quite simple words.. easy to understand..my explanation may become a bit techy.. please do ask questions if you need any more info after reading that..

[/quote]

Indeed i read it and totally understand whats written in the wiki link but my question was, why companies write 8 or 9 amps if their AC units consume less? If Mr Slim consumes 6 amps, why they state 8amps on their unit?! Thats the simple question which comes to mind.

Also, if it is actually consuming 4 or 6 amps (on turbo mode of something like that), the cooling rate will also be slow as compared to other ACs. ? :) The AC inverter only decreases the energy consumption, i don't think it maintains or increases the efficiency of the AC like it is in Energy Saving bulb.

You gentlemen are missing the forest for the trees. The point that I wished to highlight was not whether an adult dissipates 50 watts or 500. It was about various sources of heat in a room that requires removal. The heat generated by the human body is negligible compared to say the heat coming through the window on a hot summer day in PK. I used the example of the human body because most people and that includes doctors, do not look at the human body in such a fashion. Thus the shock which makes for an effective teaching point.

To all those who wrote about 8 amps and 10 amps, please understand that current consumption of an AC depends upon a host of factors as very succintly explained by Ijaz in his post. So don't worry your heads about current and btus and so forth. If your AC is cooling, just say Alhamdollilah 3 times, savour the temp. ! smile and go to sleep.

Aurangzeb

I think all above readings regarding consumption are ''hawaye''

i my self is a wetness of recording these all kind of readings , IN Pakistan normal 1.5 Ton split unit consume at start up 10-12 Amp and after 5 mints it will downgrade at about 9 -10 Amp

If you guys try to read that label which come's with brand name , It also shows about 9 Amp Current for 1.5 Ton Split .

1 Ton split consume about 6 Amp .

now if you talk about window type A.c , THERE are two types; one is Bristol second is rotary ., Bristol is piston kind of ., It Consume maximum Amp compare to rotary type ,

1.5 ton window type A.c consume 13-14 Amp at starting . and in running condition . IT consume about 10-11 Amp . this consumption is for Piston type .

Consumption for rotary are little low ,

P.s

Usage of Amp actulay depends upon your Voltage . like if you are having ideal 220 to 230 voltage , You A.c will consume ampr as described on label of any A.c ie 9 or 10amp maximum ,If voltage are low , Like below 190 Volts .It will consume maximum amp like 15 Amp and above , in end compressor will heat up . and will stop working .

[quote=“starznitez1, post:19, topic:19587”]

I think all above readings regarding consumption are ''hawaye''

[/quote]

Thats what i am thinking and trying to figure out. If those readings about consumption are 'hawaye' then why every other dealer is blabbering about them without any solid proof? You see AC units and read specifications, the manufacturer explicitly states that their product is going to consume 8 or 9 amps at full utilization, yet dealers, sellers, and people keep saying othervise. They want you to believe them instead of what the manufacturer says?? Does that even make any sense? Just for example, if Mr Slim consumes 6 amps at optimal running, then why on the earth are they going to paste that its going to consume 8 amps? They instead should paste it all over their product about how efficient their product is.Though, nobody here still seem to have any answer to that.

There is a guy above who states that Dawlance consumes 2 amps at some running mode and 8-9 at turbo.

PS: Starting consumption current does not matter, so lets ignore it.