# Compare inverter AC and normal 5 star rated AC with programmable delay circuit



## adepumadhu (May 21, 2015)

Hello,

My question is related to power savings of Inverter AC when compared with normal 5 star rated AC which turns ON and OFF automatically every 5 minutes using a programmable delay circuit.

I have given 3 cases below, and its power usage per day and total power consumption in a month.

Assumptions:

a) All 3 cases using 1 TON, and AC power wattage is 1000 Watts = 1 KW power consumption / 1 hour
b) All 3 ACs temperature is set to maintain 30 deg Celcius
c) All 3 cases are set to run for 9 HOURS, i.e from 9 PM to 6 AM (night time operation)

*
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CASE I (Non Inverter, 5 star rated AC)
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*

AC Specifications:

AC Tonnage = 1 TON
AC Watts = 1000 W = 1 KW

AC is set to run in auto mode, and set to maintain 30 deg C.

In general, in auto mode, in 9 hours period, AC will ON and running for 7 Hours, and it is OFF for 2 hours.

So, AC ON time = 7 Hours
AC OFF time = 2 Hours

Power Usage:

7 Hours x 1 KW = 7 KW per day

Monthly Usage:

30 days x 7 KW = *210 KW*

*

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CASE II (Inverter AC)
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*

AC Specifications:

AC Tonnage = 1 TON
AC Watts = 1000 W = 1 KW

AC is set to maintain 30 deg C.

Inver AC runs continuously. Inverter AC power savings quoted by AC manufacturers are 20~40% approximately. I Assume, in this case, Inverter AC power savings are 30%.

So, actual power consumption is 70% of its rated wattage.

AC ON time = 9 Hours
AC OFF time = 0 Hours

Power Usage:

9 Hours x (1 KW x 70%) = 6.3 KW per day

Monthly Usage:

30 days x 6.3 KW = *189 KW*

*
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CASE III (Non Inverter, 5 star rated AC with PROGRAMMABLE TIMER)
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*

PROGRAMMABLE TIMER:

Programmable Timer is a time delay circuit. We set it to turn ON and OFF at specific intervals. In timer ON mode, it switches ON the 230 Volts RELAY which in turn gives power supply to AC. In timer OFF mode, RELAY will be turned OFF, so there is no power supply given to AC and it turns OFF.

Assume programmable timer is set to run as :

5 MINS ON
5 MINS OFF

It means, AC turns ON and it runs for 5 minutes and turns OFF. Then AC turns OFF for 5 minutes and it wakes up after 5 minutes.
For example, in ONE hour time period, AC runs for 30 minutes and turns OFF for 30 minutes using a programmable delay circuit.

For your information, a sample timer circuit link is given below. It requires 12V DC for operation.

Electronics :: Engineering Project Kits :: 12V Multifunction Self-lock Programmable Cyclic Delay Timer Automation Module - ShopClues.com:

There are many other circuits available like this in market, this is one sample.

Now, apply programmable delay circuit with 5 star rated AC.

AC Specifications:

AC Tonnage = 1 TON
AC Watts = 1000 W = 1 KW
AC is not in auto mode. But, temperature level set to 30 deg C.

Assume, for initial room cooling at 9 PM, AC is set to run for 30 minutes without using a timer delay circuit. Once the room is chilled, the timer circuit will play a role and it turns ON and OFF the AC for every alternate 5 minutes.

AC initial run for room cooling (without timer) = 30 mins = 0.5 Hours

So, we have remaining 8.5 Hours in which AC is operated using a timer circuit.
In 8.5 hours, AC is ON half of its time. It will be 8.5/2 = 4.25 Hours

AC total ON time = 0.5 hours + 4.25 hours = 4.75 Hours
AC OFF time = 4.25 hours

Power Usage:

4.75 Hours x 1 KW = 4.75 KW per day

Monthly Usage:

30 days x 4.75 KW = *142.5 KW*

Now, compare all three cases power consumption for a month.


———————————————————————————————————
*Case .................................................. Power Consumption*
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CASE I (5 star rated).....................................*210 KW*
CASE II (Inverter model)................................* 189 KW*
CASE IIII (5 star with timer circuit)..................* 142.5 KW*
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When we compare these three, 5 star AC with a programmable timer circuit power consumption is very much lower than normal 5 star rated AC, that is 32% lower. Not only that, it is much lower than Inverter model AC, it is 25% lower.

I like to see others views and comments. And please share your ideas.

Thanks
Madhu


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## funfex (Jun 4, 2015)

adepumadhu said:


> Hello,
> 
> My question is related to power savings of Inverter AC when compared with normal 5 star rated AC which turns ON and OFF automatically every 5 minutes using a programmable delay circuit.
> 
> ...




Every time the Unit switch on and off.. the Power Consumption increases due to the Load to re-cool the room

Hence Inverter AC's Consume lesser power... i don't see Case 3 Logical


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## Nilay Anand (May 27, 2017)

Inverter AC, in most of the case, do not consume more power than regular 5 start AC. 5 star non-inverter AC (1.5 ton) consumes 1130 units yearly whereas, in same use case scenario, 5 star inverter AC (1.5 ton) consumes 815 units.

Details are here:
*www.bijlibachao.com/air-conditione...-and-how-it-is-different-from-bee-5-star.html


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## Ricky (May 28, 2017)

Further, CASE IIII (5 star with timer circuit)..................* 142.5 KW )  *will not be efficient as may not be able to provide required cooling thus hampering the actual purpose of ac. Moreover, for the period when ac was off, the coil was still cool enough but since blower was also off, its not efficiently used. However, idea of CASE III is good but you can achieve similar effect efficiently buy setting up some higher temperature in AC and it will then turn OFF/ON compressor automatically but using the blower at same time.


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## Chetan1991 (Jun 24, 2017)

Instead of a 'dumb' time delay, wouldn't a temperature based system much better? But then (I'm assuming) many ACs must already come with it.


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