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Air conditioner

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I also have like 3 York air conditioners (of the conventional kind) on my house. Very good brand, will probably work for many years. The only thing I dislike is that 5kw startup peak. But because I have (re)resolved that I'm not taking the place off-grid, but rather going to go SSEG in the long run (seeing as CoCT is engineering things so that if you already have a lot of the equipment you might as well do it), this doesn't bother me as much anymore. I simply won't have AC if the power is down, and that is okay, because the ceiling insulation does such a brilliant job already. I might miss it maybe on the two hottest days in February... and that's it.

Then again, apparently they clocked a 53 degrees Celsius in Arizona last week. Hottest year globally in recorded climate history. I truly want to smack those Americans who claims it's a cold year, then say things like "all the scientists are wrong because MONEY...", then blame it all on some Obamaesque conspiracy. So in the coming years... I might change my mind on that. And then I'd wager that the inverter AC (plus maintenance) might well cost less than the big-ass inverter in the long run. Or the same. Or perhaps a bit more, but will it really bother me?

:-)

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  • Energy-Jason
    Energy-Jason

    Hi Guys, Hope all well. In our Server room we installed a Daikin Inverter Unit. Here is a fair BTU requirement calculator based on room volume: http://www.daikinairconditioninglondon.com/calculator.p

  • Gerald_db
    Gerald_db

    I have a 17000btu Daiken inverter aircon in my bedroom. 300 to 400w draw max and as low as 50 once at temp. Amazing. Run it all night in summer with out seeing a increase in my power consumption. S

  • The compressor motor of an inverter aircon runs on DC and the speed it runs at is adjusted according to the difference in temperature between what it is set at and what it currently is at.  I'll try a

+1 on that Plonkster.

  • 5 months later...

My inverter ac is superb 17k btu and runs for 1 to 4 hours per night while on batteries. 36°c today and a 40+ for tomorrow and our bedroom is upstairs. Die without it.

Sent from my SM-G920F using Tapatalk

Chris, you wanted advice and you got a lot of advice and are probably more confused now than ever, haha.

I would say for your application you could get away with 12 000 btu, but I would recommend a 18 000 btu unit. The 12 000 btu uses less power, but as mentioned before, if it is undersized, it will run a long time to bring down the temperature. The 18 000 btu uses more power, but will get there a lot faster.

The disadvantage of conventional aircons are either on or off and when they are on, they run flat out. As an example, it is the same as putting your geyser on a timer, switching it on for 15 minutes and then switching it off for 15 minutes. Looking at your load graph, you will see this sudden jump in load and the 15 minutes later you see the sudden drop in load. The inverter type aircons will initially start off at about the same level, but as it cools down the room will start to cut back as superdiy explained. You will therefore have the gradual drop in load. Once it has reached the set temperature it will start controlling the temperature and should keep it their with relative low power consumption, until one of the kids runs into the room and don't close the door with hot air rushing into the room. 

So yes, inverter type aircons use less power, but they comes at a cost. They are probably between 25-40% more expensive than conventional aircons, depending on the make.

You can also have a look at the COP. (Coefficient of Performance). The higher the the number the better. All that means is that if the aircon has a COP of say 3.6, it means that for every 1 kW of input power, you get 3.6 kW of cooling. Therefore, if you have to make a decision between 2 aircons and the one has a COP of 3 and the other a COP of 4, go for the one with a COP of 4.

What brand? I don't think you get one that stands out above the rest. Hitachi, LG, Carrier, Samsung, Daiken, all good brands and make good quality air conditioners. I have a conventional Logic 18 000 btu I got on special at Game. Half the price of the Samsung, runs like a bomb. I think aircons are very much the same as inverters or cars, you buy what you can afford.They still get the job done, some just last longer than others. 

 

5 hours ago, Don said:

So yes, inverter type aircons use less power, but they comes at a cost. They are probably between 25-40% more expensive than conventional aircons, depending on the make.

On the smaller units (12000btu) it's often as little as R500 difference. If you shop around you can often find an inverter unit for under 8k, while the lowest I've seen for a conventional unit was around 7.5k.

Plonkster yes, after I posted, I searched a few prices on aircons. When the inverter type aircons came out, they were like 50-60% more expensive than the conventional ones. I see that gap has now shrunk considerably. I think as with any new thing, with time and increased volumes, prices do come down.

23 minutes ago, Chris Hobson said:

The drought has put this project on the back burner. 

Chris, what is the cost of that size aircon, about 2 cows?

Guys, I have the old normal type aircons in my offices and at home I have just installed  3 x inverter units ( 2 x 12000Btu and 1 x 18000Btu)

The power usage and savings compared to the older ones I also think is more of an sales talk than the real thing.

(Trojan, omnipower, Nevada, Monbat etc?) All the salesman will say their's is best and all the owners will agree on their brand. That is life!

 

What is important to me is the startup peak which is really way lower than the conventional ones. I had to take the aircons off our inverter at work, because I got "overload" ever so often. At home I have not have any hassles and it is all connected on the Imeon.

I am a distributor of SirAir aircons and will gladly supply anybody a price on the supply of a unit. You then have to get the local guy to install, which is a standard price in Bloem of R1200.. I will do this for any forum member and will guarantee the best price in South Africa! Both conventional and inverter types available.

Cheers

 

4 hours ago, Chris Hobson said:

The room I am planning to put an air-conditioner into is 3.3x4x5m so I will probably have to go for a 17k BTU. The drought has put this project on the back burner. 

You mentioned befor 30m/2 and this would be 15m/2 If it is 15M/2 a 120000BTU will comfortably cool the room.

 

Ps. That is if the ceilings is a standard 2.4 - 2.7m high

Edited by Chris-R
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6 minutes ago, Chris-R said:

I also think is more of an sales talk than the real thing.

When I asked about  inverter aircons from Co that installed my existing aircons, I was very surprised. Must have gotten him, for me, at the right time, for him a loss of a sale.

He said he can sell me if I want them but I must  understand that are issues.
a)) there is very little power saving - same as what Chris-R alluded to above.
b)) they are getting way to many issues under the warranty period. On all makes.

Things like goggas getting to place they should not get to. Water entering parts where should not. And lots of niggly problems etc. I..e stupid things costing them a lot in labour to sort under warranty. He nearly went as far as to say he does not want to sell them anymore till they can sort the problems out.

I am not saying they are bad, just saying why I have not replaced mine.

 

When I asked about  inverter aircons from Co that installed my existing aircons, I was very surprised. Must have gotten him, for me, at the right time, for him a loss of a sale.
He said he can sell me if I want them but I must  understand that are issues.
a)) there is very little power saving - same as what Chris-R alluded to above.
B)) they are getting way to many issues under the warranty period. On all makes.
Things like goggas getting to place they should not get to. Water entering parts where should not. And lots of niggly problems etc. I..e stupid things costing them a lot in labour to sort under warranty. He nearly went as far as to say he does not want to sell them anymore till they can sort the problems out.
I am not saying they are bad, just saying why I have not replaced mine.
 


Completely disagree. Very efficient especially as they dont cycle but run faster or slower as required from internal blower to outside unit. Had one for three years now.

Sent from my SM-G920F using Tapatalk

20 minutes ago, Gerald_db said:

Completely disagree. Very efficient especially as they dont cycle but run faster or slower as required from internal blower to outside unit. Had one for three years now.

I think it helps to understand how it is that these devices work, and what he differences are.

So the most obvious difference is this: The inverter AC has a VSD (variable speed drive), so it doesn't cycle on and off. I am not convinced however that this subtle difference is enough to account for all of it. The condensor has sufficient thermal mass to regulate the temperature, and the starting-spike, though heavy, is only for a second or so and probably doesn't account for much more than the additional lost efficiency through the VSD (probably similar to a normal inverter, ie around 90%).

As I understand it, what really makes the difference is the sensors. It has a temperature sensor on the evaporator (ie the outside hot exchanger), as well as a humidity sensor and an ambient temperature sensor. The temperature of the evaporator is then controlled by varying the speed of the heat pump -- something you can only do with a VSD -- and this means you can avoid doing inefficient stuff. Like freezing the evaporator for example (hence the ability to run at lower temperatures).

What this means, is that in certain areas and for certain users (high temperatures, low humidity, low dew point, and a user who doesn't crank the thing down to 16 Celsius when the dew point is 18), there might not be that big a difference between the Inverter- and the conventional AC. You may well find that the conventional AC's additional consumption is acceptable in the light of the less complicated machinery.

Or that's how I see it anyway :-)

The sensors have some interesting extra uses, eg fault finding. Over the holidays the brand new LG inverter AC at the in-laws stopped working. Looking at the indoor unit I noticed the two LEDs are flashing in a non-regular fashion, and having enough experience with cars that flash diagnostic codes via the check-engine light, I looked it up. Turns out error 63 is "Evaporator temperature too low", ie it should be getting hot and it isn't. Turns out there was a leak and we lost the all important gas... :-)

1 hour ago, plonkster said:

It has a temperature sensor on the evaporator (ie the outside hot exchanger)

No, the evaporator is on the inside, where cooling comes from. The condenser sits on the outside where you get rid of the heat.

 

1 hour ago, plonkster said:

Like freezing the evaporator

That only happens when you have insufficient gas in the system.   

  • Author
9 hours ago, Chris-R said:

You mentioned befor 30m/2 and this would be 15m/2 If it is 15M/2 a 120000BTU will comfortably cool the room.

 

Ps. That is if the ceilings is a standard 2.4 - 2.7m high

Ceilings are 3.3m  and I have measured again it is 5 X 6m not 4 X 5m

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