Suggestions for 2 Split AC's

[RishiGuru]

I wonder if you even know how an airconditioner actually works and what part of the job is done by the inverter and what part is the compressor. Please educate us on how exactly an inverter AC works.

Maybe I do not have the know how of yours. But the thing is with multiple people using inverters and getting their energy bill substantially reduced, I don't see the point of sticking to 2 star non-inverters. People all over the world are not dumb ass and almost all residential air conditioners in Japan are Inverters.

My friend use to have a 2 star non inverter and he replaced with a inverter. Now he uses 2x times per day and gets identical energy cost even though the per unit charges have increased. I was amazed by the amount of saving and got Inverters too. Everybody have their own choices and I just expressed mine in this forum. I believe my participation on this thread is no longer required.

Thanks anyway to explain your thoughts cranky.

 

[TheIndian]

I think you miss the point totally. I have no interest in continuing this discussion because it seems you are stubborn to a fault. Have you done the math before buying or not? Can you show me the math? If not, this is a subjective and silly argument.

Well Since @RishiGuru refuses to do the maths, could you do it please to prove your point. ?

 

[cranky]

^^4 posts above this one.

A 1.5T inverter AC/80% duty cycle from the pic in this thread (Fujitsu/OG, I assume) will consume 21000 units over a 5 year lifetime if running 8 hours a day.

Two 1T ACs from LG, the lowest-priced model and 'only' 3-star, will consume around 13,500 for the same period running at 40% duty cycle.

Depending on what you pay for electricity, that may end up as a saving of over 20k on electric bills.

The Fujitsu in the pic above is using 1,480W average and I've approximated 80% duty cycle/8hrs/every day/5 years

Two LGs use 1130W each, and with the same parameters I've approximated 40% duty cycle.The LGs have approx 30% more cooling power when combined.

 

[cranky]

Maybe I do not have the know how of yours. But the thing is with multiple people using inverters and getting their energy bill substantially reduced, I don't see the point of sticking to 2 star non-inverters. People all over the world are not dumb ass and almost all residential air conditioners in Japan are Inverters.

My friend use to have a 2 star non inverter and he replaced with a inverter. Now he uses 2x times per day and gets identical energy cost even though the per unit charges have increased. I was amazed by the amount of saving and got Inverters too. Everybody have their own choices and I just expressed mine in this forum. I believe my participation on this thread is no longer required.

Thanks anyway to explain your thoughts cranky.

I don't see the point of having this discussion with someone who is not prepared to read and assimilate posts before speaking.

I am comparing single unit energy consumption to multiple unit consumption. Where it is possible to do, it is the best way of reaching the lowest possible operating cost. On a single unit to single unit comparison, obviously a more energy-efficient technology will prevail. However when it comes to usage, the more powerful solution may result in lower energy cost.

I see that you have purchased an inverter unit recently. Post-purchase justification is a good thing, however stubbornness is not. If you run for 8 or more hours, the bigger units will have far lower duty cycles and eventually save energy as they are able to cool the room faster. Please study and understand before making a purchase. I actually reduced my energy bills when I went from a 1.5T AC to a 2T unit - even though the latter is listed as having 600W extra power consumption. I was able to do that because I made the correct calculations.

 

[laugh]

I can't tell if you're joking or serious.

.

What I said was oversizing as suggested by you is probably the way to go. I spoke to two engineers who are into commercial construction and they suggested me to oversize exactly like you.

 

[rdst_1]

@cranky - I got your point. It is somewhat similar to what we used to discuss about power supplies right. Better to buy a larger capacity PSU so that it functions in the range where it is most efficient.

Can you point me towards some sites or links which can help me in the calculations, especially where I can calculate the heatload requirements based on the dimensions of my room and which can factor other variables as well, like heat generated by computer and steel cupboards filled with clothes, etc.

 

[cranky]

A very nice one for India is here: http://www.ishrae.in/heatload/heatload.asp

Not sure about clothes but you can simply add 1 PC for a regular computer, for an enthusiast PC like you might have, add 2 or 3 for every PC you have. I think the estimate per PC is about 120W, a lot lower than what we might be discharging.

 

[Crazy_Eddy]

The Fujitsu in the pic above is using 1,480W average and I've approximated 80% duty cycle/8hrs/every day/5 years

Two LGs use 1130W each, and with the same parameters I've approximated 40% duty cycle.The LGs have approx 30% more cooling power when combined.

I think you made a mistake with the duty cycles, assuming you're servicing the same heat load :

(LG 1T rated cooling capacity : 3350W / 1130W input power ; x 2 for 2 units.)
But of course this only illustrates the difference between 2-star and higher efficiency ACs, and isn't the inverter's actual party piece. You might as well get a higher star rated non inverter AC since the inverter circuitry would only add to the power losses.

Compressors do not operate at 200W, they will clog almost immediately.

Actually "inverter" ACs do use PWM to drop compressor rpms and thereby vary the cooling capacity. Of course there is a limit to how low it can go. This will be listed in the tech specs under cooling capacity. The General for example in the above image, is rated 0.9-6KW (0.26T equivalent).

I have not even factored in the differential running costs by powering the second unit only when needed.

What you have described is actually a make-shift way to replicate what an inverter or rather variable-speed compressor is doing.
But you have to factor in compressor on-off cycling losses when comparing inverter and non inverter ACs. Under lab testing, this has been shown to be about a ~30% loss in efficiency. A somewhat similar analogy would be fuel efficiency in a car with the accelerator fully pressed and then braking vs cruising at a steady speed. Inverter ACs avoid the on-off cycling losses by regulating the speed instead and this is what gives it the efficiency advantage, not the rated input power.

 

[cranky]

My understanding on duty cycles is that it is affected both by cfm and cooling power. Going by the simple ratio of 400cfm/ton, the doubled units will also provide around 30% more cfm, reducing the duty cycle further than just the cooling power would suggest.

I am aware that an inverter AC will reduce rpm, but compressor power of 200W is just not possible - that's power ratio of 7:1. No compressor can operate across such a wide range, at least not yet.

And finally, the two-unit solution may not work for everybody. The whole issue that was being made here was between brand X and brand Y and technology A and B. Instead, one should look at the actual heatload and see what oversizing delivers the best operating cost.

 

[RishiGuru]

Below are some specs related to the current Carrier Inverter air conditioner lineup. The numbers may be helpful to continue the discussion.

 

[laugh]

Thanks for all the suggestions. Went for Daikin 1.9 2 star Ac for the bigger room and installed a old 1 tonne Ogeneral split in the smaller room.

Daikin costed 37000 (inclusive of 5 KVA premier stabiliser and installation) in Ratna Fan house in Chennai and installation material costed 4000rs. (4 metres of 0.8 mm copper wire+Bracket+Drain pipe+Wires and stuff.)

Ogeneral 1.5 tonne Inverter costs 52k and it looks flimsy when compared to their older models. I was very tempted by Sharp's 1.5 ton inverter but the chrome strip and colour scheme didn't suit the room's interior. Personally, I liked their 1 tonne inverter model better than their 1.5 . Daikin suited the room so well and it was the deal maker here.

Though the dealer offered free delivery on next day I choose to pick it up from godown to save a day's time. (Bad decision on my part as the units are quite big and they were stuffed in the car with considerable difficulty and I had to carry them from the car) Daikin's installer called me the next day and installed it in less 2 hours. (1 guys came, a main guy and a helper). I had called my regular installer earlier and asked him for what to check. He asked me to ensure that the copper tubes were either of Nippon/Totalline/Company's own make and Flarenet should be from GE. Daikin installer said the copper tubes were made by Daikin but there was no marking as such in the tube. Flarenet was provided by Daikin.

The unit is able to chill the room easily.

Tip: If you are opting for false ceiling ensure that there is sufficient space for indoor unit to be installed. I had some difficulty with this.

If you are from Chennai Ratna Fan house is the place to get AC's from. They are offering the best prices and are very organised. I compared with SC Shaws and Viveks and no one quoted lower. RFH don't stock Sharp and SC Shaws seems to be the major dealer. They quoted much lower (4k difference) than Viveks for sharp 1.5 tonne inverter but Viveks matched their price after a day and few phone calls. Moral of the story is compare prices! I called few small dealers asking them to match RFH's price but they won't or couldn't. If you are someone who cannot bother with price comparison and bargaining RFH is your place to go.

Questions if any are welcome.

 

[RishiGuru]

Congratulations for the purchase.

Would love some shots of you ACs in action.

 

[laugh]

Congratulations for the purchase.

Would love some shots of you ACs in action.

Thanks, Will upload pics soon![DOUBLEPOST=1366971252][/DOUBLEPOST]

Attached pictures.

1. First one is the copper pipe and drain pipes bought by the Daikin installer. My regular installer told me that good quality/full roll will be wrapped in a sheet and not exposed like this. I am not sure of what he meant exactly.

2. Second is the picture of the specs in Daikin 1.9 outdoor unit.

3. Daikin indoor unit.

4. Daikin 1.9 Indoor unit.

5. picture of the specs in Ogeneral 1.0 ton outdoor unit.

6. Ogeneral indoor unit. The unit is smaller than what you see in the picture but looks solid.

7. That the 1.5 ton Ogeneral window unit.


Must do some carpentry for the exposed pipes of Daikin and Casing for all cables.

 

[RishiGuru]

Ogeneral 1.5 tonne Inverter costs 52k and it looks flimsy when compared to their older models.

TRUE. I heard a lot about O-General, but when I saw their recent Inverter splits it seems to have build quality reminiscent of Onida. AC’s costing this much (INR 52K) must exude quality. The Daikins are much better on this aspect.

I was very tempted by Sharp's 1.5 ton inverter but the chrome strip and colour scheme didn't suit the room's interior. Personally, I liked their 1 tonne inverter model better than their 1.5 . Daikin suited the room so well and it was the deal maker here.

Why didn’t you go for Daikin Inverters? Cost?

 

[laugh]

Why didn’t you go for Daikin Inverters? Cost?

Yes, Cost is one reason, this particular ac will be used sparingly and did not make much sense to spend more. Another reason is Daikin inverter AC was few shade darker than non-inverter and did not suit the wall colour. (Redoing the interiors and hence this much obsession)

 

[RishiGuru]

laugh, as TheIndian said you can opt for O General air conditioners. Quality is said to be excellent though I have no first hand experience. They are very expensive and their Inverters can do a 46 degree centigrade max just like Sharp.

We have had apple fanbois, android fanbois, AMD and Intel fanbois even, now we have a SHARP one too who tends to snort at anything that is not sharp. OGenerals operating range ambient is 52c not 46,

I am not here to argue with you, but my suggestions are not vague and baseless as yours. To prove my point that the O General Inverters have a 46 degree max operating temperature I am providing their Inverter spec list

As you have often said, their site specs are incorrect, yesterdays ad in the paper said 52.

Today there is an ad of O-General Inverter ACs in our local newspaper. I am posting their images where it is clearly stated to work at 46C max outdoor temperature in salesman’s terms: “Maximum comfort even at 46C”

It seems either O-General is providing different specs in different cities to lure customers or someone is lying.

 

[laugh]

This ad is given in TN newspapers too and the max temperature shown is 46 degrees.

Ogeneral non-inverter models can work upto 52 degrees though.