Team-BHP (https://www.team-bhp.com/forum/)

-   Gadgets, Computers & Software (https://www.team-bhp.com/forum/gadgets-computers-software/)

-   -   The home / office air-conditioner thread (https://www.team-bhp.com/forum/gadgets-computers-software/4389-home-office-air-conditioner-thread-375.html)

Vestar?

My wife prefers to take advice from anybody but me, and has been listening to the local AC guy. That. it seems, is what he has bought.

Not that I know more about AC than he does! Far from it. But I think that his personal spending priorities would be different: He is probably not a guy to buy a "premium" brand, and who know, he might be absolutely right in not paying for a name. He certainly knows what's easy to repair!

From me, if Mrs G is uncomfortable with Daikin as a result of the incidents I previously pictured, I can live with that. This is to be installed in a room that she mostly uses. But from the same dealer, I'd be inclined towards Hitachi, perhaps, or even Panasonic.

Absolutely no reason to go for 1.5 ton rating, 1 ton would be more than sufficient for the job.

In my home town of Bhilai, the summer high crosses 48C with temperature above 40C from 9 in morning to 9 at night. Yet, for unshaded room of 200 sqft on first floor, 1 ton AC was sufficient. Yes, it would take a bit longer to cool the room down at night but maintained the temperature throughout the night perfectly.

Wrong advice. What you are saying is completely incorrect. You can check on the websites of any large manufacturer for the required rating and it will be very close to what I have said. Trust me I am a mechanical engineer by education and have enough and more experience in these aspects. Maybe SGIITK would pitch in with his views?

I won't contest your knowledge and experience about the topic. However, I read my post again and realised I had missed out adding relevant and important information.

1. The room is occupied only by me
2. We had a false ceiling constructed specifically from insulation perspective.
3. The room has direct sunlight on only one wall that too after noon and that wall has covered shelves covering almost 70% surface.
4. The room has carpet and thick blinds for further insulation.

With these taken care of I have gotten desired results. Again not making any advice at all and I would be happy to be corrected.

Well, I have gone for a I am buying a Carrier Midea 1 ton Split AC.. The dealer is someone I know personally & he is the one who told me that 1 ton would be good enough for my needs as long as I don't run it very long. I don't think I will be running it for more than a few hours at a time.

Will be installed this week.

If you still can , change your ac selected to the 1.5 T split Ac as the 1 Tonne Ac will not be enough. It will run continuously and the compressor will never cut off as it will keep on struggling to achieve the set temperature. Better to spend 5k more to get a 1.5 Tonne ac which can achieve and maintain the set temperature quickly.

This is not correct. If an AC can be run for a few hours, it can be run on a continuous basis too. Most machines reach a 'steady-state' operating temperature within the first hour or couple of hours at most.
The temperature of the room is a different matter.

Yesterday evening my General Split was not starting. At night it behaved normally, fact as the boss hd set the fan to high even abnormally. Today's paper shows that there was a low voltage issue, so that must have caused it.

All that reduced the volume of air to be cooled. Add the insulation & single occupant and you have in fact reduced the requirement by half.

With a lot of coddling you can always use much less powerful AC, but that is not what is the normal pattern
. 9'-10' ceiling
. A couple of windows
. Sun on at least one side
. At least two occupants
. Regular opening of doors

The above pattern requires at least 1T per 1000 cubic feet. In case it is top floor and the day temperature goes beyond 40 degrees, you can easily double the cooling requirement. This is where an Inverter AC shiners.
. The initial cooling will be at least 125% of nominal rating - faster cooling
. Once the set temperature is reached it will slow down and maintain a constant comfortable temperature
. The continuous running of compressor places much less load both on it and the electrical wiring die to absence of regular starting current surge due to constant on-off nature of normal AC's. As a benefit you get lower electricity bills.

When I was looking for an AC, the Daikin dealer here (who also ran an all-brand shop adjacent to it), tried to hard sell Vestar to me. Said, they are made by the same OEM that makes General.
Am not an expert, but I have a feeling that a 1 ton AC would just take a little longer (maybe a bit too longer) to cool, and once cooled there shouldn't be much difference.

They have a high star rating... but that is only thing. Any other thoughts from anyone?
Worst case: the machine doesn't have the power to ever cool the room to required temperature and will run the compressor continually.

I think I remember being told by a commercial AC engineer in London (re small server room cooling) that too much power leads to quick over-cooling, and the machine cycles on and off frequently. Have I got any part of that right?

The IDU looked ugly. Very boxy.
Which is unlikely. Heat absorbed from outside and generated by occupants cannot beat the cooling generated by a 1T compressor. Unless you have an open door/window/airhole.

Thanks. We went back to the shop today. I was ready and willing to buy wife's-choice whatever. We did not buy, but came away with Mitsubishi Electricals 1-ton at the top of the list. Imported, have to buy cable and pipe extra, total is much more than the Daikin would have been. :Frustrati

Spot on. It is better to buy a higher capacity (Based on condition) as desired temperature will be achieved faster and allows for the compressor to cut out. Energy saving is key when operating an aircon.

There is a catch. If the AC capacity is much more than required, then the frequent start/stop cycle will consume more electricity in the end. That is why it is important to "Right Size". Some methods used to tailor the capacity when requirement is large (6T+) :
. Where there are multiple IDU's, use multiple ODU units. While starting all work, but as the temperature is achieved they stop one by one, reducing power requirement.
. Use VRF. The refrigerant flow is variable (and multiple ODU cycled). Most large systems can operate efficiently, down to 15% of nominal load, so with 3 ODU you can operate down to 5% of the peak capacity efficiently.
. In large drawing rooms, the requirements vary tremendously depending on the ambient temperatures (it hits 45+ in Delhi) and the number of persons in the room. So most of my friends have installed two to five 2T units. One when it is just the family and the days are cooler. Five when there are 40+ guests and the ambient is very high. Between that the number of units used depend on the requirements.

Unfortunately all these methods are capital intensive at 50K+ per ton (and at times even more), but they last much longer.