Technical advice wanted on VRV packaged Air conditioners

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kapvin

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Hi,

We are shifting to Gurgaon and most of the flats we have looked at there for rent, have VRV packaged Airconditioners integrated into the flat. (clearly provided by the builder). now there is a lot of folklore around VRV units and how they are power guzzlers, but intuitively that seems not correct. I can understand that it would be maximally efficient at peak load and would scale down non-linearly, but would it be radically different? and if so, under which circumstances. are there any other watchouts?

secondly, and this is more future-facing thing, when we return eventually to our house in thane, would it make sense to install a VRV? Our current system comprises 7 ACs (4 1.5t and 3 -1t) installed in various ducts. only the drawing/dining ACs are on a ledge which would allow better air circulation. I cannot imagine the duct being a thermally optimal solution, but the space was assigned by the builder (along with concealed piping and wiring so installing splits was plug and play). so we have the twin objectives of better efficiency and more space (in the ducts).

our thane house is 1900sqft carpet (about as big as 2900sq. ft Gurgaon house). Our typical use-case is 2-3 AC on at night every night. and during WFH/study from home 2-3 ac on during the day. Windows are double glazed so fairly good thermal insulation.

posting here in the hope that since Hifi Aficiniados are, generally speaking, more technical, there would be someone with a clear informed view on this.

thanks for looking.

Kapvin
 

shankarcams

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My experience with VRVs in a residential context is that when you are running at 40 or 50% of full load they are efficient. But if you are running just one room they are very inefficient.

In our case we mostly used just the bedroom at night so turned out to be quite power inefficient

A couple of other points to consider -

VRVs have complex microprocessors etc. in the outdoor unit and so are more susceptible to power issues.

VRVs are mainly 3 phase and so even if only one phase is gone you need to run the DG. This is of course relevant only for houses not large apartments

The VRV is a single point of failure. If it conks, your entire apartment is without aircon. With splits you can shift to another bedroom

For these reasons I had shifted back to splits
 
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kapvin

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A couple of other points to consider -

VRVs have complex microprocessors etc. in the outdoor unit and so are more susceptible to power issues.

VRVs are mainly 3 phase and so even if only one phase is gone you need to run the DG. This is of course relevant only for houses not large apartments

The VRV is a single point of failure. If it conks, your entire apartment is without aircon. With splits you can shift to another bedroom

For these reasons I had shifted back to splits
This and the other point in the previous post are really useful. Thanks. are failure rates higher for vevahik? We have 3 phase power so that’s not a problem


thanks.
 

mshifi

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You would definitely save on power cost with the vrv. The over all maintenance cost would be higher with vrv as you need to have an amc for it.
 

sandeepmohan

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If you do a google search about VRV, the technology is actually quite efficient. There are two components;

  • Independent operation per unit.
  • Variable refrigerant flow, which is how temperature is controlled. More precise I would say so temperature fluctuations will be minimal. Its supposed to turn off to when no occupants are detected in the room. I don't know how this works. What I do know is that my cheap Mitsubishi split dials down performance if the motion sensor does not detect any movement in the room.

At the most you want to get something with has inverter based as that is one step further to be efficient. I am pretty sure any vrv system sold today is Inverter based.
 

Vivek Batra

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Good thread @kapvin. I am also considering VRV for my upcoming home. I haven't read much about it yet because I still have an year to decide.I am sure we all are gonna take away something from this thread.

Even in my case there would be around 10 air cons and hardly 2 to 3 running at any point of time.

Regards
Vivek
 

reignofchaos

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A couple of other points to consider -

VRVs have complex microprocessors etc. in the outdoor unit and so are more susceptible to power issues.

VRVs are mainly 3 phase and so even if only one phase is gone you need to run the DG. This is of course relevant only for houses not large apartments

The VRV is a single point of failure. If it conks, your entire apartment is without aircon. With splits you can shift to another bedroom

For these reasons I had shifted back to splits

Can't you split your house's load into multiple ODUs (say 10hp each) instead of a single large one and stack them at the same place on your terrace? This will definitely give you some redundancy. I'm currently evaluating Daikin VRF for my house and was wondering if going this route makes sense.

The primary advantage I'm seeing is the aesthetics vs hi-wall units as the FCUs and ducting can be hidden nicely in the false ceiling.
 

sud98

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In my community, there are multiple people who have installed VRV and havent seen any maintenance issues in the last 5 years. If you have space for a shaft and the money to spend, it makes a lot of sense as its aesthetically very good and the noise levels (in your HT) will be quite low.
 

shankarcams

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Each one of is has to evaluate relative merits of VRV vs Split based on our specific considerations. I am quite sure our decisions will differ - that's why both Splits and VRVs both have market share.

My comments were based on my situation. Obviously others will have different views and that's fine.
 

manofernando

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Hi,

We are shifting to Gurgaon and most of the flats we have looked at there for rent, have VRV packaged Airconditioners integrated into the flat. (clearly provided by the builder). now there is a lot of folklore around VRV units and how they are power guzzlers, but intuitively that seems not correct. I can understand that it would be maximally efficient at peak load and would scale down non-linearly, but would it be radically different? and if so, under which circumstances. are there any other watchouts?

secondly, and this is more future-facing thing, when we return eventually to our house in thane, would it make sense to install a VRV? Our current system comprises 7 ACs (4 1.5t and 3 -1t) installed in various ducts. only the drawing/dining ACs are on a ledge which would allow better air circulation. I cannot imagine the duct being a thermally optimal solution, but the space was assigned by the builder (along with concealed piping and wiring so installing splits was plug and play). so we have the twin objectives of better efficiency and more space (in the ducts).

our thane house is 1900sqft carpet (about as big as 2900sq. ft Gurgaon house). Our typical use-case is 2-3 AC on at night every night. and during WFH/study from home 2-3 ac on during the day. Windows are double glazed so fairly good thermal insulation.

posting here in the hope that since Hifi Aficiniados are, generally speaking, more technical, there would be someone with a clear informed view on this.

thanks for looking.

Kapvin
A small doubt, can u pls tell me what duct we are talking about.
 

Decadent_Spectre

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These would make sense only if you are making a new house or moving into a new apartment where the option is there. With pre existing structures it's difficult.
 

manofernando

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VRF or VRV both are the same and they don't need any separate ducting system. It's a common outdoor unit( the condensor ) with multiple indoor units ( evaporator coils). The main unit should be either change the rpm of the compressor according to the requirement of cooling or should be having a part unloading mechanism to unload part of the compressor according to the need depending on the type of compressor used. Indoor units are connected to the outdoor unit by the same old method used in current split AC (copper tubes, inlet n return).

VRV can be single-phase operational. Most probably the motor driving the compressor will be a DC motor as the DC efficiency will be better, so the AC will be converted by an inverter circuit.

Single point failure is a problem.
On the positive side, we can instal a 4-ton unit with multiple indoor units only using where it is necessary.
 

kapvin

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A small doubt, can u pls tell me what duct we are talking about.
I think that’s mumbai terminology. Others might call it a shaft. Regardless, its the area outside the house where all the pipes run. typically enclosed with an open or brick lattice window and normally accessed from the bathroom.
 
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