Multi Split and VRV

[Abe]

Dear Members,

I have a question, Multi Splits is where we have several indoors linked to one outdoor

VRV are similar me thinks, whats the differance between a VRV and a multi split?

Thx

[The Viking]

Aha, a language question..:D


In the old days, a multi split had a fixed speed compressor and each indoor unit had to be piped to the outdoor unit individually.

Then VRV (Variable Refrigerant Volume) or VRF (Variable Refrigerant Flow) units came along with speed controlled (Inverted) compressors and common fridge pipes to the outdoor unit.

Nowadays it seems like the border between the two is slowly disappearing, with multi splits having inverted compressors and common pipework.


Anyway, can't we just say that multi splits has more than one indoor unit and includes VRV/VRF solutions?:D


Whilst on the subject...
Did you know that the difference between VRV and VRF only is that if it's a VRV then it's a Daikin. This as Daikin got copyright/patent protection of the abbreviation VRV.;)
Sad old world isn't it, maybe I should try and get the rights for "A/C" or "Air Conditioning":D


:cool:

[Abe]

Aha, a language question..:D


In the old days, a multi split had a fixed speed compressor and each indoor unit had to be piped to the outdoor unit individually.

Then VRV (Variable Refrigerant Volume) or VRF (Variable Refrigerant Flow) units came along with speed controlled (Inverted) compressors and common fridge pipes to the outdoor unit.

Nowadays it seems like the border between the two is slowly disappearing, with multi splits having inverted compressors and common pipework.


Anyway, can't we just say that multi splits has more than one indoor unit and includes VRV/VRF solutions?:D


Whilst on the subject...
Did you know that the difference between VRV and VRF only is that if it's a VRV then it's a Daikin. This as Daikin got copyright/patent protection of the abbreviation VRV.;)
Sad old world isn't it, maybe I should try and get the rights for "A/C" or "Air Conditioning":D


:cool:

Thanks Viking

When you say " common pipe" Does that mean that from the outdoor unit there is only one set, which goes into the building, ie: one gas and one liquid.

That pair then feeds a branch controller box which has connections to the various indoor units.

What about the distances from the branch to the indoors, say one indoor is 20 metres away from branch, and one is 5 metres. Does that affect?

Does the branch have to be central so each indoor is equi distant to each other.

And how many controllers would there be ( I mean the electronic controller to switch the unit on and off )

Finally, what if one room is set for at 18C and the other at 20C

How are these set?

I presume each room will have its own control panel and these are daisy chained

Sorry I ask too much!!

[The Viking]

When you say " common pipe" Does that mean that from the outdoor unit there is only one set, which goes into the building, ie: one gas and one liquid.
Yes but it might be 3, Suction/Liquid/Discharge.

That pair then feeds a branch controller box which has connections to the various indoor units.
Not necessarily, this varies with manufacturer and whether it's a heat recovery system (simultaneous heating and cooling) or not.

What about the distances from the branch to the indoors, say one indoor is 20 metres away from branch, and one is 5 metres. Does that affect?
No, not on modern units, there are some limitations depending on which manufacturer you go for but with some design this isn't an issue.

Does the branch have to be central so each indoor is equi distant to each other.
No

And how many controllers would there be ( I mean the electronic controller to switch the unit on and off )
Again it's down to the design, these systems can run on anything from 1 controller/multiple systems (several systems can be linked together) up to several controllers/indoor unit.

Finally, what if one room is set for at 18C and the other at 20C
Not a problem, if you got a heat recovery system then one indoor unit can provide heat whilst the next provide cooling.

How are these set?
Depends on Manufacturer and design

I presume each room will have its own Control (http://www.refrigeration-engineer.com/forums/glossary.php?do=viewglossary&term=144) panel and these are daisy chained
Again, this depend on what brand you go for and how you designed it.

Sorry I ask too much!!
Only way to learn......

[suny]

Hi Viking

Thank you for the explanation given on Multi Split, VRF and VRV. Can you explain to us about the ceiling mounted cassette model air-conditioners, how it work, the efficiency & energy saving aspect of it. After going through your thread I just heard about this product.

Suny

[The Viking]

Hi Viking
Can you explain to us about the ceiling mounted cassette model air-conditioners, how it work, the efficiency & energy saving aspect of it.
Suny

Sorry Suny,
You got me there.
A ceiling cassette (as we understand the term here in UK) is only another type of indoor unit, like wall mounted or floor standing, if you want.
So no additional efficiency or energy savings from it.

What it does:
It is easy to install where there is a false ceiling with a deep enough void.
The ceiling cassette distributes the air better than the alternatives, under normal conditions.So it is really just another option to consider when installations are designed, if the ceiling height is high enough, if the void is deep enough, if you want high capacity installed with as little draughts as possible and you want uniform distribution, then go for a cassette.
At least if you can't sell a ducted unit (which normally comes out more expensive)
:cool:

[suny]

Hi Viking
Thank you very much for your explanation
Suny

[Brian_UK]

Regarding the term VRV for variable refrigerant volume.

I could never understand how Daikin managed to sell that name because the volume of the refrigerant never, ever changes within the system.

The term VRF makes much more sense to me.

Maybe I'm just getting too old ;)

[The Viking]

Ahh,
But the way Daikin see it, the volume circulating in the system and the building varies.
But then again, they are Japanese, ever read one of their (allegedly) "English" manuals?

[eggs]

Dear Members,

I have a question, Multi Splits is where we have several indoors linked to one outdoor

VRV are similar me thinks, whats the differance between a VRV and a multi split?

Thx


Sorry to ask this, but i'm sure other long term members are also keen to know.
With a basic non-knowledge such as this: are you a lawyer, a pilot or a fridgeman?
Surely a moderator on a fridge forum knows the answer to this???

cheers

eggs

[Peter_1]

Eggs, even moderators don't know everything

[Abe]

Sorry to ask this, but i'm sure other long term members are also keen to know.
With a basic non-knowledge such as this: are you a lawyer, a pilot or a fridgeman?
Surely a moderator on a fridge forum knows the answer to this???

cheers

eggs

Eggs

And Me thinks you are takin the P..........ss, Mr Know it All
:D:D

For your information, I am a qualified refrigeration engineer with over 20 years experience under my belt, running my own business and employing engineers.

And yes, I love planes and I can tell you a thing or two about law as well.

When I ask sometimes a simple question, the answers ripple out to the shores within our international community on this forum.

And thats what this forum is about, not judging or questioning other members levels of skills and knowledge, but sharing our knowledge base.

This is not a competition to see whos the brightest star, its to encourage healthy debate, and elevate the standards of our industry.


Take care and have a great day

Abes......
;)

[Obi Wan]

Dear Members,

I have a question, Multi Splits is where we have several indoors linked to one outdoor

VRV are similar me thinks, whats the differance between a VRV and a multi split?

Thx

Hello Abe,

The difference between Split, Multi Split, Sky-Air and VRV is the target market the product is aimed at. For Daikin systems the classification is as follows,

Split System
Residential - for single room air conditioning.
One outdoor unit and one indoor unit.
In fact for Daikin the correct term for a split system is “Room Air conditioner” or RA systems.
Expansion device located on the outdoor unit.

Multi Split System
Residential - for multiple room air conditioning.
One outdoor unit with up to five indoor units but with independent thermostat control.
Expansion device located on the outdoor unit.

Sky Air System
Light commercial
One outdoor unit connected to one, two, three or four indoor units. However only unit controls the thermostat.
Expansion device located on the outdoor unit.

VRV System
Commercial
An outdoor units in one, two or three combinations connected to up to 64 indoor units.
Expansion device is located on the indoor units.

All of the systems above have inverter compressors. The use of inverter compressors is now widespread because they are far more efficient in terms of energy consumption. Just because a system has an inverter compressor and more then one indoor unit, does not mean it’s a VRV system.

The terms Sky Air and VRV are registered trade marks of Daikin Industries.
To compare the Multi Split system with a VRV system is like comparing a mini with a formula 1 car. They both have four wheels and a steering wheel. But they work is a very different way and of course aimed at a very different market.

Hope it helps.

Obi Wan

[Abe]

Thank You Obi Wan

Brilliant explanation.
Youve cleared the fog, I can see clearly now......:)

I appreciate the courtesy ,helpfulness and clear cut explanations offered by all that have contributed positively on this thread.

Thank you

Abes

[mohamed khamis]

Hi Abe

The term of multi-split system is a kind of capacity modulation or control, the evaporator or indoor unit is split into several sections or rows and is called multiple-circuits evaporator.

Each set of rows (named circuit) is provided by one thermostat and one solenoid valve. The whole evaporator is installed with one outdoor unit (condenser and compressor) and some times each circuit has its own outdoor unit.

The main idea of this system to modulate capacity is to stop one or two circuit at part load by de-energizing the solenoid valve via sensing the discharge air temperature or evaporator inlet temperature. therefore the capacity is controlled according to the number of operative and inoperative circuits.

Here, if u have several rooms each room has its own circuit and the thermostat senses the desired temperature and de-energize the solenoid valve. however, in term of the saving in energy consumption comapred with the VRV or VRF is not favorable because the compressor has fixed speed and almost pumps the same refrigerant volume.

For VRV or VRF the both are the same and i will tell u why it takes this name. The idea is different from the multiple circuit system.

In these system, the compressor is variable speed compressor and the evaporator is also divided into many circuits as previously. each circuit has electronic expansion valve. By sensing the discharge temperature the EEV modulates its opening and meters the cicruit by the suitable refrigerant volume which matches the load imposed. So each circuit has variable refrigerant volume and on the same time the collected amount of refrigerant from all circuits is sucked to the compressor which is equipped by suction pressure controller. This controller determines the degree of suction pressure if it is high the compressor has to change its speed and vice versa. So the system compressor has variable refrigerant flow from the compressor responding to the cooling load variations.
this realizes a continues operation of the compressor. Both of the systems have advantages and disadvantages and i will wirte to u them afterwards because i have to go now.

Cheers

[A_Ahed]

Common eggs
Even the silliest questions may lead u to a perfect understandin of a system .
Do u agree ?

[bingshan001]

learned a lot! thank you all!

[sinewave]

Eggs

And Me thinks you are takin the P..........ss, Mr Know it All
:D:D

For your information, I am a qualified refrigeration engineer with over 20 years experience under my belt, running my own business and employing engineers.

Take care and have a great day

Abes......
;)



I'm with Eggs here :eek:


Someone who's a 'Site Moderator' and allegedly has over 20 years exp, runs their own business and employs Ref' Engineers SHOULD know basic stuff like this surely?
:confused:

[frank]

I'm with Eggs here :eek:


Someone who's a 'Site Moderator' and allegedly has over 20 years exp, runs their own business and employs Ref' Engineers SHOULD know basic stuff like this surely?
:confused:
I'm not so sure you guys are being fair.

Being a site Mod doesn't necessarily mean that you are a wizard in fridge - maybe just that you have the right temperament to help others where you can, help stop all the spam, bad language, and other items like misplaced posts, etc.

Suppose Abe had done nothing more than install and maintain cellar coolers for the past 20 years, would you then expect him to know how a VRV works? or a supermarket pack.

Come on chaps, we all have different levels of knowledge, and the only way to learn is to ask questions.

I personally admire Abe for the time he is taking to learn a new trade, i.e. Law, and I wish him all the best if he eventually succeeds in his chosen goal - he will certainly end up earning a hell of a lot more than we will. As for the remarks about the 'Pilot' - well everyone has a hobby outside of work - what's wrong with that??

I feel that Abe has given a lot to the forum. Correct me if I'm wrong.

[monkey spanners]

Knowledge is never wasted:)

Got that song that goes 'drop the pilot, try my balloon'. or something like by Joan Armoured cable going through my head after reading 'pilot' now:mad: thats the evening beggered lol

[mohamed khamis]

I totally agree with Frank, we all learn from each other it does not matter who is the tuioter and who is the student. If any body is shy from asking question that he needs to know it i do believe he does not know the answer easily or at least shortly.

cheers

[Abe]

I totally agree with Frank, we all learn from each other it does not matter who is the tuioter and who is the student. If any body is shy from asking question that he needs to know it i do believe he does not know the answer easily or at least shortly.

cheers

Mohammed

You " respond" to posters who are merely intent on "stirring" by bringing issues pertaining to a persons qualifications and credibility onto the stage.

If a member has genuine concerns about the credibility of a Moderator, then a complaint can be addressed to the site owner and Administrator who has the power to determine the appropriateness of a Moderator. He further has the power to appoint and dismiss.


The use of words like " allege" insinuate that porkies are being told, is a strong word and has been used carelessly.

I shall let this matter now be dealt with by the appropriate Moderator in charge of this section.

[frank]

I shall let this matter now be dealt with by the appropriate Moderator in charge of this section.

I thought I had Abe.

I've now closed this thread.