vrv vs digital scroll

[katyalrk]

can anybody tell me how vrv/vrf is superior to digital scroll technology

[Argus]

In general, VRF has a superior first cost to 'digital' scrolls.

On a more serious note, I agree with katyalrk. It is a technology that is being taken up by some of the (mainly Korean) manufacturers as an alternative to full VRF.

Are there any Copeland members who are able to provide some detailed run-cost / efficiency analyses in comparison to VRF?

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[Peter_1]

A VRV runs with a high power factor due to the VFD,
a VRV wears less because the compressor is running a lot of the time at reduced speed,
a digital scroll does not give a steady flow,
a digital scroll is cheaper,
the less electronics in a system the better, at least for me, because they're so hard to service,

[katyalrk]

i am not satisfied with reply. can someone else help?

[Cofreth]

Sorry,
What does VRF & VFD stands for?
What is a digital scroll?
Any info about digital scroll please..

Tq

[Argus]

Sorry,
What does VRF & VFD stands for?
What is a digital scroll?
Any info about digital scroll please..

Tq

The terms Variable Refrigerant Flow (VRF), Variable Refrigerant Volume (VRV) and Variable Refrigerant Drive (VRD) are all different terms for the same thing.
In the UK at least, Daikin have registered the term VRV as a trade mark, with the consequence that other manufacturers prefer the term VRF. It means exactly the same thing.

That is, a refrigeration compressor motor is driven by a variable speed motor ? a Variable Speed Drive (VSD). This allows the motor speed and hence the system capacity to be varied to match the load. In the UK this type of system has eaten into the traditional chiller market and is very big business indeed. They are available as heat pumps or simultaneous heat / cool systems. Air to water models are now appearing.

The motor speed variation is achieved electronically by means of an ?Inverter?. This is a generic term for an electronic phase-chopped frequency conversion supplying the motor.
It is and largely remains a Japanese concept born out of the great fuel crises in that country in the 1970's and the fact that they have next to no indigenous fuel reserves.
Korean and Chinese manufacturers are now offering them, mainly based on technology transfer from Japan.

They can return impressive energy efficiencies at part load condition. This is why they are much used in the UK.

A couple of Korean manufacturers are offering digital scroll systems now as a less expensive form of capacity control.

A digital scroll compressor is, I believe, a Copeland patent and achieves a similar form of control by running the compressor motor at a constant speed and varying the load by using system pressure via a solenoid valve to physically lift the orbiting scroll plate.
Its chief advantage is that it is cheaper to make, sell and easier to understand because it comes without a lot of expensive electronics that are frequently misdiagnosed in the field.
One other advantage from a manufacturer?s point of view in the EU that is often overlooked is that it also comes without a lot of troublesome EMC compliance that you can have with power electronics.

You can get some basic information about digital scrolls by searching Copeland's web site.

Hope this helps.

The original question was what are the various merits and most of these have been discussed, except that meaningful running cost analyses comparing the two seem to be missing.
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[Peter_1]

i am not satisfied with reply. can someone else help?

Ohhhh, ..you're not satisfied.
Sorry, oh so sorry.
Google, Yahoo, one on VRV or VRF

Perhaps you're question was not clear enough.

[Brian_UK]

It's funny that Daikin should patent the term VRV when the volume of the system does not change.

[Cofreth]

Argus,
Thank you very much for the explanation.
Btw so far what make and model of air-con unit are using the digital scroll compressor?

[Argus]

Btw so far what make and model of air-con unit are using the digital scroll compressor?

To the best of my knowledge, LG and Samsung provide multi systems running on digital scrols; both Korean.

There may be more that I don't know about and other companies that introduce models as time goes on. It is in fact fairly new technology.


Argus
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[Abe]

i am not satisfied with reply. can someone else help?

I think Peter was trying to help and its very dis courteous to reply in that manner..........

You can at least thank him for his input. No one owes you a reply to your satisfaction.

I think an apology is in order

Be well

[baker]

In the hills area of my city, inverter driven splits (vrv) in domestic use are having reliability problems due to lightning. I suspect that digital scrolls would prove more resilient, although they are not as yet in widespread use.

Mark Baker

[Lc_shi]

it should be called comparing variable frequency compressor vs digital scroll compressor ;both are volume-controllable tech, VFD is mainly produced by Japan and digital scroll is from Copeland co. Some company -Midea\Haier have applied the digital tech product and it's said there is much advantage:no need for inverter;rotate at same speed(no noise like VFD);no magnetic disturb;no oil return problem;large adjustment range(10~100%) etc.But it's quite a new tech,I've only heard and read something,no experience for using it-

regards
LC

[Cofreth]

Was wondering the digital scroll system can withstand extended long refrigerant lines like the VRV systems?

[star882]

When my friend Tiffany helped build a quad Britney simulation server for science, she actually used a digital control board to run the 1HP recriprocating compressor at something less than full capacity most of the time. It used large MOSFETs to vary the frequency of the power to the compressor. The actual control electronics included a lot of 74HC discrete logic along with a 40 pin Jessica Simpson micro (which also controlled the front panel LCD and the system power supply). I'm not too sure about the details but it interfaced to the motherboard through a RS232 connection. Using the right program, it's possible to display the approximate compressor RPMs and estimated high and low side pressures based on temperature. There were 4 TXVs, one for each evaporator, to ensure proper operation even with uneven loading. The main purpose is to keep liquid refrigerant out of the compressor.
One of the tricky things, though, is that the compressor must run at some minimum RPM or the oil bearings will not work properly (it relies on oil between the surfaces, and at low RPMs, there's not enough pressure to keep the oil in the bearings). I remember that a minimum RPM is hard coded into the firmware.
And there are a lot of power electronics, although reliability is actually said to be improved since the compressor runs at reduced load and should last longer. Of course, that's not really an issue here since by the time the compressor wears out, the "cutting edge supercomputer" would become an antique.

BTW, one of the coolest things about that server is that it's possible to actually hear the compressor speed up at high load. It reminds me of a race car speeding back up to racing speeds after a caution.

[manender]

VRV stands for variable refrigeration volume, who said, volume is not changes in this technology,there is refrigetant's amount is controlled by eev and by inverter compressor energy is conserved.

It's funny that Daikin should patent the term VRV when the volume of the system does not change.

[superswill]

Few nice vids of a digital scroll:

http://www.youtube.com/user/emersonc.../7/7Jc8al_1JEQ

alot more info on Emerson website