VRV/VRF vs Chiller (heat pump)

[nike123]

I have strong conviction that VRV/VRF is totally wrong approach to central air conditioning as opposed to Chiller (air to water or geothermal water to water heat pump) and fan-coil arrangement.
My main arguments are:
1. Technical complexity of VRV/VRF systems. They are to complicated to control, work with, service and use.
All that is much simpler with Chiller. And all indoor comfort and control is achievable also with Fan-coil units.
2. Working life span. They best expected life span is 10-15 years max. Life span of fan coil and instalation is about 30 years and fan coil is easy and cheap to upgrade.
Life span of chiller is also 10-15 years, but it is easy to replace without any problem with compatibility with indoor side of system. That we cannot said for todays VRV/VRF systems. Also, change of Chiller could be benefitial after that time period because of better COP/EER of new products.

I will throw more later!

What are yours opinions about that subject?

[The Viking]

I fully agree, almost....

The general maintenance of a VRV/VRF system is cheaper than a 4 pipe fancoil system as there aren't any water treatment needed. (this obviously depend on the water quality where you are, here in UK it's bad)
A standard 4 pipe fancoil system does not offer heat-recovery.
A fancoil system rarely achieve the same (total) COP as a VRV/VRF system.

Personally???
I'm an old-fashioned type of guy, trained on chillers and with a preference for electromechanical controls. Does the customer really need that nice digital controller that cost a small fortune to replace, or did it develop from a wet dream of someone in the manufacturer's R&D department?

Give me a fancoil system any day....

[frank]

Although 4 pipe fancoils are an excellent way of providing heating and cooling to large buildings, they cannot match the energy savings offered by the VRV/VRF systems.

With a fan coil set up, if you wanted just one fan coil on heating you would have to have the boilers on to heat the whole pipework circuit to satisfy the heat demand. The same would apply to having just one fancoil wanting cooling - the chiller would be called to create a full cooling loop at 6/12C before the room load could be satisfied.
That would equate to a large energy input for a relatively small output.
Also, to make the fancoil system operate efficiently, complex controls are required, aka, Trend or similar.
The initial cost of a chiller/boiler/fancoil/controls setup is quite high.
The VRV systems, in some cases, can be shown to be more cost effective both in initial cost and energy consumption (whole life costs) over fancoils and with heat recovery options, more adaptable.
VRV does have limitations though with pipework length restrictions but this is getting better with design.
I work on both types, the downside being that I have to employ other trades to look after the boilers (Corgi) and the controls (Trend).

[Thermatech]

In the UK the Japanese manufacturers dominate the air conditioning market in split, multi split & VRF products.
Sales of chillers have been hit hard with many office block & hotel applications with 500 to 1000 + kw using VRF in preferance to chillers & 4 pipe fan coil.

Why do consultants, contractors & endusers all prefer VRF ???

1/ first cost is cheaper & or 2/ heat recovery & COP makes the VRF the best option for energy efficency & smaller carbon foot print.
Like it or not energy efficency will become more & more important & the manufacturers who have spent the last 20 years developing the very best energy efficency products will sell the most.

Its like cars.
20 years ago they had a carburettor & distributor ignition & did about 30 mpg, had to be serviced every 6000 to 10,000 miles.
Now they have computor engine management system with many electronic sensors & will do 50+ mpg with much reduced pollution, offen only need service every 20,000 miles, but when they go wrong its more expensive to repair.

How many refrigeration & a/c engineers drive arround in a 20 year old car / van for work ?

[Lowrider]

That's all nice, but what about larger systems.

We've built one just yet of 6MW on a cold and hot well. How many VRF/VRV's will one need!

If the guys deciding on a system would look futher and decide to buy a proven system in stead of cheap junk, chiller's will outdo VRV/VRF's any time.

And what about a large IRS with a total cooling load of 30MW? Place a couple of hundred VRV/VRF's?

[Lc_shi]

VRV&VRF are used in not too large cooling load situation. It's only one type of central ac but couldn't totally substitute chiller and fancoils.

[Lowrider]

on the space needed for a 60 kW VRV/VRF we can pla ce an unit of 1MW!

[andy86]

Hello. Looks like this is an old inactive thread.

I'd like to know if there's a recommendation for maximum number of installed VRV outdoor units in a system. I'm designing HVAC system for a building requires about 4100 kW of cooling capacity and a liquid chilling system is chosen, I still wonder if a VRV system is suitable?

According to Daikin VRV-II catalog, the largest cooling capacity of an outdoor unit is 139 kW (RXY48MY1, 48 HP). So if it's a VRV system, the total number of outdoor units is around 30. Is it a problem?

This is a 15 storey hospital, 80m x 30m.

Btw, I'm a student and don't have much experience in VRV. Thanks in advance.

[TAB GUY]

Can someone help me?

I am trying to find basic information on how VRV systems work, how the branch selector works and the basic sequence of operations that might be expected for these types of systems?

Can anyone answer these questions or direct me to a webpage that has this type of basic information?