Choosing a VRF for a hotel. Advice needed...

[norad]

Hi,

I am working as a consultant for a 200-room Hotel project and we are choosing a VRF system at the moment. For sure, I've got engineers around me who inform me on how to choose a VRF system as I have no education or sufficient experience on the subject; but I still need more information.

We are quoated by Mitsubishi Heavy, Daikin and Mitsubishi Electric and they have all come up with their own systems. More or less, they calculated similar capacity and diversity. And now it has come to my decision.

1) Mitsubishi Heavy has quoated me for a KX6 system which consists of several 22-24-26-28 and 32 HP FDC-series units. They tell me that their KX6 systems have 2 inverters which is their main advantage against their competitors. Would you agree on that?

2) Daikin on the other hand quoted me for their new VRV IV system which accordingly is setting a new standard in the industry and is much more energy efficient due to many technological advancements. I've found out that it is a failry new system and I was wondering what you can tell me about it? Is it reliable? Does it really bring essential improvements?

3) Given I have the same capacity recommended to me, based on what should I make my decision? Should I compare the EER values? And more importantly, which system would recommend and why?

Many thanks!

[install monkey]

using a daikin 3 pipe will cost more in material costs and labour time, all vrv,vrf systems will have at least 1 inverter compressor, with mitsi electric you will need to allow space for the bc box, usually located in a corridor as you will need full access to this, look at local distributors for spares availability, as for vrv4 ive not installed any yet.

[RusBuka]

Кх6 - 2 inverters.

[The Viking]

Which one of the 3...

Do you prefer an Audi or a BMW?
Pretty much the same question I'm afraid.

Now, some general pointers;
With new technology comes teething problems, as some manufacturers found out at great expense in the past.
The more the system relies on technology the fewer engineers there will be that are able to fix them and the more likely it is that even a minor fault will take an awful long time to repair.
(On quite a few occasions I have been sent out to commission and set VRV/VRF systems up as the company that did the install not had the competence and/or experience to do so and therefore they messed things up)
Any VRV/VRF system is like a grand piano, finely tuned by an expert and played by a skill full musician it will sound great and bring tears of joy to your eyes. Change just a minor part of that piano, make a minor mistake on the tuning or let a less skilled musician hammer on the keys and you will cringe and get tears of pain rolling down your cheeks.

(Those of you that followed my postings over the years might want to sit down now or at least put their tea-mugs down before reading on)

The first question you have to ask must be "Why VRV/VRF?", especially when you are looking at a hotel.
What diversity will you be able to utilise? Most rooms will require heating/cooling at the same time, rarely will you see the situation where 30% of the rooms needs cooling and 70% needs heating (=something close to the conditions the manufacturer use to calculate and prove efficiency...)
What experience does the local air condition engineers have of VRV/VRF and what manufacturers' systems do they have the facility to connect computerised (i.e. laptop) troubleshooting and commissioning tools to? You don't want to have to pay for their learning by letting them "learn as they go" on your equipment, that normally ends up costly for the end user.
So if you go down the road of VRV/VRF, ask the local AC firms what system they normally works on and go with that brand. But also ask to see sites they already done and ask how often those systems have problems or are offline and for how long.
Also remember that the bigger the systems are the more rooms there will be that are affected by the same faults and the more guests there will be complaining.


So what alternatives are there?
Well, tried and tested fancoils served by chillers and boilers is one option.
Modern chillers and boilers are more energy efficient than they used to be.
The pipework can be installed by pipe fitters and the pipes can even be "plastic" instead of copper.
The components of fan coil/chiller/boiler systems are likely to be readily available if there is a breakdown. (With any VRV/VRF system all the parts are brand specific and to get spares are often an issue)
Any old A/C or fridge guy will know how to operate and repair fan coil systems. Just remember to follow the KISS principle.
The downside with wet systems is the water treatment, a good water treatment regime needs to be in place.

Just my 6p.

:cool:

.

[al]

Or go with snigle splits, connected to BMS for control.

Chillers are good too:)

al

[norad]

@The Viking:
Thank you for your reply.

I am sorry; forgot to mention that the hotel is a seasonal one; which means it would need only cooling at the same time during the summer.

All 3 manufacturers have their VRF/VRV systems installed around hotels similar size. Hence, getting tech support should not be a problem. Mitsi Heavy and Mitsi Electric operate through distributors in the country we reside; but Daikin has its own office which in my opinion is an advantage.

I agree with you on your remarks about the new technology. VRV IV is a very new and it is not field tested long enough. One could argue that Mitsi Heavy developed KX6 system in the past 3-4 years and no major problem came out, yet, so there is no need to be reluctant to new technology. But then again, I am no where an expert on this; that's why I am here :)

[mick doohan]

its got to be mitsubishi electric vrv,installed correctly these systems will provide years of service
with only filter cleaning required.great technical back up and won manufacturer of the year 2012
and no i dont work for mitsubishi.daikin seem to have dropped the ball in recent years.

[RusBuka]

For me very big problem to write that I want to tell. It is necessary to sit with the dictionary) As far as I understood systems with recovery to you aren't necessary.

MHI - good installation and start - lack of problems, in general. Improbably fast superlink protocol, diagnostic programs really allows to thrust the nose into any part of the unit. Can kill only one - not refueling and thus work on heat at an external temperature-15 - 20. Priority for work - temperature maintenance in rooms. Temperature of forcing departs to heavens, injection is cut, unload the inverter, and so repeats. As a result a wedge of compressors on the top bearing of sliding.

ME - practically too most, diagnostics is convenient, mnet allows to test even extent of opening of EEV valves in internal blocks. The recooler perfectly works even at an external temperature in 35-37 degrees. Allows to use instead of refnets ordinary refrigerating tees at installation. I can't precisely tell, but, it seems, allows to connect 200% of consumers for the external block. The truth it demands program change (patch of outdoor mainboard is necessary) and at a full load the overheat on internal blocks will be quite big. But such option can be used in hotel as the option of a constant full load is improbable.

VRV 4 didn't see, didn't start, there is a strong wish to look and feel. Units continue to warm rooms, even when the external block goes to a mode of defrost, at the expense of heat accumulator (as I understood on the basis of critical solution of salt), well and the system of calculation of necessary overcooling of ***** will theoretically save to you money on electricity. As actually all this works it isn't known)))

[VRVIII]

Кх6 - 2 inverters.

VRV IV also has 2 x inverter compressors (no standards)

[RusBuka]

Can tell anything about soft and programm for diagnostic? Have any manuals?

[norad]

Mitsi Electric is a bit out of budget at the moment. So, we'll choose between Mitsi Heavy KX6 and Daikin VRV IV.

Apart from installation difficulties and cost; which one would you choose? Are there any distinct advantages of one manufacturer over the other? Which is more reliable?

[RusBuka]

I would choose KX6 as everything is known of it, there is all information, and it is known as it works.
VRV 4 a dark horse, and its problems to you it is necessary to find out on the object.

[r.bartlett]

In a large hotel we are currently removing daikin vrv and fitting toshiba... :-)

[RusBuka]

In smms-i systems there is no subcooler. Carefully consider distances of pipes. Extraneous noises in internal blocks aren't treated.

[martinw58]

if you use daikin i hope the tecnical and customer service is better than it is in the uk

[Magoo]

I would prefer chilled water systems in sleeping areas, for fear of a refrigerant leak and killing people while they are sleeping.

[RusBuka]

How many people were lost because of suffocation by ***** from multizone systems in 10 years?
What do you think about noise from the unit? Or to put units only on turboсor?

[JoeAT50A]

Mitsi Electric is a bit out of budget at the moment. So, we'll choose between Mitsi Heavy KX6 and Daikin VRV IV.

Apart from installation difficulties and cost; which one would you choose? Are there any distinct advantages of one manufacturer over the other? Which is more reliable?

Mitsubishi Electric has the best interface cum interlock system with hotel key-card system. You should reconsider as the packaged deal, they have wonderful AG-150A interlock function especially for Hotel application.