1 Cond Unit for 4 indoor units

[carlfoster]

Hi all

We are currently designing an air con install where 34 units are required. As the cusstomer doesn't want 34 outdoor units littered about the place, we have decided the best solution is to use the Daikin Super Inverter condensing units.

Apparently, these can supply up to 4 indoor units and they have a controller to integrate the airhandling units, which we are manufacturing, with their condensing units.

Well theres the setup, now the question. We haven't worked with inverter technology before and we haven't fitted our units with heat pump technology either. We normally use TEV's as a metering device.

Any ideas on how would this affect the efficiency of the system if the inverter compressor were to "slow down"? Can TEV's work with this or are EEV's recommended?

Also, whats the best way to design the piping system for the heat pump to be used as TEV's only flow one direction?

Thanks in advance.

[nike123]

You cant do that because indoor unit need electronic who communicate with outdoor unit and have firmware compatible with outdoor unit. Also, you need EEV.

[The Viking]

It can be done, if you speak to the chaps at Daikin and/or Space (they are normally a friendly bunch), they will be able to advice you of exactly how to do it.

(Nike, Daikin makes an interface box for exactly this type of situation. I would find out what it's called but I'm on holiday now...)

[multisync]

Depending upon duty you may get away with just one condenser..

Lifted from Daikin

Daikin Sky Air and VRV Condensing Units Adapted for Air Handling Applications

Daikin Europe N.V. can now offer inverter driven Sky Air and VRV R-410A outdoor condensing units with a special communication box (EKEX) interface and expansion valve kit (EKEXV) for connection to the direct expansion cooling coils of 3^rd party manufactured air handling units


The new Sky Air condensing units, designated ERX and suitable for ‘pair’ cooling applications, are available for single phase (ERX140), 3 phase (ERX200 and 250) and single/3 phase (ERX100 and 125) connection. These units replace the company’s type EKRPER R-407C units with the exception of the earlier 200 and 250 models, which will remain available throughout 2006. Operating limits of the condensing units are based on the ambient air temperature of the air handling unit and maximum air handling unit entering temperatures of 14⁰C WB and 25⁰C WB/35⁰C DB respectively. Ambient temperatures for expansion valve and condensing unit are – 5⁰C DB to 46⁰C DB (single phase) and – 5⁰C DB to 43⁰ C DB (3 phase). Maximum system design pressure is 40bar.

Standard 5 to 18HP VRV outdoor units can also be adapted for ‘multi’ air handling unit cooling applications linking them to air handling units and VRV indoor units.

Application flexibility of these new packages is maximised for both pair and multi combinations by a choice of several expansion valve kits and two different communication boxes depending on air handling unit coil volume, VRV unit connection ratios and number of indoor units. Three alternative control formats can be selected, offering air temperature control via external DDC controller, evaporating temperature control by Daikin or air temperature control via Daikin controller.

[carlfoster]

Thanks, we're getting them in for help with this. I think it will be very interesting.

[majo]

I've put a super inverter on an air handling unit in februari. With a custom evap battery from Guntner.
Daikin just provides an extra box with electronics to be put next to the battery.
Also a flowswitch needs to be connected to the drain pump level guard.

[carlfoster]

Thank you for all the suggestions. I thought I would give you all an update on what has happened so far on this project.

It's been an absolute nightmare. It all looked so promising at first. We had a meeting with a Daikin Salesman and another chap who we thought was a technical expert but it transpired later that he was also a salesman.

They both said that what we wanted was more than possible as they had a number of customers who had done the same thing. They have a range of units they call the RZQ range which could supply up to 4 evaporator units and all that would be needed was an interface board to connect the 2 together.

Well, we were very excited. We asked for more technical info on this board as well as pricing details which we needed urgently so we could pass on the info to our customer.

Well, no information was sent. After a number of phone calls and eventually getting a response, we were told we needed to speak to their main technical expert, which we did.

He promptly told us that what we wanted would not work at all and at the very least we would need their VRV III system. He said that the smallest Fan coil needed a duty of at least 5KW and we needed various gadgets as well such as EV kits per evaporator and control boxs. All of which not only trippled the expected price, but also didn't really fulfill our need as many of the fan coils were half of the 5KW threshold.

We received no clear reason as to why the RZQ wouldn't work and to get this information required a lot of puching on our part.

We are thoroughly disappointed! If only they had told us from the beginning instead of getting our hopes high, and now we look pretty stupid to our customer as we'll have to go back and say that what we were proposing doesn't seem like a viable option. We've talked to Mitsubishi too, but they can't provide a real solution either, but at least they were up front about it from the start.

So, in conclusion I'll say from our experience that Daikin have been a very difficult company to work with. They aren't very up front with information, or at least not very clear. We would have thought that a potential £50,000 deal would have motivated them to at least try to actively help us but I suppose a big company like this can't be bothered with small fry.....

[multisync]

Welcome to the wonderful world of DUK

Try Space, they are usually better at one offs and ad hoc's

Multisync
london