Cooling for 9 x Quattro 15kVA

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Lothar Ledgerd asked May 10, '19

Cooling for 9 x Quattro 15kVA

We are looking at using nine 15kVA Quattros in a three phase system (3 per phase). With an operational efficiency of around 95% and 12kW rating, that gives 600W heat generated per Quattro. That is 5.4 kW of heat from the system, typically located in a small area such as a shipping container or switchroom. That is a lot of heat in a small space. Does anyone have suggested mounting layouts and ventilation for multi Quattro systems? Perhaps a case study?

We need to provide the customer with 100kW of power, so cannot afford derating below 11kW.

charger victron products 3 phase temperature

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Lothar Ledgerd commented · May 13, 2019 at 02:50 AM

Thank you both for your answers. Especially that pdf with the temperature and efficiency information. I am located in Australia, so I think Quattros are going to be a problem for us here. The highest loads on most sites are air conditioning during the summer when peak ambient each day can be close to 40 degrees Celsius for a week!

The temperatures in that document, are they ambient temperatures or the Victron temperature? I didn't see this stated clearly.

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Paul B Lothar Ledgerd commented · May 13, 2019 at 03:03 AM

I think you will find that all inverter systems out there all produce the same heat output on average, are the same and will all berate as the ambient temp goes up

Anyway at least Victron will give you believable figures on there equipment as do some of the other reputable brands as well.

Keep in mind that Victrons backup is exceptional as well

what ever you use dont push them to there limits all the time .

if its hot what ever you get air con the room or add more units

Another way is to pump more air directly under the units to increase air flow and bring this Air in from a shaded area were the air is cooler. I think you know the drill allready

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abrahamsolar Lothar Ledgerd commented · May 13, 2019 at 03:13 AM

Hello, @Lothar Ledgerd .

I think any high end battery based inverter/charger would impose a similar heat dissipation rate per kilowatt of converted power.

Solar "string" inverters for PV conversion have lower dissipation per kilowatt because they have an easier job to do.

Thanks & Jolliness~

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boekel ♦ abrahamsolar commented · May 13, 2019 at 07:54 AM

at the end of the document it specifies 'ambient temperature'

The derating formula (7) is applicable when the ambient temperature increases beyond the temperature at which the full output power is specified, in general 25ºC (77ºF) for inverters and 40ºC (104ºF) for battery chargers.

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Lothar Ledgerd boekel ♦ commented · May 13, 2019 at 11:04 PM

Ah yes. I see it now. Second last paragraph of the document makes the link between the data above and ambient temperature.

"The derating formula (7) is applicable when the ambient temperature increases beyond the temperature at which the full output power is specified, in general 25ºC (77ºF) for inverters and 40ºC (104ºF) for battery chargers. "

Thanks for pointing that out Boekel

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Modifications Space

Node Red Space

Answer 1 · 2019-05-10T09:11:03Z

Johannes Boonstra (Victron Energy Staff) answered · May 10, 2019 at 09:11 AM

Hello, You are right about the heat generated (it could even be more on maximal power as efficiency is a bit less then), as the total amount of heat/losses depend on the total amount of load. Having a 5-9kW heat generated at a 135kVA system running at full power is quite normal by the way. How to cool this depends on ambient temperature and isolation of the system. There are systems equipped with airco systems to ensure cool operation. Normally a temperature regulated fan(s) systems is sufficient to prevent high temperatures.

Then depending on the load the system has the fan's will be on/off. the ideal would be to keep the direct ambient of the inverters at/below 25C.

PS

Also the batteries (like lead/acid type) can generate quite some heat as well, specially during charging. So also keep that in mind please.

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Anil Ghatikar commented · May 10, 2019 at 01:13 PM

Is there an incentive to keep the ambient temp at 25 as against 35. using Air conditioning ?

Perhaps longer life of components and achieving dust free environment

I have a system of 5 x 3 KVA Quattro ( ESS with BYD lithium) normally loaded to 5 KW during the day - say 300 Watt losses

Currently Ventilated with Forced air with Ambient air of average 28 to 38 DEG .

I can air cool the room using a spare 5000 BTU ( 900 Watt of cooling) Airconditioner

Energy costs in Nigeria from the grid is typically .05 Euro cent

Any empirical studies on the increase of lifecycle of components due to lower ambients?

ps. I tried cooling before but the BYD never reported full rated current 1C even at 20 DEG ambient as the cabinet remains at +5 DEG with Ambient and the batteries report 0.7C current

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Answer 2 · 2019-05-11T01:38:16Z

abrahamsolar answered · May 11, 2019 at 01:38 AM

Hello @Lothar Ledgerd . It took me awhile to find this document again but here 'tis:

https://www.victronenergy.com/upload/documents/Output-rating-operating-temperature-and-efficiency.pdf

One can calculate the amount of heat that will dissipate from Victron inverter/chargers at various levels of loading.

If the circuit boards, heat sinks etc. are below 25 degrees Celsius (77 degrees Fahrenheit) one can expect 100% wattage throughput with no "fold back" (same as no "clipping"). Above 25 degrees the Victron inverter/chargers behave as if they are smaller rated...as a self preservation measure.

@Johannes Boonstra (Victron Energy Staff) correctly mentioned battery heating as another factor for an enclosed system--depending on the battery chemistry & efficiency, etc.

Happy Friday~

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