Grizzly
23-03-2013, 08:57 PM
Hi Guys.
I was on an Industrial site last week that was using a Danfoss controller.
Which loaded both multiple compressors and the condensers 4 fans.
These fans load one after the other in short bursts, starting at the gas intake and liquid discharge end.
Whilst the short cycling is more evident whilst we are experiencing the very cold ambients of late!
Apparently when the ambients are warmer, a Fan will take the lead and the others will load up and down around it.
I had been told that especially with the Blend refrigerants that we now have, it is better to have the fan nearest the inlet and outlet pipework as lead!
This the reduces the situation where the hot discharge gasses have travelled through the condenser. Until reaching the duty fan and being cooled.
This cooled refrigerant Liquid then travels back through the condenser before exiting.
En_route it can be influenced by the warm / hot gasses travelling towards the cooling condenser fan!
In short.
You have hot gasses travelling through the condenser and below it you have the cooled liquid flowing in the other direction.
Could you get a situation where a blend may split?
Either way it is not an ideal scenario!
I am told the rotational and sequenced start up maintains balanced fan running hours.
With none stopping for long periods the bearing wear and seizures are reduced.
Both are fair comments, any thoughts?
Grizzly
I was on an Industrial site last week that was using a Danfoss controller.
Which loaded both multiple compressors and the condensers 4 fans.
These fans load one after the other in short bursts, starting at the gas intake and liquid discharge end.
Whilst the short cycling is more evident whilst we are experiencing the very cold ambients of late!
Apparently when the ambients are warmer, a Fan will take the lead and the others will load up and down around it.
I had been told that especially with the Blend refrigerants that we now have, it is better to have the fan nearest the inlet and outlet pipework as lead!
This the reduces the situation where the hot discharge gasses have travelled through the condenser. Until reaching the duty fan and being cooled.
This cooled refrigerant Liquid then travels back through the condenser before exiting.
En_route it can be influenced by the warm / hot gasses travelling towards the cooling condenser fan!
In short.
You have hot gasses travelling through the condenser and below it you have the cooled liquid flowing in the other direction.
Could you get a situation where a blend may split?
Either way it is not an ideal scenario!
I am told the rotational and sequenced start up maintains balanced fan running hours.
With none stopping for long periods the bearing wear and seizures are reduced.
Both are fair comments, any thoughts?
Grizzly