Chiller Flow Rate?

itswayner · 07/09/2008, 10:01 AM

Is it more efficient to run more flow through a chiller or less? I have the JBJ 1/10 HP chiller and the min/max is 240/960 according to drsfostersmith.com. That is a huge range.

Currently I am running it at the low end (270ish) and it seems to work ok but I was wondering if it would cool faster with more flow? Or does the slower flow allow the chiller to cool the water more?

lvreefer · 07/09/2008, 10:24 AM

I choose to run chillers at the high end of the flow rate. The reason is that i would rather have cool water flowing out of the return vs. ice water.
The only way to truly test the efficiency would be to montior the usage (Kill A Watt).

Txmeta_b · 07/09/2008, 11:36 AM

good point, it's probably less shocking to your tank inhabitants if you have a small deltaT at the chiller/return outlet.
You don't want to generate a cold side and a hot side,since no matter how good your circulation is you'll have a temperature differential in the tank when the chiller is on.

In terms of power/work the chiller has to do,it will be pretty much the same,but the outlet temp will be linearly increase with the flow through the chiller.

itswayner · 07/09/2008, 11:44 AM

I run my chiller in my sump (input from one end of sump output on the other) so the temperature differential in the tank would be minimal since it is mixing with fresh tank water constantly?

Is that the proper way to hook up the chiller? Or should it be running directly to the tank?

Jefe12234 · 07/09/2008, 12:02 PM

Quote:

Originally posted by itswayner
I run my chiller in my sump (input from one end of sump output on the other) so the temperature differential in the tank would be minimal since it is mixing with fresh tank water constantly?

Is that the proper way to hook up the chiller? Or should it be running directly to the tank?

Well it's more efficient to run the chiller with the return pump so that you don't need a separate pump for it. And I'd guess that chillers only cool the water by a few degrees at most. I've put my hand in front of the return line when it's running and you can't feel much of a temperature difference, so I wouldn't be concerned about running it straight into the display tank. That's how most people do it.

Txmeta_b · 07/09/2008, 12:05 PM

QUOTE : I run my chiller in my sump (input from one end of sump output on the other) so the temperature differential in the tank would be minimal since it is mixing with fresh tank water constantly?

Is that the proper way to hook up the chiller? Or should it be running directly to the tank? /QUOTE

I don't really like that setup since you're feeding back the cold outlet stream (at least partially) back in the chiller,which could freeze the stream when you get a low flow condition in the sump.
I'd recommend to have the outlet of the chiller back in a high current area of the tank for quick mixing.

itswayner · 07/09/2008, 12:24 PM

Good point about the return. I probably should have just gotten a larger return pump and run it through there. I'll probably do that when I do my upgrade in a few months (55G->90G).

07/09/2008, 10:01 AM	#1
itswayner Registered Member Join Date: Dec 2005 Posts: 61	Chiller Flow Rate? Is it more efficient to run more flow through a chiller or less? I have the JBJ 1/10 HP chiller and the min/max is 240/960 according to drsfostersmith.com. That is a huge range. Currently I am running it at the low end (270ish) and it seems to work ok but I was wondering if it would cool faster with more flow? Or does the slower flow allow the chiller to cool the water more?

07/09/2008, 10:24 AM	#2
lvreefer Registered Member Join Date: May 2003 Location: Sin City Posts: 1,163	I choose to run chillers at the high end of the flow rate. The reason is that i would rather have cool water flowing out of the return vs. ice water. The only way to truly test the efficiency would be to montior the usage (Kill A Watt).

07/09/2008, 11:36 AM	#3
Txmeta_b Registered Member Join Date: Jul 2008 Location: Houston TX Posts: 6	good point, it's probably less shocking to your tank inhabitants if you have a small deltaT at the chiller/return outlet. You don't want to generate a cold side and a hot side,since no matter how good your circulation is you'll have a temperature differential in the tank when the chiller is on. In terms of power/work the chiller has to do,it will be pretty much the same,but the outlet temp will be linearly increase with the flow through the chiller.

07/09/2008, 11:44 AM	#4
itswayner Registered Member Join Date: Dec 2005 Posts: 61	I run my chiller in my sump (input from one end of sump output on the other) so the temperature differential in the tank would be minimal since it is mixing with fresh tank water constantly? Is that the proper way to hook up the chiller? Or should it be running directly to the tank?

07/09/2008, 12:05 PM	#6
Txmeta_b Registered Member Join Date: Jul 2008 Location: Houston TX Posts: 6	QUOTE : I run my chiller in my sump (input from one end of sump output on the other) so the temperature differential in the tank would be minimal since it is mixing with fresh tank water constantly? Is that the proper way to hook up the chiller? Or should it be running directly to the tank? /QUOTE I don't really like that setup since you're feeding back the cold outlet stream (at least partially) back in the chiller,which could freeze the stream when you get a low flow condition in the sump. I'd recommend to have the outlet of the chiller back in a high current area of the tank for quick mixing.

07/09/2008, 12:24 PM	#7
itswayner Registered Member Join Date: Dec 2005 Posts: 61	Good point about the return. I probably should have just gotten a larger return pump and run it through there. I'll probably do that when I do my upgrade in a few months (55G->90G).