Chiller power consumption

[Gauss2k]

Anyone is familiar with chillers power consumption?

I see in a technical data sheet that a 155 tons air-cooled chiller made by Trane requires a 310 amps disconnect switch (@575V).

But I saw elsewhere on the net that "One ton of cooling is the amount of heat absorbed by one ton of ice melting in one day: 12,000 Btu/h or 3.516 thermal kilowatts (kW)."

So I would suppose that the 155 tons chiller uses 550 kW of power. That would mean more than 500 amps @ 575V, which is a little over the 310 amps requirement... Where is my mistake?

 

[davidbeach]

The chiller is using its input energy to move heat, not to produce heat (or its absence). Therefore it is possible to make a simple power comparison and get an apparent efficiency greater than 100%, but only because it is watts of power used to move watts of heat.

 

[itsmoked]

Right on davidbeach!

You need the COP - Coefficient Of Performance, for a better approximation. They often range from 1.7 to 3.5 or there-abouts. This is the efficiency at which the system "moves heat". This means your Power estimate would be divided by the COP. A lot lower!

Keith Cress
Flamin Systems, Inc.- <

http://www.flaminsystems.com>