Electricity usage on chiller

[Cresta]

I'm looking into purchasing a new chiller and noticed that sometimes a higher horsepower chiller actually uses less electricity than a smaller one. Please correct me if I'm mistaken.

I'm looking at the specs on the Aqualogic Delta Star 1/3 and 1/2 horsepower chillers.

Model DS-4 1/3 hp= 7.2A @ 115v
Model DS-6 1/2 hp= 4.8A @ 230v

There is a 2.4A difference in electricity usage. How many watts is that? How do I make the comparison when one is in 120v (115v) and the other at 240v (230v)?

Does that mean even at a higher horsepower and higher cooling power, there is actually less electricity consumption?

 

[ChrisRD]

Power consumption is measured in watts. Watts = amps X voltage. With AC systems Watts = power factor X amps X voltage.

Assumping a power factor of 1.0 the DS-4 would be pulling 828 watts (7.2 X 115) and the DS-6 would be pulling 1104 watts (4.8 X 230).

That said, without knowing the actual power factor, this is really just a guess...

 

[ChrisRD]

Also, keep in mind that although the larger unit probably consumes more power, it may run less (greater cooling power).

 

[wade1]

It also has to do with effiency and the number of cycles it runs in, which is totally beyond me.