Chillers - KW per Ton of Refrigeration

Hello Ramkumar Allu:

The best source is the manufacturers information sheet on the particular equipment.

The old rule of thumb used to be 1 hp= 746 W per ton of air-conditioning, this will still get you in the ballpark, but it's a very big ballpark. Efficiency of the machines vary by how heavily they are loaded, ambient temperature, and humidity.

As far as air cooled condensers versus watercooled, in general I would say water cooled condensers have a slight efficiency advantage, however in extremely humid conditions that advantage is largely lost, along with the watercooled condenser comes parasitic losses associated with the pumps.

However water cooled condensers are not necessarily used for increased efficiency per ton of AC, ductwork and building design concerns often favor remote chillers /air handlers , fan coils, Located in various parts of facilities or buildings, and the heat dissipation device i.e. cooling tower on a roof or some other convenient part of the facility.

Hey,

The Energy in TR is calculated by multiblying the Flow of water in chiller cooler in USGPM by the diff in Temperatures in/out in degree Fehrenheit devided by 24 hrs for a value of an hour.

The electrical effecincy can be calculated by dividing the KW consumption of chiller motor by the Energy in TR.

Regards,

Ehab.

I checked some product data about a Carrier Corporation modular chiller. The water cooled version has a full load efficiency of about 0.7 kW/Ton. The air cooled version has a full load efficiency of about 1.1 kW/Ton.

Is this electrical KW or Mechanical KW? Please clarify?

I guess you all are referring to air conditioning. For -100°F brine, it'll cost about 8 KW/ton, since the latent heat of the refrigerant, ambient losses, compression ratios, compressor efficiency all change depending on the system temperature.

Hi ,

Tons refrigeration effect is an old fashioned measure of compressor capacity.

1 Ton/hr= 12,000 BTU. divide by 3412 to get kWs = 3.52kW/hr

You will then have to make allowance for the COP of your machine and the operating conditions both (cold and hot side) to arrive at the overall performance of your machine.

Hope this helps.

Its is simple.Kw/ton is power consumption of chiller/tonnage of refrigiration of chiller in tons.For watercooled at full load it ranges from 0.6-0.7.For part load(IPLV or NPLV) best is around 0.4.The above is for centrifugal type.For aircooled at full laod it ranges 1.23.at part load it ranges to 0.9.Less kw/ton means lesser power consumption and more saving in operating cost.