Calculating chiller and cooling tower refrigeration - in tons

Cooling towers tons pairs the water-cooled chiller tons and the water-cooled condenser tons.

Chiller Refrigeration Tons

The process of cooling is called refrigeration. Refrigeration or cooling capacity can be measured

in tons.

A water-chiller refrigeration ton is defined as:

1 Refrigeration Ton (RT) = 1 TONS cond  = 12000 Btu /h = 200 Btu /min = 3025. !  "a#orie$ /h =12%%1 !&/h = 3.51' ! 

1 ! = 0.2*3 Refrigeration Ton (RT)

A ton is the amount of heat removed by an air conditioning system that would melt1 ton (2000

#+$.) of ice in 2* hour$. The heat re,uired to me#t 1 #+ of ice at 32 o - to ater i$ 1** Btu.

1 Ton Refrigeration = (2000 #+) (1** Btu/#+) / (2* hr)

= 12000 Btu/hr 

Converting between Btu/h and Tons of Refrigeration

Btu/h Refrigeration Ton

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Cooling Tower Tons

A cooling tower ton is defined as:

1 coo#ing toer ton = 1 TONS ea = 1 TONS cond   1.25 = 15000 Btu /h = 3'2 !  "a#orie$ /h =

152% !&/h

 

The e(uivalent ton on the cooling tower side actually re)ects about 15000 Btu/h due to the heat-

e(uivalent of the energy needed to drive the chiller*s compressor. This e(uivalent ton is defined

as the heat re)ection in cooling & +.,. gallons/minute (1500 ound/hour) of water 10-  whichamounts to 15000 Btu/hour  or a chiller coefficient-of-performance C01 of *.0 - a C0

e(uivalent to an energy efficiency ratio 22R1 of 13.%5.

Heat Load and Water Flow

A water systems heat load in Btu/h can be simplified to:

h = c   , dt 

  = (1 Btu/#+m o -) (.33 #+m /4S ga#) , (%0 min/h) dt

= 500 , dt (1)

here

h = heat #oad (Btu/h)

c  = $ecific heat 1 (Btu/#+m o -) for ater 

  = .33 (#+m /4S ga#) for ater 

, = ater o#ume f#o rate (4S ga#/min)

dt = temerature difference ( o -)

Exa!le - Water Chiller Cooling

3ater flows with 1 ga#/min and 10o -  temperature difference. The ton of cooling load can be

calculated as:

"oo#ing #oad = 500 (1 4S ga#/min) (10 o -) / 12000

  = 0.*2 ton