The first step is to calculate the temperature differential, meaning the difference between the current temperature of your water and the needed temperature of your water. For example, if the water is 85°F, and you need it to be at 75°F, the temperature differential would be 10°F.
o ΔT°F = Incoming Water Temperature (°F) – Required Chilled Water Temperature
o Example: 85°F – 75°F = 10°F
British Thermal Units per Hour
Next, calculate BTU per hour. This is important because it will help us define your cooling capacity needed later on. BTU per hour is realized by multiplying your gallons of water per hour by 8.33, then multiplying that by the temperature differential.
o BTU/hr = Gallons per hr x 8.33 x ΔT°F
o Example: (4 gpm x 60) x 8.33 x 10°F = 19,992 BTU/hr
Cooling capacity is the measured ability of a cooling system to remove heat. You can find this by dividing the BTU per hour by 12,000.
o Tons = BTU/hr ÷ 12,000
o Example: 19,992 BTU/hr ÷ 12,000 = 1.666 tons
Ideal Chiller Size
The final step in finding the ideal size of chiller you need is to multiply your cooling capacity by 20% and round up to the nearest whole number. The resulting number will be the ton of chiller that will best suit your business.
o Ideal Size in Tons = Tons x 1.2
o Example: 1.666 tons x 1.2 = 1.9992 tons ; a 2 ton chiller is needed
We’re Here to Help
Each chiller is built to be the most efficient, most reliable cooling system available. Discovering which one will best help your company takes only a minute. North Slope Chillers has these formulas on their website, as well as a program that allows you to input your numbers and does the math for you. You can also call our highly seasoned solution providers at 630-629-6600 for more information of how North Slope Chillers can meet your temperature control needs.