PROCESS
Chiller
for larger industrial type applications; floor model (AutoAnalyzer, Electron Microscope, Lasers, EDM, Injection Molding)
Narrow temperature band of —15ºC to 40ºC (Heating available to 80C)
Limited stability of ±0.5ºC
Significant heat removal of up to 2850 Watts at 1 HP
On board reservoir is to provide thermal mass and cannot be used as a circulating bath.
Sizing An Industrial Chiller
Size the total Load heat application is generating, plus additional power to maintain temperature under varying loads.
to calculate the heat load of your system:
BTU/hr = (T1-T2) x gpm x 60 min/hr x 8.33 lb/gal x Cp
T1 = temperature of coolant leaving the equipment, deg F
T2 = temperature of coolant entering the equipment, deg F
gpm = gallons per minute of coolant flowing through the equipment
Cp = specific heat of coolant; Water = 1.0
Measure temperature with the same thermometer if possible of with two thermometers of known accuracy. Measure gpm using a flowmeter of by collecting the coolant in a known volume for a given period of time.
Additional Considerations:
If ambient temperature of the cooling location is above 68°F, add 1% to the calculated BTU/hr for each 0.9°F above 68°F.
If operating at 50Hz, add 20% to the calculated BTU/hr.
If line voltage is consistently below rated voltage, or if you work at high altitude, add 10% to the calculated wattage.
Future growth cooling needs or variability of heat output of existing unit.
Conversions:
Watts = BTU/hr / 3.413
Tons = (BTU’s / hr) / 12,000
Selecting a Laboratory Chiller
Watts = [DT° x (K)] / S
Where:
DT= The difference (D) between incoming and outgoing tap water temperature (T) of your instrument. Measure carefully using the same thermometer for both locations. You may measure in Celsius or Fahrenheit.
S = The number of seconds to fill a one liter container.
K = Conversion constant for density and specific heat of water.
Measured in:
Celsius: Watts = [DT°C (4,186)] / Seconds
Fahrenheit: Watts = [DT°F (2,326)] / Seconds
Additional Considerations:
If ambient temperature of the cooling location is above 20°C, add 1% to the calculated wattage for each 0.5°C above 20°C.
If operating at 50Hz, add 20% to the calculated wattage.
If line voltage is consistently below rated voltage, or if you work at high altitude, add 10% to the calculated wattage.
Future growth cooling needs or variability of heat output of existing unit.
Conversions:
BTU’s / hr = (watts) * 3.413
Tons = (BTU’s / hr) / 12,000
Calculating Process Heat Loads
Below are some basic methods for calculating the heat load of various industrial processes. In order to use the heat load calculations some general definitions need to be addressed. The calculations will reference the following basic definitions and formulas:
One Ton of Refrigeration = 12,000 Btu per Hour
