Result
Preliminary calculation: This tool is for quick sizing and information. In real projects, load calculation, selection and commissioning require engineering calculations and a site survey. Results are approximate values.
Why is glycol used?
In cooling water lines at risk of freezing (outdoors, low-temperature process water, chiller evaporator), pipes and heat exchangers can burst if the water drops below its freezing point. A glycol mixture lowers the freezing point.
| Ratio (volume) | Ethylene glycol | Propylene glycol |
|---|---|---|
| %10 | −4 °C | −3 °C |
| %20 | −8 °C | −7 °C |
| %30 | −14.5 °C | −13 °C |
| %40 | −24 °C | −21 °C |
| %50 | −37 °C | −33 °C |
Points to note
- Where there is a food or drinking water risk, propylene glycol is preferred
- Use inhibited industrial glycol; do not use automotive antifreeze
- Too much glycol reduces capacity and pump efficiency
- The ratio should be measured with a refractometer every season
- Do not mix glycol with galvanized pipe
- The quality of the water added matters
For flow rate and capacity, use the chiller flow rate calculator.
Frequently asked questions
Does freezing point or burst point matter?
A glycol mixture turns slushy before it freezes solid; that is why it is recommended to choose a freezing point about 5 K below the lowest temperature.
Ethylene or propylene?
Ethylene glycol gives better heat transfer but is toxic. Propylene glycol is preferred where there is food or drinking water contact.
How do I measure the glycol ratio?
With a refractometer or the measurement method recommended by the manufacturer; it should be checked at the start of every season.