Antifreeze - Ethylene Glycol vs. Propylene Glycol
Comparing ethylene glycol and propylene glycol antifreeze properties
| Property | Ethylene Glycol | Propylene Glycol | Comments |
|---|---|---|---|
| Freeze point depression | More effective | Less effective | More antifreeze is needed of propylene glycol to achieve the same freeze point |
| Heat transfer efficiency/capability | Better | Less | Ethylene glycol has superior heat transfer efficiency due to lower viscosity - but more fluid must be circulated to transfer the same amount of energy since Propylene glycol has higher specific heat |
| Viscosity | Lower | Higher | Propylene glycol increases major head loss in the systems. Pumps head increased |
| Flammability | Low | Low | |
| Chemical oxygen demand | Low | Higher | |
| Biodegrading | Degrades in 10 - 30 days | Needs more than 20 - 30 days to degrade | |
| Carcinogenic | No | No | A carcinogen is any substance or agent that promotes cancer |
| Toxic | High level of acute when taken orally, targets the kidneys | Lower level of acute | Ethylene glycol should never be used in any drinking water or food processing system |
| Skin irritant | Low | Low | Propylene glycol is used in small amounts in cosmetics |