Having excellent heat transfer properties, any form of glycol is a critical ingredient when needing to quickly remove large amounts of heat.
Glycol is an organic compound belonging to the alcohol family and is referred to as antifreeze. Due to its excellent heat transfer properties, glycol is ideal for cooling and chilling applications. Glycols are used in many different heating and cooling applications such as HVAC systems, plastic molding, food and pharmaceutical processes, ice rinks, and solar thermal heat transfer. Ethylene and propylene are the two types of glycol, and while they are both colorless, odorless, viscous liquids that possess a faintly sweet taste, there are a few primary differences between the two.
One of the main differences between ethylene glycol and propylene glycol is the toxicity levels. Ethylene glycol is toxic and propylene glycol is not. In applications where toxicity is not a concern, ethylene glycol is often the best choice for a heat transfer fluid. Ethylene glycol should not be used if there is the possibility of ingestion or incidental contact with food or potable water. It should also not be used for heating or cooling systems at facilities like food processing plants or other operations creating products for consumption. When low toxicity is necessary, propylene glycol is often used due to its low acute oral toxicity. While it should be avoided, propylene glycol is safe in the event of accidental contact with water or food.
The two glycols have differences in their physical properties and heat transfer characteristics. Ethylene glycol is commonly used in applications where efficiency is important and there is no human or animal contact. Ethylene glycol has excellent heat transfer and freezes protection. Its low viscosity means it has superior heat transfer efficiency and its transport properties outperform propylene glycol at lower temperatures. However, since propylene glycol has higher specific heat, more ethylene glycol fluid must be circulated to transfer the same amount of energy as propylene glycol. Propylene glycol solutions have higher viscosity and a higher freezing point than ethylene glycol at the same percentage. Especially at lower temperatures, propylene glycol is less thermally efficient than ethylene glycol.
Though both are glycol compounds, ethylene and propylene cannot be mixed because they have different fluid, toxicity, and heat transfer properties that would prevent a system from working properly. Propylene glycol has low toxicity, is biodegradable, and is a food-grade antifreeze, making it the safest choice for every club and its kitchen.