Closed System Management
Monitoring and Treatment of Closed-Loop Cooling Water Systems
When air temperatures plummet, frost and freezing protection of closed loop systems is of the utmost importance. Most commonly glycol (antifreeze) is added to the system to provide the necessary protection.
Glycol based water solutions are commonly used in heat-transfer closed loop systems, where the temperature in the heat transfer fluid can be below 0oC and therefore cause freezing and damage to the integrity of the plant.
Ethylene Glycol is the most common antifreeze fluid for standard heating and cooling applications. If there is a risk of human ingestion, Propylene Glycol which is food safe, should be used.
Protection from freezing is imperative when a system requires pumping. It is achieved when the glycol concentration in a system is sufficient to prevent ice crystals from forming when the fluid experiences its lowest temperature. The chart below under gives an idea of how the freezing point is lowered when Ethylene Glycol or Propylene Glycol (Food safe) is added to water systems.
| Percentage Ethylene Glycol | Freezing point temperature | Percentage Propylene Glycol | Freezing point temperature |
|---|---|---|---|
| 0% | 0°C | 0% | 0°C |
| 10% | -3°C | 10% | -3°C |
| 20% | -8°C | 20% | -8°C |
| 30% | -16°C | 30% | -14°C |
| 40% | -25°C | 40% | -22°C |
| 50% | -37°C | 50% | -34°C |
| 60% | -55°C | 60% | -48°C |
- Initial surveys of closed loop systems to determine the water chemistry and from that, decide on an appropriate plan of action.
- Supply of both propylene & monoethylene glycol.
- Dosing the chemical into the system.