Coolant (definition)

Coolant — is a liquid or gas used in heating systems to transfer thermal energy from a heat source to end users such as radiators, heated floors or other heating devices. The choice of a suitable heat carrier depends on the type of system, operating conditions and the required temperature regime.

Coolant: main types

1. Water:
   • Description: The most common and economical heat carrier, used in most heating systems.
   • Advantages: High heat capacity, low cost, environmentally friendly, compatible with most heating system materials.
   • Flaws: Tendency to freeze at low temperatures, possibility of corrosion of metal components of the system in the absence of anti-corrosion additives.
2. Antifreeze:
   • Types: Based on ethylene glycol and propylene glycol.
   • Ethylene glycol:
     • Description: Highly efficient heat transfer fluid with low freezing point.
     • Advantages: Suitable for use in conditions where there is a risk of freezing of water in the system.
     • Flaws: Toxic, requires careful handling, especially in residential areas.
   • Propylene glycol:
     • Description: Less toxic than ethylene glycol and can be used in residential heating systems.
     • Advantages: Suitable for use in domestic systems, has anti-corrosion properties.
     • Flaws: More expensive and less effective than ethylene glycol.
3. Oils:
   • Description: Used in specialized heating systems where operation at very high temperatures is required.
   • Advantages: High resistance to overheating, ability to work at temperatures exceeding 100°C without generating steam.
   • Flaws: High cost, complexity of operation and maintenance, need for special materials for the system.
4. Air:
   • Description: Used in air heating systems where heat is transferred by means of heated air.
   • Advantages: Does not require replacement or maintenance like liquid heat carriers, no risk of leaks.
   • Flaws: Low heat capacity compared to liquids, high system inertia, difficulty in uniform heat distribution.
5. Pair:
   • Description: Used in steam heating systems where heat is transferred by condensation of steam.
   • Advantages: High heat transfer, quickly reach the required temperature.
   • Flaws: Difficulty in temperature regulation, high risk of burns, need for high-quality pipe insulation.

Application and selection:

• Residential buildings: Water or water-based propylene glycol antifreeze are the most common options because they are safe and effective for household use.
• Industrial facilities: The use of oils or steam is justified in high temperature conditions or specific heat transfer requirements.
• Regions with cold climates: Use of antifreeze to prevent freezing and damage to the system.

The choice of coolant must take into account the operational characteristics of the system, economic feasibility and safety requirements.