Heat transfer mediums are substances or materials that allow heat to be transferred from one system or object to another. These mediums are essential in a variety of industrial, commercial, and domestic applications where effective heat exchange is required. Water: Perhaps the most common heat transfer medium, water has a large specific heat capacity, making it an efficient heat transfer medium. Because of its abundance, low cost, and little environmental impact, it is perfect for a variety of heating and cooling systems. Engine coolants, such as ethylene glycol or propylene glycol, are good heat transfer mediums in automobile applications. They save engines from overheating by absorbing heat and dissipating it through the radiator. Refrigerants: Commonly used in refrigeration and air conditioning systems, refrigerants such as Freon or hydrofluorocarbons (HFCs) absorb heat from the surrounding air or substances by transitioning between liquid and gaseous states via phase change. Thermal oils have excellent thermal stability and are used in industrial operations requiring high-temperature heat transmission, such as manufacturing, plastics processing, or solar heating systems. Steam: Water in its gaseous state is a powerful heat transfer medium, particularly in power generation via steam turbines. Its high vaporization enthalpy allows for the transfer of considerable amounts of heat energy. Heat Transfer Fluids: These fluids, such as silicone oils or specific glycol-based solutions, are designed to work over a wide temperature range while retaining their thermal properties. They are used in solar thermal systems, HVAC units, and some manufacturing processes. Molten Salts: Molten salts such as sodium nitrate or potassium nitrate operate as heat transfer mediums in concentrated solar power plants, absorbing and storing thermal energy for later use in electricity generation. Although less effective than liquids, air is used as a heat transfer medium in a variety of systems such as air-cooled engines, HVAC systems, and heat exchangers. Heat is transferred away from components or areas via forced air convection. Metal Alloys: Due to their great thermal conductivity and endurance, certain alloys, such as copper-based alloys or aluminum, are employed in heat exchangers. They enable fast heat transfer in a variety of industrial and engineering applications. PCMs are compounds that store and release thermal energy during phase transitions while keeping a constant temperature. They are used in thermal energy storage, building materials, and specialized applications that require controlled heat transport. Each heat transfer medium has unique qualities that are selected based on their suitability for the intended application, temperature range, cost-effectiveness, and environmental factors.
