How is heat transferred when heating tubes are embedded in a floor, wall, or ceiling in a conventional hydronic system?

In a conventional hydronic system where heating tubes are embedded in a floor, wall, or ceiling, heat transfer occurs primarily through conduction. This process involves the movement of heat through solid materials, in this case, the floor, wall, or ceiling itself.

When the water within the tubes is heated, it raises the temperature of the tube surfaces. The heat then transfers from the tubes to the surrounding solid material through direct contact, causing the atoms and molecules in the material to vibrate more quickly, thereby spreading the heat throughout the structure.

Convection is not the primary mode of heat transfer in this scenario because it requires the movement of fluids (like air or water), which is less relevant when the heating elements are solid and directly in contact with the surrounding structure. Radiation also plays a role in how heat is felt in a living space, but it is not the primary mechanism in the context of embedded heating tubes. Evaporation does not apply here as it relates more to phase changes of liquids rather than heat transfer in a solid medium.

Overall, conduction is the most relevant method by which heat is transferred in this type of hydronic heating system.