Kokonaislämpöresistanssi

Kokonaislämpöresistanssi, often abbreviated as R_tot, represents the total resistance to heat flow through a composite structure. It is a fundamental concept in thermal engineering and building science, used to quantify how effectively a material or a combination of materials impedes the passage of heat. In simpler terms, it's a measure of how well something insulates.

The calculation of total thermal resistance depends on the type of heat transfer involved and the arrangement of the materials. For heat conduction through a series of layers, the total thermal resistance is the sum of the individual thermal resistances of each layer. Each layer's resistance is determined by its thickness and thermal conductivity. Materials with low thermal conductivity, such as insulation, have high thermal resistance, while materials with high thermal conductivity, like metals, have low thermal resistance.

In the context of buildings, kokonaislämpöresistanssi is crucial for assessing the energy efficiency of walls, roofs, and windows. A higher total thermal resistance indicates better insulation, meaning less heat will escape in winter and less heat will enter in summer, leading to reduced energy consumption for heating and cooling. This concept is often used in conjunction with U-values, which are the reciprocal of total thermal resistance (U = 1/R_tot) and represent thermal transmittance.

Factors influencing kokonaislämpöresistanssi include the materials used, their thickness, the presence of air gaps, and even the quality of installation. Understanding and calculating total thermal resistance allows engineers and builders to design more energy-efficient and comfortable structures.