Itselämmitys

Itselämmitys, also known as self-heating, refers to the process by which a substance or material generates heat internally without an external heat source. This phenomenon typically occurs due to chemical reactions or physical processes that release energy. A common example is the slow oxidation of certain organic materials like hay or compost. As these materials decompose, the chemical reactions involved produce heat. If the material is piled thickly enough and has sufficient moisture content, this heat can accumulate, leading to a noticeable temperature increase within the pile.

Another form of self-heating can be observed in some types of batteries, particularly during charging or discharging. The electrochemical reactions within the battery can generate heat as a byproduct. In industrial settings, spontaneous combustion can be a concern with certain stored materials like oily rags or coal. The slow oxidation of these materials can generate enough heat to eventually ignite them if ventilation is insufficient and temperatures rise to their autoignition point. Understanding the conditions that lead to self-heating is crucial for safe storage, handling, and processing of various substances to prevent fires and other hazards.