Unregulated heat output of a storage heater

Abstract

In the article the factors determining the heat transfer between the outer surfaces of a storage heater and the ambient air. This heat exchange is unregulated, and its definition is a precondition for assessing heat output range of this type of units. It was made the analysis of the literature on choosing insulating materials for each of the external surfaces of storage heaters: in foreign literature, there are recommendations on the use of various types of insulation depending on the type of device and the surface, while in Ukrainian literature the use of a single type of insulation for the whole structure is mostly described. The result of this was the summary of the information on the types of insulation used in storage heaters. In particular, the paper examined their characteristics of thermal insulation materials: thermal conductivity (approximations were made to calculate the thermal conductivity of materials in known temperature range), specific heat capacity and density. Additionally, on the basis of these three parameters it was calculated the thermal diffusivity of each of the shown thermal insulation materials. It has been demonstrated that the lowest value of thermal conductivity is Microtherm material that provides the smallest contribution to size of a storage heater compared with alternatives thermal insulation materials, including basalt fiber. Also, it is shown the method of determining maximum heat flow from the front surface of a storage heater. The resulting value of the maximum heat flow from the front surface is then used to determine the required thickness of insulation. However, it should be mentioned that using of basalt fiber may cost less.