Heat engineering properties of energy-efficient material based on plant additives (dried hogweed)

Introduction. The articlecompares the heat engineering properties of construction materials: high-strength concrete, ordinary concrete, and two concrete samples containing a vegetable additive, dried stem fragments of hogweed (Heracleum sosnowskyi). The first sample contains the additive in the crushed form, while the second contains the additive in the form of tubes. The research to estimate heat conduction in the four samples under unsteady conditions. Materials and methods. The thermal diffusivity of two samples with plant additive is determined using a comparative physical experiment. When determining the thermal properties, the accumulating component of the enclosure is taken into account what leads to a long delay in the temperature variation over time. DS18B20 digital temperature sensors connected to an Arduino Uno board were used to measure the temperature. The experiment was carried out in the Challenge 250 chamber at an initial temperature of 20 ºС. Then the chamber temperature was lowered to 0 ºС within 30 minutes. In the next period, the temperature dropped from 0 ºС to –10 ºС. The data obtained are of interest for improving the energy efficiency of buildings. Results. The experiments showed that the tubular-hogweed sample is close to high-strength concrete by its heat engineering properties. The material thermal diffusivity affects the amplitude of temperature fluctuations and the accumulating capacity of the wall. Conclusions. It is established experimentally that at lower thermal diffusivity of a hogweed-containing sample, the amplitude of temperature fluctuations increases. This indicates a greater time lag, just as in the case of a high-strength concrete sample. When using the hogweed as an additive, we obtain a heat-resistant minimum-cost material for enclosures. Considering an issue of the energy efficiency in construction and existing additives to concrete, the researchers have reached the conclusion that it is efficient to use the dried hogweed as the plant additive.