| Abstract [eng] |
The aim of the final project is to investigate the thermal storage properties of soil using laboratory and field stands. Thermal conductivity of soil is a complex parameter dependent on various factors, including water content, dry density, soil composition, and particle size. It has been observed that in moist or water-saturated soil, thermal conductivity is higher compared to dry soil. Studies in different geographical locations indicate that in deeper layers, the soil temperature stabilizes, is less affected by surface factors, and this may influence the efficiency of heat storage systems. Laboratory and field experiments were conducted to determine how quickly the soil heats up, retains heat, and cools down. Two laboratory tests were performed by altering the composition of the fill material. The fills used were dry fine-grained gravel and dry fine-grained gravel with stones. Field experiments were conducted over a period of five months, observing how quickly the soil heats up depending on outdoor air temperature and the season. The fill with stones in dry fine-grained gravel exhibited faster heat transfer than the fill without stones. Heating the fill with stones took longer, but the amount of absorbed heat was only 2.38% higher than the fill without stones. The steady-state heat density from the surface to the soil varies depending on the month. In March, the heat density is the highest because the difference between the established 20 °C temperature of the heating surface and the 1.0 m depth soil temperature is the greatest. The field stand experiment showed that air temperature influences soil temperature, especially in surface layers. In March, a significant difference in heat transfer is observed between the surface and deeper soil layers. . |
