Temperature distributions around buried pipe networks in soil with a temperature dependent thermal conductivity

The temperature distribution in soil around a network of subsurface horizontal warm water pipes was investigated. Computations of soil thermal conductivity revealed a linear dependence on temperature due to the presence of moisture and induced vapour diffusion within the pore space. Solutions of the temperature distributions around various buried pipe networks were obtained in closed forms and numerically. Experiments were conducted with a single buried pipe. The data showed that the present model yields better predictions than previous constant property models. Analyses were extended to account for effects of desiccation around the heated pipes. The results are applicable in horticulture for improved designs of soil warming networks.