Soil thermal properties and heat loss from buried pipes
Sjoberg, Rod E.
The accepted practice of laying water lines has been to place them well below the anticipated frost level. This is not always possible or practical however, since the depth of frost penetration is extremely variable for different winters and for different locations. Under certain circumstances it may be desirable or necessary to limit the depth of trenching and provide a means of maintaining the pipe temperature above freezing; various means are available such as insulation, electric heaters, and recirculation. Proper application and use of these heating methods requires a knowledge of the heat loss from buried pipes under diverse conditions. The heat loss can be estimated by various theoretical equations provided the thermal conductivity of the soil (k) and a temperature difference (Äè) between the pipes and the surrounding soil are known. Therefore, the use and application of these theoretical equations presents three problems, namely: 1) The need to experimentally check their accuracy. 2) The determination of in situ thermal conductivity of Saskatchewan soils. 3) Selection of a simple means for arriving at Äè, which requires a means of predicting the soil temperature at any depth for various surface conditions. To answer these problems an investigation was undertaken in 1960.