Temperature fields under different expressions, as well as heat transfer phenomena, have many practical applications. The knowledge of the process developments involving thermal fields and heat transfer represents a major premise for promoting sustainable development, in order to get maximum efficiency conditions through minimization of the resource consumption. This paper deals with determining the temperature field in a freezing/thawing process applied to underground work execution. The complexity of the temperature field formulation is reduced by using modeling approximations. The approximation introduced depends on a parameter called the Neumann constant. The aim of this paper is to illustrate a dedicated procedure for computing the Neumann constant, implemented by the authors in the Visual C platform. The results are represented as heat load charts and are synthesized by using practical energy indicators.