This paper presents a description of thermal analyses of forced-air ventilation and thermosyphon cooling systems, which were carried out in connection with the design of the concrete raft foundations that support hangars and other major structures to be constructed by the Department of National Defence adjacent to the existing airport near Inuvik, N.W.T. The cooling systems are required to prevent heat from the buildings from thawing the ice-rich permafrost present below the site. The analyses identified those parameters that have the most significant effect on the efficiency of each system. Based partially on the results of the analyses, it was decided to utilize air ventilation for cooling. The system is expected to perform satisfactorily under natural convection; however, the design includes a provision to install air blowers, if this should prove necessary in the future. A number of areas in which further,zesearch appears useful have been identified.Cet article prCsente une description des analyses thermiques des systkmes de ventilation d'air force et de thermosyphons qui ont CtC rCalisCes en relation avec la conception de fondations de radiers de bCton supportant des hangars et autres structures majeures qui doivent hre construites par le DCpartement de la DCfense Nationale, a cBtC de 17aCroport d71nuvik, T.N.-0. Les systkmes de refroidissernent sont nkcessaires pour empCcher la chaleur des bltiments de faire fondre le pergCliso1 riche en glace sous le site. Les analyses ont identifie ceux parmi les paramktres qui ont l'effet le plus significatif sur I'efficacitC de chaque systkme. En se basant partiellement sur les rCsultats des analyses, l'on a dCcidC d'utiliser la ventilation d'air pour le refroidissement. L'on s'attend a ce que la performance du systkme soit satisfaisante dans des conditions de convexion naturelle; cependant, la conception offre la possibilitC d'installer des ventilateurs s'ils devenaient nCcessaires dans le futur. Un certain nombre de domaines dans lesquels de la recherche semblerait utile ont Ct C identifies.

Boiling heat transfer serves as an efficient mechanism to dissipate large amounts of thermal energy due to the latent heat of phase change. In academic studies, typically ultra-pure deionized (DI) water is used to avoid contamination. However, in industrial and commercial settings, the working fluid might be contaminated with sediments, dust, salts, or organic matter. Long-term boiling processes in non-DI water cause substantial build-up of a stable layer of deposit that dramatically reduces the heat transfer coefficient. Therefore, heating applications in a contaminated medium demand strategies to prevent such fouling. Here, we studied the use of lubricant infused surfaces (LIS) and their ability to possibly minimize the deposition of calcium sulfate. Aluminum samples were infused with Krytox 102 oil and the heat transfer coefficient was investigated at a vertical and horizontal surface orientation. Fouling effects were introduced by pool boiling for 7.5 hours in a 6.97 mM calcium sulfate solution at constant heat flux. Heat flux curves for both plain aluminum and LIS were calibrated before contamination. Initially, the LIS was unable to support a nucleate phase and transitioned directly from liquid convection to film boiling heat transfer. Upon partial degradation of the lubricant layer during long-run experiments, nucleate boiling ensued. Over 7.5 hours, the heat transfer coefficient of each sample (Al and LIS) degraded between 5.4% and 7.9% with no significant correlation with either lubricant treatment or surface orientation. Post boiling profilometry was conducted on each sample to characterize the thickness and distribution of the calcium sulfate layer. In these experiments, the plain aluminum surface outperformed the LIS at both orientations in minimizing calcium layer thickness. The LIS oriented vertically outperformed the LIS oriented horizontally.