Analytical model for thermal performance analysis of enclosure heated by aligned thermosyphons

An analytical model is developed to analyze the thermal performance of a rectangular enclosure heated by two-phase thermosyphons. The model is used to predict temperatures and thermal resistances between the elements of the enclosure based on experimental data obtained from an actual enclosure heated with a total heat input of 1280 W from room temperature and up to a maximum temperature of 330 degrees C. The rms differences between the model and the experimental data vary between 3.4 and 7.6 degrees C. Thermal joint resistances that are difficult to predict are evaluated indirectly by means of the proposed model. The model is also used to estimate the relative importance of the three heat-transfer modes inside the enclosure. The results show that, given the very isothermal characteristic of the air inside the enclosure, which does not lead to effective natural convection heat transfer, most of the heat inside the enclosure is transported by radiation and by conduction. Also, the usual approach of riveted joints employed in domestic ovens is shown to be thermally inefficient.