Integration of Planar Heat Pipes to Solid Oxide Cell Short Stacks

Abstract

This work presents the results of a thermal balancing, heat removal and supply mechanism via high temperature heat spreaders integrated to the solid oxide cell (SOC) stacks. Planar alkali metal heat pipes for almost isothermal two‐directional heat transfer at high power densities are incorporated into the metal interconnector structure of SOC‐short stacks. The objective of this concept is a temperature gradient shrinking within the stacks and a thermal control of SOFC system with a largely reduced additional air cooling. Subsequent to the development of planar heat pipe interconnectors with thickness down to 4 mm and heat transfer rates of up to 150 W per cm2 cross sectional area at isothermal operation, this paper describes their integration into the SOC stack structure. Therefore, short stacks with incorporated planar heat pipes are designed and built up for evaluation. The experimental study focuses on the influence of planar heat pipe interconnectors on temperature distributions within short stacks under various thermal load conditions. The experiments demonstrate the beneficial effects on thermal control of the stack structure and allow a first estimation of their amplitudes.

Thermal contact resistance in solid oxide fuel cell stacks

“…Heat transfer for set-up 3 is clearly higher than in other cases (especially for low temperatures) as a result of the increased contact conductance due to cathode contacting paste applied according to Table 3. These values are used to compute resistances at the contact points within one SOFC repeating unit following the procedure described in equations (14) and (15). Fig.…”

“…In the concept displayed in Fig. 1 planar liquid metal heat pipe with isothermal heat transfer capability are incorporated into the interconnector structure of a SOFC stack [14]. Due to the increased heat distribution, reduction of mandatory excess air flow, reduction of stack internal temperature gradients and high temperature heat transfer to secondary processes are the promising targets of this concept.…”