Plate-style recuperator for a solar Brayton cycle using high-temperature sealant

Abstract

A large, efficient recuperator is required for high cycle efficiency in a solar Brayton cycle (STBC) with an open-cavity solar receiver and air as working fluid. A recuperator often requires complex and costly manufacturing methods. In this work, a clamped plate-type recuperator with a metal gasket is investigated, together with a low-cost high-temperature sodium silicate-based sealant. Experimental investigations were performed to validate a mathematical model using a novel bone-shape design as well as a wide-channel design. The high-temperature sealant worked well on the bone-shape recuperator; however, a leak occurred on the hot-side header tube of the wide-channel recuperator. For the recuperator core of the wide-channel test rig, a cold-side effectiveness of 82.5% and a total pressure loss of 24.9 kPa were found at an average mass flow rate of 0.74 g/s per channel. The validated mathematical model was used in a parametric study to analyse the performance of the recuperator in an STBC by taking the stress and deflection of the plates into consideration. Results show that, for a total mass flow rate of 0.06 kg/s, a cold-side effectiveness of 90% and total pressure loss of less than 5% could be achieved, if a spacer is implemented to prevent deflection.