REPRODUCIBLE DAYTIME SUPPRESSION AND NIGHT-TIME SURFACE ADVANTAGE IN A SOLAR-DRIVEN PCM RADIANT FLOOR: A CROSS-DAY PAIRED ANALYSIS.

Abstract

Abstract. Two parallel hydronic radiant-floor panels, a conventional concrete slab and a slab with eleven steel capsules filled with paraffin RT52, were driven by a parabolic solar concentrator and compared using paired temperature differences only. Over three independent test days, the PCM-integrated surface was cooler during charging by  on average, and the return water by . In both long-duration tests the sign later reversed, with a maximum surface advantage of  and  about  after heat-flow reversal. The results show reproducible thermal-load shifting by the PCM-integrated assembly under real solar forcing.