Performance evaluation of silicoaluminophosphate with SFO topology for water-sorption-driven heating and cooling systems

Abstract

Low-grade thermal-driven water-based sorption chillers and heat pumps are promising strategies to realize the near-zero-carbon target. However, developing excellent-performance water-sorption materials driven by ultralow-temperature thermal energy is still a key issue. In this study, silicoaluminophosphate with SFO topology (SAPO-SFO) synthesized by hydrothermal method is proposed as a more-effective adsorbent for water-based sorption applications. SAPO-SFO exhibits large micropore volume of 0.22–0.28 ml g−1, high water uptake of 0.24–0.28 g g−1 at P/P0 = 0.2, low regeneration temperature, and excellent hydrothermal stability. Importantly, the water-based sorption applications employing SAPO-SFO with 7 wt% Si achieve extremely high coefficients of performance of 0.86 for cooling and 1.76 for heating at low-driven temperatures of 64 °C and 82 °C, respectively. Furthermore, the mechanism of water adsorption for SAPO-SFO is revealed as that large purely siliceous regions and defects induced by uneven silicon insertion result in low enthalpy of adsorption. These results make SAPO-SFO a potential high-performance and ultralow-temperature thermal driven porous material for water-based sorption applications.