Composite adsorbents of CaCl₂ and sawdust prepared by carbonization for ammonia adsorption refrigeration

Abstract

Composite adsorbents of CaCl₂ and sawdust prepared by carbonization for adsorption refrigeration with NH₃ as refrigerant are tested, and the effects of carbonization temperature on the sorption capacity and rate are analyzed. The results show that the amount of pores in the sawdust of the composite adsorbents carbonized, apart from the content of CaCl₂, is the most dominant factor influencing the NH₃ sorption on composite adsorbents. The optimum carbonization temperature is 700°C, which gives the maximal NH₃ sorption capacity as high as 0.774 kg of NH₃ per kg of the composite, and the specific cooling power is approximately between 338 and 869 W/kg with the cycle duration varying from 5 to 20 minutes. The present study demonstrates that the composite absorbent of CaCl₂ and sawdust prepared by carbonization is more promising and competitive for adsorption refrigeration application.

Keywords

adsorption refrigeration / composite adsorbent / calcium chloride / sawdust / carbonization

References

[1] Rezk A R M, Al-Dadah R K. Physical and operating conditions effects on silica gel/water adsorption chiller performance. Applied Energy, 2012, 89(1): 142–149

[2] Aristov Y I. Challenging offers of material science for adsorption heat transformation: A review. Applied Thermal Engineering, 2011,

[3] Wang K, Wu J Y, Wang R Z, Wang L W. Composite adsorbent of CaCl₂ and expanded graphite for adsorption ice maker on fishing boats. International Journal of Refrigeration, 2006, 29(2): 199–210

[4] Aristov Y I, Restuccia G, Cacciola G, Parmon V N. A family of new working materials for solid sorption air conditioning systems. Applied Thermal Engineering, 2002, 22(2): 191–204

[5] Fujioka K, Hatanaka K, Hirata Y. Composite reactants of calcium chloride combined with functional carbon materials for chemical heat pump. Applied Thermal Engineering, 2008, 28(4): 304–310

[6] Oliveira R G, Wang R Z. A consolidated calcium chloride-expanded graphite compound for use in sorption refrigeration systems. Carbon, 2007, 45(2): 390–396

[7] Batzias F A, Sidiras D K. Dye adsorption by prehydrolysed beech sawdust in batch and fixed-bed systems. Bioresource Technology, 2007, 98(6): 1208–1217

[8] Attan D, Alghoul M A, Saha B B, Assadeq J, Sopian K. The role of activated carbon fiber in adsorption cooling cycles. Renewable & Sustainable Energy Reviews, 2011, 15(3): 1708–1721

[9] Veselovskaya J V, Tokarev M M. Novel ammonia sorbents “porous matrix modified by active salt” for adsorptive heat transformation: 4. Dynamics of quasi-isobaric ammonia sorption and desorption on BaCl₂/vermiculite. Applied Thermal Engineering, 2011, 31(4): 566–572

[10] Yong L, Wang R Z. Adsorption refrigeration: A survey of novel technologies. Recent Patents on Engineering, 2007, 1(1): 1–21

[11] Veselovskaya J V, Critoph R E, Thorpe R N, Metcalf S, Tokarev M M, Aristov Y I. Novel ammonia sorbents “porous matrix modified by active salt” for adsorptive heat transformation: 3. Testing of “BaCl₂/vermiculite” composite in the lab-scale adsorption chiller. Applied Thermal Engineering, 2010, 30(10): 1188–1192

Acknowledgments

This work is funded by the Innovation Programs of Chinese Academy of Sciences (Nos. 0907r7 and 0907z1) and a project from the Administration of Foreign Experts Affairs of Guangdong Province, China.

RIGHTS & PERMISSIONS

2014 Higher Education Press and Springer-Verlag Berlin Heidelberg