Investigation of the heat transfer properties of granular activated carbon with R723 for adsorption refrigeration and heat pump

Abstract

This paper investigates the heat transfer coefficient of the wall to packed carbon contact (h) and the thermal conductivity of the packed bed (λ) by using parameters estimation method. A numerical heat conduction method was used in conjunction with an iterative process of minimizing the Mean Square Error (MSE) between both experimentally measured and model predicted temperatures in order to estimate h and λ parameters simultaneously. Experimental work was carried out by measuring the wall and centre temperatures of the sample reactor when suddenly submerged in a temperature controlled water bath at around 90 °C. Four samples with packed bed density ranging from 600 kg m−3 to 750 kg m−3 were tested. The results for the GAC-R723 refrigerant pair show a quasi-linear increase in both thermal conductivity (λ) and wall contact heat transfer coefficient (h) with packed bed density. The thermal conductivity of GAC-R723 refrigerant varies between 0.77 W m−1 K−1 and 1.36 W m−1 K−1 (about three times the values without R723 refrigerant) while the wall contact heat transfer coefficient varied between 390 W m−2 K−1 and 735 W m−2 K−1 (up to 30% better than values without R723).