Commercially available adsorption cooling systems use water/silica gel, water/zeolite and ammonia/ chloride salts working pairs. The water based pairs are limited to work above 0°C due to the water high freezing temperature, while ammonia has the disadvantage of being toxic. Ethanol is a promising refrigerant due to its low freezing point (161 K), non-toxicity, zero ozone depletion and low global warming potential. Activated carbon (AC) is a porous material with high degree of porosity (500–3000 m2/g) that has been used in wide range of applications. Using Dynamic Vapour Sorption (DVS) test facility, this work characterizes the ethanol adsorption of eleven commercially available activated carbon materials for cooling at low temperature of −15°C. DVS adsorption results show that Maxsorb has the best performance in terms of ethanol uptake and adsorption kinetics compared to the other tested materials. The Maxsorb/ethanol adsorption process has been numerically modeled using computational fluid dynamics (CFD) and simulation results are validated using the DVS experimental measurements. The validated CFD simulation of the adsorption process is used to predict the effects of adsorbent layer thickness and packing density on cycle uptake for evaporating temperature of −15°C. Simulation results show that as the thickness of the Maxsorb adsorbent layer increases, its uptake decreases. As for the packing density, the amount of ethanol adsorbed per plate increases with the packing density reaching maximum at 750 kg/m3. This work shows the potential of using Maxsorb/ethanol in producing low temperature cooling down to −15°C with specific cooling energy reaching 400 kJ/kg. Publisher statement: This is an Accepted Manuscript of an article published by Taylor & Francis in International Journal of Green Energy on 14th December 2015, available online: http://www.tandfonline.com/10.1080/15435075.2014.937867
Bibliographical noteThis article is currently in press. Full citation details will be uploaded when available.
This is an Accepted Manuscript of an article published by Taylor & Francis in International Journal of Green Energy on 14th December 2015, available online: http://www.tandfonline.com/10.1080/15435075.2014.937867
- activated carbons/ethanol
- adsorption cooling
- computational fluid dynamics (CFD)
- low temperature refrigeration