Author : Ayman Adnan AL-Maaitah and Faeza Mahdi Hadi

Two stages adsorption chiller with four beads using active carbon-methanol adsorption pair based on Patent No. US 8479529 B2 is studied in this work. In addition to the four sorption/adsorption generator beds the adsorption cycle consist of the following main parts, air cooled a condenser, expansion valve and coaxial evaporator where the refrigerant passes in the inner tube while the water is in the outer. To complete the cycle solenoid valves, piping system, three way valves and pumps to circulate the water in this unit were used. Four beds of inner dimensions of 66.7 c m x 52.4 cm x 23.5 cm each is imbedded with activated carbon filled in between heat transfer fins. The bed acts as a methanol adsorpber/generator. The using of four generators is to build refrigerant pressure in two stages through a continuous adsorption-desorption cycle, by allowing the generators to work alternatively either adsorbing or desorbing the medium. The switching between desorption and adsorption phases is achieved by computer controlled system. The adsorption chiller was driven by hot water ranging from 70 to 85 oC. The chiller was charged by 24 kg of active carbon and 5kg of methanol, giving an initial concentration of (0.228 kg CH3OH/kg AC). The results showed that average calculated cycle cooling power is 2.33kW while the experimentally obtained cooling power cycle is 1.98kw. The COP of that chiller was at 0.5, 0.41, and 0.1 for cooling temperature of 25 , 35, and 50 oC respectively. As such, the present chiller is proven to me much more superior for single stage Celica gel commercially available chiller at high ambient temperature conditions.

Keywords: Adsorption, Refrigeration, multi-beds refrigeration, active carbon-methanol adsorption.

Article published in International Journal of Current Engineering and Technology, Vol.7, No.1 (Feb-2017)