RP-School of Engineering And Technology

Permanent URI for this community

https://repository.ku.ac.ke/handle/123456789/5394

Browse

Browsing RP-School of Engineering And Technology by Subject "Adsorption"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    A combined doubleway chemisorption refrigeration cycle based on adsorption and resorption processes
    (2009) Kiplagat, J.K.; Li, T.X.; Wang, R.Z.; Wang, L.W.; Oliveira, R.G.
    An innovative combined double-way chemisorption refrigeration cycle based on adsorption and resorption processes is presented. Two different reactive salts were used as sorbents and ammonia was utilized as the refrigerant in the proposed cycle. The useful cold was obtained from the evaporation heat of the refrigerant during the adsorption process and from the reaction heat of the low-temperature salt during the resorption process. The proposed combined double-way cycle has a distinct advantage of higher coefficient of performance (COP) in comparison with conventional adsorption cycle or resorption cycle. Experimental verification indicated that the advanced combined double-way cycle is feasible for refrigeration application, and the ideal COP of the basic cycle was about 1.24. Theoretical results showed that the proposed combined double-way cycle could improve COP by 167% and 60% when compared with conventional adsorption cycle and resorption cycle, respectively.
  • Thumbnail Image
    Item
    Lithium Chloride–Expanded Graphite Composite Sorbent for Solar Powered Ice Make
    (2010) Kiplagat, J.K.; Wang, R.Z.; Oliveira, R.G.; Li, T.X.
    Consolidated composite material made from expanded graphite (EG) powder impregnated with LiCl salt is proposed for use in solar powered adsorption ice makers. Laboratory experiments were done to test the adsorption and desorption performance of the sorbent under different temperature conditions suitable for solar energy utilization. More than 75% of the reaction between LiCl and ammonia was completed after 30 min of synthesis at evaporation temperatures of −10 and −5°C and adsorption temperature between 25 and 35°C. Under the same period, it was possible to obtain 80% conversion in the desorption phase, when the generation temperatures ranged between 75 and 80°C, and the condensation temperature varied from 25 to 35°C. The highest average specific cooling power during the synthesis phase was 117 W per kg of the block. The calculated theoretical coefficient of performance (COP) under different cycle conditions was nearly constant at 0.47. Moreover, the new composite sorbent showed higher Specific Cooling Capacity (SCC), compared to activated carbon (AC)/methanol pair. Experiments done with blocks with different proportion of EG, showed that the proportion of EG influence the cooling capacity per unit mass of salt and had almost no influence on the cooling capacity per unit mass of the block. Moreover, the reaction enthalpy (ΔH) and entropy (ΔS) were calculated from experimental data obtained experimentally, and confirmed previous reported