J.K. Kiplagat

Enhancement of Heat and Mass Transfer in Solid Gas Sorption Systems

Solid gas sorption systems driven by heat have gained much attention due to their energy conservation and environmental benefits. These sorption machines can be driven by waste heat or renewable energy source such as solar energy, and can utilize natural working fluids with no GWP and ODP, such as water, methanol, and ammonia. However, poor heat transfer process and slow diffusion rate of the refrigeration gas in the adsorber have been identified as the main drawbacks limiting the cooling density performance, and consequently, commercialization of sorption machines. This paper provides a review of techniques that have been applied to enhance heat and mass transfer in solid gas sorption systems. These techniques mainly include the use of materials with high thermal conductivity, consolidation of adsorbents, and the use of specially designed heat exchangers in the adsorbers. The effect of these methods on the coefficient of performance and the specific cooling power is also discussed.