Development of solar/waste heat driven dualmode, multi-stage, multi-bed regenerative adsorption system

Abstract

Over the past three decades there have been considerable efforts to use adsorption (solid/vapor) for cooling and heat pump applications, but intensified efforts were initiated only since the imposition of international restrictions on the production and use of CFCs (chloroflurocarbons) and HCFCs (hydrochloroflurocarbons). Closed-type, conventional adsorption refrigeration and heat pump systems have an increasing market share in Japan. In this paper, a dual-mode, three-stage non-regenerative, 6-bed regenerative silica gel-water adsorption chiller design is outlined along with the performance evaluation of the innovative chiller. This adsorption chiller utilizes effectively solar or waste heat sources. Two operation modes are possible for the advanced chiller. The first operation mode will be to work as a highly efficient conventional chiller where the driving source temperature is between 60 and 95°C. The second operation mode will be to work as an advanced three-stage adsorption chiller where the available driving source temperature is very low (between 40 and 60°C). With this very low driving source temperature, no other cycle except an advanced adsorption cycle with staged regeneration will be operational. The drawbacks of this operational mode are its poor efficiency in terms of cooling capacity and COP.