Performance analysis of four bed adsorption water desalination/refrigeration system, comparison of AQSOA-Z02 to silica-gel

Although many water desalination techniques have been introduced decades ago, there are still areas around the world suffering from fresh water shortages. The widespread of desalination technologies is limited due to their high energy consumption, cost and adverse environmental impact. Recently, adsorption technology for water desalination has been investigated showing potential of using low temperature waste heat (50-85 °C) thus reducing energy consumption and CO2 emissions. This work mathematically investigates the performance of 4 bed adsorption cycle using two different adsorbents, silica-gel and an advanced zeolite material AQSOA-Z02, produced by Mitsubishi-plastics for fresh water production and cooling. The work studied effects of evaporator and heat source temperatures on water production rate and cooling capacity. Results showed that at low chilled water temperatures below 20 °C, AQSOA-Z02 outperforms silica-gel with water production of 6.2 m3 of water/day and cooling of 53.7 Rton/tonne of AQSOA-Z02 compared to 3.5 m3 of water/day and 15.0 Rton/tonne of silica-gel. While, at chilled water temperatures above 20 °C, AQSOA-Z02 and silica-gel have comparable performance with around 7 m3 of water/day and 60 Rton of cooling. Since cooling applications require chilled water temperature less than 20 °C, therefore AQSOA-Z02 is more suitable for applications where cooling and fresh water are needed.