An improved low pressure steam operated adsorption cycle: Pressure swing adsorption cycle

Over the last century, fresh water and cooling demand have been increased tremendously due to improved living standard, industrial and economic development. The conventional air-conditioning and refrigeration processes consume 15% of total global electricity and it is expected to increase any fold due to harsh weather conditions. In terms of fresh water supplies, the current 38 billion m3 per year desalination capacity is projected to increase to 54 billion m3 per year by 2030, 40% more compared to 2016. The current business as usual trend of cooling and desalination is not sustainable due to high energy consumption and CO2 emissions. In contrast, the adsorption (AD) cycle operate at low-grade waste heat or renewable energy and produce fresh water and cooling simultaneously. The major bottleneck of conventional thermally driven AD cycle is its large foot print and capital cost due to complex packed bed arrangements. We proposed pressure swing adsorption cycle (PSAD) that can utilise low-pressure steam (2-5 bar) for regeneration using thermal vapor compressor (TVC). In this paper, an experimental investigation on PSAD has been presented. It was demonstrated successfully that primary steam at 3-5 bar pressure can regenerate silica gel at less than 1 kPa using correctly designed TVC system. The proposed system will reduce CAPEX and OPEX due to simple design and operation.