A new physisorption power generation system using advanced adsorbent materials

Abstract

A large number of people worldwide lack access to secure power systems, particularly in developing countries. The abundant solar energy and waste heat energy can be used to generate electric power cleanly using absorption and adsorption systems to build small localized power generation units. The inclusion of a turbine within the physisorption system opens great opportunities to use low-grade and medium-grade heat sources, such as solar energy, geothermal energy and industrial waste heat, for power generation. In this numerical study, the water adsorption system for cooling and electricity (ASCE) is utilized for the first time to generate electric power only using advanced metal organic framework (MOF) materials. The main components of the physisorption power generation cycle (PPGC) are similar to those of ASCE, where the only difference is in the applied operating conditions. In PPGC, the water temperature entering the evaporator is relatively high, so that no cooling effect within the normal range can be obtained. This helps to increase the adsorption uptake in some adsorbent materials like MIL101-Cr, which increases the mass flow rate of the working fluid and improves the power generation process. According to these considerations, the two-bed PPGC system adopted in this study can generate electricity of up to 5.24 kW utilizing about 14.28 kg of MIL101-Cr with heating temperature of 320 ºC. This study highlights the potential of using advanced physical adsorbent materials like MOFs (e.g. MIL101-Cr) in power generation utilizing two-bed PPGC under a range of operating conditions.