Performance Assessment of a Solar and Biomass-based Energy System Having Metal Hydride-based Thermal Compressors

Abstract

It is well known that renewable energy sources suffer from intermittency. Thus, they are often compensated using energy storage or by combining two or more such resources to ensure continuous operation. This paper presents a multi-generation system that integrates two renewable resources i.e. solar and biomass. The proposed system can produce five useful outputs which are electricity, oxygen gas, compressed hydrogen gas (up to 150 bar), and dried biomass (for off-season storage). The system consists of a Gas Turbine cycle running on biomass combustion. The gases at the turbine exit further support Rankine cycle primarily run on energy received by the solar parabolic trough collector (PTC). The excess electricity from the two sources is used to electrolyze water and produce hydrogen, and oxygen. A metal hydride bed (LaNi5) stores hydrogen which can be used to run fuel cells or is compressed via metal hydride-based thermal compressors. The thermal energy required for metal hydride beds is provided using hot water from the intercooler of the gas turbine cycle. Energy and Exergy analyses are used to analyse the complete system and the efficiencies of the subsystem are computed.

Keywords: Thermal, solar, biomass, metal hydride compressors, exergy