With the adjustment of energy structure, the proportion of renewable energy is gradually increasing, and how to solve the problem of renewable energy consumption is becoming more and more prominent. Therefore, a novel thermoelectric-hydrogen co-generation system combining compressed air energy storage (CAES) and chemical energy (CE) is proposed. For energy storage, the system uses adiabatic compression with liquid piston to r. With the adjustment of energy structure, the proportion of renewable energy is gradually increasing, and how to solve the problem of renewable energy consumption is becoming more and more prominent. Therefore, a novel thermoelectric-hydrogen co-generation system combining compressed air energy storage (CAES) and chemical energy (CE) is proposed. For energy storage, the system uses adiabatic compression with liquid piston to reduce the generation of compression heat, while using the generated compression heat to preheat the methanol. For energy release, the methanol is fed into the methanol steam reforming reactor (MSR) and the methanol decomposition reactor (MDR) in certain proportions for the hydrogen production reaction; the unreacted methanol and the carbon monoxide produced by the MDR are used as make-up heat for the reactors and the high-pressure air before the turbine, while the exhaust waste heat supplies heat to the customer. The thermodynamic, economic and environmental performances of the system were investigated separately by developing a mathematical model describing the system. The results show that under the design conditions, the system has an energy storage density of 12.00 kWh/m3, an energy efficiency of 88.47 %, an exergy efficiency of 77.04 %, a lifetime net present value of 59.20 M$, a payback period of 4 years, and a CO2 emission per unit of energy output of 227.85 kg/MWh. Increasing the thermostatic heat source temperature and increasing the react. ••A novel thermoelectric-hydrogen co-generation system combining CAES and chemical energy was proposed.••The proposed system used two chemical reactions to maximize hydrogen production.••A mathematical model of the proposed system was developed for performance analysis.••The thermodynamic, economic, and environmental performance of the proposed system was evaluated.Compressed air energy storageLiquid piston compressionMethanol hydrogen productionPerformance analysisWith the rapid consumption of fossil fuels and the growth of the demand of the people for a better environment, the share of renewable energy in the energy structure of China is increasing [1,2]. How to use renewable energy economically, effectively and safely has become a focus of attention [3,4]. Electric energy storage (EES) technology has the advantages of peak-shaving, faster response and flexible arrangement, and is an important technical means to promote the consumption of renewable energy and improve the stability of grid operation [5,6]. At present, EES technologies mainly include pumped energy storage (PES), flywheel energy storage (FES), compressed air energy storage (CAES), battery energy storage (BES) and phase change energy storage (PCES). CAES stands out among many EES technologies due to a series of advantages such as less destructive to the geographical environment, large scale energy storage, reliable operation and low cost construction [7,8]. CAES systems can be divided into three categories: diabatic CAES, adiabatic CAES and isothermal CAES, according to the different treatments that generate compression heat in the system and make up the gas at the expander inlet. The two CAES plants currently operating commercially in the world both utilize diabatic CAES technology. The heat of compression generated by the compressor is not utilized in these two CAES plants during energy storage, and fossil fuels need to be burned to make up the heat for the high-pressure air du. Fig. 1 shows a diagram of CE-CAES system, which consists of a compressed air storage module, a methanol decomposition module and a methanol steam reforming module. The CAES module energy storage section consists of an adiabatic compression and a two-tank liquid piston compression, specifically comprising motor (M), compressor (COMP), heat exchanger (HX), buffer tank (BT), water pump (WP1), liquid piston device (LP) and air storage tank (AST). The CAES module energy release section is a two-stage expansion with a combustion chamber (CC) heating the high-pressure gas before each stage expander (EXP), including throttle valve (TV), CC, EXP and generator (G). The methanol decomposition module consists of methanol tank (MT), methanol pump (MP), CC1 and MDR. The methanol steam reforming module consists of WP2, water storage tank (WT), evaporator (EVA), mixer (MIX) and MSR. The CAES module, the methanol decomposition module and the methanol steam reforming module are followed by heat supply (HS) unit. M can convert electrical energy into mechanical energy, COMP can convert mechanical energy into the internal energy of air, HX can exchange heat, BT can ensure that COMP meets the air flow requirements of LP when it is in continuous operation, WP is used to raise the pressure, AST is used to store the air, CC raises the temperature of the gas by combusting the fuel, EXP can convert the internal energy of the gas into electricity, MSR is used for the reaction of meth.
