Thermodynamic carbon pump 2.0: Elucidating energy efficiency through the thermodynamic cycle

Abstract Excessive energy consumption has become a recurring obstacle for scaling up the development of CO2 capture. Thermodynamics can be applied to elucidate this issue through an in-depth analysis of the energy conversion mechanism. A better understanding of energy efficiency can be attained through a developed description of the thermodynamic carbon pump (TCP), which is presented as an updated version of the carbon pump reported in our previous study. Extending the scope of traditional thermodynamics also enables a novel application scenario of the thermodynamic cycle into specific industrial technologies. The TCP cycle is developed inspired by the development of the heat pump cycle, to evaluate the performance of the actual CO2 capture technology. As the coefficient of performance for CO2 capture (COPCO2) is defined, the upper bound of energy conversion efficiency in the specific technology can be illustrated. The ideal TCP cycle is depicted in the μ-n diagram first, which is extended into temperature-dependent three-dimensional (3D) coordinates. Considering the process of temperature swing adsorption (TSA) for CO2 capture as a case study, COPCO2 in the actual TSA cycle is obtained in the range of 1.81–2.21, which is half of that in the ideal cycle. Consequently, the normalized performance evaluation of the actual technology can be obtained.