Indoor CO₂ capture-driven passive cooling for photovoltaics with ventilation energy reduction utilizing amine-functionalized adsorbents

In carbon capture, utilization, and storage processes, CO₂ capture consumes 80 % of total energy consumption, reaching 3–8 MJ/kg which poses a formidable challenge. Conversely, buildings are responsible for approximately 40 % of final energy consumption and contribute over 30 % of CO₂ emissions, highlighting the urgent need to reduce the building energy. In this work, a sustainable indoor CO₂ capture-driven passive cooling system is developed for building-integrated photovoltaics with ventilation energy reduction by coating amine-impregnated mesoporous silica (PEI/MCM-41) to the rear of PV cells using supersonic cold spraying method. During nighttime, it effectively mitigates indoor CO₂ concentration increase due to human respiration by capturing 1.64 mmol/g of CO₂, enabling a reduction of 180 MJ/kg-thermal in winter and 30.4 MJ/kg-electric in summer within the building. In daylight hours, PV cells generate electricity, and the supplied radiant solar heat is consumed for CO₂ desorption (latent cooling), lowering the average temperature of the PV cells and improving the power efficiency. PEI/MCM-41 achieves a remarkable cooling energy density of 242 J/g and average cooling power of 357 W/m². It has been demonstrated that the present system can simultaneously reduce the building energy consumption and CO₂ emission.