Hourly weather-driven techno-economic assessment of heat pump-assisted direct air capture across climatically diverse regions of China

Abstract

Regional performance of solid-sorbent direct air capture (DAC) reflects nonlinear interactions among weather, atmospheric pressure, electrified regeneration, and electricity pricing, yet these factors are often evaluated separately or using temporally averaged inputs. This study develops an hourly techno-economic framework for temperature–vacuum swing adsorption (TVSA) DAC coupled with an electrically driven high-temperature heat pump and applies it to five climatically contrasting Chinese locations at a common annual capture target of 50 $t_{C{O}_2}$/a. Hourly ERA5 temperature, relative humidity, and surface pressure for 2010–2025 are coupled to a process-based TVSA key performance indicator surrogate. A first-order pressure correction and a weather-dependent heat pump model are then used to calculate capture performance, energy use, water co-adsorption, equipment capacity, and the levelized cost of direct air capture (LCOD). Hourly loads for 2025 are additionally matched to contemporaneous provincial time-of-use (TOU) tariffs without load shifting. Fixed-price LCOD exhibits limited interannual variability, with coefficients of variation of 0.33%–1.57%, and the regional economic ordering remains stable across the 16 weather years. Temporal aggregation nevertheless introduces systematic downward bias: monthly- and annual-mean meteorology underestimate LCOD by 2.81%–6.89% and 3.92%–12.1%, respectively, while annual means understate rated heat pump capacity and peak electrical load by up to 46.4% and 48.5%. In the 2025 hourly cases, specific electricity use spans 1.64–2.19 MWh_e/$t_{C{O}_2}$, and fixed-price LCOD lies between 4740 and 6610 CNY/$t_{C{O}_2}$. Passive TOU pricing changes the least-cost location from Huizhou to Turpan, where LCOD decreases to 4690 CNY/$t_{C{O}_2}$. These findings demonstrate the value of hourly, weather- and location-resolved techno-economic analysis for regional planning and deployment of DAC and other electrified carbon-removal technologies.