Bridging summer and winter: A comprehensive techno-economic and environmental analysis of an integrated radiative cooling system for diverse climates

Radiative sky cooling (RSC) technology can reduce building cooling demand by reflecting solar radiation and emitting infrared radiation, but its application is limited due to insufficient daytime cooling and winter overcooling. This study proposes and evaluates a thermal storage-heat pipe-radiative sky cooling system (TS-HP-RSC) that enhances daytime cooling via unidirectional heat transfer and integrated thermal storage, while mitigating winter energy penalties by increasing roof thermal resistance. Three-comparative studies (baseline case, standalone RSC coating, and TS-HP-RSC) are conducted for five representative Chinese cities across distinct climate zones and multiple roof constructions. Results show that both RSC and TS-HP-RSC reduce annual cooling loads with improvement ratios of 21.8%∼96.7%, and TS-HP-RSC performs best on lightweight roofs. In the heating season, standalone RSC consistently increases heating loads with penalties of 12.59%∼100.0%, whereas TS-HP-RSC not only drastically lowers the heating penalty but even reduces heating loads below the baseline level in certain scenarios by raising roof thermal resistance (24.0%∼145.5%). Economic and environmental assessments indicate that TS-HP-RSC achieves higher net cost savings (−1.67%∼64.45%) and larger net CO2 emission reductions (8.22%∼64.49%) than standalone RSC (−16.42%∼56.96% for cost; −10.20%∼57.10% for emission), demonstrating robust climate adaptability.