Analisis Mekanisme Pendinginan Pasif Sistem Green Roof melalui Proses Evapotranspirasi Tanaman Krokot Mawar (Portulaca grandiflora)

Abstract

Peningkatan konsumsi energi bangunan merupakan dampak nyata dari fenomena Urban Heat Island (UHI) di area perkotaan. Penerapan green roof ekstensif menjadi salah satu solusi berbasis alam yang potensial, namun kajian mengenai dinamika termal secara diurnal pada kawasan tropis masih sangat terbatas. Penelitian ini bertujuan menganalisis mekanisme pendinginan pasif sistem bervegetasi krokot mawar (Portulaca grandiflora) dibandingkan dengan sistem tanpa vegetasi pada kondisi kering dan basah. Metode ini dilakukan secara eksperimental menggunakan kotak uji skala lapangan berukuran 1 m × 1 m × 0,3 m dengan pemantauan kontinu 24 jam terhadap parameter iklim mikro, keseimbangan energi, serta karakteristik distribusi dan perambatan profil suhu multilapis vertikal. Hasil penelitian menunjukkan bahwa sistem bervegetasi lebih efektif dalam mereduksi fluktuasi panas ekstrem melalui pengalihan energi matahari menjadi fluks panas laten. Pada kondisi kering, suhu puncak permukaan mampu ditekan hingga 11,23 °C lebih dingin dibandingkan sistem tanpa vegetasi

The escalating energy consumption in buildings represents a critical consequence of the Urban Heat Island (UHI) phenomenon in metropolitan areas. The implementation of extensive green roofs has emerged as a promising nature-based solution; nevertheless, research elucidating their diurnal thermal dynamics within tropical regions remains profoundly limited. This study aims to investigate the passive cooling mechanisms of a vegetated green roof system utilizing krokot mawar (Portulaca grandiflora) in comparison to a non-vegetated system under both dry and wet conditions. An experimental methodology was deployed utilizing field-scale test boxes measuring 1 m × 1 m × 0.3 m, integrated with continuous 24-hour monitoring of microclimate parameters, energy balance, as well as vertical multilayer temperature profiles and propagation characteristics. The empirical findings indicate that the vegetated system is more effective in mitigating extreme thermal fluctuations by partitioning solar radiation into latent heat flux. Under dry conditions, the peak surface temperature was successfully suppressed to 11.23 °C cooler than the non-vegetated system