A Pedestrian-Load-Bearing, Integrated Electrostatic Green Infrastructure System for Urban Heat Island Mitigation: Evaluation of the Mowing-Free EMG System

The present study proposes an innovative infrastructure for greening pedestrian spaces that enables both low-maintenance, sustainable weed management and vegetation-based mitigation of the urban heat island (UHI) effect. The system replaces conventional paving stones with pedestrian-load-bearing expanded metal (52% opening ratio) and cultivates plant species that develop dense foliage while suppressing hypocotyl elongation beneath it. The expanded metal is safely pulse-charged with a solar-powered voltage booster and integrated with automatic irrigation and mechanical aeration. Its practicality was evaluated by measuring evapotranspiration from water mint (Mentha aquatica) seedlings and well-irrigated soil beneath the expanded metal using a gas-exchange box method. The warming–cooling performance of the system, together with sensible and latent heat fluxes, was assessed through measurements of surface temperature and relative humidity (RH), air temperature and RH at a predetermined height, and wind speed under intense midsummer solar radiation. These measurements were compared with those of concrete pavements and natural grasslands. The results showed that the system provided effective weed control without periodic mowing. Specifically, the total daily evapotranspiration from the EMG system reached 180% of that under natural conditions over a 24 h period. Furthermore, under peak midday solar radiation, the latent heat flux of the system reached approximately 1000 W m−2, and the system successfully reduced upward sensible heat flux by 70% compared with a standard concrete pavement. These findings demonstrate the strong potential of the proposed Expanded-Metal-based Greening System as a novel green infrastructure for mitigating the UHI effect while minimizing maintenance requirements.