Microclimatic cooling performance of a modular vertical greenery system in a temperate urban environment: field monitoring evidence from Košice, Slovakia

Abstract

Abstract

Urban areas are increasingly experiencing rising temperatures and intensifying urban heat island effects, creating growing pressure for climate adaptation in temperate Central European cities. This study evaluates the thermal performance of a modular vertical greenery system installed on a northeast-oriented university façade in Košice, Slovakia, using continuous multi-sensor field monitoring conducted during the summer period from July to September 2025. Surface temperatures were continuously monitored on the exposed façade, beneath the vegetation layer, within the cavity space, and in the near-façade air environment at 5-min intervals, while air temperature, relative humidity, and atmospheric pressure were recorded using an environmental sensor. Two complementary aggregation approaches (hourly maxima and hourly averages) were combined with non-parametric repeated-measures statistics to evaluate thermal behaviour across six monitoring locations under three objectively selected weather scenarios (hot, typical, and cool/rainy summer days). Maximum façade surface temperatures measured beneath the vegetation were up to approximately 11 °C lower than those recorded on the exposed reference façade. Temperature differences were most pronounced during periods of elevated thermal load and direct solar exposure, whereas under cooler and rainy conditions the system was primarily associated with thermal stabilization and reduced short-term temperature fluctuations. These findings indicate that the investigated modular vertical greenery system was associated with substantially lower façade surface temperatures and improved near-façade thermal conditions under the monitored summer conditions, supporting its potential role as a nature-based component of blue–green infrastructure strategies for enhancing urban climate resilience.