Heat Fluxes in a Green Façade System: Mathematical Relations and an Experimental Case

The need of greater environmental sustainability in today’s living contexts can be significantly coped through the introduction of green infrastructures. Their benefits concern improvement of climate and comfort conditions. Among green infrastructures, vertical greenery systems, applied to buildings, contribute to the energy efficiency of buildings and to the improvement of outdoor and indoor microclimatic conditions. Green façades, a typology of vertical greenings, allow a considerable energy saving for air conditioning, by reducing the surface temperature of buildings and increasing the envelope thermal insulation. A realistic description of the functioning of green façades is essential to comprehend the real extent of their advantages. This paper aims to provide a first answer to the need of energy simulation models for green façades’ thermal behavior. The paper proposes a theoretical and an experimental approach. The main heat fluxes involved into the green façade system are investigated and described, by resorting to a schematic representation. The defined mathematical relations are applied to data collected during an experiment on a green façade conducted at the University of Bari. This work represents a contribution to the development of a model to forecast the thermal behavior of green façades and of the microclimate of buildings equipped with them

Robustness Assessment of a Low Poly Modeling Strategy for Performance Simulation of Double-Skin Green Facades

Performance simulation of building vegetal envelope can be very resource intensive and time consuming when made with a high number of polygons. The aim of this study is to assess the robustness of a low poly modeling strategy based on raster image sampling, with the scope of reducing the simulation burden of natural illumination performance, in several scenarios of operation. The image-based approach is implemented for the geometric reconstruction of vegetation, starting from an ivy (Hedera Helix L.) leaf, to model a double skin green facade. Due to the high influence of foliage density on natural lighting performance of green walls and its variability in real cases, the strategy behavior is evaluated for the variation of this parameter, addressed as Wall Coverage Ratio (WCR). Five scenarios of WCR are taken into account to perform the analysis of several levels of detail of the low poly mesh geometries, obtained with different sample densities of the raster image. The strategy appears to be reliable and delivers a 21% decrease of the simulation time, compared to the duration of a high level of detail simulation, with an acceptable performance deviation and the result is robust across the analyzed scenarios. A peak 39% decrease is obtained too, but with a considerable performance deviation. The outcomes also show a high dependency of the performance deviation on WCR, especially for simulations with very few polygons. Useful insights on calibration of green modeling accuracy for lighting performance simulation can be drawn from the results of this work

Bioactive Facade System Symbiosis as a Key for Eco-Beneficial Building Element

7th Global Conference on Global Warming (GCGW) -- JUN 24-28, 2018 -- Izmir, TURKEYWOS: 000587895700005The problems in today's built environment have a strong interrelation with key factors like pollution, global warming, energy and limited natural resources. When thinking of an ideal city the management of all these factors plays an important role in sustainability. Searching a magical solution to all these problems in this dynamic structure is not realistic, but some novel approaches like using the greenery (plants and microalgae) as bioactive elements adapted throughout the urban environment especially in the form of living facades on the buildings is getting more attention with regards to their eco-friendly potential. Bioactive facades can create a positive impact on managing some important parameters like thermal comfort, energy efficiency, wastewater recycle, CO2 capture and real estate price increase in microscale focusing on a single building aswell as global warming, pollution control, urban heat islands, social wealth and sustainable future in macroscale focusing on a big city. the aim of this review will be the key parameters for an efficient bioactive facade with regards to pros and cons, challenges and future. the review will cover the background of using plants as living walls or green walls and then will focus on the microalgae and photobioreactor adapted buildings