Innovative design, fabrication, and evaluation of an integrated smart green facade and photovoltaic: A double-layer air circulation system for air retention time expose to plants and PV cooling to enhance air purification

Air pollution in densely populated cities adversely affects indoor air quality, and traditional air conditioning systems are highly energy-intensive. Urban greening can mitigate these harmful effects, but cities lack sufficient space for planting trees. Combining Building-Integrated Photovoltaics (BIPV) with green facades in urban environments offers a promising solution that requires further research. This paper presents an innovative environmental air purification system using renewable energy to achieve energy self-sufficiency. The study involves designing, constructing, and evaluating a smart, zero-energy, double-skin green element to reduce building energy consumption and purify air for ventilation. The front shell features solar panels with trackers and a movement system for cooling, while the rear compartment attaches to the building façade. The system operates with hydroponically grown plants, controlling light, temperature, and humidity. Initial tests confirmed the element's effectiveness in maintaining optimal plant conditions, providing over 60 % light intensity and 38 % bed moisture. The element's performance with four air-purifying plants (Pothos, Spider Plant, Ivy, and Sansevieria) was evaluated. Results indicated that even without plants, the element significantly reduced pollutants such as ozone, particulate matter, nitrogen dioxide, sulfur dioxide, lead, and carbon monoxide. The plants further enhanced pollutant reduction, with the Spider Plant reducing pollutants by 60 % in 80 minutes, Ivy by 52 % in 30 minutes, Sansevieria by 35 % in 20 minutes, and Pothos by 33 % in 50 minutes. An analysis over 24 hours in winter showed that the element consumed 76.3 % of the solar-generated power. The thermal transfer coefficient, calculated to assess the element's insulating performance, was found to be 80.2 kW per square meter per degree Celsius, and the thermal flux was 741.8 kW over 16 hours. This design is suitable for buildings without structural changes and can be widely implemented in metropolitan areas, increasing urban green spaces. It contributes to achieving sustainable buildings and cities by enhancing natural air purification and energy efficiency.