Search Results (17)

The construction sector presently consumes about 40% of global energy and generates 36% of CO₂ emissions, making facade retrofits a priority for decarbonising buildings. This review clarifies how ventilated facades (VFs), wall assemblies that interpose a ventilated air cavity between outer cladding and the insulated structure, address that challenge. First, the paper categorises VFs by structural configuration, ventilation strategy and functional control into four principal families: double-skin, rainscreen, hybrid/adaptive and active–passive systems, with further extensions such as BIPV, PCM and green-wall integrations that couple energy generation or storage with envelope performance. Heat-transfer analysis shows that the cavity interrupts conductive paths, promotes buoyancy- or wind-driven convection, and curtails radiative exchange. Key design parameters, including cavity depth, vent-area ratio, airflow velocity and surface emissivity, govern this balance, while hybrid ventilation offers the most excellent peak-load mitigation with modest energy input. A synthesis of simulation and field studies indicates that properly detailed VFs reduce envelope cooling loads by 20–55% across diverse climates and cut winter heating demand by 10–20% when vents are seasonally managed or coupled with heat-recovery devices. These thermal benefits translate into steadier interior surface temperatures, lower radiant asymmetry and fewer drafts, thereby expanding the hours occupants remain within comfort bands without mechanical conditioning. Climate-responsive guidance emerges in tropical and arid regions, favouring highly ventilated, low-absorptance cladding; temperate and continental zones gain from adaptive vents, movable insulation or PCM layers; multi-skin adaptive facades promise balanced year-round savings by re-configuring in real time. Overall, the review demonstrates that VFs constitute a versatile, passive-plus platform for low-carbon buildings, simultaneously enhancing energy efficiency, durability and indoor comfort. Future advances in smart controls, bio-based materials and integrated energy-recovery systems are poised to unlock further performance gains and accelerate the sector’s transition to net-zero. Emerging multifunctional materials such as phase-change composites, nanostructured coatings, and perovskite-integrated systems also show promise in enhancing facade adaptability and energy responsiveness. Full article

The Naturally Ventilated Double-Skin Facades (NVDSF) functional mechanism is based on thermal performance of the components and airflow in the cavity. In this paper, 90 simulation scenarios by changing the geometric features of NVDSF are examined. To obtain the optimal duration of calculations, the simulations of different scales of the 3D model and mesh dimensions were examined and 33% scale 3D model with 8 mm meshes dimension were determined. In this study, 124 different simulation scenarios were investigated to assess the effect of NVDSF performance. The results showed that excessive increase or decrease of ventilation flow deviates the NVDSF from the optimal thermal performance. The best thermal performance of the NVDSF occurs in those scenarios where at the inlet, the air flow is divided into two parts, a part is directed to the shading device and the other part directed to the inner glass. The mean reduction of the transmittance heat flux of the inner glass surface for this scenario was obtained 9.5% compared to the standard commercial grille mode of the inlet of NVDSF-box window type. Full article

The response to the climate emergency requires solutions that address multiple sustainability targets, which could be conducted by merging scientific research from areas that have traditionally evolved separately. This investigation presents advances in that direction by studying a building prototype designated for vertical farming, which enables the wind energy potential across built-up areas to be explored, in this case through the implementation of micro-wind turbines on the surface of the prototype. The study includes a parametric analysis consisting of varying locations of wind turbines across the building envelope, and the width of ventilation corridors. The effects of different widths of outdoor ventilation corridors, various locations, and additional wind angles on the capacity to harvest wind resources were investigated. The results showed that the 5 m wide outdoor corridor has the best ventilation effect, and the wind turbine placed on the roof has the best wind energy potential. The efficiency of wind turbines decreases significantly when multiple devices are placed at the same height on the façades, although overall, the potential for energy harvesting seems incremental. Full article

The increasing trend towards decarbonization requires the reduction of the environmental impact of the building sector that currently accounts for approximately 40% of the total CO₂ emissions of European countries. Even though Luminescent Solar Concentrator (LSC) panels could be a very promising technology to be installed in urban environments, there is still little implementation of LSC panels in building façades. Here, the realization of a Ventilated Façade (VF) integrating an LSC device as an external pane is presented and a preliminary numerical and experimental investigation is used to evaluate the interaction between the different structure components. Thanks to the realization of a dedicated mock-up finite element method, models are calibrated and validated against experimental measurements, showing a good correspondence between simulated and measured data. Moreover, the electrical characterization of the LSC panel confirms that large area devices can be used as an external skin of VF, reporting a photovoltaic efficiency of 0.5%. The system’s thermal and optical properties (estimated thanks to the software COMSOL Multiphysics) encourage the continuation of the research by considering different technologies for the VF internal skin, by scaling up the case study, and by running the simulation of an entire building considering winter and summer energy demands. Full article

This study investigates the thermal performance of the ventilated mask wall used in the low-income neo-vernacular dwellings designed by André Ravéreau to cope with the warm desert climate conditions of M’zab Valley, Ghardaia, in southern Algeria. This device is a ventilated façade provided with an opaque external massive cladding. It is designed to be particularly efficient in hot climates, functioning simultaneously as a brise-soleil and a ventilated façade, compared with conventional façade systems. Based on a typical experiment conducted during the summertime (12–14 August), a residential unit in Sidi Abbaz selected as a case study was modeled and calibrated using EnergyPlus (v8.4) software, and then a dynamic simulation was performed in order to assess the efficiency of the ventilated mask wall as a cooling strategy. By means of the validated thermal model, various alternatives for the façade materials were investigated, and the thermal behavior of the current ventilated mask wall was compared with a 45 cm thick limestone façade wall, and a 30 cm thick hollow clay brick wall under the same conditions. Countless benefits were achieved by the application of the mask wall system, including a stable and less fluctuant inner surface temperature, and a reduction in the incoming summer heat flux. The improvements performed, in particular the time lag of 12 h and the related decrement factor of 0.28 indicate the effectiveness of this wall system, which enabled radiant temperature drops of more than 10 °C, and an air temperature decrease of about 6 °C, during the summer sunniest hours. The results demonstrate that this solution is suitable for buildings design applications to meet the objective of low-energy demand in warm desert climates. Full article

This article deals with the investigation of wind effects on a façade of a rectangular residential building with explicit modelling of the windows for specific wind conditions. The external wind pressure coefficients were treated on the façade and at the places of the window sills, linings, and lintel for the direction of the wind from 0° to 90° with increments of 22.5°. For a detailed analysis, the CFD simulation using Ansys Fluent was used. The method selected for the CFD simulation solution and its setting (quality of meshing, horizontal homogeneity of the boundary layer, etc.) were verified by known results of similar objects. The purpose of this analysis is to show how important it is to consider wind effects to determine the suitable placement of passive ventilation devices. Research shows the potential optimal position of ventilation units in terms of favourable pressure distribution. Zones with negative pressure and corners or façades in a wake are not suitable for applying passive ventilation units. The results can serve as a basis for designers to achieve optimal comfort in residential buildings. Full article

Adaptive façades are gaining greater importance in highly efficient buildings under a warming climate. There is an increasing demand for adaptive façades designed to regulate solar and thermal gains/losses, as well as avoid discomfort and glare issues. Occupants and developers of office buildings ask for a healthy and energy-neutral working environment. Adaptive façades are appropriate dynamic solutions controlled automatically or through occupant interaction. However, relatively few studies compared their energy and overheating risk performance, and there is still a vast knowledge gap on occupant behavior in operation. Therefore, we chose to study four dynamic envelopes representing four different façade families: dynamic shading, electrochromic glazing, double-skin, and active ventilative façades. Three control strategies were chosen to study the dynamic aspect of solar control, operative temperature, and glare control. Simulations were realized with EnergyPlus on the BESTEST case 600 from the ASHRAE standard 140/2020 for the temperate climate of Brussels. A sensitivity analysis was conducted to study the most influential parameters. The study findings indicate that dynamic shading devices and electrochromic glazing have a remarkable influence on the annual thermal energy demand, decreasing the total annual loads that can reach 30%. On the other hand, BIPV double-skin façades and active ventilative façades (cavity façades) could be more appropriate for cold climates. The study ranks the four façade technologies and provides novel insights for façade designers and building owners regarding the annual energy performance and overheating risk. Full article

The purpose of the article was to present information on heat recovery in ventilation systems and to highlight what has not been sufficiently researched in this regard. A lot of information can be found on methods and exchangers for heat recovery in centralized systems. Decentralized, façade systems for cyclical supply and exhaust air have not been sufficiently researched. It is known that these devices are sensitive to the influence of wind and temperature, hence heat recovery may be ineffective in their case. The literature describes the aspect of heat recovery depending on the location in climatic zones, depending on the number of degree days (HDD). Attention was also paid to the risk of freezing of heat recovery exchangers. The literature review also showed the lack of a universal method for assessing heat recovery exchangers and the method of their selection depending on the climate. Full article

The study contains an analysis of a decentralised unit installed in a building façade, where air supply and exhaust cycles are swapped by proper positioning of dampers. The analysis was carried out in real conditions in an office building. The Computational Fluid Dynamics (CFD) simulation is an important element of the system design, and has become more and more widely used. Simulation of the analysed unit has shown air stream distribution in a room. Moreover, it allowed for determination of indoor air temperature. Completed analysis and CFD simulations allow for the observation that façade ventilation systems provide a good way to improve the indoor microclimate, as they effectively reduce air pollution. The decentralised façade ventilation unit reduced the carbon dioxide concentration to a level lower than 1000 ppm and maintained the indoor air temperature in the range of 19.5–22 °C. The error for CFD simulation equals 0.5%, which is not much. The results of research and analysis show that the highest reduction of carbon dioxide concentration occurred when supply/exhaust time equalled 10 min. At the same time, when supply/exhaust time equalled 10 min, the indoor air temperature was the lowest of the recorded values. Full article

Poor indoor air quality affects the health of the occupants of a given structure or building. It reduces the effectiveness of learning and work efficiency. Among many pollutants, PM 2.5 and 10 dusts are extremely important. They can be eliminated using mechanical ventilation equipped with filters. Façade ventilation devices are used as a way to improve indoor air quality (IAQ) in existing buildings. For their analysis, researchers used carbon dioxide as a tracer gas. They have shown that façade ventilation devices are an effective way to improve IAQ, but require further analysis due to the sensitivity of façade ventilation devices to the effects of wind and outdoor temperature. In addition, legal regulations in some countries require verification in order to enable the use of this type of solution as a way to improve IAQ in an era characterised by the effort to transform buildings into passive houses (standard for energy efficiency in a building). Full article

Many building are characterized by insufficient air exchange, which may result in the symptoms of sick building syndrome (SBS). A large number of existing buildings are equipped with natural ventilation, whose work is disturbed by activities going to energy-saving. The thermomodernization activities are about mounting new sealed windows and laying thermal isolation, which reduces the amount of infiltrating/exfiltrating air. In many cases, the mechanical ventilation cannot be used due to a lack of a place in building or architectural and construction requirements. One of the solutions to improve the indoor microclimate is the decentralized façade ventilation. In the article, the internal air parameters in an office room equipped with decentralized façade ventilation device were analyzed. The room was equipped with a decentralized façade unit, which cyclically supplied and removed air from the room. The time of the supply/exhaust was changed to 2 min, 4 min, and 10 min. The temperature and the humidity of the indoor air and the outdoor air and the concentration of carbon dioxide inside the room were measured. The analysis showed that despite the lack of a heater in the device, the air temperature in the workplace and in the central point of the room was in the range of 20–22 °C. The air humidity was in the range of 27–43%. Full article

A novel façade element is presented that forms a symbiosis between an enhanced box-type window, a closed cavity façade, and a Trombe wall. This hybrid, transparent-opaque façade element features an absorbing water tank, that is installed behind a controlled shading device toward the cavity of a non-ventilated Double Skin Façade in the parapet section. To evaluate the potential impact on building performance, a transient simulation model is developed in Modelica and calibrated by comparison with measurements on a prototype. The effect of the absorbing thermal storage on heat transfers under solar radiation is analyzed in comparison to (i) conditions excluding solar radiation and (ii) an empty tank. An evaluation for four European cities demonstrates that the annual heating demand can be reduced by more than 4.2% and cooling demand by at least 6.6% compared to a façade without thermal storage. The effect is explained not only by the increased thermal mass, but also by the effective modulation of solar gains by the controlled absorbing storage. The dampening of heat flow fluctuations and the control of solar gains is a promising means to reduce the installed power of HVAC (heating/ventilating/air conditioning) installations. Full article

Shading techniques constitute one of the most passive, beneficial strategies for reducing energy consumption in urban dwellings. Shading affects many factors, for example, the solar gains and radiations falling on the façade, which are considered the most significant in increasing the cooling energy demand in hot climates. This paper conducts a parametric study on external and internal shading devices and establishes their impact on energy consumption, daylight levels, and ventilation. The work was conducted using Integrated Environmental Simulation Virtual Environment (IES-VE) and Computational Fluid Dynamics (CFD) numerical methods. The results revealed that optimised shading can influence savings in terms of energy and cooling, in addition to the enhancement of daylighting and reduction of glare. After studying all these factors associated with the different shading techniques investigated, the findings revealed that all shades affect the energy, daylight and ventilation parameters positively. However, despite all external and internal shadings showing improvements, the egg crate shade was determined as that which provided the optimum energy saving, while enhancing daylight and improving natural ventilation for a sustainable building design. Full article

The air quality of indoor spaces is the most significant parameter in providing a healthy living environment. Low indoor air quality (IAQ) leads to Sick Building Syndrome—one of the major reasons for labor loss in office buildings. The fundamental measure to ensure indoor air quality is ventilation, which includes two basic types: mechanical ventilation and natural ventilation. Natural ventilation is an exchange of stale indoor air with fresh outdoor air by means of a pressure difference due to wind and/or stack effect. Trickle Vents, known also as background ventilators, are natural ventilation devices which can be integrated into façades or window systems as an alternative to operable vents, specifically in high-rise buildings. The major design criteria of Trickle Vents are ventilation capacity, controllability, actuation, thermal insulation, air permeability, water tightness, climatic adaptation, security, and acoustic attenuation. Other important parameters in Trickle Vents design are positioning, equivalent area, and control strategy. This paper aims to review all these aspects, particularly with reference to building regulations and commercial products. Furthermore, simulation, experimental, monitoring, and survey studies of Trickle Vents are also discussed. This literature review is presented from the perspective of performance parameters, control strategies, positioning, etc., with an aim to provide a comprehensive overview of such technology. Full article

With global efforts to strengthen various energy-saving policies for buildings to reduce greenhouse gas emissions, in South Korea, new laws and regulations have been in force since May 2015 to install shading devices in public buildings and to include the solar heat gain coefficient (SHGC) reduction performance of shading devices in the evaluation of building performance. By making a ventilated air layer outer glass and inner glass to lower the temperatures of the air layer and glass surface, it is possible to reduce the amount of heat flowing into the building while maintaining the same level of light transmission as plain window systems. This study proposes a double-skin façade window with a 20 mm ventilated air cavity, and assumes that insolation inflow indoors would be reduced through ventilation in the air cavity. The artificial solar lab test results show that the SHGC can be lowered through ventilation by 28% to 52.9%. Additionally, in an outdoor test cell experiment, the results show that the mean temperature was 0.6 K and the peak temperature was 0.9 K lower with ventilation in the air cavity than that without ventilation in the air cavity. Full article