Green building analysis plays a crucial role in sustainable building design. Current building simulation software focuses on various environments, including wind (Fluent, Phoenics), light (Ecotect, Radiance), energy consumption (ASK, DesignBuilder), and sound (Raynoise, Cadna/A). However, these tools often use different modeling methods, causing engineers to spend significant time creating multiple models for a single project.
With advances in software technology, many green analysis programs now support compatible interfaces with other formats. The introduction of Building Information Modeling (BIM) technology allows the creation of a single model that can be used across multiple software platforms for analysis, significantly reducing engineers’ workload.
Building Information Modeling (BIM) involves developing a comprehensive building model based on various project data, simulating real-world building information through digital means. The BIM model applies throughout all phases of project construction and supports multiple disciplines across the project lifecycle.
1. Project Introduction
The project is a low-carbon experience hall located in an ecological new city. It consists of two above-ground floors, stands 12.7 meters tall, and covers a total area of 15,595 square meters. This complex integrates a low-carbon exhibition hall, tourist center, scenic area management office, commercial catering facilities, and a clubhouse.
Designed to showcase low-carbon technology, cultural heritage, and scenic area reception management, the building adheres to a green and low-carbon concept. It incorporates innovative low-carbon technology, modern advancements, and ecological landscaping to achieve a three-star green building standard in both design and operation.
2. Outdoor Environment Analysis
2.1 Outdoor Wind Environment
Using Rhino, a preliminary architectural form was created, with the roof designed as a hyperbolic surface that follows the terrain’s undulations to harmonize the building with the landscape. This hyperbolic roof model was imported into Revit to build a preliminary structural model.
The model was then exported in .sat format, and the surrounding site was refined using SketchUp and Rhino. Finally, the model was converted to STL format and imported into Phoenics software for outdoor wind environment simulations. This process helped optimize the building’s form and structure.
The planned building extends approximately 250 meters in length. Preliminary simulations revealed that strip-shaped buildings can cause sudden wind speed changes and create local dead zones, which are unfavorable for a comfortable outdoor wind environment. By integrating the terrain and using curved shapes, the airflow around outdoor pedestrian areas improves, enhancing outdoor comfort.
2.2 Wind Pressure on Building Surfaces
The building’s south side faces a lake with no tall structures blocking the wind. The dominant wind direction in Huai’an during summer and transitional seasons is from the southeast. Under this condition, wind pressure on the windward side exceeds 2.2 Pa.
The low-carbon experience hall has a relatively low height, with soil covering the north side. The lowest wind pressure, about -1.6 Pa, occurs at the building’s rooftop. This makes the installation of an openable skylight at the roof top an effective way to promote natural indoor ventilation.
The pressure difference between the windward and leeward sides exceeds 3 Pa, as illustrated in Figures 3 and 4.
Dividing the over 200-meter-long building into three connected zones via a central corridor prevents vortex formation and dead zones, improving the outdoor wind environment around the main activity areas. This design also reduces the indoor depth, shortens airflow distance indoors, and decreases air residence time, benefiting natural ventilation.
The central section of the building is dedicated to a low-carbon exhibition hall. By modifying the building’s form, the middle section achieves maximum wind speed, making it an ideal location for wind turbines and enhancing the building façade’s wind display effect.
3. Indoor Environment Analysis
3.1 Lighting Optimization
The Revit architectural model was exported as a GBXML file and imported into Ecotect for indoor environment simulation. Skylights were installed at the tops of both the main and annex buildings.
By comparing different skylight shapes and placements, a design was selected that balances building form, ventilation, and lighting requirements.
3.2 Ventilation Optimization
During transitional seasons when outdoor temperatures are around 20°C, indoor temperatures tend to be higher, causing airflow to move outward driven by thermal pressure. When skylights are open, indoor airflow reaches approximately 0.5 m/s.
The presence of an openable skylight at the top of the low-carbon exhibition hall significantly enhances natural indoor ventilation.
Without skylights, the maximum indoor air age is about 2800 seconds. Installing an openable skylight reduces this to 2000 seconds, promoting ventilation through thermal pressure, reducing indoor air residence time, and improving air quality.
4. Other Key Green Building Features
4.1 Ground Source Heat Pump System
The building’s central low-carbon display area uses ground source heat pumps for heating and cooling. Two units provide 190 kW for cooling and heating each; one is a heat recovery type that recycles heat for domestic hot water.
The heat pump room doubles as a touring exhibition hall. Using 3D BIM design, equipment locations and piping layouts were optimized to improve the space’s visual appeal.
4.2 Rainwater System
The project uses a siphon rainwater drainage system on the roof. Initial rainwater from some roofs is diverted to outdoor drainage pools for removal. Subsequent rainwater is collected in an underground raw water pool for treatment and reuse, while the remaining roof rainwater drains directly into the municipal rainwater network.
Outdoor areas, including parking lots, are paved with permeable bricks. Rainwater from fire lanes flows into permeable zones or grass areas alongside roads, enhancing groundwater recharge and reducing the surface heat island effect. These measures significantly decrease surface runoff and its environmental impact.
4.3 Solar Photovoltaic Power Generation
Facing south towards the lake, the building’s south façade receives ample sunlight. Based on sunlight analysis and green building standards, external shading systems were installed on both sides of the south façade.
An automatic outdoor display system in the central low-carbon display area adjusts according to the sun’s height and integrates solar photovoltaic panels. This design maximizes solar radiation capture on the building’s façade-mounted solar panels.
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