C: Paper Session_T3: Design Integrated CFD and Energy Performance
A Framework for the Integration of CFD into the Early Stages of Architectural Design
1Virginia Tech, United States of America; 2Louisiana State University, United States of America
Computational Fluid Dynamics (CFD) refers to computational methods to predict the movement of fluids, e.g. air, around and through objects. Due to its efficiency, CFD has been widely used since the 1970s in various fields including aerospace engineering and the automobile industry. More recently, it is being applied to architecture since airflow analysis has become an important issue while the shapes and the interior layouts of many modern buildings have become complex, making it difficult to intuitively predict airflow in and around a building. Although CFD can be helpful in predicting airflow in relation to architectural design, the users of CFD in the building industry tend to be limited to researchers or consulting engineers. It may be desirable to make CFD analysis more accessible to architectural designers throughout the whole design process. However, the current literature related to CFD implementation in architecture mostly focuses on a single domain of decision-making, such as wind load analysis, rather than the comprehensive design process. The present study aims to show how CFD can be utilized throughout the architectural design process and how the airflow simulations can interact with the dynamics of design thinking. This research will suggest an implementation framework that can be expanded to different architectural projects while supporting architectural designers to utilize CFD simulation in the early stages of design. To achieve this goal, a design project was selected and developed in the following order: pre-design, site interpretation, massing, and façade design. Airflow simulations were conducted for each design step, and the details of the simulation process were tracked using a reflective practitioner approach. Furthermore, the design decision-making processes in interaction with the CFD simulation results were observed and documented. These works ultimately will open a discussion about how CFD can be effectively used for architectural design in a broader perspective.
Integrating Parametric Design and Computational Fluid Dynamics (CFD) to Maximize Electricity Generation from Pavilion
University of Illinois at Urbana-Champaign, United States of America
It is common knowledge that one source of renewable energy can’t replace fossil fuel and it is necessary to adopt various renewable technologies. However, wind energy was not fully utilized. It is typically installed coastline or open rural areas and has a limited application that can be found near the urban area. The paper is developing a new design strategy to find an aerodynamic form of a pavilion that is optimized to generate on-site electricity with attached wind turbines.
Wind farms built in rural areas have the issue of energy losses and infrastructure like the cable construction expense for connecting from wind farms to cities is hard to avoid. Also, recently wind farms in open fields confronted with the waste problem. The blades are made of a pliable mix of resin and fiberglass. Decommissioned blades are also notoriously difficult and expensive to transport. They can be anywhere from 100 to 300 feet long and need to be cut up on-site before getting trucked away on specialized equipment.
For this reason, the paper is interest to investigate possible structures that can generate electricity in the urban area on a small scale. However, it is very difficult to utilize wind turbines around an urban area, because of the negative opinion on the appearance of wind turbines .
The paper proposes a structure that hides a wind turbine and able to generate electricity from wind. However, the most significant limitation of wind turbine applications in urban areas can be found in its complexity with surrounding site conditions. Unlike the open field, where no obstructions are nearby, it is comparatively easy to find the proper orientation of the turbine should face maximizing generating electricity. Since ground-level wind speed and directions vary by location, turbulent, low-velocity wind conditions it is difficult to design a wind turbine near an urban area. For that reason, further research must consider site-specific wind conditions that able to find better orientation, and the shape of the structure must be found.
The paper integrates advanced computational tools to find a form that maximizes electricity generation. Based on a parametric (Non-uniform rational basis spline, NURBS) modeling, the various geometries will be generated and passed to the (Computational Fluid Dynamics) to find a more site-specific wind condition for the whole year around. These performance outcomes are passed to the evaluation process where the objective functions determine whether the geometry satisfies the goal. If the objective function values don’t meet the requirements, the next population is generated based on the selection process and passed to parametric modeling to generate a new structure to evaluate the next generation’s performance. This loop continues until the goal is reached.
The outcome of the paper is demonstrating a design method that integrates different computational tools to find geometry that able to maximize site-specific wind potential to generate electricity and overcome the certain limitation of installing wind turbines close to urban areas.
Energy Performance Of Solar- Reflective Building Envelope On Retail Strip Malls - a Case Study
University of Kansas-School of Architecture & Design, United States of America
In the United States as with many other countries, building energy consumption has dramatically increased over the past decade due to population growth, increased demand for indoor environmental quality, and global climate change. One of the goals of architectural design is to provide indoor conditions where individuals can carry out their daily activities in a comfortable energy efficient environment. Space conditioning which is greatly impacted by heat transfer through the building envelope makes up a major portion of a building’s energy consumption. One method of minimizing heat transfer and reducing solar heat gain is by optimizing the building envelope thermal performance. This can be accomplished by increasing the R-value through more insulation. However, increasing insulation in existing buildings is more difficult than with new construction. Several studies have shown that surface treatments and application of solar-reflective coatings can reduce the solar absorption rate of a building envelope, which may result in the reduction of cooling load in summer.
This paper presents the findings of a study that examined the effectiveness of improving the thermal performance of existing building envelopes without adding thickness to the walls with additional insulation but instead with a thin exterior solar-reflective coating. EnergyPlus was used to simulate the thermal performance of a case study retail strip mall in four different climate zones in the United States. The simulation was performed for two building envelope conditions in each zone. The first condition was without surface treatment and the second condition was with a solar-reflective coating with a solar reflectance value of 0.6. Results showed potential energy savings between 0-10% depending on the climate zone. The hot-humid climate achieved the most energy savings while climate zone with cold winters saw no energy benefits and instead were penalized with increased heating.
Energy saving, solar reflectance, solar absorption, building envelope