Today, it is estimated that energy usage of cities (and more specifically ‘urban structures’) accounts for more than 70% of the global energy consumption along with 75% of the world’s greenhouse gas emissions; and with a projected estimate of over 900 billion square feet of new construction by the year 2050, solutions for urban built environments will be critical in reaching that global temperature increase limit of 1.5 deg. Celsius as decreed in the Paris Climate Agreement.
Advanced architectural design features which will impact the energy load on a building can be incorporated directly into the building’s structure as a passive energy control system – and can achieve up to 50% energy savings according to ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers).
Of all the sustainable building systems and materials available, the engineering and design of hybrid energy systems that incorporate active solar energy systems, high-efficiency mechanical systems along with passive building strategies are yielding the greatest results for high-performance buildings. Some elements for a hybrid A&E sustainable design which will use both passive and active energy systems, include:
- regional climate analysis (solar resources and photo-voltaic power potential)
- sun and shadow studies (micro-analysis of the sun’s path over a site)
- 3D solar shading analysis and simulation (for sun control and shading device implementation)
- building envelope thermal modeling (to minimize the transfer of thermal energy)
- high-efficiency BIM-designed mechanical, electrical and plumbing system (MEP BIM)
- photovoltaic active systems (solar generated electricity, solar hot water heaters)
- water efficiency (rainwater collection and storage, native plant landscaping, low-flow fixtures)
Active Solar System Design using 3D Solar Shading Analysis
Determining the shading effect of surrounding structures or landscapes on solar panel arrays can be a challenging problem that is dependent on many parameters, including the time of year, the time of day, and the tilt, angle, and dimensions of the panels. A high-quality 3D computer model which analyzes and simulates the shading effect of environmentall structures is useful to increase photovoltaic energy performance and lower energy costs from inappropriate panel inclinations and orientation.
A 3D solar shading analysis protects your solar system investment by avoiding shadows on solar collectors where even partial shading on solar panels can possibly compromise the efficiency of the entire system. Solar photovoltaic (PV) systems consist of multiple strings of solar collector panels arrayed to meet the voltage requirements of the building’s electrical needs. When a shadow is cast on any portion of a single panel within a string, the flow of energy is blocked and the output of the entire string can possibly be reduced to virtually zero.
A solar shading analysis will determine if any portion of the solar system will be affected by cast shadows during any portion of the day, at any time of the year. The resulting analysis can help engineers make an informed decision to building site orientation, optimum solar system installation location, performance parameters for building facade systems such as curtain wall arrangement, and as input into 3D BIM facility management protocols.
Using 3D Solar Shading Analysis to Design Passive Energy Systems
Interior cooling loads are drastically reduced when the heat and glare from the sun can be shaded, reflected, or absorbed and stored for secondary use through sun control and shading devices.
The effective planning of a passive solar control system will begin with an analysis of the seasonal sun resources, annual variations of climate, and the frequency of extreme climatic conditions. A solar site analysis is then performed to obtain a detailed study of the daily path the sun makes over the project site; this information can also be used to determine the best site orientation for optimizing solar energy system potential and specifying shading devices to minimize radiant and convection heat gains through walls and windows.
Finally, a 3D solar shading analysis is critical to determine the extent in which structural or environmental shadows are cast. The goal of a 3D solar shade study for passive solar management is to provide an understanding of the amount of sunlight available for interior daylighting schemes, interior and exterior shading devices during sunny months, and passive solar heating potential in cooler months.
Sun shading devices can either block or allow solar radiation to provide a comfortable interior environment in both the summer and winter months. They are useful in reducing the HVAC load, decreasing energy costs, and improving building energy performance.
3D solar shading analysis offers thermal management insight to determine design strategies for building materials, openings, thermal mass, and facade design, along with the other efficient avenues to harnessing the sun’s light and energy. Passive heat gain or heat reduction options can then be specified, namely:
- double-skin facade systems
- fixed horizontal devices – soffits, overhangs, and awnings
- fixed vertical devices – louvers, fins, and screens
- dynamic shading systems – mechanized louvered systems or fabric-based roller shades
- internal shading – operable louvers integrated into glass panels
- E-rated windows – Low E-glass and other special glazing systems
- landscaping features which incorporate trees, shrubbery, and walls
Output of 3D Solar Shading Analysis for Modeling and Simulations
The output of a 3D solar shading analysis can be used to model different shading scenarios across a range of complex situations. Shadow visualization software applications can animate the cast shadows from surrounding objects as they would appear on the building structure throughout the day. This type of visualization is instrumental in solar collector placements and finding the best position to optimize photovoltaic potential.
Shadow calculations can also be charted on graphs and table for easy analysis by engineers. This profile will give a visual comparison between many useful characteristics, such as energy losses and the annual energy yield of the entire system. Often many potential and hidden problems can be avoided especially with large, complex solar arrays including more cost-effective optimizations. Sun tracking and solar shading illustrations are instrumental in achieving BIM Level 2 Compliance which incorporates building information in a data-rich 3D environment.
Benefits of a 3D Solar Shading Analysis
Solar energy installations and high-performing built structures require a major capital investment, yet the returns over the lifecycle of the building are substantial for both the owner and the environment. A 3D solar shading analysis is of benefit to engineers, architects, systems designers, solar energy sales teams, site surveyors, and building performance analysts.
Industry standard mathematical models can enhance presentations by quantifying design decisions concerning site selection, system layouts, energy calculations, and economic analysis. Work with an outsourced engineering firm experienced in 3D CAD modeling and solar system design application that can guide your project throug a variety of analytical tools and visualization models that calculate or simulate sun and shadows to:
- provide a full solar site analysis
- verify the sun’s available energy and the duration of sunshine
- to clarify the reduction of sun exposure by obstacles like trees, houses or mountains
- determine solar geometry variables for designing shading devices
- identify the pattern of shading to improves the building thermal efficiency
- provide a 3D site model of a solar system’s energy potential
- optimization of your solar project
- simulate the photovoltaic performance
- determine shading for proper landscaping
- model and compare alternate site orientations