Presenting results visually
Energy modeling results have little value if decision makers do not understand them. When presenting results to owners and design teams here are two recommendations.
- Focus on answering design questions rather than presenting simulation results
- Present information visually
This section includes several examples of energy model results presented graphically.
Answering Design Questions
As discussed earlier in the section Simple Box Modeling Approach, design questions should be identified prior to starting a simple box modeling analysis. Addressing those questions is a good framework for presenting your results, and this section provides a few examples.
- What is the impact of window area on EUI?
- Which of three building massing options provides the best performance?
- Which envelope components contribute most to peak cooling load?
- Which end uses contribute most to EUI?
- How does estimated EUI compare to the target?
What is the impact of window area on EUI?
A simple box model is often used to estimate the impact of design features such as window area, and the following graph shows results of an analysis that looks at the change in EUI as window-wall ratio (WWR) is increased from 10 percent to 50 percent, with and without automatic daylighting control. These results show that in this example the lighting energy savings provided by larger windows will partially offset the extra HVAC energy, and the EUI at WWR of 40% is roughly equal to the result at WWR of 10% if automatic daylighting controls are included. This type of graph can also be useful for presenting the impact of other features such as wall and roof insulation or glazing U-factor or SHGC.
Which of three building massing options provides the best performance?
Comparing conceptual design alternatives is an important role for simple box modeling analysis. To be most effective, the presentation of results should focus on information of interest to the design team. The following graphic compares three massing alternatives and shows the EUI, energy cost and peak cooling load for each case. EUI may be interesting if the team has set a performance target. Energy cost and peak cooling load will help the team understand the operating cost and construction cost impact. The column charts help the reader more quickly interpret the results.
Which envelope components contribute most to peak cooling load?
A simple box model can help identify priorities for strategies to reduce peak cooling load and the required HVAC system capacity. The availability of this information may vary between simulation programs, but in most cases it is possible to get output showing how sources of space heat gain add up to the peak cooling load. The following chart shows results ranked from largest to smallest contribution and highlights the contributions from envelope components, showing window conduction is the biggest contributor in this example.
Which end uses contribute most to EUI?
One of the useful results of a simple box model is an estimate of the magnitude of each energy end use. A graph such as the following can clearly illustrate to the design team how each end use contributes to the total energy consumption.
How does estimated EUI compare to the target?
If efficiency measures are added incrementally to a baseline simple box model, then charts such as the two following column graphs are useful for showing how each measure contributes to meeting targeted performance.
Visualizing data using the building model
Some energy modeling software tools provide the capability to overlay data on the building's 3-D geometry model. This can be a useful way of visualizing the magnitude of (for example) solar gains on different facade surfaces, heating/cooling gains in each room or zone, and many other output variables from the simulation. See below for a few examples.
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