What is the pathway to Net Zero Energy (NZE) for an existing building retrofit?

Graphic Name:

What is the pathway to Net Zero Energy (NZE) for an existing building retrofit?

Submitted By:

Jared Landsman

Firm Name:

Integral Group

Other contributors or acknowledgements (optional):

Michael Esposito

What tools did you use to create the graphic?

Project Information

What are the primary inputs of the analysis/analyses included in the case study?

The primary inputs in the analysis are program distribution, envelope, mechanical system, and solar PV size.

What are the primary outputs/metrics of the analysis/analyses included in this case study?

The primary metric for this analysis is annual building energy consumption.

Gross Floor Area of Project Covered by Analysis

67,000 sq ft

ASHRAE Climate Zone


Project Zip Code (optional)

Primary Building/Space Type Covered by Analysis
  • Office
If you selected 'Mixed Use' on the previous question, what are the different uses?


List the investigations questions that drove your analysis process.

What are the minimum envelope requirements to achieve reduced envelope loads? How much energy can be generated from solar PV on the available roof area? How will the distribution of programming throughout the building affect energy performance? What is the best mechanical system to achieve zero net energy?

Who performed the simulation analysis? (select all that apply)
  • MEP Firm
What tools were used for the simulation analysis? (select all that apply)
  • OpenStudio + Eplus
  • IES-VE
  • Grasshopper Honeybee
What phase of the project was analysis conducted? (select all that apply)
  • Schematic Design
  • Design Development
How was simulation integrated into the overall design process?

We worked hand in hand with the architects and mechanical designers throughout the early stages of the design to provide effective insight into making impactful design decisions. For every stage of the design process, the simulations were refined to answer each specific question that was asked of the design team.

How did you set up the simulation analysis and workflow?

First, a simplified energy model was built in EnergyPlus, using an ASHRAE baseline HVAC system, to assess the impacts of envelope decisions on building energy consumption. Once envelope decisions were made, a more detailed energy model was created in IES-VE to look at the energy impacts of different HVAC systems. Using the selected HVAC system, the model was then used to assess the energy implications of how the architectural program was distributed across the building. One option had the building with mixed program usage on each floor, and the other option had different program uses separated. A separate model was developed in Grasshopper to assess the energy generation potential from Solar PV.

How did you visualize the results to the design team? What was successful about the graphics that you used to communicate the data?

All outputs were extracted from the energy simulation softwares and post-processed in either Microsoft Excel or Adobe Photoshop. Finally, they were presented to the client and design team, via PowerPoint, in several design charrettes. The visualizations used for the case study conveyed the results of our study in a concise manner than the clients were easily able to grasp.

Most importantly, what did you learn from the investigation? How did simulation and its outputs influence the design of the project?

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