Efficiency Strategies

Our Team has been using the energy simulation program eQUEST and other programs to perform detailed, hourly building energy simulations to understand the behavior of building elements on the building heating and cooling loads, and the annual building electricity and natural gas consumption. The simulation engine within eQUEST is derived from the latest official version of DOE-2, the simulation program developed by the United States Department of Energy (USDOE).

The program allows us to create three-dimensional computer models of our engineering designs, with individual definitions of all the engineering and mechanical components in the project. Weather data available in the form of TMY2 weather files is used to simulate the building in accordance with the geographic location and climate that is specific to the project. We define hourly schedules for occupancy, daylighting, interior lighting, equipment, and all mechanical system components in order to accurately simulate the daily, monthly, and annual building energy performance. Our computational fluid dynamics (CFD) software is Airpak, which is based on Fluent. The main elements that we analyze through the energy simulations include:
  1. Building shell alternatives involving insulation amounts and types, cool-roofs, and high performance glazing types
  2. Daylighting systems including but not limited to daylight monitors, clerestory windows, efficient artificial lighting systems
  3. HVAC system alternatives
  4. Energy-efficient interior equipment


The Raincatcher program was developed by Innovative Design Architects of Raleigh, NC and sponsored by the State Energy Office of North Carolina to estimate rainwater collection potential, determine optimum cistern sizing and collection area, and provide a life cycle cost analysis for the recommended system.

The program is made available to architects and engineers across the United States. Elm Engineering wrote the North Carolina Building Code for rainwater collection requirements, which has been adopted by the North Carolina Building Code Council.


Daylighting analysis aids engineers, architects and lighting consultants to determine the quality and quantity of daylight available inside a space. The program allows us to determine the availability and quality of daylight in a variety of space types. The program has a wide range of applications. It can be used in simulating daily, monthly, and annual lighting performance of a daylighting system, recognizing problems that might occur due to direct sunlight penetration and glare, determining solar gains, and calculating lighting energy use due to supplemental electric lighting inside daylight spaces.

Different input variables inside the program allow us to vary daylighting design elements like windows, clerestories, and monitors, in order to achieve the required daylighting footcandle objective. The output from the program can be used to make important design decisions, both during the early stages, as well as later advanced stages during any design project. We use the program output to design daylighting in spaces for two-third of all available daylight hours.

This helps us in optimizing daylight aperture sizes, while keeping solar heat gains down, and thus reducing the penalty on cooling loads. We use the hourly output from the program to create custom lighting schedules that are then used as inputs into the energy simulation software eQUEST. Our firm has always considered daylighting and building energy analysis as two invariable and extremely important parts of the design process and our commitment to sustainable design.