Technical Information on the AIM Calculations

This article contains some basic technical reference information on the calculations performed by the AIM Report software. Some additional information is included in the AIM Report FAQs.

The Savings Calculator

To perform its energy savings calculations, the AIM Report uses its own web-based calculator that was designed specifically to be used for lab buildings. The tool focuses on the factors driving airflow rates in a building's lab spaces, including ventilation requirements, fume hoods, and equipment loads, and performs whole-building energy use calculations for a wide range of building design and operational parameters. The calculator is equipped with an extensive library of typical weather data for many locations, and occupancy levels, outside air temperatures, and outside humidity are binned into representative groupings to allow a full year of simulation to be performed quickly.

The Assumptions

One of the key parts of the AIM Report software is the Assumptions module. For each building, AIM uses a series of intelligent assumptions to assign values to any building parameters not provided by the tool user. The assumed values are based on the other properties of the building and on industry standard practices and trends; the assumptions logic was developed in consultation with a broad range of industry experts comprising the Labs2Zero Baseline Assumptions Technical Advisory Council. The use of intelligent assumptions is a critical aspect of the AIM process: by assigning assumptions, AIM can allow users to quickly obtain meaningful results without the need to enter hundreds of pieces of data on each building. Users with time or additional information can override many of the assumptions in order to tweak the model to better reflect the conditions of their own building and improve the accuracy of the savings calculations.

The Measure Calculations

AIM is equipped with a library of energy efficiency measures, each of which includes the logic to determine its applicability to a given building and a calculation protocol to specify the building parameter changes produced by application of the measure. To estimate measure savings, the results of a calculation with the measure changes in place are compared against the results without the measure changes. Measures in packages are applied sequentially, meaning that measure savings are always incremental, i.e. the savings are relative to the previous measure in the package. This allows AIM to take into account the interactivity between different measures, which is an important factor affecting the savings associated with many lab building measures. The measures, their descriptions, and their calculation protocols were developed in collaboration with the Labs2Zero Measures and Impacts Technical Advisory Council.

The Implementation Cost Estimates

AIM's measure implementation cost estimates are calculated for each measure based on the specific properties of each building. The cost estimates contain cost components corresponding to materials, labor, project management, staff time, and maintenance costs. The costs are also adjusted based on building location, using typical regional cost factors. Like the measure savings, the installed cost estimates within a package are incremental, i.e. a measure's cost is based on the additional cost required to implement a measure given that the other measures already in a package would also be installed as part of the same project. For example, if two measures in a package require air balancing in each lab space, only the first measure added to the package would include this cost. This method avoids overcounting costs and helps users identify areas of synergy between related measures. The cost formulas were developed in collaboration with the members of the Labs2Zero Installed Costs Technical Advisory Council.

The Case Studies and their Match Scores

AIM includes a large library of case studies relating to energy efficiency projects in lab buildings. These case studies were assembled by I2SL and the Labs2Zero Case Studies Technical Advisory Council. Relevant case studies are automatically assigned to each package of measures based on their match scores. These scores take into account the quality of the case study itself (for example, the level of detail available), the level of similarity of the case study building to the user's building, and the number of measures the case study and the current package have in common.