Energy Modeling

One of the most critical, and difficult, aspects of an energy audit is energy calculations. There are multiple different types of energy consuming systems in any given facility, each needing a specific calculation methodology. And a lot of systems interact with one another, so knowing and being able to account for all of those interactions is an added layer of difficulty.

When calculating energy usage, the output must also closely match the utility data (for all given fuel types on-site). For example, the annual calculated electricity usage must match the annual electricity consumption from the bills. And same would go for natural gas, water, etc. And for an accurate calculation, annual values are not sufficient. Monthly values should closely correlate, even interval hourly (or even 15-minute) loads should correlate.

Elliott Energy has been specializing in energy calculations for the last several years. We have custom built calculations for the following baseline energy systems:

·         Heating/cooling equipment (chillers, boilers, etc.)

·         Ventilation (air handlers, exhaust fans, etc.)

·         Pumps

·         Domestic hot water systems

·         Lighting

·         Kitchen equipment

·         Pools

·         Conveyance systems (elevators, etc.)

·         Refrigeration equipment

·         IT equipment

·         CHP systems

·         Renewable energy (solar, wind, etc.)

Elliott Energy has also built calculations for the following energy conservation measures:

·         Equipment replacements

·         Lighting upgrades

·         VFD installations

·         Hot water heater changeouts

·         Plumbing (aerator installations, showerhead replacements, etc.)

·         Setpoint and scheduling changes, including optimal start/stop

·         Airside/waterside economizing

·         Energy/heat recovery

·         Building envelope improvements

·         Demand control ventilation

·         Kitchen demand control ventilation

·         Chilled water reset

·         Condenser water reset

·         Hot water reset

·         Static pressure reset

·         Supply air temperature reset

·         And more…

Below is a sample of ECMs found in one particular building audited by Elliott Energy.

Elliott Energy uses two main metrics to analyze the accuracy of the energy model: the Coefficient of the Variation of the Root Mean Square Error (CVRMSE) and the Normalized Mean Bias Error (NMBE). These metrics compare the monthly calculated energy consumption to the actual billed utility consumption, across all fuel types. ASHRAE standard 211 states that energy model satisfies the requirement of a Level 3 if the following values are met: CVRMSE ≤ 15% and NMBE ≤ 5%.

Elliott Energy models, on average, result in the following: 10% > CVRMSE < 15% and 5% > NMBE < 10%. This means that the calculated energy model far surpasses the necessary level of accuracy for Level 2 analysis. 

Contact Elliott Energy today for assistance with any energy calculations today!