Energy Simulation & Energy Audits – A Comprehensive Building Energy Efficiency Package
Updated: Mar 8
Energy audits have long been used as a means to identify different ways to improve the energy efficiency of a building. Energy audits can broadly be classified into the following categories:
· Preliminary Energy Audit (Walk-Through Audit)
· Detailed Energy Audit (Diagnostic Energy Audit)
· Investment-Grade Energy Audit
Preliminary Energy Audit
Typically, an experienced energy auditor identifies a variety of low-cost energy saving measures during the course of a walk-through audit; that can easily be implemented by the building owners. These energy saving measures usually tend to have a relatively quick payback period. Such measures might include the retrofitting of existing T8 lights to LED lights, installing VFDs (Variable Frequency Drives) on compressors etc.
This type of energy audit does not usually involve any kind of detailed engineering or economic analysis & the measures suggested are often based on visual inspection of equipment. Future scope for further engineering analysis is also suggested during this audit.
Detailed Energy Audit
This type of analysis is a lot more detailed than a preliminary energy audit & a detailed energy use survey is conducted. This is done to provide a comprehensive analysis of the building, a breakdown of the end-use energy consumption; and an evaluation of the identified ECMs. This level of energy audit can involve taking advanced measurements on-site and the use of building energy performance simulation software to evaluate the identified energy efficiency improvements.
Investment-Grade Energy Audit
An Investment-Grade Energy Audit requires detailed analysis of capital-intensive modifications focusing on expensive ECMs. This kind of audit usually requires rigorous engineering study. Usually, a detailed building performance simulation is used during this type of audit. Existing sub-metering & monitoring data and on-site measurements are used to refine the calibration of the building energy simulation tool.
Once the energy model has been calibrated, the energy model can then be used to evaluate and validate different energy efficiency measures.
Energy Audits & Energy Modeling – A Two-Pronged Approach
While energy audits can be a great tool to identify low-cost equipment upgrades, they have their limitations. The primary focus of energy audits is on a building’s systems & is very effective for smaller sized buildings such as single-family dwellings.
Larger buildings, however have a greater level of complexity. It is therefore important to understand how the building envelope, occupants, systems, weather & controls interact as a single entity. An energy model combined with the on-site data obtained from an energy audit can be very useful in evaluating & verifying holistic building energy efficiency measures. The accuracy provided by using this approach is very high & can save the building owner a lot of money.
NYC Local Law 97
New York City has been a trend setter for more than a decade in ensuring that buildings reduce their carbon emissions. A hallmark of the city’s approach has been its strong energy efficiency mandates through the implementation of various local laws. The city currently intends to reduce its carbon footprint by 90 percent in 2050. In the wake of this, Local Law 97 was passed and targets buildings over 25,000 sq.ft.
Although certain energy efficient technologies & measures have been identified for potential mass implementation; the use of building energy simulation can help ensure that these measures are implemented in an optimal manner.
Several major cities in the world have set ambitious targets to become net-zero in terms of energy by around 2050. The use of a similar approach for huge metropolises can reap huge rewards in terms of energy & cost savings.