Want to go “Green?”
Start with Measurement & Verification
International Performance Measurement and Verification Protocol (IPMVP)
Option C Type
The same trope has been used in numerous realms, “You can’t know where you’re going if you don’t know where you’ve been.” Sayings like this gain popularity as they’re universally relevant in many different areas of life. This saying is especially relevant in the world of measurement and verification – you don’t know how to improve your facilities if you don’t know how they’re operated.
For example: A building owner owns a portfolio of buildings and wants develop initiatives to go “Green.” Where would they start?
Typically, the first area to look at is which buildings are performing poorly by looking through the utility bills over the past few years (if available). There are numerous sites to visit to compare the buildings’ energy use (kBtu/sf) with those of similar occupancy types to determine the buildings’ performance among its peers (normalized for weather, of course). This energy assessment is known as the baseline with a nice yearly energy use profile. The baseline is how a building’s energy reduction will be determined and provides data to compare against for realized savings.
No 2 projects are alike. How do you determine which energy savings measures to pursue and how are those savings measured? According to the International Performance Measurement and Verification Protocol (IPMVP), energy conservation measures (ECMs) are classified into 4 categories. We will focus on the first 3 categories as the 4th involves energy model simulations when historical building data is unavailable.
The first option (Option A) is widely used to measure simple constant load ECMs for smaller projects. This could include lighting replacement and motor replacement where simply swapping out less efficient equipment for more efficient equipment under constant load, and then applying some quick math to provide a fairly accurate savings figure, assuming facility operations have not changed with the equipment replacement.
The second option (Option B) is typically used to measure improvements under variable load where more “measurement” of equipment operation is needed to determine the actual performance to “verify” earlier assumptions when generating the ECM list. This can be done by benchmarking the performance of original equipment such as boilers, chillers, and other HVAC equipment. This helps in determining the baseline for the equipment and provides a load profile during different equipment operations. After implementing different modifications to the system from the ECM list, determining your system’s new performance is simply comparing the new load profile and efficiency level with the original baseline. The difference between the two will be the avoided energy waste. Obtaining this information can be done in a number of ways from the BMS data down to submeters on specific equipment.
Lastly, the third option (Option C). This option is typically best for projects where expected building savings are above the 10% to 20% range. This is done on projects where there is a large aggregate of various ECMs all to be implemented for full-building improvement. This is also useful for projects where there is not a large time allotment for M&V on each specific ECM and there’s multiple ECMs. It will help a project’s timeline to avoid getting into the nitty gritty of specific ECMs but prove the building’s performance has improved as a whole.
It’s important to remember that every project will have different performance requirements and different M&V requirements. However, follow-up for periodic check-ups is extremely important. If ECMs are implemented with an ROI in mind, the ROI will never be realized if the ECMs do not stick or different changes are made to the system after implementation.