Commissioning: Getting It Right: Using Measuring And Verification During Commissioning
- How is commissioning different from Measurement & Verification (M&V)?
- When would you use one vs. the other?
- Are they mutually exclusive?
It seems that these two processes have developed along separate but parallel paths over the past five to 10 years. Commissioning is the primary focus of this monthly column, but what is M&V?
More on M&VM&V is a process by which energy goals for specific projects are measured and verified as having been achieved. It has become "business as usual" and is often contractually required for many utility-sponsored conservation programs and energy performance contracts.
When a utility puts up money towards implementing energy conservation measures for its customers, they want confirmation that the new or renovated systems consume no more energy than expected. This often involves "baselining" the original system performance by measuring energy consumption through a representative period of time (typically no less than a year), or by creating a computer model of the existing conditions.
Following installation and startup of the energy conservation measures, actual energy consumption is measured via permanent and/or temporary instruments such as electric, water, and gas meters; temperature sensors; etc. This provides much needed feedback to the utility confirming that the funds were appropriately spent and that the conservation programs are working.
Energy performance contractors are typically compensated based on the energy consumption of their projects. In order to know how much the contractors should be paid, it is necessary to measure the energy consumption and apply that data to a contractual formula. This may need to be repeated throughout a 10- to 20-year life of a contract to verify that the systems continue to operate as efficiently as they did following startup.
How Does It Relate To Commissioning?It seems that the two processes should go hand-in-hand for the best project results. For M&V to be verification that energy goals are met, it would be a good idea to make sure the systems are commissioned as a part of their design and construction process. Commissioning aids the M&V process by not only confirming that systems physically perform properly at the end of construction, but that those systems will continue to operate efficiently throughout their lives.
Similarly, commissioning can clearly benefit from formal M&V techniques as part of the verification testing portion of a construction project. Recommissioning (i.e., periodic "checkups" following commissioning of new systems) can also utilize M&V as part of the process of making sure that the systems are still operating at or near their peak performance.
Finally, M&V makes a lot of sense for retrocommissioning (commissioning systems which were not commissioned originally), where it can be used to demonstrate the effectiveness of the retrocommissioning process by measuring before and after energy consumption and other parameters.
Tell Them Apart, Use Them BothIn summary, M&V is not commissioning, and commissioning is not M&V. It is important to remember that you cannot make systems work by measuring them. Alternately, you cannot make systems work by testing them. The commissioning process is more than both of these, because it starts during design and continues through construction. Testing and measurement is simply the culmination of the commissioning process.
M&V and commissioning are like any good team members. They are each important, but when combined, they enhance each other to be greater than the sum of their parts.