Electrical consumption of controls and instrumentation.

Figure 22.21 Control System Costs and Benefits

Figure 22.21 Control System Costs and Benefits suggested for most applications, although there are cases where no de-rate is needed.


• Easy to Quantify. A lighting replacement project with 24-7 operation need not be de-rated at all since there are few, if any, uncertainties. This is easy to quantify, since only one parameter has changed (light fixture energy efficiency).

• Hard to Quantify. An Automatic Control project that includes multiple control system improvements implemented at the same time, such as variable pumping, free cooling modes, supply air reset, boiler lock-out, morning warm-up, and new quarter-turn (no leak by) terminal unit control valves. This adds uncertainty for what savings comes from individual measures.

From a pure simplicity standpoint, a project consisting of several control improvements could be implemented one at a time, with six months of post-project Measurement and Verification (M&V), therefore changing only one thing at a time. This would have the clear advantage of knowing what savings occurred from what measure, but would probably not be done in practice due to the protracted length of time for the entire project to be implemented, as well as lost savings from delayed implementation.

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