2722 Role of MV

Each Energy Conservation Measure (ECM) presents particular requirements. These can be grouped in functional sections as shown in Table 27.18. Unfortu nately, in most projects, numerous variables exist so the assessments can be easily disputed. In general, the low risk (L)—reasonable payback ECMs exhibit steady performance characteristics that tend not to degrade or become easily noticed when savings degradation occurs. These include lighting, constant speed motors, two-speed motors and IR radiant heating. The high risk (H)—reasonable payback ECMs include EMCSs, variable speed drives and control retrofits. The savings from these ECMs can be overridden by building operators and not be noticed until years later. Most other ECMs fall in the category of "it depends." The attention that the operations and maintenance directs at these dramatically impacts the sustainability of the operation and the savings. With an EMCS, operators can set up trend reports to measure and track occupancy schedule overrides, the various reset schedule overrides, variable speed drive controls and even monitor critical parameters which track mechanical systems performance. illustrates a "most likely" range of ratings for the various categories.183

Often, building envelope or mechanical systems need to be replaced. Building systems have finite life-

Figure 27.18: Temperature Bin Calibration Plots. This figure shows the measured and simulated hourly weekday data as scatter plots against temperature in the upper plots and as statistical binned box-whisker-mean plots in the lower plots.181
Figure 27.19: Comparative Three-dimensional Plots. (a) Measured Data. (b) Simulated Data. (c) Simulated-Measured Data. (d) Measured-Simulated Data.
Table 27.17: Calibrated, whole-building Simulation Procedures from ASHRAE Guideline 14-2002.177
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