Sep 9, 2012 Energy Talks
5.1 Strategic Measuring Points
During the measurement, the sensors should be located at points that can best reflect the need or function of the controlled parameters. For example, for the office environment, a lux meter should be placed at about 0.8m above floor level (or at level of the working plane) and a thermometer at about 1.1m (seating thermal comfort) above floor level and pressure and flow sensors in ductwork at points according to general engineering practice.
For measurement requiring interfacing with the stream of flow, the system may already have test holes/plugs or gauge cocks. However, many systems may not have such provisions and the audit team may need to install the test holes/plugs or to use the ultrasonic type meter. In fact, it is impractical in most cases to install additional flow meter or gauge cocks in water
pipework. Under such circumstances, the audit team may have to make use of the existing ones available, e.g. gauge cocks before and after pump, coil, etc. to measure the pressure of the flow and to calculate the flow rate by referring to pressure/flow curves of pump, valve, pipe section, etc. If the original O&M manuals showing the pressure/flow curves are
not available, make reference to those of similar size/rating.
Whilst much data and characteristics on equipment/systems can be obtained from the O&M personnel, the information may not be adequate to provide a full picture of their operation. To obtain accurate operating conditions and operating performance of equipment/systems, the auditor should have the necessary measuring instruments to take readings of corresponding parameters such as temperature, pressure, flow, lighting lux level, running current, etc. A list of the commonly used instruments is given in Appendix A.
6. Analysing Data Collected
At this stage of the audit, the audit team has collected a lot of
a) Equipment/system characteristics obtained from site surveys;
b) Equipment/system performance data obtained from O&M log sheets;
c) Equipment/system performance data obtained from site measurements; and
d) Equipment/system operating conditions of equipment/systems based on design and/or general engineering practices.
Based on the above, the audit team should screen and spot the parameters with values and trends that deviate from what would be anticipated or required respectively. These are the potential EMOs. However, they should take into account the analysis of the irregularities caused by changes in occupancy or other activities.