New Zealand Post - Commissioning Audits
Enercon performed commissioning audits on three new Mail Service Centres (MSCs) for NZ Post during 2008.
Commissioning audits are performed to primarily check whether systems are installed and operating as designed, ensure the design and controls are appropriate for the end use and identify opportunities to increase energy efficiency. Commissioning audits follow a similar process to Level 2 Energy Audits.
Ideally, commissioning audits should be the next step for the energy management team after a design review has been completed on the plans. Design reviews offer the best time to identify opportunities for improvement.
The three audits identified energy costs savings of 29% ($175,000) of the total energy costs. Some of the opportunities found to reduce energy costs include:
- Shift to the appropriate electricity tariff
- Optimise the use of the engine generator
- Reduce peak electricity demands
- Reset time schedules to suit usage
- Connect the lights to BMS time schedule
- Reduce the mechanical ventilation
- Implement additional BMS time schedules
- Control lights with lux sensors
- Install 1-hour timers for over-ride switches
- Widen the heating/cooling dead-bands
Following the audits, Enercon and the client managed the implementation of the opportunities found from the audits. Enercon is currently completing verification studies to confirm that the energy savings are realised.
Although it is currently too soon to fully see the realised savings, the figure below shows some initial analysis of the energy consumption of the Christchurch MSC before and after opportunities were implemented with a notable reduction.
Figure 1: Electricity consumption against DDH for the Christchurch MSC
When contractors are aware that a commissioning audit is forthcoming, they are more careful about completing their commissioning process before handing over the job.
Commissioning audits are essential to ensuring new buildings and/or plant is operating efficiently and is appropriate for its end use. Opportunities from commissioning audits often only require simple adjustments to controls with minimal costs and can often save considerable amounts of energy.