Commissioning and Retrocommissioning
Goal: An efficient datacenter not only requires a reliable and efficient design, it also requires proper construction and operation of the space. Commissioning is a methodical and thorough process to ensure the systems are installed and operating correctly in all aspects, including efficiency. [Read more in the Resources section.]
- Objective 1: Engage additional design expertise for review and guidance. Design recommendations from a designer not directly involved in the project details and/or the assistance of a dedicated commissioning agent can greatly improve the final quality of the facility.
- Strategies:
- Perform a Peer Review. A peer review offers the benefit of having the design evaluated by a professional without the preconceived assumptions that the main designer will inevitably develop over the course of the project. Often, efficiency, reliability and cost benefits can be achieved through the simple process of having a fresh set of eyes, unencumbered by the myriad small details of the project, review the design and offer suggestions for improvement.
- Engage a Commissioning Agent. Commissioning is a major task that requires considerable management and coordination throughout the design and construction process. A dedicated commissioning agent can ensure that commissioning is done in a thorough manner, with a minimum of disruption and cost.
- Strategies:
- Objective 2: Perform system commissioning. Ensure that all systems and control sequences, including ones that are only relevant to efficient operation, are installed per design.
- Strategies:
- Document Testing of All Equipment and Control Sequences. Develop a detailed testing plant for all components. The plan should encompass all expected sequence of operation conditions and states. Perform testing at with the support of all relevant trades — it is most efficient if small errors in the sequence or programming can be corrected on-the-spot rather than relegated to the back and forth of a traditional punchlist. Functional testing performed for commissioning does not take the place of equipment startup testing, control point-to-point testing or other standard installation tests.
- Measure Equipment Energy Efficiency Onsite. Measure and verify that major pieces of equipment meet the specified efficiency requirements. Chillers in particular can have seriously degraded cooling efficiency due to minor installation damage or errors with no outward symptoms, such as loss of capacity or unusual noise.
- Provide Appropriate Budget and Scheduling for Commissioning. Commissioning is a separate, non-standard, procedure that is necessary to ensure the facility is constructed to and operating at peak efficiency. Additional time commitment beyond a standard construction project will be required from the contractors. Coordination meetings dedicated to commissioning are often required at several points during construction to ensure a smooth and effective commissioning.
- Perform Full Operational Testing of All Equipment. Commissioning testing of all equipment should be performed after the full installation of the systems are complete, immediately prior to occupancy. Normal operation and all failure modes should be tested. In many critical facility cases, the use of load banks to produce a realistic load on the system is justified to ensure system reliability under design conditions.
- Strategies:
- Objective 3: Perform Retrocommissioning. Verify that the system is operating as designed.
- Strategies:
- Perform a Full Retrocommissioning. Many older datacenters may have never been commissioned, and even if they had performance degrades over time. Perform a full commissioning and correct any problems found. Where control loops have been overridden due to immediate operational concerns, such as locking out condenser water reset due to chiller instability, diagnose and correct the underlying problem to maximize system efficiency, effectiveness, and reliability.
- Recalibrate All Control Sensors.
- Where Appropriate, Install Efficiency Monitoring Equipment. As a rule, a thorough retrocommissioning will locate a number of low-cost or no-cost areas where efficiency can be improved. However, without a simple means of continuous monitoring, the persistence of the savings is likely to be low. A number of simple metrics (cooling plant kW/ton, economizer hours of operation, humidification/dehumidification operation, etc.) should be identified and continuously monitored and displayed to allow facilities personnel to recognize when system efficiency has been compromised.
- Strategies:
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