At-A-Glance
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NA7.5.10 Automatic Demand Shed Control Acceptance |
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Use Document NRCA-MCH-11-A |
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Purpose of the Test |
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All control systems with DDC to the zone level are required to enable centralized demand shed at non-critical control zones from either a single software or hardware point in the system §120.2(h). Field studies have shown that in typical commercial buildings resetting the zone temperatures up by 2°F to 4°F during on-peak times can reduce the peak electrical cooling demand by as much as 30 percent. This test ensures the central demand shed sequences have been properly programmed into the DDC system |
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Instrumentation |
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The instrumentation needed to perform the task may include, but is not limited to: The front end computer to the DDC system |
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Test Conditions |
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To perform the test, use the control system to manipulate system. The entire HVAC installation and control system must be completed prior. |
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Estimated Time to Complete |
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Construction inspection: 0.5 hour to review the EMCS programming Functional testing: 0.5 to 1 hour (depending on familiarity with BAS) |
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Acceptance Criteria |
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The control system changes the setpoints of non-critical zones on activation of a single central hardware or software point. Then the system restores the initial setpoints when the point is released. |
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Potential Problems and Cautions |
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Difficulties could be encountered with manipulating the control system if not familiar with the programming language. Therefore, a controls contractor should be on-site to assist with the testing. |
A. Test Application
Newly Constructed and Additions/Alterations: Applies to construction inspection of the EMCS interface shed controls and testing.
B. Construction Inspection
•Inspect the EMCS interface enable activation of the central demand shed controls.
C. Functional Testing
Step 1: Engage the global demand shed system.
•This step can be done by either jumping the digital contact or simply overriding its condition in the EMCS front end. Wait 5-10 minutes to let the changes take effect.
Verify and Document
The cooling setpoints in the non-critical spaces increase by the expected amount.
The cooling setpoints in the critical spaces do not change.
Step 2: Disengage the global demand shed system.
•This step can be done by either removing the jumper from the digital contact or simply releasing the override of the point in the EMCS front end. Wait 5-10 minutes to let the changes take effect.
Verify and Document
The cooling setpoints in the non-critical spaces return to their original setpoint.
The cooling setpoints in the critical spaces do not change.