Making Use of the Building Control System for

Improved Operations and Energy Efficiency

Engineer Cohort Week 5, Day 8 (14th)

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1

June 12-14, 2024

Nic Lehoux for Bullitt Center

• 8:00 AM Review of Day 2 and Questions
• 8:20 AM What is a PID Loop
• 10:00 AM Break
• 10:15 AM PID Loop Tuning Lab Exercise
• 12:00 PM Lunch
• 1:00 PM Discussion of Troubleshooting Strategies and Methods
• 3:00 PM Break
• 3:15 PM Troubleshooting - continued
• 4:30 PM Wrap up

Agenda - Day 8 In Person

PID Loops

Discussion and Exercise

Morning

• Attendees brought in a pitot tube so a discussion ensued about balancing
• Attendees programmed remaining parts of the VAV box.
• PID was then discussed.
• Proportional gain:
• Sp of 70, extreme low, 65 produces an error of 5F
• Output Signal, 0-100%,
• Hi - 10
• Lo - 0
• Diff is 100 or signal range
• To get starting point for kP,
• Signal range - Max error
• 100/5 = 20 Kp

NOTES:

Morning - Continued

CFM SP

Max - 75

Min - 70

Range - 600 (800-200)

Max error could be 85 (eg - when unit starts up and goes into max cooling)

600/5 = 120 Kp

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Integral (K_I)

Initial kP / 10 = Ki so - 120/10 = 12 (instructor feels that may be a little aggressive)

Derivative (K_D) = 0

Afternoon

• MV(t) = Ke(t) + 1/Ti integral 0-t E(x)dx + Td de(t)/dt

NOTES:

Troubleshooting

Strategies

Methods

Root cause analysis (RCA)

A systematic process for identifying the underlying causes

• To find solutions and prevent future occurrences.

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RCA is based on the idea that it's more effective to address root causes than to treat symptoms.

Steps

1. Define the problem
2. Collect data
3. Map out the events to identify root causes
4. Implement solutions to solve the problem

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Curriculum Links for Attendees