中央空调冷冻主机程序编程

Runtime time Totalization
CCT – CHWP Module
Pump start command
Fault to start check
Pump Enable Check
Runtime time Totalization
CCT – 1 Valve Stoad Set Point
1. Chiller Plant Start Up
(No chiller is running)
1. Open Valve
2
2. Start pump if valve status is
1
open
3. Start chiller if flow switch is
3
activated
Chiller Start Up Sequencing
m = water flow rate c = water density ∆T = diff. temperature of supply & return
Condition for Down Chiller
1. Return water temperature ( <12 Deg C)
AND 2. Building Load = mC∆T (l/s x 4.2 x ∆T)
2 3
pump
1
3. After a time delay, close
the valve.
Condition for Up Chiller
1. Return water temperature ( >12 Deg C)
OR 2. Building Load = mC∆T (l/s x 4.2 x ∆T)
• CCT Programming
Control Component & Signal
1. Main Heater Temperature, Flow rate for building load calculation
2. Chiller flow switch & isolation valve for chiller monitoring
(At least 2 chillers is running) 1. Stop Chiller 2. After a time delay, stop
2 2
pump & valve
1
Chiller Shut Down Sequencing
1. Shut Down Chiller Plant
(Open 1 Chiller is running) 1. Stop Chiller 2. After a time delay, stop
CCT – Equipment Avaliable
CCT – Up Call
CCT – Down Call
CCT - LOAD
Condition for Equipment Selection
• Not manual mode, trip • Select by running time
– Start first with lowest total running hours – Stop first with highest total running hours
CCT - Sequencer
Proactive
Value of Up & Down
Internal timer, better set to zero
CCT – Chiller Module
Chiller & valve start command
Fault to start check
Chiller Enable Check
m = water flow rate c = water density ∆T = diff. temperature of supply & return
Building Load Set Point
Up Set Point = 90% x Full Capacity of Running Chiller Down Set Point = 50% x Full Capacity of Running Chiller
2. Add Chiller
(At least 1 chiller is running)
1. Open Valve & Start pump
1
2. Start chiller if flow switch is
1
activated
2
Chiller Shut Down Sequencing
1. Shut Down Chiller
Equipment Trip/ Fault Handling
• If equipment is trip or fault to start, start another available equipment with lowest total running hours.
Program Architecture
CCT – Chiller Plant Programming
Leo Yip
Topics
• Chiller control component • Basic Chiller Sequencing
– Condition for add/ down chiller – Chiller start/ stop sequencing – Condition for equipment selection – Equipment Trip/ Fault handling
- Output how many device need to start - Check which equipment is available or not - Select the next start/stop equipment by equipment running time
- Check available of equipment - Start procedure of equipment - Count the total running hour
3. Bypass valve control for system protection
4. Chiller & Pump control & monitoring
Auto/ Manual
Fault Alarm
Running Status
Start/Stop Control
Chiller Start Up Sequencing