Automatic Control Solution for Chiller Unit Operation Count

Typical Refrigeration System Software:
Typical baddc automatic control system:
Based on the spacing of ground-source radiant heating pipes, start and stop refrigeration unit.
Estimated cooling capacity = flow rate (f) × difference in flow rate and ground heating pipe spacing (t2 - t1)
Adjust intake valve oil tube pressure based on set pressure difference.
Cooling Capacity (q) = Flow Rate (f) × Temperature Difference (t2 - t1)
=4.2×50l/s×(12℃-7℃)=1055kw
Based on the spacing of ground heating pipes, the start and stop refrigeration unit.
Radiant heating pipe spacing > set point (e.g., 12℃)
2)Cooling capacity exceeds the overload cooling capacity of the generator set.
The generator set startup delay has been resolved.
Adjust intake valve oil pipe pressure based on set pressure difference.
Unstable Control System
Today, water flow temperature control is widely used in generator set operation, instead of controlling the spacing of ground heating pipes.
Improper spacing of underfloor heating pipes can lead to insufficient cooling capacity under certain conditions.
Overall, the spacing of underfloor heating pipes is susceptible to the harm of bypass valve oil pipe pressure due to differential pressure. After the intake valve is opened, the spacing of the underfloor heating pipes converges with the water output temperature, causing the overall spacing of the underfloor heating pipes to decrease immediately.
Load (q) = Flow Rate (f) × Difference in Pipe Spacing between Flow Rate and Ground Heating (t2 - t1)
The manipulation process often leads to frequent shutdowns.
Environmental Protection and Energy Saving Short of Actual Effect
The ddc automatic control system keeps the generator set operating at a partial load for most of the time.
ddc's operation overlooks the specific operations of the generator sets, with a simple and clear standard:
The calculated cooling capacity requirement exceeds the cooling capacity of the generator set air conditioning.
The ground heating pipe spacing exceeds the preset value.
The more the generator set operates, the higher the energy consumption of the centrifugal pump.
The ddc Automatic Control System will encounter an issue at startup due to excessive spacing between radiant heating pipes and an over-investment in power generation units.
Typical CNCGenerator Set Automatic Control System
Steps for Loading ACR (Additional Cooling Required)
When the ACR temperature sensor determines the chilled water supply temperature exceeds the sum of the current chilled water supply temperature set point and a adjustable temperature error value.
b. The current power generation units have ample time to operate from 0% to near full load.
c. The load on the generator set exceeds a pre-set value (95%).
d. The temperature reduction rate of the operating refrigeration units is below 0.5°F per minute.
All regulations a to d must be considered before proceeding to the loading program for the generator set.
The startup delay for the new refrigeration unit has been resolved (the delay time can be set).
f. The directive to cease operation of the new refrigeration unit has not been activated.
g. The new refrigeration unit is not in error, steep ramp loading, or in the shutdown and restart power phase.
All regulations e~g can be considered, and the new refrigeration unit will be immediately started up.
Increased Cooling Requirements: Additional Cooling Required - ACR
Reduced Cooling Requirements - RCR
The number of operational generator sets currently exceeds one.
b. The average load of the operational generator sets is below a predetermined threshold (usually between 65% to 69%).
c. When the RCR temperature sensor determines the chilled water supply temperature, it is below the sum of the current chilled water supply temperature set point and 0.6 times the adjustable temperature error value.
All regulations a-c must be considered before proceeding to the generator set unload procedure.
The delay for shutting down the generator set has now been completed (the delay can be set).
In accordance with the above regulations, the generator set should be immediately shut down upon activation.
Reduced Cooling Requirements – RCR
During working hours from 7:00 to 23:00, when should the generator set be started?
ProvideThe generator was allowed to run for an extended period (e.g., 20 minutes) to reduce the outflow temperature of the system software.
ProvideThe generator set runs for an adequate duration to reduce the outlet water temperature of the system software (e.g., for 20 minutes).
Increased Refrigeration Requirement: Additional Cooling Needed, ACR
Water output temperature > (preset value + error value) (error value = 1℃)
Generator Set Operation Load > (Greater than the designated 95%)
Cooling rate < (0.5 f/min)
Additional Cooling Required – ACR
Additional Cooling Required: Increase Refrigeration Requirement, ACR Standard 4: Standards 1, 2, & 3 Remain Unchanged - Time Delay Completed (10 mins)
Increased Cooling Requirement: Additional Cooling Needed, ACR Start-UpTaiwan Generator Set
If applying steep gradient loading, cThe operation of the power generation unit will first be commanded to unload to the calculated percentage of kW, demonstrating a smooth handover of stable operation.
As applied, the kw equilibrium effect, cLoad will be evenly distributed to each operational power generation unit.
7.6℃ is less than (7.0℃ + 1.0℃); the ACR standard does not comply.
cIn this case, it is not easy to increase the generator set output to lower the water output temperature to the preset value.
8.3°C > 7.0°C + 1.0°C; System software load increases with time
Additional Cooling Required - Increased Refrigeration Capacity Needed, ACR
Standard 1: Water Output Temperature > (Set Value + Error Value) (Error Value = 1℃)
Standard 2: Generator set operating load > (greater than the specified 95%)
Standard 3: Cooling rate < (0.5 f/min).
Standard 4: Standards 1, 2, and 3 will not alter the time delay completion (10 minutes).
Additional cooling required; increased refrigeration capacity needed, ACR startupTaiwan Generator Set
If applying steep gradient loading, cThe operation of the power generation unit will first be commanded to unload to the calculated percentage of kW, demonstrating a smooth handover of stable operation.
If applied, the kw equilibrium effect,Load will be evenly distributed to each operational power generation unit.
As time progresses, the system software load gradually decreases.
7.0℃＜7.0℃+(0.6×1℃)
Reduced Cooling Requirements – RCR
Reduced Cooling Requirements (RCR) – Decision Making on Shutdown Timing
Standard 1: Mean Load of Operational Generator Sets ≤ Adjusted Limit Value
Standard 2: Refrigerated water supply temperature < set temperature + (0.6 times the adjustable temperature error value)
Standard 3: Standards 1 and 2 will remain unchanged; time delay completed (5cin).
Shut-down delay has ended, powering off immediately.
Reduced Cooling Requirements – RCR
cOperators will command the generator set to increase load to compensate for the reduced cooling caused by the recent shutdown.
Reduced Cooling Requirements (RCR) - Decision Making for Shutdown Timing
Standard 1: Mean Load of Operating Generator Sets ≤ Adjustable Limit
Standard 2: Refrigerated water supply temperature < temperature set point + (0.6 times the adjustable temperature error value)
Standard 3: Standards 1 and 2 will remain unchanged; time delay completed (5cin).
Power-down delay completed, shutdown imminent.
According to the schedule allocation, the power generation unit is finally shut down (at 23:30) after completing 24 hours of operation.
According to the schedule allocation, the generating set was finally shut down (at 23:31) after completing 24 hours of operation.
According to the schedule allocation, the power generation unit was finally shut down (at 23:32) after completing 24 hours of operation.
chillerplantcontrol–cChart of Main Parameters Transformation for Automatic Control Systems
If there are 3 generator sets in the main server room, two of them have a large cooling capacity, while one has a smaller cooling capacity.
If the cooling capacities of the generator sets in the main server room are not identical and do not utilize interactive control.