Heat Source Machine Count Control to Prevent Frequent Cycling
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Solution Overview
Problem
Existing heat source systems experience frequent start and stop cycles of heat source machines due to rigid load factor range controls, leading to inefficient operation and repeated adjustments in the number of machines.
Innovation Solution
A number-of-machines control device that uses predefined basic conditions for increasing or decreasing the number of heat source machines based on refrigeration load and required load, with additional checks to prevent erroneous determinations and noise influences, including forced load factors to ensure stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of heat source machines is controlled using a preset load factor range, then the load factors of operating heat source machines can be maintained within an optimal range, but the start and stop of heat source machines occur frequently
Solution Approach 1:
The control device performs preliminary calculations to determine the load factor that would result from increasing or decreasing the number of heat source machines by one, before actually making the change. This allows the system to predict the outcome of potential machine number adjustments and select the optimal direction (increase or decrease) to maintain load factors within the target range, thereby preventing frequent start-stop cycles.
Solution Approach 2:
The control device continuously monitors the current number of heat source machines, their operational status, and load factors. Based on this feedback, it calculates whether increasing or decreasing the machine count would achieve better load factor distribution, and adjusts the machine number accordingly to maintain optimal operation without frequent changes.
2Productivity
If the number of heat source machines is increased or decreased based on load factor conditions, then the load distribution can be optimized, but erroneous determinations and noise influences cause repeated adjustments
Solution Approach 1:
Before changing the number of heat source machines, the control device preliminarily calculates the resulting load factor for each machine and compares it with the target range. This preliminary assessment prevents erroneous determinations by ensuring that any machine number change will actually improve load distribution, rather than causing fluctuations due to noise or temporary conditions.
Solution Approach 2:
The control device applies preliminary anti-action by calculating the opposite scenario (both increasing and decreasing machine count) and selecting the direction that leads to better load factor distribution. This prevents premature or erroneous machine start-stop decisions by evaluating both possibilities before committing to a change.
Data Source
AI summary
An object of the invention is to prevent the start and stop of heat source machines from being frequently repeated. Whether or not basic conditions for decreasing the number of machines are satisfied when the number of currently operating machines is increased by one is determined if a current operational status satisfies basic conditions for increasing the number of machines, and one heat source machine is started if it is determined that the basic conditions for decreasing the number of machines are not satisfied. Additionally, whether or not the basic conditions for increasing the number of machines are satisfied when the number of currently operating machines is decreased by one are satisfied if a current operational status satisfies the basic conditions for decreasing the number of machines, and one heat source machine is stopped if it is determined that the basic conditions for increasing the number of machines are not satisfied.