Heat source system controlling device, heat source system, heat source system controlling method, and heat source system controlling program
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Solution Overview
Problem
Complex heat source systems face challenges with underload and overload operations due to differences in responding speeds between heat-pump type and absorption-type chillers when changing chilled or heated water leaving temperatures, leading to potential stops and inefficiencies.
Innovation Solution
A heat source system controlling device and method that adjusts the heat transfer medium leaving temperature of the higher COP heat source machine to prevent underload stops in the lower COP machine by predicting and managing the post-change operation state, using thresholds and load factors to avoid transient fluctuations and ensure stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the heat transfer medium leaving temperature of the first heat source machine is changed to improve system COP, then the overall efficiency is improved, but the second heat source machine may experience underload stop due to rapid temperature changes
Solution Approach 1:
The control device predicts the post-change operation state of the second heat source machine before actually changing the heat transfer medium leaving temperature. This preliminary prediction action allows the system to anticipate potential underload stop conditions and adjust the temperature change accordingly, preventing reliability issues before they occur.
Solution Approach 2:
The control device uses feedback from the predicted operation state to determine whether to change the heat transfer medium leaving temperature. By continuously monitoring predicted load factors and comparing them against underload stop threshold values, the system adjusts temperature changes in real-time to maintain both efficiency and operational reliability.
2Speed
If the heat transfer medium leaving temperature is changed rapidly to adjust heat generation, then the system responds faster to load changes, but transient fluctuations cause underload stops in absorption-type chillers
Solution Approach 1:
The control device performs preliminary prediction of the operation state before executing temperature changes. This advance assessment allows the system to plan temperature adjustments that achieve rapid response while avoiding the transient fluctuations that cause underload stops in absorption-type chillers.
Solution Approach 2:
The control device takes preliminary anti-action by predicting and preventing underload stop conditions before they occur. By assessing the predicted load factor and comparing it against threshold values, the system counteracts potential instability before transient fluctuations can cause operational disruptions.
3Stability of the object's composition
If the setting value for heat transfer medium leaving temperature is returned to original state, then the system maintains temperature balance, but the first heat source machine may experience underload stop due to insufficient temperature difference
Solution Approach 1:
The control device performs preliminary prediction before returning the heat transfer medium leaving temperature to its original setting value. This advance assessment determines whether the first heat source machine would experience underload stop due to insufficient temperature difference, allowing the system to maintain temperature balance while preventing operational disruptions.
4Loss of energy
If the heat transfer medium leaving temperature is changed to optimize heat distribution, then system efficiency improves, but the first heat source machine may experience overload operation
Solution Approach 1:
The control device uses feedback from the predicted operation state to determine whether changing the heat transfer medium leaving temperature would cause overload in the first heat source machine. By monitoring predicted load factors and comparing them against overload threshold values, the system optimizes heat distribution efficiency while maintaining operational safety.
Data Source
AI summary
A superordinate controlling device for a heat source system (1) including a plurality of heat sources, the superordinate controlling device being applied to the heat source system (1) and controlling heat-pump type chillers (2a) and (2b) and absorption-type chillers (2c) and (2d) in such a manner that a heat transfer medium leaving temperature that is the temperature of a heat transfer medium supplied to an external load (6) is equal to a setting temperature. The heat-pump type chillers (2a) and (2b) each have a higher Coefficient of Performance (COP) than that of each of the absorption-type chillers (2c) and (2d). The superordinate controlling device includes a heat transfer medium leaving temperature changing means for carrying out heat transfer medium leaving temperature control, by changing the heat transfer medium leaving temperatures of the heat-pump type chillers (2a) and (2b), when a post-change prediction value of each of the absorption-type chiller (2c) and (2d) predicted based on a supposition that the heat transfer medium leaving temperatures of the heat-pump type chillers (2a) and (2b) are changed exceeds a second underload stop threshold value at which the corresponding one of the absorption-type chiller (2c) and (2d) would have an underload stop.