Parallel Heat Source Flow Control for Uneven Pipe Resistance
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Solution Overview
Problem
When operating multiple heat source units, differences in pipe resistances can lead to abnormal slowdown and stoppage of pumps due to varying flow rates of the heat-transfer medium, resulting in inadequate heat or cold energy supply to the load side.
Innovation Solution
A heat source apparatus with a controller that adjusts the operation of flow control valves and pumps by detecting load-side pipe resistance characteristics and allocating flow rates to ensure consistent water flow across units, preventing pump failure and ensuring appropriate energy supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple heat source units are operated in parallel, then the heat or cold energy supply capacity is improved, but the flow rate distribution becomes uneven due to different pipe resistances, causing pump malfunction
Solution Approach 1:
The control device measures the actual flow rates of heat-transfer medium in each heat source unit and uses this feedback information to adjust pump operations. By continuously monitoring flow rates and comparing them against target values, the system dynamically adjusts pump speeds to maintain equal flow distribution across all heat source units, preventing pump malfunction while preserving the enhanced energy supply capacity of parallel operation
Solution Approach 2:
The system dynamically adjusts the operating speeds of pumps in each heat source unit based on real-time flow rate measurements and pipe resistance characteristics. Rather than operating all pumps at fixed speeds, the control device varies pump speeds adaptively to compensate for differences in pipe resistances, ensuring that each heat source unit receives the appropriate flow rate to maintain reliable operation
2Use of energy by moving object
If pump power is controlled according to load requirements, then energy efficiency is improved, but flow rate variations due to pipe resistance differences cause abnormal pump slowdown and stoppage
Solution Approach 1:
The control device uses flow rate measurements as feedback to adjust pump power consumption. By monitoring actual flow rates and comparing them to target values, the system optimizes pump power usage to match actual load requirements while preventing abnormal slowdown or stoppage. This feedback mechanism ensures that energy efficiency improvements do not compromise pump reliability
Solution Approach 2:
The system changes the operating parameters (speeds) of pumps based on measured flow rates and calculated pipe resistance characteristics. By adjusting pump speeds to compensate for pipe resistance differences, the system maintains reliable operation while optimizing energy consumption according to actual load requirements rather than operating at fixed power levels
3Adaptability or versatility
If heat source units are connected in parallel via heat-transfer medium pipes, then system flexibility and load adaptability are improved, but pipe resistance differences cause uneven flow distribution and pump failure
Solution Approach 1:
The control device implements feedback control by measuring flow rates in each parallel heat source unit and using this information to adjust pump operations. This ensures that the flexibility and load adaptability provided by parallel connection do not lead to flow distribution problems, as the system continuously monitors and corrects flow imbalances to maintain reliable operation of all units
Solution Approach 2:
The system applies different operating conditions to individual pumps in parallel heat source units based on their specific pipe resistance characteristics. Rather than treating all units uniformly, the control device adjusts each pump's speed according to its local flow conditions, ensuring that the parallel architecture's adaptability benefits are realized without causing reliability issues from uneven flow distribution
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution ensures continuous operation of heat source units by equalizing flow rates, preventing pump failure and ensuring consistent heat or cold energy delivery, even with varying pipe resistances, thus maintaining efficient energy distribution.
Implementation Method 1
The heat source unit takes in a heat-transfer medium (water or brine) by the operation of a pump
Implementation Method 2
heats or cools the taken-in heat-transfer medium by the operation of a heat-pump-type refrigerating cycle
Data Source
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AI summary
A controller controls the number of the heat source units to be operated and an amount of the heat-transfer medium which flows to the load side in accordance with required capability from the load side. The controller detects the flow rate of the heat-transfer medium flowing to the load side, and controls an amount of the heat-transfer medium which bypass flowing to the load side in accordance with the detected flow rate. The controller divides the detected flow rate and allocates the divided flow rate to each of the heat source units in operation, thereby controlling a power of the pump in each of the heat source units in operation in accordance with the allocated amount.