Manifold-Pipe Heat Source System Flow Rate Control for Parallel Units
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Solution Overview
Problem
Manifold-pipe-type heat source systems face challenges in ensuring stable operation when there are differences in the number and capacity of heat source units and pumps, leading to inefficiencies in flow rate management and potential instability due to varying pipe lengths and pump capacities.
Innovation Solution
A control unit is implemented to determine and manage the requested flow rate by adjusting the number of operating heat source units and pumps, utilizing a collective pipe to collect flow paths and incorporating VFD control to optimize pump and heat source unit operations, ensuring minimum required flow rates are met while stabilizing system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a manifold-pipe-type heat source system uses multiple heat source units and pumps connected in parallel, then system reliability is improved through redundancy, but flow rate management becomes complex and unstable due to varying pipe lengths and pump capacities
Solution Approach 1:
The control unit dynamically adjusts operating parameters (flow rates, pump speeds via VFD) based on real-time system conditions. It calculates requested flow rates for each heat source unit and compares them with current water supply amounts, continuously optimizing parameters to maintain stable operation despite variations in pipe lengths and pump capacities.
Solution Approach 2:
The control unit implements a feedback mechanism by continuously monitoring operation states of heat source units and pumps, comparing requested flow rates with current water supply amounts, and adjusting pump operations accordingly. This closed-loop control ensures stable flow rate management while maintaining system redundancy.
2Stability of the object's composition
If the system fixes a minimum number of pumps and VFD command values to ensure minimum required flow rates, then flow rate stability is improved, but system adaptability and efficiency deteriorate
Solution Approach 1:
The control unit dynamically determines requested flow rates based on current operation states of heat source units and adjusts pump operations in real-time. Instead of fixed settings, the system continuously adapts flow rate allocations to match actual thermal demands and operational conditions, maintaining stability through active control rather than rigid constraints.
Solution Approach 2:
The system changes operating parameters (pump speeds, flow rates) dynamically based on real-time conditions. The control unit calculates requested flow rates for each heat source unit based on its current operation state and adjusts pump VFD commands accordingly, allowing the system to adapt to varying thermal demands while maintaining minimum required flow rates.
3Adaptability or versatility
If pumps with different capacities and heat source units with varying pipe lengths are used, then system versatility is improved, but flow rate distribution becomes uneven and unstable
Solution Approach 1:
The control unit applies local quality control by determining requested flow rates for each heat source unit based on its specific characteristics and operation state. It individually manages flow rate allocations to account for varying pipe lengths and pump capacities, optimizing each branch's flow rate independently while maintaining overall system balance.
Solution Approach 2:
The system dynamically adjusts flow rate parameters for each heat source unit based on its specific conditions. The control unit calculates requested flow rates considering individual unit characteristics and pipe length variations, then adjusts pump operations to achieve stable and balanced flow rate distribution across all branches despite hardware variations.
Data Source
AI summary
A heat source system includes a plurality of heat source units provided in parallel, a plurality of pumps provided in parallel, a collective pipe that collects flow paths between the plurality of heat source units and the plurality of pumps into one, and a control unit. The control unit determines a requested flow rate, based on at least a minimum required flow rate set for each heat source unit and an operation state of each heat source unit, determines a current water supply amount or a maximum water supply amount, based on a flow rate set for each pump and an operation state of each pump, makes a comparison between the requested flow rate and the current water supply amount or the maximum water supply amount, and controls operation of the plurality of heat source units or the plurality of pumps according to a result of the comparison.