Heat Exchanger Flow-Free Control Using Pump Parameter Inference
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Solution Overview
Problem
Existing heat exchanger control systems are not independent of inlet stream temperature changes and require flow meters, which increase costs and reduce reliability.
Innovation Solution
A heat exchanger control and diagnostic apparatus with additional temperature sensors and a control unit that includes a temperature module, power calculation module, and heat flow controller, allowing for independent heat flow regulation and diagnostics, eliminating the need for flow meters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flow meter is used to measure the flow rate for calculating actual absolute heat exchanger power, then measurement precision is improved, but device complexity and cost increase, and reliability decreases
Solution Approach 1:
The patent extracts the flow measurement function from a dedicated flow meter and integrates it into the pump system by inferring flow rate from pump operational parameters (revolutions, electric power consumption, motor temperature). This eliminates the need for a separate flow meter while maintaining measurement capability.
Solution Approach 2:
The patent uses pump operational parameters as an intermediary to indirectly measure flow rate. Instead of directly measuring flow with a flow meter, the system uses easily measurable pump parameters (revolutions, power consumption) that correlate with flow rate through pre-stored characteristics.
2Reliability
If pump operational parameters are used to infer flow rate, then device complexity is reduced and reliability is improved, but measurement precision deteriorates
Solution Approach 1:
The patent performs preliminary characterization of pump performance by storing pump power characteristics and flow-rate characteristics at different revolutions in memory before actual operation. During operation, the system retrieves these pre-stored characteristics to accurately infer flow rate from current pump parameters, ensuring measurement precision without requiring complex real-time calculations.
3Ease of operation
If temperature difference control is used for power output control of terminal heat exchangers, then ease of operation is improved, but heat delivery control independence from inlet stream temperature changes deteriorates
Solution Approach 1:
The patent implements a feedback control system that continuously monitors actual heat delivery and compares it with the setpoint. The control unit adjusts pump revolutions based on this feedback to maintain the desired heat delivery level, compensating for inlet stream temperature variations and ensuring independent heat delivery control.
Solution Approach 2:
The patent transitions from static temperature difference control to dynamic control by adjusting pump revolutions based on real-time conditions. The system dynamically adapts pump speed to maintain consistent heat delivery despite varying inlet temperatures, combining ease of operation with control independence.
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
Enables precise control of heat flow and zone temperature, providing early alerts for degrading efficiency or malfunctions, and accurate energy billing through independent heat flow regulation and diagnostics.
Implementation Method 1
an actual absolute heat exchanger power (a heat flow between primary and secondary heat-transfer liquid)
Implementation Method 2
Heat from a heat source is transported through a distribution network into terminal heat exchangers
Data Source
Figure 1
Figure 2~4
AI summary
A heat exchanger (1) controlled by the device has its primary inlet (4) of a primary heat- transport liquid mounted with a first temperature sensor (15); and its primary outlet (5) of the primary heat-transport liquid mounted with a second temperature sensor (20), where this primary outlet (5) is piped to a pump (2), comprising a pump impeller (6) connected to a motor (9), from where the primary heat-transport liquid is piped by a plumbing (7) to a heat source and from there back to the primary inlet (4). At the same time, there is a control unit (3) connected to the heat exchanger (1) and the pump (2) and contains a motor control unit (10) bi- directionally connected to the motor (9). The heat exchanger (1) also has a secondary inlet (23) for a secondary heat-transport liquid and a secondary outlet (24) ducted to a temperature zone (25) and back to the secondary inlet (23). The control unit (3) also has a temperature module (17), whose first input is connected by a communication channel (16) to an output of the temperature sensor (15), and whose second input is connected by a communication channel (21) to an output of the second temperature sensor (20). The temperature module (17) has its output (18) - a primary inlet temperature - connected to one input of a power calculation module (19), and its output (22) - a primary outlet temperature - connected to other input of the power calculation module (19). The third input (14) of the power calculation module (19) is connected to a flow estimation module (12). The flow estimation module has one input connected to an output of a memory unit (13), and the other input connected by a bus (11) to an output of the motor control unit (10). At the same time, there is an output (26) - a heat flow estimate - of the power calculation module (19) connected to one input of a heat flow controller (27), whose other input (28) - a heat flow demand - is connected to an output of an operator unit (29), and whose output (30) is connected to an input of the motor control unit (10).