Method and system for controlling energy transfer of a thermal energy exchanger
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Solution Overview
Problem
Existing HVAC systems face challenges in accurately controlling energy transfer in thermal energy exchangers, especially during transient events and processes, as the basic calculation of energy transfer based on flow rate and temperature differential is insufficient in dynamic scenarios.
Innovation Solution
A control system that uses flow sensors and temperature sensors to measure fluid flow and temperatures, determining flow-dependent model parameters to estimate energy transfer and regulate fluid flow through the thermal energy exchanger, thereby accurately controlling energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the basic calculation method (Q≈Φ·ΔT) is used for energy transfer, then the control system is simple, but the measurement precision is insufficient during transient events
Solution Approach 1:
The control system pre-determines flow-dependent model parameters (including heat transfer coefficients, thermal capacities, and delay times) through offline measurements and model fitting before actual operation. During transient events, these pre-determined parameters enable accurate energy transfer calculation without requiring complex real-time computations, thus improving measurement precision while keeping the control system manageable.
Solution Approach 2:
The patent introduces flow-dependent model parameters as an intermediary between the simple flow rate measurement and the complex energy transfer calculation. These parameters (determined through offline model fitting) act as a bridge that enables accurate energy transfer estimation during transient events without requiring the control system to handle full computational complexity in real-time.
2Productivity
If flow rate is increased through the thermal energy exchanger, then the productivity is improved, but the efficiency of energy transfer is reduced
Solution Approach 1:
The control system dynamically adjusts the flow rate through the thermal energy exchanger based on real-time conditions (temperature differentials, flow rate changes, and pre-determined model parameters). During transient events, the system optimizes flow rate to maintain high energy transfer efficiency while still achieving required productivity, avoiding the static high-flow approach that causes efficiency losses.
Solution Approach 2:
The system changes operating parameters (flow rate, temperature differential utilization) based on the determined energy transfer model and current system state. By using flow-dependent model parameters and real-time measurements, the system adapts parameters to maintain optimal efficiency across varying productivity requirements, rather than operating at fixed high flow rates.
3Adaptability or versatility
If the thermal energy exchanger operates during transient events, then the adaptability is improved, but the measurement precision of energy transfer deteriorates
Solution Approach 1:
The control system performs offline measurements and model fitting to pre-determine flow-dependent parameters (heat transfer coefficients, thermal capacities, delay times) before transient events occur. This preliminary action creates a ready-to-use energy transfer model that can be rapidly applied during transient events, maintaining measurement precision while enabling high adaptability to changing conditions.
Solution Approach 2:
The system continuously monitors flow rate and temperature differential during transient events and uses this feedback with the pre-determined model parameters to calculate accurate energy transfer values in real-time. The feedback loop ensures that even during dynamic transient conditions, the energy transfer measurement remains precise by constantly updating calculations with current measurements and the validated energy transfer model.
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
This approach allows for precise regulation of energy transfer in HVAC systems, even during transient events, by using flow-dependent model parameters to calculate and adjust fluid flow, enhancing the efficiency and accuracy of energy management.
Implementation Method 1
thermal energy exchanger
Implementation Method 2
fluid rushes at an increased rate through the thermal energy exchangers
Data Source
AI summary
For controlling energy transfer (Q) of a thermal energy exchanger of an HVAC system, a control system determines flow-dependent model parameters (M) for modelling performance of the thermal energy exchanger, using a plurality of measurement data sets, each measurement data set including for a respective measurement time a value of a measured flow of fluid (Φact), a value of a measured supply temperature (Tsup) of the fluid, and a value of the measured return temperature (Tret) of the fluid. The control system calculates an estimated energy transfer (Qest) of the thermal energy exchanger, using the flow-dependent model parameters (M), and controls (S4) the energy transfer (Q) of the thermal energy exchanger by regulating (S5) the flow of fluid (Φ) through the thermal energy exchanger, using the estimated energy transfer (Qest).