HVAC Flow Control Using Secondary Circuit Temperature Feedback

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Solution Overview

Problem

Existing HVAC systems operating with thermal energy transfer devices connected by primary and secondary fluid circuits often operate sub-optimally due to neglecting conditions within the secondary fluid circuit when controlling parameters of the primary fluid circuit.

Innovation Solution

A method and flow control device that determine and control the flow rate of the primary fluid circuit based on the temperature of the secondary fluid circuit, using sensors and actuators to maintain optimal thermal energy transfer rates and prevent overheating or freezing, ensuring efficient operation and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the flow rate of the primary fluid circuit is controlled without considering secondary fluid circuit conditions, then the system operation is simplified, but the thermal energy transfer efficiency deteriorates

Engineering Contradiction:
Improvecontrol simplicityVSAvoidthermal energy transfer efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The system implements feedback control by continuously monitoring the temperature of the secondary fluid circuit and using this information to adjust the flow rate of the primary fluid circuit. The processing unit receives temperature data from sensors in the secondary circuit and dynamically modifies the primary circuit flow rate accordingly, creating a closed-loop control system that optimizes thermal energy transfer efficiency while maintaining operational simplicity.

Inventive Principle:
Principle #23Feedback

2Productivity

If the flow rate of the primary fluid circuit is increased to improve thermal energy transfer, then the thermal energy transfer rate improves, but the energy consumption increases

Engineering Contradiction:
Improvethermal energy transfer rateVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The system employs dynamic flow rate adjustment based on real-time temperature conditions in the secondary fluid circuit. Rather than maintaining a constant high flow rate, the system dynamically adapts the primary circuit flow rate to match actual thermal energy transfer needs, ensuring optimal transfer rates while minimizing unnecessary energy consumption during periods of lower demand.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control system changes the flow rate parameter of the primary fluid circuit based on detected temperature parameters of the secondary fluid circuit. By continuously adjusting this parameter according to actual thermal conditions, the system achieves high thermal energy transfer rates when needed while reducing energy consumption when thermal demand is lower.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the flow rate of the primary fluid circuit is not monitored and controlled, then the system complexity is reduced, but the system reliability deteriorates

Engineering Contradiction:
Improvesystem complexityVSAvoidsystem reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system incorporates feedback mechanisms with temperature sensors in the secondary fluid circuit and a processing unit that continuously monitors thermal conditions. This feedback loop enables the system to detect and respond to abnormal thermal conditions, preventing failures and ensuring reliable operation without requiring overly complex monitoring infrastructure.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-monitoring and self-adjustment of the primary fluid circuit flow rate based on temperature conditions in the secondary circuit. The processing unit automatically detects thermal conditions and adjusts flow rates without external intervention, enabling the system to maintain high reliability through autonomous operation while keeping the control architecture relatively simple.

Inventive Principle:
Principle #25Self-service

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 enhances the operational efficiency and reliability of HVAC systems by optimizing thermal energy transfer, preventing system failures, and ensuring consistent comfort levels while minimizing energy consumption and wear on components.

Implementation Method 1

a thermal energy transfer device fluidically connected to a thermal energy source by a primary fluid circuit and further fluidically connected to thermal energy consumer(s) by a secondary fluid circuit

Methodology Applied
Scientific EffectThermal energy transfer: Heat Exchanger

Data Source

PatentEP4450881A1A method, flow control device and computer program product for operating an HVAC system
Publication Date: 2024.10.23 BELIMO HOLDING AG
  • EP4450881A1 patent drawingFigure 1
  • EP4450881A1 patent drawingFigure 2
  • EP4450881A1 patent drawingFigure 3

AI summary

Method of operating an HVAC system (1) comprising a thermal energy transfer device (200) fluidically connected to a thermal energy source (100) by a primary fluid circuit (400) and further fluidically connected to thermal energy consumer(s) (300) by a secondary fluid circuit (500), the method comprising determining a flow rate (Φ) of a fluid in the primary fluid circuit (400); determining a temperature of a fluid in the secondary fluid circuit (500); and controlling, by a flow control device (10) arranged in the primary fluid circuit (400), the flow rate (Φ) of the fluid in the primary fluid circuit (400) using the temperature of the fluid in the secondary fluid circuit (500).