Heating Curve Preheat Control Using Valve Opening Feedback

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Solution Overview

Problem

Conventional heating systems face inefficiencies due to steeply set heating curves, leading to excessive energy consumption and reduced efficiency, especially when using heat pumps, as they require significant technical effort and additional sensors, and are not suitable for systems with constant power output or underfloor heating.

Innovation Solution

A method that adjusts the flow temperature setpoint of a heating curve using pulse-width-modulated control signals to control control valves, determining the optimal flow temperature based on averaged outside temperatures and the percentage ratio of control valve opening times, allowing for continuous adaptation without additional sensors or complex installations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the heating curve is set steeply to prevent customer complaints about low room temperatures, then room temperature comfort is improved, but energy efficiency and system efficiency deteriorate due to excessively high flow temperatures

Engineering Contradiction:
Improveroom temperature comfortVSAvoidenergy efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The heating curve is made dynamically adjustable through automated optimization. The control device continuously adapts the heating curve parameters (slope, offset) based on actual system operation data, transforming a static, overly conservative heating curve into a dynamic, optimized one that balances comfort and energy efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from control valve positions and temperature measurements to automatically adjust the heating curve. The control device receives data about actual valve positions during operation and uses this feedback to optimize the heating curve parameters, creating a closed-loop system that continuously improves efficiency while maintaining comfort.

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If additional sensors and complex installations are added to adjust the heating curve, then heating system optimization capability is improved, but device complexity and technical effort increase

Engineering Contradiction:
Improveheating curve optimization capabilityVSAvoidtechnical effort
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The heating system performs self-optimization using data already available from normal operation. The control device automatically adjusts the heating curve based on information from existing control valves and temperature sensors, eliminating the need for additional measurement devices or complex manual commissioning procedures.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The control device performs multiple functions: it controls the heating system operation, monitors valve positions, measures temperatures, and automatically optimizes the heating curve parameters. This multi-functionality eliminates the need for separate optimization systems or additional specialized sensors.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Power

If the flow temperature is increased to meet heating demands, then heat dissipation from heating surfaces is improved, but energy losses and system inefficiency worsen

Engineering Contradiction:
Improveheat dissipationVSAvoidenergy losses
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The system dynamically changes the flow temperature parameter based on actual heating needs and outdoor conditions. By continuously optimizing the heating curve, the system adjusts flow temperatures to match real demands, avoiding both excessive temperatures (causing energy losses) and insufficient temperatures (causing comfort issues).

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2369245B1Method for altering a preheat temperature target value of a heating curve for a heating assembly
Publication Date: 2012.09.26 REHAU AG & CO
  • EP2369245B1 patent drawingFigure 1
  • EP2369245B1 patent drawingFigure 2
  • EP2369245B1 patent drawingFigure 3

AI summary

The method involves producing (F) an average value from total opening times of adjusting valves, and determining (G) a preheating temperature threshold value of a heating curve from a medium external temperature. The threshold value is increased when a percentage ratio of the average value to detection time is greater than or equal to an upper limit that amounts to 55 percentages. The threshold value is reduced when the ratio is smaller than or equal to a lower limit that amounts to 45 percentages, and the threshold value is maintained when the ratio lies in an area between the limits.