Thermostatic Valve Control Using Peltier-Based Temperature Compensation

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Solution Overview

Problem

Thermostatic elements in valve arrangements for heat exchangers exhibit proportional control behavior, resulting in a permanent control deviation between target and actual temperatures, and traditional motor-driven solutions are slow and costly.

Innovation Solution

Incorporating a temperature and/or pressure influencing device that adjusts the thermostatic element's control characteristics based on physical parameters, such as pressure and temperature, to improve control behavior, potentially enabling PI or PID control, using a Peltier element for heating or cooling, and a thermally conductive connection for rapid temperature transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a thermostatic element is used to control the valve, then the response speed is quick, but a permanent control deviation remains between target and actual temperatures

Engineering Contradiction:
Improveresponse speedVSAvoidtemperature control accuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

A temperature and/or pressure influencing device is introduced as an intermediary between the physical parameters and the thermostatic element. This device modifies the control characteristics of the thermostatic element by adjusting its temperature and/or pressure based on control deviation signals, enabling the system to eliminate permanent control deviation while preserving the quick response特性 of the thermostatic element

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The control characteristics of the thermostatic element are changed by dynamically adjusting its temperature and/or pressure parameters. The temperature and/or pressure influencing device alters these parameters in response to control deviation, transforming the proportional control behavior into a more accurate control system that can achieve PI or PID control characteristics

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If a motor is used to control the valve, then the control accuracy can be improved, but the response speed becomes slow and the cost increases

Engineering Contradiction:
Improvetemperature control accuracyVSAvoidresponse speed
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The temperature and/or pressure influencing device serves as an intermediary that enables accurate control without requiring a motor. By modifying the control characteristics of the thermostatic element through temperature and/or pressure adjustments, the system achieves motor-level control accuracy while maintaining the inherent speed advantage of thermostatic elements

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mechanical motor-driven control system is replaced with a thermodynamic control approach. Instead of using mechanical force to adjust the valve, the system uses temperature and/or pressure influences on the thermostatic element to achieve precise control, eliminating the need for motors and their associated complexity and cost

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 reduces control deviations and enhances the stability and responsiveness of the valve control loop, achieving better temperature regulation with reduced residual temperature deviations in heat exchangers, particularly in domestic water heaters.

Implementation Method 1

using a Peltier element for heating or cooling

Methodology Applied
Scientific EffectPeltier effect: Peltier Effect

Implementation Method 2

a thermally conductive connection for rapid temperature transfer

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2435887B1Enhanced control of a thermostatic valve
Publication Date: 2013.12.18 DANFOSS AS
  • EP2435887B1 patent drawingFigure 1~4
  • EP2435887B1 patent drawingFigure 2a~5
  • EP2435887B1 patent drawingFigure 6

AI summary

The invention relates to a valve arrangement (1), having a valve (2), which controls a flow of a heat-transfer medium through a heat exchanger arrangement, which comprises a primary side and a secondary side (11), and having a valve actuating device, which comprises a thermostat element (6), which is exposed to a temperature on the secondary side (11) and can be acted on by a temperature- and/or pressure-influencing device (14). The aim of the invention is to achieve good control behavior and fast reaction. For this purpose, the temperature- and/or pressure-influencing device (14) is influenced by a physical variable that can be determined at the valve (2) or the heat exchanger arrangement.