One-Pipe Heating Riser Control Using Return Temperature Feedback

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Solution Overview

Problem

One-pipe heating systems face challenges in regulating flow rates and temperatures efficiently, leading to uncontrolled heating and energy losses due to fixed flow rates and lack of central control, causing discomfort and inefficiency.

Innovation Solution

Implementing a decentralized control system that regulates the supply temperature based on external conditions and adjusts flow rates according to the return line temperature, using a flow controller and temperature sensors to maintain constant flow and optimize energy use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a one-pipe system is used with fixed flow rates, then the system structure is simple, but energy losses increase and heating becomes uncontrolled

Engineering Contradiction:
Improvesystem structureVSAvoidenergy losses
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent implements dynamic flow control by replacing fixed flow rates with variable flow rates that automatically adjust based on return line temperature. Flow controllers in each riser modify the flow rate of heat exchanging fluid in real-time, transforming the static one-pipe system into a dynamic one that adapts to changing thermal conditions, thereby reducing energy losses while maintaining structural simplicity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the parameter of flow rate from constant to variable based on temperature feedback. By monitoring return line temperature and adjusting flow rates accordingly, the system optimizes heat delivery efficiency. When return temperature is high (indicating low demand), flow rate is reduced; when return temperature is low (indicating high demand), flow rate is increased, thus minimizing energy losses.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If flow rates are fixed in traditional systems, then the system operation is simple, but heating control becomes uncontrolled leading to discomfort

Engineering Contradiction:
Improvesystem operationVSAvoiduncontrolled heating
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent implements feedback control by continuously monitoring return line temperature and using this information to automatically adjust flow rates in each riser. Temperature sensors detect the thermal state of the system, and this feedback signal drives the flow controllers to modify flow rates, creating a closed-loop control system that prevents uncontrolled heating while maintaining simple operation through automation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-regulation by automatically adjusting its own flow rates based on thermal conditions without requiring manual intervention. The flow controllers respond autonomously to temperature changes in the return line, enabling the system to self-correct and maintain optimal heating levels, thus preventing discomfort while keeping operation simple.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If radiator thermostats are closed on hot days, then individual room control is achieved, but return line temperature becomes excessively high causing heat losses

Engineering Contradiction:
Improveindividual room controlVSAvoidheat losses in lines
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent segments the flow control function by installing individual flow controllers in each riser rather than using a single centralized control. This segmentation allows independent adjustment of flow rates for different building sections based on their specific thermal conditions. When some rooms have closed thermostats, the corresponding riser's flow rate is reduced, preventing excess heat from circulating through the entire system and reducing heat losses in the lines.

Inventive Principle:
Principle #1Segmentation

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 transforms one-pipe systems into energy-efficient, load-dependent systems by ensuring that heat is delivered according to actual demand, reducing energy waste and maintaining comfortable living spaces.

Implementation Method 1

a temperature sensor positioned in heat exchanging connection to the heat exchanging fluid in the return line

Methodology Applied
Scientific EffectTemperature sensing:

Implementation Method 2

a supply line system feeds some heat exchanging fluid medium (typically water) and a supply temperature (typically water) at a flow rate to a collection of heat exchanging devices

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

The individual radiators are connected in series with one after the other, such that the return line of one radiator is the feeding line of a next radiator

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2395289B1Method to regulate a one-pipe heat supply system
Publication Date: 2016.03.23 DANFOSS AS
  • EP2395289B1 patent drawingFigure 1
  • EP2395289B1 patent drawingFigure 2
  • EP2395289B1 patent drawingFigure 3

AI summary

Method to control the flow rate and of a heat exchanging fluid medium to a riser in a one-pipe system being a typical pipe set up in for example building cooperatives for supplying heat to the radiators of the flats. The method being to regulate the temperature of the supplied heat exchanging fluid medium in response to changes in external parameters (temperature) and the flow rate in response to the temperature of the heat exchanging fluid medium in an return line.