Demand-Triggered Hot Water Circulation for Distant Tapping Points

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Solution Overview

Problem

Conventional central water heating systems face challenges in providing hot water efficiently and economically, especially at distant tapping points, leading to energy losses, Legionella proliferation, and discomfort due to temperature fluctuations and the need for continuous circulation, which increases energy consumption and system costs.

Innovation Solution

A system comprising a container with a hot water reservoir near the tapping point, connected by first and second line sections to the central water heating device, with a pump and demand sensor, allowing for continuous hot water supply without interrupting flow or cooling, using thermal valves and mixers to maintain temperature, and optionally incorporating Peltier elements or heat exchangers for energy recovery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If circulation systems are used to provide hot water at distant tapping points, then hot water availability is improved, but energy loss increases due to continuous circulation

Engineering Contradiction:
Improvehot water availabilityVSAvoidenergy loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The system uses periodic circulation instead of continuous circulation. The circulation pump operates only when hot water is demanded at a tapping point, circulating hot water from the storage system to the demand point and then returning it. This periodic operation eliminates energy waste during periods when no hot water is needed, while still ensuring hot water availability when required.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The invention extracts the circulation function from a continuous operation and implements it as a demand-triggered periodic operation. The circulation system is taken out of constant operation and activated only when needed, separating the circulation function from continuous energy consumption.

Inventive Principle:
Principle #2Taking out (Extraction)

2Loss of energy

If circulation is interrupted to save energy, then energy loss is reduced, but hot water delivery time increases

Engineering Contradiction:
Improveenergy lossVSAvoidhot water delivery time
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The system performs preliminary action by pre-circulating hot water to the demand point before actual hot water demand occurs. When a demand sensor detects hot water demand, the circulation system is already positioned to immediately deliver hot water without waiting for the pipes to heat up, thus reducing delivery time while maintaining energy efficiency through demand-triggered operation.

Inventive Principle:
Principle #10Preliminary action

3Use of energy by moving object

If hot water temperature is reduced to save energy, then energy consumption is lowered, but Legionella proliferation risk increases

Engineering Contradiction:
Improveenergy consumptionVSAvoidLegionella proliferation
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The system maintains continuous hot water circulation during demand periods, ensuring that hot water continuously flows through the system at temperatures sufficient to prevent Legionella proliferation. The circulation continues throughout the hot water demand period rather than allowing temperature drops, eliminating the harmful effect while managing energy consumption through demand-triggered operation.

Inventive Principle:
Principle #20Continuity of useful action

4Reliability

If central water heating systems are used for distant tapping points, then hot water supply is improved, but energy loss in pipes increases

Engineering Contradiction:
Improvehot water supplyVSAvoidenergy loss in pipes
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The system uses self-service by utilizing the return line from the tapping point as part of the circulation path. The cold water line that returns to the central heating system is converted into a useful circulation path for hot water, allowing the system to serve itself by eliminating the need for separate circulation pipes and reducing energy loss through more efficient heat utilization.

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

The system ensures rapid, continuous, and energy-efficient hot water supply at tapping points, minimizing energy losses and Legionella risks, while reducing the need for circulation lines and enhancing water hygiene by maintaining optimal temperatures.

Implementation Method 1

at least one pump

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 2

using thermal valves and mixers to maintain temperature

Methodology Applied
Scientific EffectThermal mixing: Heat Exchanger

Implementation Method 3

optionally incorporating Peltier elements or heat exchangers for energy recovery

Methodology Applied
Scientific EffectHeat exchanger: Heat Exchanger

Implementation Method 4

optionally incorporating Peltier elements or heat exchangers for energy recovery

Methodology Applied
Scientific EffectPeltier effect: Peltier Effect

Data Source

PatentEP2503252B1System for producing heated service water in a line system
Publication Date: 2020.04.29 KEITSCH MARKUS
  • EP2503252B1 patent drawingFigure 1
  • EP2503252B1 patent drawingFigure 2
  • EP2503252B1 patent drawingFigure 3

AI summary

The system comprises a hot-water reservoir (W), a thermo-valve (5a), a discharge sensor (13), a water storage system (6), line sections (1,2), and a pump (8). The line section (1) supplies the inflowing hot water from the hot water reservoir or hot water storage system, to the hot water extraction point (12). The pump is arranged to control the transport of cold water through the line section (2) and to control the flow of hot water to the hot-water reservoir.