Threshold-Triggered Secondary Heating for Domestic Hot Water

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Solution Overview

Problem

Existing systems for supplying hot service water struggle to maintain a consistent temperature when there is a sudden increase in water volume flow, leading to temperature drops that cannot be quickly mitigated by the primary heat source, especially when multiple outlets are used simultaneously.

Innovation Solution

A method and device that utilize a secondary heat source, such as an electric heater, strategically positioned close to the outlet of the service water, which is activated based on rapid changes in volume flow or temperature, allowing it to quickly stabilize the outlet temperature within a desired tolerance range by switching on when thresholds are exceeded, and can be integrated into existing systems without significant additional equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the primary heat source is used to heat service water, then the system can maintain normal operation, but the response time is too slow when volume flow suddenly increases

Engineering Contradiction:
Improveresponse time of primary heat sourceVSAvoidtemperature stability of service water
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The control unit activates the secondary heat source in advance when detecting a sudden increase in volume flow, before the primary heat source can respond. This preliminary action prevents temperature drops by providing immediate supplemental heating capacity during transient high-demand periods.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the secondary heat source is activated to prevent temperature drops, then temperature stability improves, but energy consumption increases

Engineering Contradiction:
Improvetemperature stability of service waterVSAvoidenergy consumption of heat sources
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The control unit dynamically adjusts the operation of the secondary heat source based on real-time monitoring of volume flow and temperature. The secondary heat source is activated only when necessary (during sudden volume flow increases) and deactivated when not needed, optimizing energy consumption while maintaining temperature stability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control unit continuously monitors volume flow and outlet temperature, using this feedback to determine when to activate or deactivate the secondary heat source. This closed-loop control ensures the secondary heat source operates only when required to maintain temperature within the tolerance range, avoiding unnecessary energy consumption.

Inventive Principle:
Principle #23Feedback

3Reliability

If a larger service water storage tank is used to buffer temperature changes, then temperature stability improves, but system complexity and cost increase

Engineering Contradiction:
Improvetemperature stability of service waterVSAvoidsystem equipment requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control unit acts as an intermediary that coordinates between the volume flow sensor, temperature sensor, primary heat source, and secondary heat source. This intelligent control mechanism provides temperature stability without requiring additional physical buffering components like larger storage tanks, thereby avoiding increased system complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 secondary heat source effectively reduces and prevents temperature fluctuations within seconds, ensuring the outlet temperature remains within a specified range, even during sudden increases in water demand, enhancing comfort and safety without increasing equipment costs.

Implementation Method 1

A method and device that utilize a secondary heat source, such as an electric heater, strategically positioned close to the outlet of the service water

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a secondary heat exchanger typically present for heating the service water

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3812659A1Method and device for reducing temperature variations in a hot water system
Publication Date: 2021.04.28 VAILLANT GMBH(DE)
  • EP3812659A1 patent drawingFigure 1
  • EP3812659A1 patent drawingFigure 2
  • EP3812659A1 patent drawing

AI summary

The invention relates to a method for reducing temperature fluctuations in a system for hot domestic water that can be heated by a primary heat source (4) when there are changes in the volume flow rate of the domestic water drawn off at a domestic water outlet (9), wherein the change in volume flow rate or a change in the outlet temperature of the domestic water is detected and a secondary heat source (50) is switched on when a threshold value is exceeded.The invention also relates to a device for reducing temperature fluctuations in a domestic hot water system heated by a primary heat source (4) when the volume flow rate of the domestic hot water drawn from a domestic hot water outlet (9) changes, wherein a volume flow sensor (15) for measuring a change in the volume flow rate and/or a temperature sensor (16) for measuring a change in the outlet temperature of the domestic hot water are provided, wherein a secondary heat source (50) is further provided, which is arranged such that its activation affects the outlet temperature of the domestic hot water within less than 10 s, preferably less than 5 s, and wherein the secondary heat source (50) can be activated by means of an evaluation logic (17) when the volume flow rate or the outlet temperature or their respective changes per unit of time exceed a threshold value.