Hybrid heating device and method for operating a hybrid heating device

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Solution Overview

Problem

Conventional hybrid heating devices face limitations in their modulation range, often requiring frequent switching between fossil fuel and electrical sources to meet varying heat demands, leading to inefficiencies and increased operational costs.

Innovation Solution

A hybrid heating device with a burner and an additional electric heater, where the electric heater is used to supplement or replace the burner based on heat demand, with a control system that adjusts the heat sources to maintain a stable flow temperature by switching between them only when necessary, thereby avoiding frequent switching and optimizing energy use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the burner operates at minimum output to meet low heat demand, then the modulation range is extended downwards, but the flow temperature becomes excessively high leading to frequent switching

Engineering Contradiction:
Improvemodulation rangeVSAvoidswitching stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent combines the burner and electric auxiliary heater into a hybrid heating system where both heat sources work together. The electric auxiliary heater supplements the burner output in the low-power range, allowing the burner to operate at minimum output without causing excessive flow temperature, thereby extending the modulation range while maintaining switching stability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electric auxiliary heater acts as an intermediary element that bridges the gap between the burner's minimum output and the actual low heat demand. It provides additional heating capacity when needed, preventing the flow temperature from rising too high and avoiding frequent switching cycles.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the electric auxiliary heater is operated to cover the entire low power range up to the burner's minimum output, then the modulation range is fully extended, but the burner switches on and off frequently in the transition area

Engineering Contradiction:
Improvemodulation rangeVSAvoidswitching frequency
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The electric auxiliary heater is operated partially - not for the entire low power range up to the burner's minimum output, but only for a portion of it. This partial action allows the burner to remain on continuously while the electric heater provides supplemental heat, avoiding frequent burner switching while still extending the modulation range.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system dynamically adjusts the output of the electric auxiliary heater based on the current heat demand and burner output. The electric heater's contribution varies continuously to maintain the flow temperature within the hysteresis band, optimizing the division of labor between the two heat sources and minimizing switching frequency.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If a small hysteresis band is used for flow temperature control, then the temperature control precision is improved, but the switching frequency increases

Engineering Contradiction:
Improvetemperature control precisionVSAvoidswitching stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

By combining both heat sources, the system can maintain a larger hysteresis band without sacrificing temperature control precision. The electric auxiliary heater compensates for the temperature deviation more gradually, allowing a wider control band that reduces switching frequency while still achieving adequate temperature regulation.

Inventive Principle:
Principle #5Merging (Combining)

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 extends the modulation range of the heating device, reducing energy wastage and improving efficiency by ensuring that the appropriate heat source is used according to current demand, minimizing temperature deviations and operational costs.

Implementation Method 1

an additional electric heater (4), wherein the additional electric heater (4) is used in a hybrid heating device for heat generation in at least a portion of the modulation range of the heating device

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

A hybrid heater within the meaning of this invention is a heater that generates heat both from the combustion of a fossil fuel such as natural gas and from an electrical energy source

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 3

the additional electric heater is operated as soon as the heat requirement falls below the minimum output of the burner or exceeds the maximum output

Methodology Applied
Scientific EffectThermal energy transfer: Heat Exchanger

Data Source

PatentEP3553408B1Hybrid heating device and method for operating a hybrid heating device
Publication Date: 2020.12.16 VAILLANT GMBH(DE)
  • EP3553408B1 patent drawingFigure 1
  • EP3553408B1 patent drawingFigure 2
  • EP3553408B1 patent drawingFigure 3

AI summary

The invention relates to a method for operating a hybrid heating device (1) and a hybrid heating device (1). The heating device (1) comprises a first heat source (3) based on the combustion of a mixture of fuel gas and air and a second heat source (4) based on electrical energy. If the heat demand (101) falls below the minimum output (P1,min) of the first heat source, the system switches to the second heat source (4) and vice versa.