Condensing Boiler Return Cooling for Efficient Hot Water Heating

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Solution Overview

Problem

Condensing boilers face inefficiencies when operating in low temperature ranges for simultaneous heating and hot water provision, particularly due to the need for separate temperature control and energy consumption, and existing heat pump integration methods can worsen heat transfer efficiency.

Innovation Solution

A heating system with a condensing boiler integrates a heat pump that routes the return flow of the heating circuit through its evaporator, transferring heat at a higher temperature level to the hot water tank, and uses a heat pump to manage temperature fluctuations and optimize energy use by connecting the return flow to the evaporator and condenser, allowing for load-dependent operation and integration with solar thermal systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the return temperature is increased to improve hot water heating efficiency, then hot water production is enhanced, but the condensing boiler efficiency decreases

Engineering Contradiction:
Improvehot water heating efficiencyVSAvoidcondensing boiler efficiency
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

Different temperature levels are maintained in different parts of the system: the return flow to the calorific value exchanger maintains a lower temperature for condensing boiler efficiency, while the hot water heating circuit receives heated water at higher temperatures through the heat pump's condenser, achieving local optimization for each function.

Inventive Principle:
Principle #3Local quality

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 configuration enhances energy efficiency by maintaining optimal condensing boiler operation, reduces energy consumption, and effectively manages temperature fluctuations, improving the overall efficiency of heat transfer and fossil fuel usage, especially during seasonal variations.

Implementation Method 1

a heat pump (12) which extracts thermal energy from at least part of the water in the return (15) of the heating circuit

Methodology Applied
Scientific EffectHeat extraction through evaporator: Evaporation

Implementation Method 2

the heat obtained in the heat pump is given at a higher temperature level to the inlet to the hot water tank (6)

Methodology Applied
Scientific EffectHeat transfer through condenser: Condensation

Implementation Method 3

a condensing boiler (1) with a calorific value heat exchanger (2) to generate heat for heating purposes

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 4

exhaust gas heat exchanger in the exhaust gas outlet also increases the degree of utilization of the fuel's energy by further cooling the exhaust gas and using the heat of condensation

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3214377B1Method for operating a heating system with a condensing boiler and heating system
Publication Date: 2018.12.05 JASKE WOLFGANG
  • EP3214377B1 patent drawingFigure 1
  • EP3214377B1 patent drawingFigure 2

AI summary

This document describes a device for heat generation and water heating to improve fuel efficiency in a condensing boiler by cooling the return flow of the heating water using an evaporator of a heat pump and transferring the heat extracted to the inlet of the hot water tank. The aim is to operate the condensing boiler at the lowest possible temperature level and at the same time maintain the hot water temperature required to prevent contamination without having to generate this temperature via the heating circuit in the boiler. In a further embodiment, the principle used is extended by a solar thermal system with a heat accumulator. If the temperature in the heat accumulator of the solar thermal system is not sufficient, the heat is transferred to the evaporator of a heat pump and brought to operating temperature there in the heat pump process and transferred to the heating circuit. If the heat accumulator is sufficiently heated, the heat is transferred directly to the heating circuit.