Heat Pump Circulation for Multi-Temperature District Heating

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Solution Overview

Problem

Existing heating networks face inefficiencies in maintaining heat transfer medium at multiple temperature levels, leading to energy wastage and increased costs due to suboptimal heat management and separation of heat transfer circuits.

Innovation Solution

The method involves passing the heat transfer medium through both the condenser and evaporator of a heat pump, with targeted control to maintain heat transfer medium at required temperature levels, utilizing a heat exchanger and mixer to direct flows between the heat pump and heat storage, allowing for efficient heat management and temperature regulation across multiple levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If heat transfer circuits are hydraulically separated for different temperature levels, then temperature control precision is improved, but system complexity increases

Engineering Contradiction:
Improvetemperature control precisionVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The heating system is divided into multiple hydraulically separated heat transfer circuits, each operating at a specific temperature level (e.g., low-temperature circuit for floor heating, high-temperature circuit for radiators). This segmentation allows independent temperature control for each circuit, achieving precise temperature management while avoiding the complexity of mixing all temperature levels in a single circuit.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Heat storage units serve as intermediaries between different temperature levels. The first heat storage unit stores heat from the low-temperature circuit, while the second heat storage unit stores heat from the high-temperature circuit. These intermediary storage units enable temperature level conversion and circulation without direct hydraulic connection between circuits, maintaining both precision and manageable complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If heat storage units are used for buffering at different temperature levels, then heat supply reliability is improved, but device complexity increases

Engineering Contradiction:
Improveheat supply reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple heat storage units are implemented, with each unit dedicated to a specific temperature level. The first heat storage unit buffers heat for the low-temperature circuit, while the second heat storage unit buffers heat for the high-temperature circuit. This segmentation ensures that each temperature level has its own buffer capacity, improving heat supply reliability without requiring a single complex oversized storage system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The heat storage units serve multiple functions: they act as buffers for their respective temperature levels, as heat sources for circulation pumps, and as intermediaries for heat transfer between different temperature levels. This multi-functionality reduces the need for separate dedicated components for each function, thereby improving reliability while limiting the increase in overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Loss of energy

If heat transfer medium is circulated through both condenser and evaporator of heat pump, then energy efficiency is improved, but system complexity increases

Engineering Contradiction:
Improveenergy efficiencyVSAvoidsystem complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The heat transfer medium circulation system merges the functions of the condenser and evaporator into a unified circulation loop. The heat pump's condenser and evaporator are integrated such that the same heat transfer medium flows through both components, enabling heat to be extracted at the evaporator and released at the condenser within a single continuous circuit. This merging improves energy efficiency by maximizing heat recovery while reducing the number of separate circulation systems needed.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heat transfer medium circulates continuously through both the evaporator and condenser of the heat pump, maintaining an unbroken cycle of heat extraction and heat release. This continuous circulation ensures that heat is constantly being transferred from the low-temperature circuit to the high-temperature circuit, maximizing energy efficiency. The system design allows this continuous action to proceed with minimal interruptions, and the control system manages the complexity of coordinating both heat pump operations with multiple circulation pumps.

Inventive Principle:
Principle #20Continuity of useful action

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 enables efficient heat management, ensuring heat transfer medium is maintained at the required temperature levels, reducing energy consumption and costs by optimizing heat transfer and circulation between the heat pump and heat storage, allowing for flexible operation across different temperature levels.

Implementation Method 1

heat is extracted from the heat transfer medium in the evaporator

Methodology Applied
Scientific EffectHeat extraction in evaporator: Evaporation

Implementation Method 2

the heat which was extracted from the heat transfer medium in the evaporator is fed to the heat transfer medium in the condenser

Methodology Applied
Scientific EffectHeat release in condenser: Condensation

Implementation Method 3

heat from a heat source, in particular a low-temperature heat source, is transferred to the heat transfer medium in the heat exchanger

Methodology Applied
Scientific EffectHeat transfer in heat exchanger: Heat Exchanger

Data Source

PatentEP3862712B1Method and device for providing and storing a heat carrier with at least three temperature levels for a heating network
Publication Date: 2024.06.26 WOLFGANG JASKE UND DR PETER WOLF GBR
  • EP3862712B1 patent drawingFigure 1
  • EP3862712B1 patent drawingFigure 2

AI summary

The invention relates to a method for providing a heat transfer fluid with at least three temperature levels for a district heating network, in which at least one heat storage unit is connected to the district heating network pipes via a heat transfer fluid conductor and enables the storage of heat transfer fluid at the respective temperature levels of the district heating network. The method is characterized in that the heat transfer fluid circulates between at least one heat pump and at least one heat storage unit, and that the heat transfer fluid is passed through a condenser and an evaporator of the heat pump. Heat transfer fluid from the heat storage unit is supplied to the evaporator at a lower temperature level of the heat storage unit, whereby heat is extracted from the heat transfer fluid in the evaporator and the heat extracted from the heat transfer fluid in the evaporator is supplied to the condenser.The heat transfer fluid leaving the condenser then has a temperature that is equal to or higher than an upper temperature level in the working memory.