Heat pump system and related method

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Solution Overview

Problem

Existing heat pump systems using flammable refrigerants like propane face the risk of flammable gas mixtures forming in residential areas due to refrigerant leaks into the secondary circuit, which can go unnoticed and lead to dangerous situations.

Innovation Solution

A heat pump system with a primary circuit for refrigerant management, a secondary circuit for water guidance, and a heat exchanger, incorporating a gas separator, one or more sensors, and a first shut-off device. The system monitors gas amounts in the secondary circuit and activates the shut-off device when a predefined threshold is exceeded, preventing refrigerant from entering the heating area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple drain valves and automatic vents are installed in the secondary circuit, then refrigerant can be removed from the system, but a dangerous amount of flammable refrigerant (over 150 g) can still enter the secondary circuit unnoticed

Engineering Contradiction:
Improverefrigerant removal capabilityVSAvoidflammable refrigerant accumulation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The gas separator is installed upstream in the secondary circuit to proactively separate and remove refrigerant bubbles before they can travel to the heating zone and living areas. This preliminary action prevents the harmful accumulation of flammable refrigerant in residential spaces, addressing the inadequacy of downstream drain valves and vents that only react after refrigerant has already entered the system.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The gas separator acts as an intermediary device between the heat exchanger and the heating distribution system. It intercepts and removes refrigerant bubbles from the water flow, preventing them from reaching the heating zones. This intermediary function fills the safety gap left by traditional drain valves and automatic vents that allow refrigerant to enter living spaces before being removed.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If drain valves and automatic vents are used to prevent refrigerant from entering the residential building, then refrigerant can be safely removed, but additional drain valves and open automatic vents can allow flammable refrigerant to leak directly into the living space

Engineering Contradiction:
Improverefrigerant safety removalVSAvoidrefrigerant leakage into living space
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The gas separator performs preliminary removal of refrigerant bubbles from the water flow before the water enters the heating distribution system. By acting upstream, it prevents refrigerant from reaching positions where drain valves and automatic vents are located, thereby eliminating the risk that these components could become leakage points into living spaces.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The gas separator serves as an intermediary that intercepts refrigerant bubbles in the water flow, preventing them from reaching the heating zones and potential leakage points. This intermediary function ensures that even when drain valves and automatic vents are present in the system, they cannot leak refrigerant into living spaces because the refrigerant has already been removed upstream.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If the secondary circuit relies on automatic vent and drain valve without active monitoring, then the system structure remains simple, but refrigerant entry into the heating system goes unnoticed

Engineering Contradiction:
Improvesystem structure simplicityVSAvoidrefrigerant presence detection
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The sensor in the gas separator provides continuous feedback about the presence and quantity of refrigerant bubbles in the water flow. This feedback mechanism enables the control unit to detect when refrigerant has entered the secondary circuit and to activate the shut-off valve, transforming the passive system into an actively monitored safety system that prevents harmful refrigerant accumulation.

Inventive Principle:
Principle #23Feedback

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 effectively reduces the risk of flammable refrigerant entering the residential area, thereby minimizing the danger of fire and ensuring a safer living environment.

Implementation Method 1

a heat exchanger for transferring heat between the refrigerant and the water

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

the secondary circuit comprises a gas separator... monitor a value that correlates with a quantity of gas in the liquid of the secondary circuit

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentEP4549824A1Heat pump system and related method
Publication Date: 2025.05.07 STIEBEL ELTRON GMBH & CO KG
  • EP4549824A1 patent drawingFigure 1
  • EP4549824A1 patent drawingFigure 2
  • EP4549824A1 patent drawingFigure 3

AI summary

The present invention relates to a heat pump system (100) comprising: a controller (131), a primary circuit (110) for conveying a refrigerant, a secondary circuit (120) for conveying water, and a heat exchanger (113) for transferring heat between the refrigerant and the water, wherein the secondary circuit (120) comprises a gas separator (121, 400, 500, 600), one or more sensors (130), and a first shut-off device (122, 422), wherein the controller (131) is configured to (a) monitor a value that correlates with a quantity of gas in the liquid of the secondary circuit (120), (b) detect an exceedance of the value that correlates with the quantity of gas in the liquid of the secondary circuit (120) above a predefined threshold, and (c) in the event that the value that correlates with the quantity of gas in the liquid of the secondary circuit (120) correlates, exceeding the predefined threshold, to close the first shut-off device (122, 422).