Method for operating a heat pump, and a refrigeration machine

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Solution Overview

Problem

Heat pumps and refrigeration systems face challenges in protecting electronic components from excessive temperature and moisture, leading to malfunctions, residual currents, and corrosion, while also requiring energy-efficient operation.

Innovation Solution

The system employs a second refrigerant circuit to transfer inverter heat to a heat transfer fluid, with controlled mass flow and temperature management to prevent overheating or underheating, using a valve to adjust the refrigerant flow based on the inverter's operating state and incorporating a third refrigerant that remains gaseous to delay heat transfer until necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If inverter heat is transferred to the heat transfer fluid to improve energy efficiency, then the coefficient of performance increases, but the inverter temperature may fall below the minimum temperature causing moisture and corrosion

Engineering Contradiction:
Improveinverter heat recoveryVSAvoidinverter protection from moisture
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

A second refrigerant circuit is introduced as an intermediary between the inverter and the heat transfer fluid. The second refrigerant absorbs heat from the inverter and transfers it to the heat transfer fluid through a heat exchanger, allowing controlled heat recovery while maintaining the inverter temperature above the minimum threshold to prevent condensation and corrosion

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mass flow of the second refrigerant is dynamically adjusted based on the inverter's operating state and temperature. By changing the refrigerant flow parameters, the system optimizes heat recovery while ensuring the inverter temperature remains within the safe operating range, preventing both overheating and excessive cooling that would cause moisture

Inventive Principle:
Principle #35Parameter changes

2Temperature

If the mass flow of the second refrigerant is increased to cool the inverter, then the inverter temperature is maintained, but the heat transfer to the heat transfer fluid is reduced

Engineering Contradiction:
Improveinverter temperature controlVSAvoidheat transfer efficiency
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The system dynamically adjusts the mass flow of the second refrigerant based on real-time inverter temperature and operating conditions. The control unit modifies refrigerant flow parameters to optimize the balance between cooling the inverter and transferring heat to the heat transfer fluid, ensuring maximum energy recovery while maintaining safe operating temperatures

Inventive Principle:
Principle #15Dynamics

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 enhances the efficiency of the heat pump by utilizing waste inverter heat effectively, maintaining the inverter within a safe temperature range, and preventing corrosion, thereby improving the overall coefficient of performance and extending component lifespan.

Implementation Method 1

The second refrigerant is evaporated by inverter heat in a first heat exchanger zone (301)

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

where it is liquefied and flows back to the first heat exchanger zone (301)

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

The second refrigerant circuit (310) is connected to the heat transfer circuit (20)

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3810999B1Method for operating a heat pump, and a refrigeration machine
Publication Date: 2024.01.03 STIEBEL ELTRON GMBH & CO KG
  • EP3810999B1 patent drawingFigure 1~2
  • EP3810999B1 patent drawingFigure 3~4
  • EP3810999B1 patent drawingFigure 5~7

AI summary

The invention relates to a method for operating a heat pump (1) in a heating or cooling operating mode. Heat is transferred between a first refrigerant and a heat carrier fluid (22), wherein the first refrigerant is forcibly circulated in a first refrigerant circuit (100) by means of a compressor (110). A first mass flow (101) of the first refrigerant is controlled through the first refrigerant circuit (100) by means of an adjustment of a rotational speed at the compressor (110) with an inverter (200). The inverter heat (201) that arises owing to electrical losses in the inverter (200) is released to the heat carrier fluid (22). In a second refrigerant circuit (300), the inverter heat (201) is transferred to a second refrigerant (312) for the purposes of cooling the inverter (200). The second refrigerant (312, 313) releases the inverter heat to the heat carrier fluid (22). The invention furthermore relates to a refrigeration machine (10), in particular a heat pump (1) for connection to a heat carrier circuit (20), for the purposes of heating or cooling, with a first heat exchanger (120) between a first refrigerant circuit (100) and the heat carrier circuit (20). Arranged in the first refrigerant circuit (100) is a rotational-speed-controlled compressor (110) which is electrically connected to an inverter (200) and is controlled by the compressor (110). The inverter (200) is connected to a second refrigerant circuit (310). A second refrigerant (312, 313) is contained in the second refrigerant circuit (310). Furthermore, the second refrigerant circuit (310) is connected to the heat carrier circuit (20).