Heat Pump Refrigerant Circuit With Direct Evaporator for Cooling Reuse

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Solution Overview

Problem

Existing heat pump systems lack the ability to provide full functionality, particularly cooling, in retrofitted installations, as they require significant modifications and waste heat during cooling is not utilized, limiting their efficiency and economic feasibility.

Innovation Solution

Incorporating a direct evaporator in the refrigerant circuit parallel to the heat exchanger and external heat exchanger, along with expansion valves and a four-way switching valve, allows for easy switching between heating and cooling modes, enabling the reuse of absorbed heat and efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a direct evaporator is installed in parallel to enable cooling function, then cooling capability is provided with minimal retrofit effort, but device complexity increases due to additional components

Engineering Contradiction:
Improvecooling functionVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The heat pump system is designed to perform multiple functions (heating and cooling) using a unified architecture. The direct evaporator is integrated into the existing refrigerant circuit, allowing the same system to provide both heating mode (using the heat exchanger) and cooling mode (using the direct evaporator), thereby avoiding the need for separate cooling systems and reducing overall device complexity despite adding cooling capability.

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

Solution Approach 2:

The refrigerant circuit is segmented into parallel paths: one through the heat exchanger and another through the direct evaporator. This segmentation allows independent operation of each component based on the desired mode (heating or cooling), enabling flexible functionality while maintaining a relatively simple overall structure that can be retrofitted with minimal modifications.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If heat is released into the environment during cooling, then cooling function is achieved, but energy efficiency decreases due to waste of absorbed heat

Engineering Contradiction:
Improvecooling functionVSAvoidheat waste
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

During cooling operation, the heat absorbed from the indoor environment by the direct evaporator is not simply discarded to the outdoors but is recovered and transferred to the heating circuit via the heat exchanger. This allows the system to simultaneously provide cooling to the indoor space and useful heat to the heating circuit, eliminating energy waste and improving overall system efficiency.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The heat that would normally be considered waste heat during cooling operation is converted into a useful resource. By routing the refrigerant through the heat exchanger after the direct evaporator, the system transforms the absorbed heat into a beneficial output for the heating circuit, turning what would be energy loss into energy gain.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of operation

If expansion valves are added to control refrigerant flow, then switching between heating and cooling modes becomes easier, but device complexity increases

Engineering Contradiction:
Improvemode switchingVSAvoidvalve quantity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The expansion valves are designed to serve multiple functions: they control refrigerant flow during heating mode, cooling mode, and mode transitions. By making the expansion valves multi-functional rather than adding separate control mechanisms for each mode, the system achieves easy mode switching without proportionally increasing device complexity.

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

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 enables the heat pump to provide both heating and cooling functions with minimal retrofit effort, increasing efficiency by approximately 30% and allowing heat reuse during cooling, thus enhancing the system's overall performance and economic viability.

Implementation Method 1

at least one direct evaporator is arranged in the refrigerant circuit parallel to the heat exchanger and the outdoor heat exchanger

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

connected to each other via a heat exchanger for heat transfer

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 3

at least one outdoor heat exchanger and a compressor are arranged in the refrigerant circuit

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP2932168B1Heat pump arrangement and method for operating a heat pump arrangement
Publication Date: 2019.02.20 ROBERT BOSCH GMBH
  • EP2932168B1 patent drawingFigure 1~2
  • EP2932168B1 patent drawingFigure 3~4
  • EP2932168B1 patent drawingFigure 5

AI summary

The invention relates to a heat pump arrangement and a method for operating such a heat pump arrangement. The heat pump arrangement comprises a refrigerant circuit (2) and a heating circuit (3), with a pump (11) conveying a heat transfer medium, the two circuits being connected to one another so as to transfer heat via a heat exchanger (7). At least one exterior heat exchanger (4) and a compressor (5) are arranged in the refrigerant circuit (2), the heating circuit (3) having at least one heat consumer (12) and/or a hot water tank heater (14). In order to enable a functional extension of existing installations and be able to use absorbed heat in cooling mode, at least one direct evaporator (15) is arranged in the refrigerant circuit (2) in parallel with the heat exchanger (7) and the exterior heat exchanger (4).